SDSS Bitmasks
SDSS makes heavy use of the concept of a bitmask in spectroscopic target flags and other contexts. For the actual bit values for all SDSS flags, see the lists below.
The first section of this page is a primer for those who have never used bitmasks before. Further sections of the page explain how to use bitmasks in CAS and in IDL. The spectroscopic documentation also contains documentation on how to use bitmasks in the SEGUE survey.
Introduction to Bitmasks
A bitmask uses the bits in the binary representation of an integer as “toggles” to indicate whether certain conditions are met. For a more general introduction to this concept, consult Wikipedia or other online resources on the subject.
Converting between hex, binary, and decimal values
| Hex | Binary | Decimal |
|---|---|---|
| 0x1 | 1 | 1 |
| 0x2 | 10 | 2 |
| 0x4 | 100 | 4 |
| 0x8 | 1000 | 8 |
| 0x10 | 10000 | 16 |
| 0x20 | 100000 | 32 |
| 0x40 | 1000000 | 64 |
| 0x80 | 10000000 | 128 |
| ... | ... | ... |
| 0x80000000 | 1000000....0 | 2147483648 |
Within the SDSS, the most common use of a bitmask is to indicate the status of an object (or spectrum, or target, or whatever) with respect to some set of conditions. For example, a given photometric object might be saturated, and be deblended, and have some interpolated pixels. All of these conditions are tracked as “bits” in a bitmask-encoded value called “flags”. For instance, if bit 18 is set, it indicates there is a saturated pixel in the object; if bit 18 is not set, there is no saturated pixel in the object. This sort of bitmask is useful when there are many possible Boolean (true/false) conditions to track, since it doesn't require an individual variable for each one.
In more detail, when we refer above to “bit 18,” we are referring to the eighteenth bit, counting right to left with the least significant digit indexed as digit number zero. Thus, if only bit 18 is set, the integer is equal to 218 = 262144. Of course, in general, many bits can be set, so the value of the variable is not necessarily a power of two. If the integer is signed, note that bit 31 indicates the sign of the integer, so the integer value of a bitmask might be interpreted by the computer as negative.
Note also that many people express bitmasks in hexadecimal instead of decimal. You can tell when people are doing this because they will start with “0x” as in “0x00000100” instead of “8”. The choice to write the numbers in hexadecimal is just a convention; the values in the files and in CAS are regular (decimal) integers. However, this choice does often make it easier to figure out which bit is being referred to. For example, it is easy to figure out that “0x00040000” is bit 18 than to figure out that 262144 is bit 18. The table above shows examples of converting among hex, binary and decimal numbers. Be aware that many programming languages provide tools for translating between binary, hex, and decimal (commands for IDL are given in the IDL section below).
Examples of using bitmasks
To get a sense of this behavior, consider some one-byte unsigned integers, and what their bits are:
| bit 7 | bit 6 | bit 5 | bit 4 | bit 3 | bit 2 | bit 1 | bit 0 | integer value | |
|---|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | = | 75 |
| 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | = | 130 |
| 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | = | 7 |
To check the value of one or more bits, one needs to execute a “bitwise and” on the bitmask. The simplest case is checking the value of a single bit. In C, for example, the bitwise and operator is “&”, so you can write an if statement like:
if((myflag & 4) != 0) {printf("Bit 2 is set\n"); } else {printf("Bit 2 is not set\n"); }
which will output whether or not bit 2 is set.
What is the code doing here? It is asking, for each bit, “is this bit set in both myflag and in 4?” If so, the result (an integer) will have that bit set. We can look, for example, at what this operation would look like if myflag were equal to 13:
| bit 7 | bit 6 | bit 5 | bit 4 | bit 3 | bit 2 | bit 1 | bit 0 | ||
|---|---|---|---|---|---|---|---|---|---|
| myflag | = | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 |
| 4 | = | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| myflag & 4 | = | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
Clearly the result equals “4”, so the condition is satisfied: bit 2 is set! You can easily generalize these sort of operations to bitwise “or” or “exclusive or”, or “and not”. Consult a good computer science reference for those details.
For SDSS, the important thing to know is what each bit means for each type of bitmask. If you expand this page's Table of Contents, within-page links there will lead to tables for each bitmask-encoded variable, telling you what it means when each bit it set.
SDSS Bitmasks in CAS
The query tools of the SDSS CAS allow you to check values of a bitmask variable; see the tables below for detailed information on the meanings of all bitmask values. Checking bitmasks can be included in the
where clause of an SQL query, using a form such as:
(flagname & value) != 0
where & is a bitwise AND operator.
Similarly, | is a bitwise OR operator. A simple example is as follows:
SELECT plate, mjd, fiberid FROM specObjAll WHERE (zWarning & 128) != 0
The bitmask value can also be specified in hex, preceded by "0x". Important: even though bitmask bits take the values {0, 1}, take care to always compare bit values using the := inequality operator, rather than the greater than operator. Because computers can sometimes interpret bitmask values as signed integers, a greater than check may fail, while an inequality check will always return correct results.
More usage of bitmasks in CAS is documented in a set of examples on the SkyServer website. Some values of each bitmask variable are also enumerated there as part of the Data Constants documentation in the schema browser. As a final note, you will see in some of the documentation that there are some functions that return the values associated with each bitmask (e.g. fPhotoFlags). Those lookup functions are useful for readability; however, note that they come with a performance cost, and that using the bitmask value explicitly will result in faster queries.
SDSS Bitmasks in CAS
The query tools of the SDSS CAS allow you to check values of a bitmask variable; see the tables below for detailed information on the meanings of all bitmask values. Checking bitmasks can be included in the
where clause of an SQL query, using a form such as:
(flagname & value) != 0
where & is a bitwise AND operator.
Similarly, | is a bitwise OR operator. A simple example is as follows:
SELECT plate, mjd, fiberid FROM specObjAll WHERE (zWarning & 128) != 0
The bitmask value can also be specified in hex, preceded by "0x". Important: even though bitmask bits take the values {0, 1}, take care to always compare bit values using the := inequality operator, rather than the greater than operator. Because computers can sometimes interpret bitmask values as signed integers, a greater than check may fail, while an inequality check will always return correct results.
More usage of bitmasks in CAS is documented in a set of examples on the SkyServer website. Some values of each bitmask variable are also enumerated there as part of the Data Constants documentation in the schema browser. As a final note, you will see in some of the documentation that there are some functions that return the values associated with each bitmask (e.g. fPhotoFlags). Those lookup functions are useful for readability; however, note that they come with a performance cost, and that using the bitmask value explicitly will result in faster queries.
SDSS Bitmasks in IDL
SDSS flat files contain all of the bitmasks. Using them is particularly convenient for IDL users who use the idlutils product.
Inside of idlutils, there is a file, $IDLUTILS_DIR/data/sdss/sdssMaskbits.par, which contains a listing of all mask bits defined for SDSS.
To access these from within IDL, one uses either sdss_flagval() or sdss_flagname(). The first tells you the integer value corresponding to each bit mask name. The second returns the names of the bits set, given an integer.
For example, you can ask what the integer corresponding to NEGATIVE_EMISSION is as follows:
IDL> PRINT, sdss_flagval('ZWARNING', 'NEGATIVE_EMISSION')
64
Or, if ZWARNING for a spectrum is set to “246”, then you can check what that means as follows:
IDL> PRINT, sdss_flagname('ZWARNING', 246)
LITTLE_COVERAGE SMALL_DELTA_CHI2 MANY_OUTLIERS Z_FITLIMIT NEGATIVE_EMISSION UNPLUGGED
Uh oh! That spectrum must be Very Bad!
The most common usage is within a program. For example, let's say you want to find all spectrum for which MANY_OUTLIERS is set. In IDL you can do this as follows (assuming that “spobj” is a structure which has “zwarning” as a tag):
imany= WHERE((spobj.zwarning AND sdss_flagval('ZWARNING', 'MANY_OUTLIERS')) NE 0, nmany)
which returns “imany” as an array of those elements with ZWARNING set. You should be careful in calls such as those above to always ask for the AND to return a non-zero output (do not check for LT 0, which can get you in trouble if zwarning happens to be cast as a signed integer).
A useful tool in IDL is the ability to write out an integer in hex format. For example, the command below outputs “80000000”:
IDL> PRINT, STRING(2L^31, FORMAT='(Z)') 80000000
List of Bitmasks
Photometric
SDSS/BOSS Spectroscopic
APOGEE Spectroscopic
In the flat-files, the photo flags are split into two 32-bit variables (
objc_flags1 and objc_flags2). In the CAS, these are combined into a single variable flags. The flags listed here are associated with objc_flags1, and the first 32-bits of flags. Note there are also flags on a per-band basis. The names of these flags in the CAS are appended with the band, e.g. flags_r. In the flat files an array of length 5 is used flags[5] ordered u,g,r,i,z.
| Bit name | Binary digit | Description |
|---|---|---|
| CANONICAL_CENTER | 0 | The quantities (psf counts, model fits and likelihoods) that are usually determined at an object's center as determined band-by-band were in fact determined at the canonical center (suitably transformed). This is due to the object being to close to the edge to extract a profile at the local center, and OBJECT1_EDGE is also set. |
| BRIGHT | 1 | Indicates that the object was detected as a bright object. Since these are typically remeasured as faint objects, most users can ignore BRIGHT objects. |
| EDGE | 2 | Object is too close to edge of frame in this band. |
| BLENDED | 3 | Object was determined to be a blend. The flag is set if: more than one peak is detected within an object in a single band together; distinct peaks are found when merging different colors of one object together; or distinct peaks result when merging different objects together. |
| CHILD | 4 | Object is a child, created by the deblender. |
| PEAKCENTER | 5 | Given center is position of peak pixel, as attempts to determine a better centroid failed. |
| NODEBLEND | 6 | Although this object was marked as a blend, no deblending was attempted. |
| NOPROFILE | 7 | Frames couldn't extract a radial profile. |
| NOPETRO | 8 | No Petrosian radius or other Petrosian quantities could be measured. |
| MANYPETRO | 9 | Object has more than one possible Petrosian radius. |
| NOPETRO_BIG | 10 | The Petrosian ratio has not fallen to the value at which the Petrosian radius is defined at the outermost point of the extracted radial profile. NOPETRO is set, and the Petrosian radius is set to the outermost point in the profile. |
| DEBLEND_TOO_MANY_PEAKS | 11 | The object had the OBJECT1_DEBLEND flag set, but it contained too many candidate children to be fully deblended. This flag is only set in the parent, i.e. the object with too many peaks. |
| CR | 12 | Object contains at least one pixel which was contaminated by a cosmic ray. The OBJECT1_INTERP flag is also set. This flag does not mean that this object is a cosmic ray; rather it means that a cosmic ray has been removed. |
| MANYR50 | 13 | More than one radius was found to contain 50% of the Petrosian flux. (For this to happen part of the radial profile must be negative). |
| MANYR90 | 14 | More than one radius was found to contain 90% of the Petrosian flux. (For this to happen part of the radial profile must be negative). |
| BAD_RADIAL | 15 | Measured profile includes points with a S/N <= 0. In practice this flag is essentially meaningless. |
| INCOMPLETE_PROFILE | 16 | A circle, centered on the object, of radius the canonical Petrosian radius extends beyond the edge of the frame. The radial profile is still measured from those parts of the object that do lie on the frame. |
| INTERP | 17 | The object contains interpolated pixels (e.g. cosmic rays or bad columns). |
| SATUR | 18 | The object contains saturated pixels; INTERP is also set. |
| NOTCHECKED | 19 | Object includes pixels that were not checked for peaks, for example the unsmoothed edges of frames, and the cores of subtracted or saturated stars. |
| SUBTRACTED | 20 | Object (presumably a star) had wings subtracted. |
| NOSTOKES | 21 | Object has no measured Stokes parameters. |
| BADSKY | 22 | The estimated sky level is so bad that the central value of the radial profile is crazily negative; this is usually the result of the subtraction of the wings of bright stars failing. |
| PETROFAINT | 23 | At least one candidate Petrosian radius occurred at an unacceptably low surface brightness. |
| TOO_LARGE | 24 | The object is (as it says) too large. Either the object is still detectable at the outermost point of the extracted radial profile (a radius of approximately 260 arcsec), or when attempting to deblend an object, at least one child is larger than half a frame (in either row or column). |
| DEBLENDED_AS_PSF | 25 | When deblending an object, in this band this child was treated as a PSF. |
| DEBLEND_PRUNED | 26 | When solving for the weights to be assigned to each child the deblender encountered a nearly singular matrix, and therefore deleted at least one of them. |
| ELLIPFAINT | 27 | No isophotal fits were performed. |
| BINNED1 | 28 | The object was detected in an unbinned image. |
| BINNED2 | 29 | The object was detected in a 2x2 binned image after all unbinned detections have been replaced by the background level. |
| BINNED4 | 30 | The object was detected in a 4x4 binned image. The objects detected in the 2x2 binned image are not removed before doing this. |
| MOVED | 31 | The object appears to have moved during the exposure. Such objects are candidates to be deblended as moving objects. |
In the flat-files, the photo flags are split into two 32-bit variables (
objc_flags1 and objc_flags2). In the CAS, these are combined into a single variable flags. The flags listed here are associated with objc_flags2, and the second 32-bits of flags. Note there are also flags on a per-band basis. The names of these flags in the CAS are appended with the band, e.g., flags_r. In the flat files an array of length 5 is used flags2[5] ordered u,g,r,i,z.
| Bit name | Binary digit | Description |
|---|---|---|
| DEBLENDED_AS_MOVING | 0 | The object has the MOVED flag set, and was deblended on the assumption that it was moving. |
| NODEBLEND_MOVING | 1 | The object has the MOVED flag set, but was not deblended as a moving object. |
| TOO_FEW_DETECTIONS | 2 | The object has the MOVED flag set, but has too few detection to be deblended as moving. |
| BAD_MOVING_FIT | 3 | The fit to the object as a moving object is too bad to be believed. |
| STATIONARY | 4 | A moving objects velocity is consistent with zero |
| PEAKS_TOO_CLOSE | 5 | Peaks in object were too close (set only in parent objects). |
| BINNED_CENTER | 6 | When centroiding the object the object's size is larger than the (PSF) filter used to smooth the image. |
| LOCAL_EDGE | 7 | The object's center in some band was too close to the edge of the frame to extract a profile. |
| BAD_COUNTS_ERROR | 8 | An object containing interpolated pixels had too few good pixels to form a reliable estimate of its error |
| BAD_MOVING_FIT_CHILD | 9 | A putative moving child's velocity fit was too poor, so it was discarded, and the parent was not deblended as moving |
| DEBLEND_UNASSIGNED_FLUX | 10 | After deblending, the fraction of flux assigned to none of the children was too large (this flux is then shared out as described elsewhere). |
| SATUR_CENTER | 11 | An object's center is very close to at least one saturated pixel; the object may well be causing the saturation. |
| INTERP_CENTER | 12 | An object's center is very close to at least one interpolated pixel. |
| DEBLENDED_AT_EDGE | 13 | An object so close to the edge of the frame that it would not ordinarily be deblended has been deblended anyway. Only set for objects large enough to be EDGE in all fields/strips. |
| DEBLEND_NOPEAK | 14 | A child had no detected peak in a given band, but we centroided it anyway and set the BINNED1 |
| PSF_FLUX_INTERP | 15 | The fraction of light actually detected (as opposed to guessed at by the interpolator) was less than some number (currently 80%) of the total. |
| TOO_FEW_GOOD_DETECTIONS | 16 | A child of this object had too few good detections to be deblended as moving. |
| CENTER_OFF_AIMAGE | 17 | At least one peak's center lay off the atlas image in some band. This can happen when the object's being deblended as moving, or if the astrometry is badly confused. |
| DEBLEND_DEGENERATE | 18 | At least one potential child has been pruned because its template was too similar to some other child's template. |
| BRIGHTEST_GALAXY_CHILD | 19 | This is the brightest child galaxy in a blend. |
| CANONICAL_BAND | 20 | This band was the canonical band. This is the band used to measure the Petrosian radius used to calculate the Petrosian counts in each band, and to define the model used to calculate model colors; it has no effect upon the coordinate system used for the OBJC center. |
| AMOMENT_UNWEIGHTED | 21 | 'Adaptive' moments are actually unweighted. |
| AMOMENT_SHIFT | 22 | Object's center moved too far while determining adaptive moments. In this case, the M_e1 and M_e2 give the (row, column) shift, not the object's shape. |
| AMOMENT_MAXITER | 23 | Too many iterations while determining adaptive moments. |
| MAYBE_CR | 24 | This object may be a cosmic ray. This bit can get set in the cores of bright stars, and is quite likely to be set for the cores of saturated stars. |
| MAYBE_EGHOST | 25 | Object appears in the right place to be an electronics ghost. |
| NOTCHECKED_CENTER | 26 | Center of object lies in a NOTCHECKED region. The object is almost certainly bogus. |
| HAS_SATUR_DN | 27 | This object is saturated in this band and the bleed trail doesn't touch the edge of the frame, we we've made an attempt to add up all the flux in the bleed trails, and to include it in the object's photometry. |
| DEBLEND_PEEPHOLE | 28 | The deblend was modified by the optimizer |
| SPARE3 | 29 | |
| SPARE2 | 30 | |
| SPARE1 | 31 |
In the flat-files, the photo flags are split into two 32-bit variables (
objc_flags1 and objc_flags2). In the CAS, these are combined into a single variable flags. The flags listed here are associated with objc_flags2, and the second 32-bits of flags. Note there are also flags on a per-band basis. The names of these flags in the CAS are appended with the band, e.g., flags_r. In the flat files an array of length 5 is used flags2[5] ordered u,g,r,i,z.
| Bit name | Binary digit | Description |
|---|---|---|
| DEBLENDED_AS_MOVING | 0 | The object has the MOVED flag set, and was deblended on the assumption that it was moving. |
| NODEBLEND_MOVING | 1 | The object has the MOVED flag set, but was not deblended as a moving object. |
| TOO_FEW_DETECTIONS | 2 | The object has the MOVED flag set, but has too few detection to be deblended as moving. |
| BAD_MOVING_FIT | 3 | The fit to the object as a moving object is too bad to be believed. |
| STATIONARY | 4 | A moving objects velocity is consistent with zero |
| PEAKS_TOO_CLOSE | 5 | Peaks in object were too close (set only in parent objects). |
| BINNED_CENTER | 6 | When centroiding the object the object's size is larger than the (PSF) filter used to smooth the image. |
| LOCAL_EDGE | 7 | The object's center in some band was too close to the edge of the frame to extract a profile. |
| BAD_COUNTS_ERROR | 8 | An object containing interpolated pixels had too few good pixels to form a reliable estimate of its error |
| BAD_MOVING_FIT_CHILD | 9 | A putative moving child's velocity fit was too poor, so it was discarded, and the parent was not deblended as moving |
| DEBLEND_UNASSIGNED_FLUX | 10 | After deblending, the fraction of flux assigned to none of the children was too large (this flux is then shared out as described elsewhere). |
| SATUR_CENTER | 11 | An object's center is very close to at least one saturated pixel; the object may well be causing the saturation. |
| INTERP_CENTER | 12 | An object's center is very close to at least one interpolated pixel. |
| DEBLENDED_AT_EDGE | 13 | An object so close to the edge of the frame that it would not ordinarily be deblended has been deblended anyway. Only set for objects large enough to be EDGE in all fields/strips. |
| DEBLEND_NOPEAK | 14 | A child had no detected peak in a given band, but we centroided it anyway and set the BINNED1 |
| PSF_FLUX_INTERP | 15 | The fraction of light actually detected (as opposed to guessed at by the interpolator) was less than some number (currently 80%) of the total. |
| TOO_FEW_GOOD_DETECTIONS | 16 | A child of this object had too few good detections to be deblended as moving. |
| CENTER_OFF_AIMAGE | 17 | At least one peak's center lay off the atlas image in some band. This can happen when the object's being deblended as moving, or if the astrometry is badly confused. |
| DEBLEND_DEGENERATE | 18 | At least one potential child has been pruned because its template was too similar to some other child's template. |
| BRIGHTEST_GALAXY_CHILD | 19 | This is the brightest child galaxy in a blend. |
| CANONICAL_BAND | 20 | This band was the canonical band. This is the band used to measure the Petrosian radius used to calculate the Petrosian counts in each band, and to define the model used to calculate model colors; it has no effect upon the coordinate system used for the OBJC center. |
| AMOMENT_UNWEIGHTED | 21 | 'Adaptive' moments are actually unweighted. |
| AMOMENT_SHIFT | 22 | Object's center moved too far while determining adaptive moments. In this case, the M_e1 and M_e2 give the (row, column) shift, not the object's shape. |
| AMOMENT_MAXITER | 23 | Too many iterations while determining adaptive moments. |
| MAYBE_CR | 24 | This object may be a cosmic ray. This bit can get set in the cores of bright stars, and is quite likely to be set for the cores of saturated stars. |
| MAYBE_EGHOST | 25 | Object appears in the right place to be an electronics ghost. |
| NOTCHECKED_CENTER | 26 | Center of object lies in a NOTCHECKED region. The object is almost certainly bogus. |
| HAS_SATUR_DN | 27 | This object is saturated in this band and the bleed trail doesn't touch the edge of the frame, we we've made an attempt to add up all the flux in the bleed trails, and to include it in the object's photometry. |
| DEBLEND_PEEPHOLE | 28 | The deblend was modified by the optimizer |
| SPARE3 | 29 | |
| SPARE2 | 30 | |
| SPARE1 | 31 |
Resolve status for an SDSS catalog entry. Only one of bits RUN_PRIMARY, RUN_RAMP, RUN_OVERLAPONLY, RUN_IGNORE, and RUN_DUPLICATE can be set. RUN_EDGE can be set for any object. To get a unique set of objects across the whole survey, search for objects with SURVEY_PRIMARY set. To get a unique set of objects within a run, search for objects with RUN_PRIMARY set.
| Bit Name | Binary Digit | Description |
|---|---|---|
| RUN_PRIMARY | 0 | primary within the objects own run (but not necessarily for the survey as a whole) |
| RUN_RAMP | 1 | in what would be the overlap area of a field, but with no neighboring field |
| RUN_OVERLAPONLY | 2 | only appears in the overlap between two fields |
| RUN_IGNORE | 3 | bright or parent object that should be ignored |
| RUN_EDGE | 4 | near lowest or highest column |
| RUN_DUPLICATE | 5 | duplicate measurement of same pixels in two different fields |
| SURVEY_PRIMARY | 8 | Primary observation within the full survey, where it appears in the primary observation of this part of the sky |
| SURVEY_BEST | 9 | Best observation within the full survey, but it does not appear in the primary observation of this part of the sky |
| SURVEY_SECONDARY | 10 | Repeat (independent) observation of an object that has a different primary or best observation |
| SURVEY_BADFIELD | 11 | In field with score=0 |
| SURVEY_EDGE | 12 | Not kept as secondary because it is RUN_RAMP or RUN_EDGE object |
In the flat files there are arrays of length five for each band
calib_status[5] ordered u,g,r,i,z. In the CAS these are named by band pass calibstatus_{band}.
| Bit Name | Binary Digit | Description |
|---|---|---|
| PHOTOMETRIC | 0 | Photometric observations |
| UNPHOT_OVERLAP | 1 | Unphotometric observations, calibrated based on overlaps with clear, ubercalibrated data; done on a field-by-field basis. Use with caution. |
| UNPHOT_EXTRAP_CLEAR | 2 | Extrapolate the solution from the clear part of a night (that was ubercalibrated) to the cloudy part. Not recommended for use. |
| UNPHOT_EXTRAP_CLOUDY | 3 | Extrapolate the solution from a cloudy part of the night (where there is overlap) to a region of no overlap. Not recommended for use. |
| UNPHOT_DISJOINT | 4 | Data is disjoint from the rest of the survey (even though conditions may be photometric), the calibration is suspect. Not recommended for use. |
| INCREMENT_CALIB | 5 | Incrementally calibrated by considering overlaps with ubercalibrated data |
| PS1_UNPHOT | 6 | PS1 comparison reveals unphotometric conditions |
| PS1_CONTRAIL | 7 | PS1 comparison shows slightly unphotometric conditions |
| PT_CLEAR | 8 | (INTERNAL USE ONLY in DR8 and later) PT calibration for clear data |
| PT_CLOUDY | 9 | (INTERNAL USE ONLY in DR8 and later) PT calibration for cloudy data |
| DEFAULT | 10 | (INTERNAL USE ONLY in DR8 and later) a default calibration used |
| NO_UBERCAL | 11 | (INTERNAL USE ONLY in DR8 and later) not uber-calibrated |
| PS1_PCOMP_MODEL | 13 | PS1 Used PCA model for flats |
| PS1_LOW_RMS | 14 | PS1 comparison to SDSS has low noise |
| Bit Name | Binary Digit | Description |
|---|---|---|
| CLEAR | 0 | Clear skies |
| CLOUDY | 1 | Cloudy skies (unphotometric) |
| UNKNOWN | 2 | Sky conditions unknown (unphotometric) |
| BAD_ROTATOR | 3 | Rotator problems (set score=0) |
| BAD_ASTROM | 4 | Astrometry problems (set score=0) |
| BAD_FOCUS | 5 | Focus bad (set score=0) |
| SHUTTERS | 6 | Shutter out of place (set score=0) |
| FF_PETALS | 7 | Flat-field petals out of place (unphotometric) |
| DEAD_CCD | 8 | CCD bad (unphotometric) |
| NOISY_CCD | 9 | CCD noisy (unphotometric) |
| Bit Name | Binary Digit | Description |
|---|---|---|
| QSO_HIZ | 0 | High-redshift (griz) QSO target |
| QSO_CAP | 1 | ugri-selected quasar at high Galactic latitude |
| QSO_SKIRT | 2 | ugri-selected quasar at low Galactic latitude |
| QSO_FIRST_CAP | 3 | FIRST source with stellar colors at high Galactic latitude |
| QSO_FIRST_SKIRT | 4 | FIRST source with stellar colors at low Galactic latitude |
| GALAXY_RED | 5 | Luminous Red Galaxy target (any criteria) |
| GALAXY | 6 | Main sample galaxy |
| GALAXY_BIG | 7 | Low-surface brightness main sample galaxy (mu50 > 23 in r-band) |
| GALAXY_BRIGHT_CORE | 8 | Galaxy targets who fail all the surface brightness selection limits but have r-band fiber magnitudes brighter than 19 |
| ROSAT_A | 9 | ROSAT All-Sky Survey match, also a radio source |
| ROSAT_B | 10 | ROSAT All-Sky Survey match, have SDSS colors of AGNs or quasars |
| ROSAT_C | 11 | ROSAT All-Sky Survey match, fall in a broad intermediate category that includes stars that are bright, moderately blue, or both |
| ROSAT_D | 12 | ROSAT All-Sky Survey match, are otherwise bright enough for SDSS spectroscopy |
| STAR_BHB | 13 | blue horizontal-branch stars |
| STAR_CARBON | 14 | dwarf and giant carbon stars |
| STAR_BROWN_DWARF | 15 | brown dwarfs (note this sample is tiled) |
| STAR_SUB_DWARF | 16 | low-luminosity subdwarfs |
| STAR_CATY_VAR | 17 | cataclysmic variables |
| STAR_RED_DWARF | 18 | red dwarfs |
| STAR_WHITE_DWARF | 19 | hot white dwarfs |
| SERENDIP_BLUE | 20 | lying outside the stellar locus in color space |
| SERENDIP_FIRST | 21 | coincident with FIRST sources but fainter than the equivalent in quasar target selection (also includes non-PSF sources) |
| SERENDIP_RED | 22 | lying outside the stellar locus in color space |
| SERENDIP_DISTANT | 23 | lying outside the stellar locus in color space |
| SERENDIP_MANUAL | 24 | manual serendipity flag |
| QSO_MAG_OUTLIER | 25 | Stellar outlier; too faint or too bright to be targeted |
| GALAXY_RED_II | 26 | Luminous Red Galaxy target (Cut II criteria) |
| ROSAT_E | 27 | ROSAT All-Sky Survey match, but too faint or too bright for SDSS spectroscopy |
| STAR_PN | 28 | central stars of planetary nebulae |
| QSO_REJECT | 29 | Object in explicitly excluded region of color space, therefore not targeted at QSO |
| SOUTHERN_SURVEY | 31 | Set in primtarget if this is a special program target |
These bitmask values are appropriate for the following bitmasks used for SDSS-I and -II: LEGACY_TARGET2, SPECIAL_TARGET2 or SECTARGET.
| Bit Name | Binary Digit | Description |
|---|---|---|
| LIGHT_TRAP | 0 | hole drilled for bright star, to avoid scattered light |
| REDDEN_STD | 1 | reddening standard star |
| TEST_TARGET | 2 | a test target |
| QA | 3 | quality assurance target |
| SKY | 4 | sky target |
| SPECTROPHOTO_STD | 5 | spectrophotometry standard (typically an F-star) |
| GUIDE_STAR | 6 | guide star hole |
| BUNDLE_HOLE | 7 | fiber bundle hole |
| QUALITY_HOLE | 8 | hole drilled for plate shop quality measurements |
| HOT_STD | 9 | hot standard star |
| SOUTHERN_SURVEY | 31 | a segue or southern survey target |
| Bit Name | Binary Digit | Description |
|---|---|---|
| SEGUE1_FG | 9 | F and G stars, based on g-r color (0.2 < g-r < 0.48 and 14 < g < 20.2) |
| SEG1LOW_KG | 10 | low latitude selection of K-giant stars |
| SEG1LOW_TO | 11 | low latitude selection of bluetip stars |
| SEGUE1_MSWD | 12 | main-sequence, white dwarf pair |
| SEGUE1_BHB | 13 | blue horizontal branch star |
| SEGUE1_KG | 14 | K-giants (l and red) |
| SEGUE1_KD | 15 | K-dwarfs |
| SEGUE1_LM | 16 | low metallicity star |
| SEGUE1_CWD | 17 | cool white dwarf |
| SEGUE1_GD | 18 | G-dwarf |
| SEGUE1_WD | 19 | white dwarf |
| SEGUE1_MPMSTO | 20 | metal-poor main sequence turn-off |
| SEGUE1_BD | 21 | brown dwarfs |
| SEGUE1_SDM | 22 | M sub-dwarfs |
| SEGUE1_AGB | 23 | asymptotic giant branch stars |
| SEGUE1_MAN | 24 | manual selection |
| SEG1LOW_AGB | 27 | low latitude selection of AGB stars |
| SEGUE1_CHECKED | 31 | was a checked object |
More detailed information about the selection criteria for SEGUE-1 is available on the SEGUE Target Selection page.
| Bit Name | Binary Digit | Description |
|---|---|---|
Notes
|
||
| REDDEN_STD | 1 | reddening standard star |
| SEGUE1_QA 1 | 3 | QA Duplicate Observations (unused) |
| SKY | 4 | sky target |
| SPECTROPHOTO_STD | 5 | spectrophotometry standard (typically an F-star) |
| SEGUE1_SCIENCE 2 | 30 | SEGUE-1 science target |
| SEGUE1_TEST 3 | 31 | SEGUE-1 test target |
| Bit Name | Binary Digit | Description |
|---|---|---|
| SEGUE2_MSTO | 0 | Main-sequence turnoff |
| SEGUE2_REDKG | 1 | Red K-giant stars |
| SEGUE2_LKG | 2 | K-giant star identified by l-color |
| SEGUE2_PMKG | 3 | K-giant star identified by proper motions |
| SEGUE2_LM | 4 | Low metallicity |
| SEGUE2_HVS | 5 | hyper velocity candidate |
| SEGUE2_XDM | 6 | extreme sdM star |
| SEGUE2_MII | 7 | M giant |
| SEGUE2_HHV | 8 | High-velocity halo star candidate |
| SEGUE2_BHB | 13 | Blue horizontal branch star |
| SEGUE2_CWD | 17 | Cool white dwarf |
| SEGUE2_CHECKED | 31 | was a checked object |
More detailed information about the selection criteria for SEGUE-2 is available on the SEGUE Target Selection page.
| Bit Name | Binary Digit | Description |
|---|---|---|
| LIGHT_TRAP | 0 | light trap hole |
| SEGUE2_REDDENING | 1 | reddening standard |
| SEGUE2_TEST | 2 | test target |
| SEGUE2_QA* | 3 | repeat target across plates |
| SKY | 4 | empty area for sky-subtraction |
| SEGUE2_SPECPHOTO | 5 | spectrophotometric star |
| GUIDE_STAR | 6 | guide star |
| BUNDLE_HOLE | 7 | bundle hole |
| QUALITY_HOLE | 8 | quality hole |
| HOT_STD | 9 | hot standard |
| SEGUE2_CLUSTER | 10 | SEGUE-2 stellar cluster target |
| SEGUE2_STETSON | 11 | Stetson standard target |
| SEGUE2_CHECKED | 31 | was a checked object |
*QA duplicate observations are not currently marked in SEGUE2_TARGET2 bitmasks. These are only marked in sourcetype in SpecObjAll.
| Bit Name | Binary Digit | Description |
|---|---|---|
| APBIAS | 0 | aperture bias target |
| LOWZ_ANNIS | 1 | low-redshift cluster galaxy |
| QSO_M31 | 2 | QSO in M31 |
| COMMISSIONING_STAR | 3 | star in commissioning |
| DISKSTAR | 4 | thin/thick disk star |
| FSTAR | 5 | F-stars |
| HYADES_MSTAR | 6 | M-star in Hyades |
| LOWZ_GALAXY | 7 | low-redshift galaxy |
| DEEP_GALAXY_RED | 8 | deep LRG |
| DEEP_GALAXY_RED_II | 9 | deep LRG |
| BCG | 10 | brightest cluster galaxy |
| MSTURNOFF | 11 | main sequence turnoff |
| ORION_BD | 12 | Brown dwarf in Orion |
| ORION_MSTAR_EARLY | 13 | Early-type M-star (M0-3) in Orion |
| ORION_MSTAR_LATE | 14 | Late-type M-star (M4-) in Orion |
| SPECIAL_FILLER | 15 | filler from completeTile, check primtarget for details |
| PHOTOZ_GALAXY | 16 | test galaxy for photometric redshifts |
| PREBOSS_QSO | 17 | QSO for pre-BOSS observations |
| PREBOSS_LRG | 18 | QSO for pre-BOSS observations |
| PREMARVELS | 19 | pre-MARVELS stellar target |
| SOUTHERN_EXTENDED | 20 | simple extension of southern targets |
| SOUTHERN_COMPLETE | 21 | completion in south of main targets |
| U_PRIORITY | 22 | priority u-band target |
| U_EXTRA | 23 | extra u-band target |
| U_EXTRA2 | 24 | extra u-band target |
| FAINT_LRG | 25 | faint LRG in south |
| FAINT_QSO | 26 | faint QSO in south |
| BENT_RADIO | 27 | bent double-lobed radio source |
| STRAIGHT_RADIO | 28 | straight double-lobed radio source |
| VARIABLE_HIPRI | 29 | high priority variable |
| VARIABLE_LOPRI | 30 | low priority variable |
| ALLPSF | 31 | i < 19.1 point sources |
| ALLPSF_NONSTELLAR | 32 | i < 19.1 point sources off stellar locus |
| ALLPSF_STELLAR | 33 | i < 19.1 point sources on stellar locus |
| HIPM | 34 | high proper motion |
| TAURUS_STAR | 35 | star on Taurus or reddening plate |
| TAURUS_GALAXY | 36 | galaxy on Taurus or reddening plate |
| PERSEUS | 37 | galaxy in Perseus-Pisces |
| LOWZ_LOVEDAY | 38 | low redshift galaxy selected by Loveday |
These bitmask values are appropriate for the following bitmasks used for SDSS-I and -II: LEGACY_TARGET2, SPECIAL_TARGET2 or SECTARGET.
| Bit Name | Binary Digit | Description |
|---|---|---|
| LIGHT_TRAP | 0 | hole drilled for bright star, to avoid scattered light |
| REDDEN_STD | 1 | reddening standard star |
| TEST_TARGET | 2 | a test target |
| QA | 3 | quality assurance target |
| SKY | 4 | sky target |
| SPECTROPHOTO_STD | 5 | spectrophotometry standard (typically an F-star) |
| GUIDE_STAR | 6 | guide star hole |
| BUNDLE_HOLE | 7 | fiber bundle hole |
| QUALITY_HOLE | 8 | hole drilled for plate shop quality measurements |
| HOT_STD | 9 | hot standard star |
| SOUTHERN_SURVEY | 31 | a segue or southern survey target |
| Bit Name | Binary Digit | Description |
|---|---|---|
| GAL_LOZ | 0 | low-z lrgs |
| GAL_CMASS | 1 | dperp > 0.55, color-mag cut |
| GAL_CMASS_COMM | 2 | dperp > 0.55, commissioning color-mag cut |
| GAL_CMASS_SPARSE | 3 | GAL_CMASS_COMM & (!GAL_CMASS) & (i < 19.9) sparsely sampled |
| GAL_LODPERP_DEPRECATED | 5 | (DEPRECATED) Same as hiz but between dperp00 and dperp0 |
| SDSS_KNOWN | 6 | Matches a known SDSS spectra |
| GAL_CMASS_ALL | 7 | GAL_CMASS and the entire sparsely sampled region |
| GAL_IFIBER2_FAINT | 8 | ifiber2 > 21.5, extinction corrected. Used after Nov 2010 |
| QSO_CORE | 10 | restrictive qso selection: commissioning only |
| QSO_BONUS | 11 | permissive qso selection: commissioning only |
| QSO_KNOWN_MIDZ | 12 | known qso between [2.2,9.99] |
| QSO_KNOWN_LOHIZ | 13 | known qso outside of miz range. never target |
| QSO_NN | 14 | Neural Net that match to sweeps/pass cuts |
| QSO_UKIDSS | 15 | UKIDSS stars that match sweeps/pass flag cuts |
| QSO_KDE_COADD | 16 | kde targets from the stripe82 coadd |
| QSO_LIKE | 17 | likelihood method |
| QSO_FIRST_BOSS | 18 | FIRST radio match |
| QSO_KDE | 19 | selected by kde+chi2 |
| STD_FSTAR | 20 | standard f-stars |
| STD_WD | 21 | white dwarfs |
| STD_QSO | 22 | qso |
| TEMPLATE_GAL_PHOTO | 32 | galaxy templates |
| TEMPLATE_QSO_SDSS1 | 33 | QSO templates |
| TEMPLATE_STAR_PHOTO | 34 | stellar templates |
| TEMPLATE_STAR_SPECTRO | 35 | stellar templates (spectroscopically known) |
| QSO_CORE_MAIN | 40 | Main survey core sample |
| QSO_BONUS_MAIN | 41 | Main survey bonus sample |
| QSO_CORE_ED | 42 | Extreme Deconvolution in Core |
| QSO_CORE_LIKE | 43 | Likelihood that make it into core |
| QSO_KNOWN_SUPPZ | 44 | known qso between [1.8,2.15] |
| Bit Name | Binary Digit | Description |
|---|---|---|
| DO_NOT_OBSERVE | 0 | Don't put a fiber on this object |
| LRG_IZW | 1 | LRG selection in i/z/W plane |
| LRG_RIW | 2 | LRG selection in r/i/W plan with (i-z) cut |
| QSO_EBOSS_CORE | 10 | QSOs in XDQSOz+WISE selection for clustering |
| QSO_PTF | 11 | QSOs with variability in PTF imaging |
| QSO_REOBS | 12 | QSOs from BOSS to be reobserved |
| QSO_EBOSS_KDE | 13 | KDE-selected QSOs (sequels only) |
| QSO_EBOSS_FIRST | 14 | Objects with FIRST radio matches |
| QSO_BAD_BOSS | 15 | QSOs from BOSS with bad spectra |
| QSO_BOSS_TARGET | 16 | Known TARGETS from BOSS with spectra |
| QSO_SDSS_TARGET | 17 | Known TARGETS from SDSS with spectra |
| QSO_KNOWN | 18 | Known QSOs from previous surveys |
| DR9_CALIB_TARGET | 19 | Target found in DR9-calibrated imaging |
| SPIDERS_RASS_AGN | 20 | RASS AGN sources |
| SPIDERS_RASS_CLUS | 21 | RASS Cluster sources |
| SPIDERS_ERASS_AGN | 22 | ERASS AGN sources |
| SPIDERS_ERASS_CLUS | 23 | ERASS Cluster sources |
| TDSS_A | 30 | Main PanSTARRS selection for TDSS |
| TDSS_FES_DE | 31 | TDSS Few epoch spectroscopy |
| TDSS_FES_DWARFC | 32 | TDSS Few epoch spectroscopy |
| TDSS_FES_NQHISN | 33 | TDSS Few epoch spectroscopy |
| TDSS_FES_MGII | 34 | TDSS Few epoch spectroscopy |
| TDSS_FES_VARBAL | 35 | TDSS Few epoch spectroscopy |
| SEQUELS_PTF_VARIABLE | 40 | Variability objects from PTF |
| SEQUELS_COLLIDED | 41 | Collided galaxies from BOSS |
| Bit Name | Binary Digit | Description |
|---|---|---|
| DO_NOT_OBSERVE | 0 | Don't put a fiber on this object |
| LRG1_WISE | 1 | LRG selection in i/z/W plane |
| LRG1_IDROP | 2 | LRG selection in r/i/W plan with (i-z) cut |
| LRG_KNOWN | 3 | LRG selection in r/i/W plan with (i-z) cut |
| QSO1_VAR_S82 | 9 | Variability-selected QSOs in the repeated Stripe 82 imaging |
| QSO1_EBOSS_CORE | 10 | QSOs in XDQSOz+WISE selection for clustering |
| QSO1_PTF | 11 | QSOs with variability in PTF imaging |
| QSO1_REOBS | 12 | QSOs from BOSS to be reobserved |
| QSO1_EBOSS_KDE | 13 | KDE-selected QSOs (sequels only) |
| QSO1_EBOSS_FIRST | 14 | Ojbects with FIRST radio matches |
| QSO1_BAD_BOSS | 15 | QSOs from BOSS with bad spectra |
| QSO_BOSS_TARGET | 16 | Known TARGETS from BOSS with spectra |
| QSO_SDSS_TARGET | 17 | Known TARGETS from SDSS with spectra |
| QSO_KNOWN | 18 | Known QSOs from previous surveys |
| TDSS_TARGET | 30 | Target for TDSS (subclass found in eboss_target2) |
| SPIDERS_TARGET | 31 | Target for SPIDERS (subclass found in eboss_target2) |
| S82X_TILE1 | 32 | |
| S82X_TILE2 | 33 | |
| S82X_TILE3 | 34 | |
| ELG_TEST1 | 40 | Test targets for ELG selection |
| ELG1_EBOSS | 41 | Standard DECALS ELG target selection |
| ELG1_EXTENDED | 42 | Extended DECALS ELG target selection |
| ELG1_SGC | 43 | Final ELG selection, SGC data |
| ELG1_NGC | 44 | Final ELG selection, NGC data |
| STD_FSTAR | 50 | standard f-stars |
| STD_WD | 51 | white dwarfs |
| STD_QSO | 52 | qso |
| Bit Name | Binary Digit | Description |
|---|---|---|
| SPIDERS_RASS_AGN | 0 | RASS AGN sources |
| SPIDERS_RASS_CLUS | 1 | RASS Cluster sources |
| SPIDERS_ERASS_AGN | 2 | ERASS AGN sources |
| SPIDERS_ERASS_CLUS | 3 | ERASS Cluster sources |
| SPIDERS_XMMSL_AGN | 4 | XMM Slew survey |
| SPIDERS_XCLASS_CLUS | 5 | XMM serendipitous clusters |
| TDSS_A | 20 | Main PanSTARRS selection for TDSS |
| TDSS_FES_DE | 21 | QSOs with disk emitter broad line profiles |
| TDSS_FES_DWARFC | 22 | dwarf carbon stars |
| TDSS_FES_NQHISN | 23 | QSOs with previous spectra of S/N>25 |
| TDSS_FES_MGII | 24 | binary AGN candidate |
| TDSS_FES_VARBAL | 25 | broad absorption line QSOs |
| TDSS_B | 26 | Main TDSS SES version B |
| TDSS_FES_HYPQSO | 27 | strongly variable QSOs |
| TDSS_FES_HYPSTAR | 28 | strongly variable star |
| TDSS_FES_WDDM | 29 | white dwarf/M dwarf pairs with Halpha emission |
| TDSS_FES_ACTSTAR | 30 | late-M and L stars with Halpha emission |
| TDSS_CP | 31 | TDSS in common with CORE/PTF |
| TDSS_S82X_FES_HYPQSO | 32 | |
| TDSS_S82X_SESQSO | 33 | |
| TDSS_RQS1 | 34 | quasars targeted at high priority |
| TDSS_RQS2 | 35 | quasars targeted at medium priority |
| TDSS_RQS3 | 36 | quasars targeted at lower priority |
| TDSS_RQS2v | 37 | variability selected quasars targeted at medium priority |
| TDSS_RQS3v | 38 | variability selected quasars targeted at lower priority |
| ELG_SCUSS_TEST1 | 40 | SCUSS selection for test1 ELG plates |
| ELG_DES_TEST1 | 41 | DES selection for test1 ELG plates |
| ELG_DESI_TEST1 | 42 | DESI selection for test1 ELG plates |
| ELG_SDSS_TEST1 | 43 | SDSS-only selection for test1 ELG plates |
| ELG_UGRIZW_TEST1 | 44 | WISE selection for test1 ELG plates |
| ELG_UGRIZWbright_TEST1 | 45 | WISE selection for test1 ELG plates |
| ELG_GRIW_TEST1 | 46 | WISE selection for test1 ELG plates |
| ELG_DECALS_TEST1 | 47 | DECALS ELG selection, added sept 2015 |
| ELG1_SGC | 48 | repeated bit from eboss_target1 for tiling purposes |
| ELG1_NGC | 49 | repeated bit from eboss_target1 for tiling purposes |
| S82X_BRIGHT_TARGET | 50 | |
| S82X_XMM_TARGET | 51 | |
| S82X_WISE_TARGET | 52 | |
| S82X_SACLAY_VAR_TARGET | 53 | |
| S82X_SACLAY_BDT_TARGET | 54 | |
| S82X_SACLAY_HIZ_TARGET | 55 | |
| S82X_RICHARDS15_PHOTOQSO_TARGET | 56 | |
| S82X_PETERS15_COLORVAR_TARGET | 57 | |
| S82X_LSSTZ4_TARGET | 58 | |
| S82X_UNWISE_TARGET | 59 | |
| S82X_GTRADMZ4_TARGET | 60 | |
| S82X_CLAGN1_TARGET | 61 | |
| S82X_CLAGN2_TARGET | 62 |
The presence of a nonzero value for this target flag indicates that the object was selected through one or more of the BOSS ancillary target selection programs.
If you don't see the ancillary target bit you're looking for here, try the other ancillary target flag parameter,
If you don't see the ancillary target bit you're looking for here, try the other ancillary target flag parameter,
ANCILLARY_TARGET2.
| Bit Name | Binary Digit | Description |
|---|---|---|
| AMC | 0 | Candidate Am CVn variables in Stripe 82 |
| FLARE1 | 1 | Flaring M stars in Stripe 82 (year 1 targets) |
| FLARE2 | 2 | Flaring M stars in Stripe 82 (year 2 targets) |
| HPM | 3 | High Proper Motion stars in Stripe 82 |
| LOW_MET | 4 | Low-metallicity M dwarfs in Stripe 82 |
| VARS | 5 | Unusual variable objects (colors outside the stellar and quasar loci) in Stripe 82 |
| BLAZGVAR | 6 | A flag used in a pilot version of the ancillary targeting program High-Energy Blazars and Optical Counterparts to Gamma-Ray Sources; no longer used |
| BLAZR | 7 | A flag used in a pilot version of the ancillary targeting program High-Energy Blazars and Optical Counterparts to Gamma-Ray Sources; no longer used |
| BLAZXR | 8 | A target that might have a match with a Fermi source, but which is now below the detection limits of the early Fermi source catalogs |
| BLAZXRSAM | 9 | A flag used in a pilot version of the ancillary targeting program High-Energy Blazars and Optical Counterparts to Gamma-Ray Sources; no longer used |
| BLAZXRVAR | 10 | A flag used in a pilot version of the ancillary targeting program High-Energy Blazars and Optical Counterparts to Gamma-Ray Sources; no longer used |
| XMMBRIGHT | 11 | An object that matches a serendipitous x-ray source from the Second XMM-Newton Serendipitous Source Catalog (2XMMi), with bright i magnitudes (i < 20.5) and bright 2-12 keV fluxes (f2-12 keV > 5 × 10-14 erg*cm-2*s-1) |
| XMMGRIZ | 12 | An object that matches a serendipitous x-ray source from the Second XMM-Newton Serendipitous Source Catalog (2XMMi), with outlier SDSS colors (g - r > 1.2 or r - i > 1.0 or i - z > 1.4) |
| XMMHR | 13 | An object that matches a serendipitous x-ray source from the Second XMM-Newton Serendipitous Source Catalog (2XMMi), with unusual hardness ratios in the HR2-HR3 plane |
| XMMRED | 14 | An object that matches a serendipitous x-ray source from the Second XMM-Newton Serendipitous Source Catalog (2XMMi) with highly red SDSS colors (g - i > 1.0) |
| FBQSBAL | 15 | Broad absorption line (BAL) quasar with spectrum from the FIRST Bright Quasar Survey |
| LBQSBAL | 16 | Broad absorption line (BAL) quasar with spectrum from the Large Bright Quasar Survey |
| ODDBAL | 17 | Broad absorption line (BAL) quasar with various unusual properties (selected by hand) |
| OTBAL | 18 | Photometrically-selected overlapping-trough (OT) broad absorption line (BAL) quasar |
| PREVBAL | 19 | Broad absorption line (BAL) quasar with prior spectrum from SDSS-I/-II |
| VARBAL | 20 | Photometrically-selected candidate broad absorption line (BAL) quasar |
| BRIGHTGAL | 21 | Bright (r < 16) galaxies whose spectra were missed by the original SDSS spectroscopic survey |
| QSO_AAL | 22 | Radio-quiet variable quasar candidates with one absorption system associated with the quasar (v ≤ 5000 km/s in the quasar rest frame) |
| QSO_AALS | 23 | Radio-quiet variable quasar candidates with multiple absorption systems (associated and/or intervening) |
| QSO_IAL | 24 | Radio-quiet variable quasar candidates with one absorption system in the intervening space along our line-of-sight (v > 5000 km/s in the quasar rest frame) |
| QSO_RADIO | 25 | Radio-loud variable quasar candidates with multiple absorption systems (associated and/or intervening) |
| QSO_RADIO_AAL | 26 | Radio-loud variable quasar candidates with one absorption system associated with the quasar (v ≤ 5000 km/s in the quasar rest frame) |
| QSO_RADIO_IAL | 27 | Radio-loud variable quasar candidates with one absorption system in the intervening space along our line-of-sight (v > 5000 km/s in the quasar rest frame) |
| QSO_NOAALS | 28 | Radio-quiet variable quasar candidates with no associated absorption systems and multiple intervening absorption systems |
| QSO_GRI | 29 | Candidate high-redshift quasar (z > 3.6), selected in gri color space |
| QSO_HIZ | 30 | Candidate high-redshift quasar (z > 5.6), detected only in SDSS i and z filters. |
| QSO_RIZ | 31 | Candidate high-redshift quasar (z > 4.5), selected in riz color space |
| RQSS_SF | 32 | Candidate reddened quasar ( E(B-V)) > 0.5 ), selected from an SDSS primary catalog object matched with FIRST catalog data |
| RQSS_SFC | 33 | Candidate reddened quasar ( E(B-V)) > 0.5 ), selected from an SDSS child catalog object matched with FIRST catalog data |
| RQSS_STM | 34 | Candidate reddened quasar ( E(B-V)) > 0.5 ), selected from an SDSS primary catalog object matched with 2MASS catalog data |
| RQSS_STMC | 35 | Candidate reddened quasar ( E(B-V)) > 0.5 ), selected from an SDSS child catalog object matched with 2MASS catalog data |
| SN_GAL1 | 36 | Likely host galaxy for an SDSS-II supernova, with the BOSS fiber assigned to the galaxy closest to the supernova's position |
| SN_GAL2 | 37 | Likely host galaxy for an SDSS-II supernova, with the BOSS fiber assigned to the second-closest galaxy |
| SN_GAL3 | 38 | Likely host galaxy for an SDSS-II supernova, with the BOSS fiber assigned to the third-closest galaxy |
| SN_LOC | 39 | Likely host galaxy for an SDSS-II supernova, with the BOSS fiber assigned to the position of the original supernova |
| SPEC_SN | 40 | Likely host galaxy for an SDSS-II supernova, where the original supernova was identified from SDSS spectroscopic data |
| SPOKE | 41 | Widely-separated binary systems in which both stars are low-mass (spectral class M) |
| WHITEDWARF_NEW | 42 | White dwarf candidate whose spectrum had not been observed previously by the SDSS |
| WHITEDWARF_SDSS | 43 | White dwarf candidate with a pre-existing SDSS spectrum |
| BRIGHTERL | 44 | Bright L dwarf candidate (iPSF < 19.5, iPSF - zPSF) > 1.14) |
| BRIGHTERM | 45 | Bright M dwarf candidate (iPSF < 19.5, iPSF - zPSF) < 1.14) |
| FAINTERL | 46 | Faint L dwarf candidate (iPSF > 19.5, iPSF - zPSF) > 1.14) |
| FAINTERM | 47 | Faint M dwarf candidate (iPSF > 19.5, iPSF - zPSF) < 1.14) |
| RED_KG | 48 | Giant star in the Milky Way outer halo |
| RVTEST | 49 | Known giant star selected as a test of radial velocity measurement techniques |
| BLAZGRFLAT | 50 | Candidate optical counterpart to a Fermi gamma-ray source, within 2" of a CRATES radio source and within a Fermi error ellipse |
| BLAZGRQSO | 51 | Candidate optical counterpart to a Fermi gamma-ray source, within 2" of a FIRST radio source and within a Fermi error ellipse |
| BLAZGX | 52 | Candidate optical counterpart to a Fermi gamma-ray source, within 1' of a ROSAT All-Sky Survey x-ray source and within a Fermi error ellipse, and without typical signs of blazar activity |
| BLAZGXQSO | 53 | Candidate optical counterpart to a Fermi gamma-ray source, within 1' of a ROSAT All-Sky Survey x-ray source and within a Fermi error ellipse |
| BLAZGXR | 54 | Candidate optical counterpart to a Fermi gamma-ray source, with matches in both radio and x-ray wavelengths: within 1' of a ROSAT All-Sky Survey x-ray source, within 2" of a FIRST radio source, and within a Fermi error ellipse |
| BLUE_RADIO | 56 | Likely star-forming AGN: blue galaxies that match with FIRST radio sources |
| CHANDRAV1 | 57 | An object with a Chandra match that is likely to be a star-forming galaxy with black hole accretion |
| CXOBRIGHT | 58 | An object that matches a serendipitous x-ray source from the Chandra Source Catalog, with bright i magnitudes (i < 20.0) and bright 2-8 keV fluxes (f2-8 keV > 5 x 10-14 erg*cm-2*s-1) |
| CXOGRIZ | 59 | An object that matches a serendipitous x-ray source from the Chandra Source Catalog, with outlier SDSS colors (g - r > 1.2 or r - i > 1.0 or i - z > 1.4) |
| CXORED | 60 | An object that matches a serendipitous x-ray source from the Chandra Source Catalog, with highly red SDSS colors (g - i > 1.0) |
| ELG | 61 | Luminous blue galaxy with gPSF < 22.5 |
| GAL_NEAR_QSO | 62 | A galaxy that lies between 0.006' and 1' of the line-of-sight for a spectroscopically-confirmed quasar |
| MTEMP | 63 | Template M-stars observed as a comparison sample in Stripe 82 |
The presence of a nonzero value for this target flag indicates that the object was selected through one or more of the BOSS ancillary target selection programs.
If you don't see the ancillary target bit you're looking for here, try the other ancillary target flag parameter,
If you don't see the ancillary target bit you're looking for here, try the other ancillary target flag parameter,
ANCILLARY_TARGET1.
| Bit Name | Binary Digit | Description |
|---|---|---|
| HIZQSO82 | 0 | Quasar candidate in SDSS stripe 82 selected with UKIDSS YJHK photometry using a more relaxed color cut |
| HIZQSOIR | 1 | Quasar candidate selected with UKIDSS YJHK photometry |
| KQSO_BOSS | 2 | Quasar candidate selected with UKIDSS YJHK photometry |
| QSO_VAR | 3 | Candidate quasar in Stripe 82 survey area, selected from variability alone |
| QSO_VAR_FPG | 4 | Candidate quasar in Stripe 82 survey area, selected from variability alone |
| RADIO_2LOBE_QSO | 5 | Object near the midpoint of a double-lobed object identified in FIRST Catalogs |
| STRIPE82BCG | 6 | The brightest cluster member of a galaxy cluster or group identified in the Stripe 82 survey area |
| QSO_SUPPZ | 7 | A subset of SDSS-I/-II quasars with 1.8 < z < 2.15 that were reobserved with the BOSS spectrograph to measure metal absorption free of any effects from the Lyman-α forest (no longer used in DR12) |
| QSO_VAR_SDSS | 8 | Quasars selected by photometric variability in the overlap regions between stripes of SDSS-I/-II imaging, accounting for roughly 30% of the total BOSS footprint (no longer used in DR12) |
| QSO_WISE_SUPP | 9 | Quasar targets selected on their mid-infrared colors from the WISE satellite, thought to be z>2.2 quasars, as a supplement to the primary BOSS quasar sample (no longer used in DR12) |
| QSO_WISE_FULL_SKY | 10 | Quasar selected from the WISE All-Sky Survey |
| XMMSDSS | 11 | Hard x-ray-selected AGN from XMM |
| IAMASERS | 12 | Known or potential maser |
| DISKEMITTER_REPEAT | 13 | Candidate massive binary black hole pair |
| WISE_BOSS_QSO | 14 | Quasar identified in the WISE All-Sky Survey |
| QSO_XD_KDE_PAIR | 15 | Candidate closely-separated quasar pair |
| CLUSTER_MEMBER | 16 | Member of a galaxy cluster selected from ROSAT All-Sky Survey data |
| SPOKE2 | 17 | Candidate binary pair in which one star is an M dwarf |
| FAINT_ELG | 18 | Blue star-forming galaxy selected from CFHT-LS photometry |
| PTF_GAL | 19 | A nearby galaxy identified in PTF imaging with an SDSS counterpart |
| QSO_STD | 20 | A standard star targeted to improve BOSS spectrophotometric calibration |
| HIZ_LRG | 21 | A candidate z > 0.6 LRG, selected using a narrower r-i color constraint and observed at higher priority |
| LRG_ROUND3 | 22 | A candidate z > 0.6 LRG, selected using a broader r-i color constraint and observed at lower priority |
| WISE_COMPLETE | 23 | Galaxy in the same redshift range as the BOSS CMASS sample, but selected with a more relaxed color cut |
| TDSS_PILOT | 24 | Objects identified from PanSTARRS imaging using the selection criteria described on the BOSS ancillary target page |
| SPIDERS_PILOT | 25 | Objects identified from PanSTARRS imaging using the selection criteria described on the BOSS ancillary target page |
| TDSS_SPIDERS_PILOT | 26 | Objects identified using both sets of selection criteria for TDSS_PILOT and SPIDERS_PILOT |
| QSO_VAR_LF | 27 | Candidate quasar in stripe 82, selected by color and variability |
| TDSS_PILOT_PM | 28 | Objects identified using X-ray imaging that has high proper motions |
| TDSS_PILOT_SNHOST | 29 | Objects identified in PanSTARRS imaging that showed transient behavior in extended objects |
| FAINT_HIZ_LRG | 30 | Candidate galaxy in the redshift range 0.6 < z < 0.9, defined by color cuts |
| QSO_EBOSS_W3_ADM | 31 | Candidate quasar, defined by one of the complex color cuts described below and recorded in the W3bitmask parameter of the original targeting file |
| XMM_PRIME | 32 | Candidate AGN identified from the XMM-XXL survey observed at higher priority |
| XMM_SECOND | 33 | Candidate AGN identified from the XMM-XXL survey observed at lower priority |
| SEQUELS_ELG | 34 | Emission-line galaxy targeted by the SEQUELS program |
| GES | 35 | Star observed by the Gaia/ESO Survey (GES) |
| SEGUE1 | 36 | Star observed by the prior SDSS spectroscopic SEGUE-1 survey |
| SEGUE2 | 37 | Star observed by SEGUE-2 |
| SDSSFILLER | 38 | Star in the GES survey area, targeted from prior SDSS photometry |
| SEQUELS_ELG_LOWP | 39 | Emission-line galaxy targeted by the SEQUELS program at lower priority |
| 25_ORI_WISE | 40 | WISE-selected target near the star 25 Ori |
| 25_ORI_WISE_W3 | 41 | WISE-selected target near the star 25 Ori, selected from data in the W3 band |
| KOEKAP_STAR | 42 | WISE-selected source in the star-forming region Kappa Ori, selected from WISE infrared excess |
| KOE2023_STAR | 43 | WISE-selected source in the star-forming region NGC 2023, selected from WISE infrared excess |
| KOE2068_STAR | 44 | WISE-selected source in the star-forming region NGC 2068, selected from WISE infrared excess |
| KOE2023BSTAR | 45 | Other WISE-selected source in the star-forming region NGC 2023 |
| KOE2068BSTAR | 46 | Other WISE-selected source in the star-forming region NGC 2068 |
| KOEKAPAPBSTAR | 47 | Other WISE-selected source in the star-forming region Kappa Ori |
| COROTGESAPOG | 48 | Star observed by both the CoRoT survey and by APOGEE |
| COROTGES | 49 | Star observed by both CoRoT and GES |
| APOGEE | 50 | Star in the CoRoT survey area, not observed by CoRoT but with an APOGEE spectrum |
| 2MASSFILL | 51 | Star in the CoRoT survey area targeted from 2MASS photometry |
| TAU_STAR | 52 | Spitzer-selected source in the Taurus Heiles 2 molecular cloud |
| SEQUELS_TARGET | 53 | A target from the SEQUELS program (no longer used, replaced by EBOSS_TARGET0 flag) |
| RM_TILE1 | 54 | AGN selected for reverberation mapping study at high priority |
| RM_TILE2 | 55 | AGN selected for reverberation mapping study at lower priority |
| QSO_DEEP | 56 | Candidate quasar selected by time variability |
| LBG | 57 | Candidate Lyman-break galaxy selected by color |
| ELAIS_N1_LOFAR | 58 | LOFAR source selected with RMS noise criteria |
| ELAIS_N1_FIRST | 59 | Source detected in the FIRST radio catalog |
| ELAIS_N1_GMRT_GARN | 60 | Source identified from deeper GMRT radio data |
| ELAIS_N1_GMRT_TAYLOR | 61 | Fainter source identified from deeper GMRT radio data |
| ELAIS_N1_JVLA | 62 | Very faint source detected in JVLA radio data |
| Bit Name | Binary Digit | Description |
|---|---|---|
| TILED | 0 | assigned a fiber |
| NAKED | 1 | not in area covered by tiles |
| BOSSTARGET | 2 | in the high priority set of targets |
| DECOLLIDED | 3 | in the decollided set of high priority |
| ANCILLARY | 4 | in the lower priority, ancillary set |
| POSSIBLE_KNOCKOUT | 5 | knocked out of at least one tile by BOSSTARGET |
| IGNORE_PRIORITY | 6 | priority exceeds max (ANCILLARY only) |
| TOOBRIGHT | 7 | fibermag too bright |
| BLUEFIBER | 8 | allocate this object a blue fiber |
| CENTERPOST | 9 | 92 arcsec collision with center post |
| REPEAT | 10 | included on more than one tile |
| FILLER | 11 | was a filler (not normal repeat) |
| NOT_TILED_TARGET | 12 | though in input file, not a tiled target |
| OUT_OF_BOUNDS | 13 | outside bounds for this sort of target (for restricted QSO geometry, e.g.) |
| BAD_CALIB_STATUS | 14 | bad CALIB_STATUS |
| PREVIOUS_CHUNK | 15 | included because not tiled in previous overlapping chunk |
| KNOWN_OBJECT | 16 | galaxy has known redshift |
| DUPLICATE | 17 | trimmed as a duplicate object (only checked if not trimmed for any other reason) |
| DUPLICATE_PRIMARY | 18 | has associated duplicate object that were trimmed (but this one is kept) |
| DUPLICATE_TILED | 19 | trimmed as a duplicate object, and its primary was tiled |
| TOOFAINT | 20 | trimmed because it was fainter than the ifiber2mag limit |
| SUPPLEMENTARY | 21 | supplementary targets tiles after the ancillaries (subset of ancillaries) |
| Bit Name | Binary Digit | Description |
|---|---|---|
| ORIGINAL_FLUXMATCH | 0 | used the original positional match (which exists) |
| FIBER_FLUXMATCH | 1 | flagged due to fiberflux/aperflux issue |
| NONMATCH_FLUXMATCH | 2 | flagged due to non-match |
| NOPARENT_FLUXMATCH | 3 | no overlapping parent in primary field |
| PARENT_FLUXMATCH | 4 | overlapping parent has no children, so used it |
| BRIGHTEST_FLUXMATCH | 5 | picked the brightest child |
Each of these bits is set for each fiber and each pixel. Bits 0-15 indicate something about the spectrum as a whole, or at least about its red or blue half (corresponding to the two spectrographs). Within a spectrum, if these bits are set they will be set for all the bits in one or both of the halves. Bits 16-31 indicate something about each particular pixel.
The conditions that are considered very bad are already used to set the errors to infinity for the effected pixels (specifically, the inverse variance is set to zero). The most useful mask bit to look at is BRIGHTSKY, which indicates when the sky is so bright relative to the object that perhaps one shouldn't trust any of the object flux there. Our reported errors are meant to include sky-subtraction errors, but there are instances (particularly around 5577) where these errors may be untrustworthy.
The conditions that are considered very bad are already used to set the errors to infinity for the effected pixels (specifically, the inverse variance is set to zero). The most useful mask bit to look at is BRIGHTSKY, which indicates when the sky is so bright relative to the object that perhaps one shouldn't trust any of the object flux there. Our reported errors are meant to include sky-subtraction errors, but there are instances (particularly around 5577) where these errors may be untrustworthy.
| Bit Name | Binary Digit | Description |
|---|---|---|
| NOPLUG | 0 | Fiber not listed in plugmap file |
| BADTRACE | 1 | Bad trace from routine TRACE320CRUDE |
| BADFLAT | 2 | Low counts in fiberflat |
| BADARC | 3 | Bad arc solution |
| MANYBADCOLUMNS | 4 | More than 10% of pixels are bad columns |
| MANYREJECTED | 5 | More than 10% of pixels are rejected in extraction |
| LARGESHIFT | 6 | Large spatial shift between flat and object position |
| BADSKYFIBER | 7 | Sky fiber shows extreme residuals |
| NEARWHOPPER | 8 | DEPRECATED, no longer set as of BOSS DR9. Prior to DR9 meant within 2 fibers of a whopping fiber (exclusive) |
| WHOPPER | 9 | Whopping fiber, with a very bright source. |
| SMEARIMAGE | 10 | DEPRECATED. Prior to DR9 meant smear available for red and blue cameras |
| SMEARHIGHSN | 11 | DEPRECATED. Prior to DR9 meant S/N sufficient for full smear fit |
| SMEARMEDSN | 12 | DEPRECATED. Prior to DR9 meant S/N only sufficient for scaled median fit |
| NEARBADPIXEL | 16 | Bad pixel within 3 pixels of trace. |
| LOWFLAT | 17 | Flat field less than 0.5 |
| FULLREJECT | 18 | Pixel fully rejected in extraction (INVVAR=0) |
| PARTIALREJECT | 19 | Some pixels rejected in extraction |
| SCATTEREDLIGHT | 20 | Scattered light significant |
| CROSSTALK | 21 | Cross-talk significant |
| NOSKY | 22 | Sky level unknown at this wavelength (INVVAR=0) |
| BRIGHTSKY | 23 | Sky level > flux + 10*(flux_err) AND sky > 1.25 * median(sky,99 pixels) |
| NODATA | 24 | DEPRECATED, should be ignored in favor of flagging on INVVAR=0. Prior to DR9 meant no data available in combine B-spline (INVVAR=0) |
| COMBINEREJ | 25 | Rejected in combine B-spline |
| BADFLUXFACTOR | 26 | Low flux-calibration or flux-correction factor |
| BADSKYCHI | 27 | Relative ?2 > 3 in sky residuals at this wavelength |
| REDMONSTER | 28 | Contiguous region of bad ?2 in sky residuals (with threshold of relative ?2 > 3). |
Spectra with
zWarning equal to zero have no known problems. MANY_OUTLIERS is only ever set in the data taken with the SDSS spectrograph, not the BOSS spectrograph (the SDSS-I, -II and SEGUE-2 surveys). If it is set, that usually indicates a high signal-to-noise spectrum or broad emission lines in a galaxy; that is, MANY_OUTLIERS only rarely signifies a real error.
| Bit Name | Binary Digit | Description |
|---|---|---|
| SKY | 0 | sky fiber |
| LITTLE_COVERAGE | 1 | too little wavelength coverage (WCOVERAGE < 0.18) |
| SMALL_DELTA_CHI2 | 2 | chi-squared of best fit is too close to that of second best (< 0.01 in reduced chi-squared) |
| NEGATIVE_MODEL | 3 | synthetic spectrum is negative (only set for stars and QSOs) |
| MANY_OUTLIERS | 4 | fraction of points more than 5 sigma away from best model is too large (> 0.05) |
| Z_FITLIMIT | 5 | chi-squared minimum at edge of the redshift fitting range (Z_ERR set to -1) |
| NEGATIVE_EMISSION | 6 | a QSO line exhibits negative emission, triggered only in QSO spectra, if C_IV, C_III, Mg_II, H_beta, or H_alpha has LINEAREA + 3 * LINEAREA_ERR < 0 |
| UNPLUGGED | 7 | the fiber was unplugged or damaged, and the location of any spectrum is unknown |
| BAD_TARGET | 8 | catastrophically bad targeting data (e.g. bad astrometry) |
| NODATA | 9 | No data for this fiber, e.g. because spectrograph was broken during this exposure (ivar=0 for all pixels) |
Same as
ZWARNING above but without taking into account QSO templates when determining the best fit template model to the spectra. It only compares GALAXY and STAR templates. It is the target bit used to select confident galaxy redshifts in BOSS and eBOSS.| Bit Name | Binary Digit | Description |
|---|---|---|
| APOGEE_FAINT | 0 | Star selected in faint bin of cohort |
| APOGEE_MEDIUM | 1 | Star selected in medium bin of cohort |
| APOGEE_BRIGHT | 2 | Star selected in bright bin of cohort |
| APOGEE_IRAC_DERED | 3 | Star selected using RJCE-IRAC dereddening |
| APOGEE_WISE_DERED | 4 | Star selected using RJCE-WISE dereddening |
| APOGEE_SFD_DERED | 5 | Selected using SFD E(B-V) dereddening |
| APOGEE_NO_DERED | 6 | Star selected using no dereddening |
| APOGEE_WASH_GIANT | 7 | Selected as giant star via Washington+DDO51 photometry |
| APOGEE_WASH_DWARF | 8 | Selected as dwarf star via Washington+DDO51 photometry |
| APOGEE_SCI_CLUSTER | 9 | Probable stellar cluster member |
| APOGEE_EXTENDED | 10 | Extended object |
| APOGEE_SHORT | 11 | Short cohort target star |
| APOGEE_INTERMEDIATE | 12 | Intermediate cohort target star |
| APOGEE_LONG | 13 | Long cohort target star |
| --- | 14 | --- |
| APOGEE_SERENDIPITOUS | 15 | Serendipitous interesting target to re-observe |
| APOGEE_FIRST_LIGHT | 16 | "First Light" cluster target |
| APOGEE_ANCILLARY | 17 | An ancillary program target (particular program specified in other bits, see below) |
| APOGEE_M31_CLUSTER | 18 | M31 cluster target (ancillary) |
| APOGEE_MDWARF | 19 | M dwarf star selected for RV/metallicity program (ancillary) |
| APOGEE_HIRES | 20 | Star with optical hi-res spectra (ancillary) |
| APOGEE_OLD_STAR | 21 | Selected as old star (ancillary) |
| APOGEE_DISK_RED_GIANT | 22 | Disk red giant star (ancillary) |
| APOGEE_KEPLER_EB | 23 | Eclipsing binary star from Kepler (ancillary) |
| APOGEE_GC_PAL1 | 24 | Star in Pal1 globular cluster (ancillary) |
| APOGEE_MASSIVE_STAR | 25 | Massive star (ancillary) |
| APOGEE_SGR_DSPH | 26 | Sagittarius dwarf galaxy member |
| APOGEE_KEPLER_SEISMO | 27 | Kepler astroseismology program target star |
| APOGEE_KEPLER_HOST | 28 | Kepler planet-host program target star |
| APOGEE_FAINT_EXTRA | 29 | Selected as faint target for low target density field |
| APOGEE_SEGUE_OVERLAP | 30 | Selected because of overlap with SEGUE survey |
| APOGEE_CHECKED | 31 | This object was checked for APOGEE target selection. |
| Bit Name | Binary Digit | Description |
|---|---|---|
| --- | 0 | --- |
| APOGEE_FLUX_STANDARD | 1 | Flux standard |
| APOGEE_STANDARD_STAR | 2 | Stellar abundance and/or parameters standard |
| APOGEE_RV_STANDARD | 3 | Stellar radial velocity standard |
| SKY | 4 | Blank sky position |
| --- | 5 | --- |
| --- | 6 | --- |
| --- | 7 | --- |
| --- | 8 | --- |
| APOGEE_TELLURIC | 9 | Hot (telluric) standard star |
| APOGEE_CALIB_CLUSTER | 10 | Known calibration cluster member star |
| APOGEE_BULGE_GIANT | 11 | Probable giant star in Galactic bulge |
| APOGEE_BULGE_SUPER_GIANT | 12 | Probable supergiant star in Galactic bulge |
| APOGEE_EMBEDDEDCLUSTER_STAR | 13 | Young embedded cluster member (ancillary) |
| APOGEE_LONGBAR | 14 | Probable RC star in long bar (ancillary) |
| APOGEE_EMISSION_STAR | 15 | Emission-line star (ancillary) |
| APOGEE_KEPLER_COOLDWARF | 16 | Kepler cool dwarf or subgiant (ancillary) |
| APOGEE_MIRCLUSTER_STAR | 17 | MIR-detected candidate cluster member (ancillary) |
| APOGEE_RV_MONITOR_IC348 | 18 | IC 348 star monitored for RV variability (ancillary) |
| APOGEE_RV_MONITOR_KEPLER | 19 | Kepler planet host or binary monitored for RV variability (ancillary) |
| APOGEE_GES_CALIBRATE | 20 | Gaia-ESO calibrator |
| APOGEE_BULGE_RV_VERIFY | 21 | Bulge commissioning RV verification |
| APOGEE_1M_TARGET | 22 | Targeted with the 1-m telescope |
| --- | 23 | --- |
| --- | 24 | --- |
| --- | 25 | --- |
| --- | 26 | --- |
| --- | 27 | --- |
| --- | 28 | --- |
| --- | 29 | --- |
| --- | 30 | --- |
| APOGEE_CHECKED | 31 | This object was checked for APOGEE target selection. |
| Bit Name | Binary Digit | Description |
|---|---|---|
| APOGEE2_ONEBIN_GT_0_5 | 0 | Selected in single $(J-K_s)_0 \gt 0.5$ color bin |
| APOGEE2_TWOBIN_0_5_TO_0_8 | 1 | Selected in "blue" $0.5 \lt (J-K_s)_0 \lt 0.8$ color bin |
| APOGEE2_TWOBIN_GT_0_8 | 2 | Selected in "red" $(J-K_s)_0 \gt 0.8$ color bin |
| APOGEE2_IRAC_DERED | 3 | Star selected using RJCE-IRAC dereddening |
| APOGEE2_WISE_DERED | 4 | Star selected using RJCE-WISE dereddening |
| APOGEE2_SFD_DERED | 5 | Selected using SFD $E(B-V)$ dereddening |
| APOGEE2_NO_DERED | 6 | Star selected using no dereddening |
| APOGEE2_WASH_GIANT | 7 | Selected as giant star via Washington+DDO51 photometry |
| APOGEE2_WASH_DWARF | 8 | Selected as dwarf star via Washington+DDO51 photometry |
| APOGEE2_SCI_CLUSTER | 9 | Science cluster candidate member |
| APOGEE2_EXTENDED | 10 | Extended object |
| APOGEE2_SHORT | 11 | Short cohort target star |
| APOGEE2_MEDIUM | 12 | Intermediate cohort target star |
| APOGEE2_LONG | 13 | Long cohort target star |
| APOGEE2_NORMAL_SAMPLE | 14 | Selected as part of the random sample |
| APOGEE2_MANGA_LED | 15 | Star on a shared MaNGA-led design |
| APOGEE2_ONEBIN_GT_0_3 | 16 | Selected in single $(J-K_s)_0 \gt 0.3$ color bin |
| APOGEE2_WASH_NOCLASS | 17 | Selected because it has no W+D classification |
| APOGEE2_STREAM_MEMBER | 18 | Selected as confirmed halo tidal stream member |
| APOGEE2_STREAM_CANDIDATE | 19 | Selected as potential halo tidal stream member |
| APOGEE2_DSPH_MEMBER | 20 | Selected as confirmed dSph member (non Sgr) |
| APOGEE2_DSPH_CANDIDATE | 21 | Selected as potential dSph member (non Sgr) (based on photometry) |
| APOGEE2_MAGCLOUD_MEMBER | 22 | Selected as confirmed Mag Cloud member |
| APOGEE2_MAGCLOUD_CANDIDATE | 23 | Selected as potential Mag Cloud member (based on photometry) |
| APOGEE2_RRLYR | 24 | Selected as an RR Lyrae star |
| APOGEE2_BULGE_RC | 25 | Selected as a bulge candidate RC star |
| APOGEE2_SGR_DSPH | 26 | Sagittarius dwarf galaxy member |
| APOGEE2_APOKASC_GIANT | 27 | Selected as part of APOKASC "giant" sample |
| APOGEE2_APOKASC_DWARF | 28 | Selected as part of APOKASC "dwarf" sample |
| APOGEE2_FAINT_EXTRA | 29 | Selected as faint target for low target density field |
| APOGEE2_APOKASC | 30 | Selected as part of the APOKASC program (incl. seismic/gyro targets and others, both the Cygnus field and K2) |
| APOGEE2_CHECKED | 31 | This object was checked for APOGEE target selection. |
| Bit Name | Binary Digit | Description |
|---|---|---|
| --- | 0 | --- |
| --- | 1 | --- |
| APOGEE2_STANDARD_STAR | 2 | Stellar parameters/abundance standard |
| APOGEE2_RV_STANDARD | 3 | Stellar RV standard |
| APOGEE2_SKY | 4 | Sky fiber |
| APOGEE2_EXTERNAL_CALIB | 5 | External survey calibration target |
| APOGEE2_INTERNAL_CALIB | 6 | Internal survey calibration target |
| --- | 7 | --- |
| --- | 8 | --- |
| APOGEE2_TELLURIC | 9 | Telluric calibrator target |
| APOGEE2_CALIB_CLUSTER | 10 | Selected as calibration cluster member |
| --- | 11 | --- |
| --- | 12 | --- |
| APOGEE2_LITERATURE_CALIB | 13 | Overlap with high-resolution literature studies |
| APOGEE2_GES_OVERLAP | 14 | Overlap with Gaia-ESO |
| APOGEE2_ARGOS_OVERLAP | 15 | Overlap with ARGOS |
| APOGEE2_GAIA_OVERLAP | 16 | Overlap with Gaia |
| APOGEE2_GALAH_OVERLAP | 17 | Overlap with GALAH |
| APOGEE2_RAVE_OVERLAP | 18 | Overlap with RAVE |
| APOGEE2_COMMIS_SOUTH_SPEC | 19 | Commissioning special targets for APOGEE-2S |
| --- | 20 | --- |
| --- | 21 | --- |
| APOGEE2_1M_TARGET | 22 | Selected as a 1-m target |
| APOGEE2_MOD_BRIGHT_LIMIT | 23 | Selected in a cohort with H>10 rather than H>7 |
| APOGEE2_CIS | 24 | Carnegie program target |
| APOGEE2_CNTAC | 25 | Chilean community target |
| APOGEE2_EXTERNAL | 26 | Proprietary external target |
| --- | 27 | --- |
| --- | 28 | --- |
| --- | 29 | --- |
| APOGEE2_OBJECT | 30 | An APOGEE-2 object |
| --- | 31 | --- |
| Bit Name | Binary Digit | Description |
|---|---|---|
| APOGEE2_KOI | 0 | Selected as part of the long cadence KOI study |
| APOGEE2_EB | 1 | Selected as part of the EB program |
| APOGEE2_KOI_CONTROL | 2 | Selected as part of the long cadence KOI "control sample" |
| APOGEE2_MDWARF | 3 | Selected as part of the M dwarf study |
| APOGEE2_SUBSTELLAR_COMPANIONS | 4 | Selected as part of the substellar companion search |
| APOGEE2_YOUNG_CLUSTER | 5 | Selected as part of the young cluster study (IN-SYNC) |
| --- | 6 | --- |
| --- | 7 | --- |
| APOGEE2_ANCILLARY | 8 | Selected as an ancillary target |
| APOGEE2_MASSIVE_STAR | 9 | Selected as part of the Massive Star program |
| APOGEE2_QSO | 10 | ancillary QSO program |
| APOGEE2_CEPHEID | 11 | ancillary Cepheid sparse targets |
| APOGEE2_LOW_AV_WINDOWS | 12 | ancillary Deep Disk sample |
| APOGEE2_BE_STAR | 13 | ancillary ASHELS sample |
| APOGEE2_YOUNG_MOVING_GROUP | 14 | ancillary young moving group members |
| APOGEE2_NGC6791 | 15 | ancillary NGC 6791 star |
| APOGEE2_LABEL_STAR | 16 | ancillary Cannon calibrator sample (Ness) |
| APOGEE2_FAINT_KEPLER_GIANTS | 17 | ancillary APOKASC faint giants |
| APOGEE2_W345 | 18 | ancillary W3/4/5 star forming complex |
| APOGEE2_MASSIVE_EVOLVED | 19 | ancillary massive/evolved star targets |
| APOGEE2_REDDENING_TARGETS | 20 | ancillary extinction targets |
| APOGEE2_KEPLER_MDWARF_KOI | 21 | ancillary M dwarf targets |
| APOGEE2_AGB | 22 | ancillary AGB sample |
| --- | 23 | --- |
| --- | 24 | --- |
| --- | 25 | --- |
| --- | 26 | --- |
| --- | 27 | --- |
| --- | 28 | --- |
| --- | 29 | --- |
| --- | 30 | --- |
| --- | 31 | --- |
This bit mask provides a convenient way to select only main survey targets (EXTRATARG==0) and identifies the main classes of other targets.
| Bit Name | Binary Digit | Description |
|---|---|---|
| NOT_MAIN | 0 | Not main survey target |
| COMMISSIONING | 1 | Commissioning data |
| TELLURIC | 2 | Telluric target |
| APO1M | 3 | 1m observation |
| DUPLICATE | 4 | Duplicate observation |
This bit mask describes the warnings and failures for pixels within the 1D spectra for APOGEE. The bits are set on a per-pixel basis.
| Bit Name | Binary Digit | Description |
|---|---|---|
| BADPIX | 0 | Pixel marked as BAD in bad pixel mask |
| CRPIX | 1 | Pixel marked as cosmic ray in ap3d |
| SATPIX | 2 | Pixel marked as saturated in ap3d |
| UNFIXABLE | 3 | Pixel marked as unfixable in ap3d |
| BADDARK | 4 | Pixel marked as bad as determined from dark frame |
| BADFLAT | 5 | Pixel marked as bad as determined from flat frame |
| BADERR | 6 | Pixel set to have very high error (not used) |
| NOSKY | 7 | No sky available for this pixel from sky fibers |
| LITTROW_GHOST | 8 | Pixel falls in Littrow ghost, may be affected |
| PERSIST_HIGH | 9 | Pixel falls in high persistence region, may be affected |
| PERSIST_MED | 10 | Pixel falls in medium persistence region, may be affected |
| PERSIST_LOW | 11 | Pixel falls in low persistence region, may be affected |
| SIG_SKYLINE | 12 | Pixel falls near sky line that has significant flux compared with object |
| SIG_TELLURIC | 13 | Pixel falls near telluric line that has significant absorption |
| NOT_ENOUGH_PSF | 14 | Less than 50 percent PSF in good pixels |
| 15 |
| Bit Name | Binary Digit | Description |
|---|---|---|
| BAD_PIXELS | 0 | Spectrum has many bad pixels (>40%): BAD |
| COMMISSIONING | 1 | Commissioning data (MJD<55761), non-standard configuration, poor LSF: WARN |
| BRIGHT_NEIGHBOR | 2 | Star has neighbor more than 10 times brighter: WARN |
| VERY_BRIGHT_NEIGHBOR | 3 | Star has neighbor more than 100 times brighter: BAD |
| LOW_SNR | 4 | Spectrum has low S/N (S/N<5): BAD |
| 5 | ||
| 6 | ||
| 7 | ||
| 8 | ||
| PERSIST_HIGH | 9 | Spectrum has significant number (>20%) of pixels in high persistence region: WARN |
| PERSIST_MED | 10 | Spectrum has significant number (>20%) of pixels in medium persistence region: WARN |
| PERSIST_LOW | 11 | Spectrum has significant number (>20%) of pixels in low persistence region: WARN |
| PERSIST_JUMP_POS | 12 | Spectrum show obvious positive jump in blue chip: WARN |
| PERSIST_JUMP_NEG | 13 | Spectrum show obvious negative jump in blue chip: WARN |
| 14 | ||
| 15 | ||
| SUSPECT_RV_COMBINATION | 16 | WARNING: RVs from synthetic template differ significantly from those from combined template |
| SUSPECT_BROAD_LINES | 17 | WARNING: cross-correlation peak with template significantly broader than autocorrelation of template |
| 18 | ||
| 19 | ||
| 20 | ||
| 21 | ||
| 22 | ||
| 23 | ||
| 24 | ||
| 25 | ||
| 26 | ||
| 27 | ||
| 28 | ||
| 29 | ||
| 30 | ||
| 31 |
| Bit Name | Binary Digit | Description |
|---|---|---|
| TEFF_WARN | 0 | WARNING on effective temperature (see PARAMFLAG[0] for details) |
| LOGG_WARN | 1 | WARNING on log g (see PARAMFLAG[1] for details) |
| VMICRO_WARN | 2 | WARNING on vmicro (see PARAMFLAG[2] for details) |
| METALS_WARN | 3 | WARNING on metals (see PARAMFLAG[3] for details) |
| ALPHAFE_WARN | 4 | WARNING on [alpha/Fe] (see PARAMFLAG[4] for details) |
| CFE_WARN | 5 | WARNING on [C/Fe] (see PARAMFLAG[5] for details) |
| NFE_WARN | 6 | WARNING on [N/Fe] (see PARAMFLAG[6] for details) |
| STAR_WARN | 7 | WARNING overall for star: set if any of TEFF, LOGG, CHI2, COLORTE, ROTATION, SN warn are set |
| CHI2_WARN | 8 | high chi^2 (> 2*median at ASPCAP temperature (WARN) |
| COLORTE_WARN | 9 | effective temperature more than 500K from photometric temperature for dereddened color (WARN) |
| ROTATION_WARN | 10 | Spectrum has broad lines, with possible bad effects: FWHM of cross-correlation of spectrum with best RV template relative to auto-correltion of template > 1.5 (WARN) |
| SN_WARN | 11 | S/N<70 (WARN) |
| 12 | ||
| 13 | ||
| VSINI_WARN | 14 | |
| 15 | ||
| TEFF_BAD | 16 | BAD effective temperature (see PARAMFLAG[0] for details) |
| LOGG_BAD | 17 | BAD log g (see PARAMFLAG[1] for details) |
| VMICRO_BAD | 18 | BAD vmicro (see PARAMFLAG[2] for details) |
| METALS_BAD | 19 | BAD metals (see PARAMFLAG[3] for details) |
| ALPHAFE_BAD | 20 | BAD [alpha/Fe] (see PARAMFLAG[4] for details) |
| CFE_BAD | 21 | BAD [C/Fe] (see PARAMFLAG[5] for details) |
| NFE_BAD | 22 | BAD [N/Fe] (see PARAMFLAG[6] for details) |
| STAR_BAD | 23 | BAD overall for star: set if any of TEFF, LOGG, CHI2, COLORTE, ROTATION, SN error are set, or any parameter is near grid edge (GRIDEDGE_BAD is set in any PARAMFLAG) |
| CHI2_BAD | 24 | high chi^2 (> 5*median at ASPCAP temperature (BAD) |
| COLORTE_BAD | 25 | effective temperature more than 1000K from photometric temperature for dereddened color (BAD) |
| ROTATION_BAD | 26 | Spectrum has broad lines, with possible bad effects: FWHM of cross-correlation of spectrum with best RV template relative to auto-correltion of template > 2 (BAD) |
| SN_BAD | 27 | S/N<50 (BAD) |
| 28 | ||
| 29 | ||
| VSINI_BAD | 30 | |
| NO_ASPCAP_RESULT | 31 |
| Bit Name | Binary Digit | Description |
|---|---|---|
| GRIDEDGE_BAD | 0 | Parameter within 1/8 grid spacing of grid edge |
| CALRANGE_BAD | 1 | Parameter outside valid range of calibration determination |
| OTHER_BAD | 2 | Other error condition |
| FERRE_BAD | 3 | FERRE failed to return a value |
| PARAM_MISMATCH_BAD | 4 | Elemental abundance from window differs > 0.5 dex from parameter abundance |
| 5-7 | Currently unused | |
| GRIDEDGE_WARN | 8 | Parameter within 1/2 grid spacing of grid edge |
| CALRANGE_WARN | 9 | Parameter in possibly unreliable range of calibration determination |
| OTHER_WARN | 10 | Other warning condition |
| FERRE_WARN | 11 | FERRE provided a value and a warning |
| PARAM_MISMATCH_WARN | 12 | Elemental abundance from window differs > 0.25 dex from parameter abundance |
| 13-15 | Currently unused | |
| PARAM_FIXED | 16 | Parameter set at fixed value, not fit |
| 17-31 | Currently unused |
The MANGA_TARGET1, MANGA_TARGET2, and MANGA_TARGET3 integers are used to track the target type (e.g., primary sample galaxies, F-standard stars, etc). Loosely speaking, all galaxy targets have a non-zero bit set for MANGA_TARGET1, all non-galaxy targets (e.g., MaStar) have a non-zero bit set for MANGA_TARGET2, and all ancillary program targets have a non-zero bit set for MANGA_TARGET3.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| NONE | 0 | 1 | Unused. |
| PRIMARY_PLUS_COM | 1 | 2 | March 2014 commissioning |
| SECONDARY_COM | 2 | 4 | March 2014 commissioning |
| COLOR_ENHANCED_COM | 3 | 8 | March 2014 commissioning |
| PRIMARY_v1_1_0 | 4 | 16 | First tag, August 2014 plates |
| SECONDARY_v1_1_0 | 5 | 32 | First tag, August 2014 plates |
| COLOR_ENHANCED_v1_1_0 | 6 | 64 | First tag, August 2014 plates |
| PRIMARY_COM2 | 7 | 128 | July 2014 commissioning |
| SECONDARY_COM2 | 8 | 256 | July 2014 commissioning |
| COLOR_ENHANCED_COM2 | 9 | 512 | July 2014 commissioning |
| PRIMARY_v1_2_0 | 10 | 1024 | MaNGA main survey primary selection |
| SECONDARY_v1_2_0 | 11 | 2048 | MaNGA main survey secondary selection |
| COLOR_ENHANCED_v1_2_0 | 12 | 4096 | MaNGA main survey color-enhanced selection |
| FILLER | 13 | 8192 | Filler targets |
| RETIRED | 14 | 16384 | Retired bit; do not use |
The MANGA_TARGET1, MANGA_TARGET2, and MANGA_TARGET3 integers are used to track the target type (e.g., primary sample galaxies, F-standard stars, etc). Loosely speaking, all galaxy targets have a non-zero bit set for MANGA_TARGET1, all non-galaxy targets (e.g., MaStar) have a non-zero bit set for MANGA_TARGET2, and all ancillary program targets have a non-zero bit set for MANGA_TARGET3.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| NONE | 0 | 1 | Unused. |
| SKY | 1 | 2 | |
| MaStar stellar library targets: | |||
| STELLIB_SDSS_COM | 2 | 4 | Commissioning selection using SDSS photometry. |
| STELLIB_2MASS_COM | 3 | 8 | Commissioning selection using 2MASS photometry. |
| STELLIB_KNOWN_COM | 4 | 16 | Commissioning selection of known parameter stars. |
| STELLIB_COM_mar2015 | 5 | 32 | Commissioning selection in March 2015. |
| STELLIB_COM_jun2015 | 6 | 64 | Commissioning selection in June 2015. |
| STELLIB_PS1 | 7 | 128 | Library stars using PS1 photometry. |
| STELLIB_APASS | 8 | 256 | Library stars using APASS photometry. |
| STELLIB_PHOTO_COM | 9 | 512 | Commissioning selection using photo-derived para. |
| STELLIB_aug2015 | 10 | 1024 | Global Selection generated in Aug 2015. |
| STELLIB_SDSS | 11 | 2048 | Library stars using SDSS photometry. | STELLIB_GAIA | 12 | 4096 | Library stars using GAIA photometry, g band only. |
| STELLIB_TYCHO2 | 13 | 8192 | Library stars using TYCHO2 photometry (B and V in place of u and r). |
| STELLIB_BRIGHT | 14 | 16384 | Bright stars observed with short exposures. |
| STELLIB_UNRELIABLE | 15 | 32768 | Library stars with unreliable photometry |
| Spetrophotometric calibration standards: | |||
| STD_FSTAR_COM | 20 | 1048576 | |
| STD_WD_COM | 21 | 2097152 | |
| STD_STD_COM | 22 | 4194304 | |
| STD_FSTAR | 23 | 8388608 | |
| STD_WD | 24 | 16777216 | |
| STD_APASS_COM | 25 | 33554432 | Commissioning selection of stds using APASS photometry |
| STD_PS1_COM | 26 | 67108864 | Commissioning selection of stds using PS1 photometry |
| STD_BRIGHT | 27 | 134217728 | standards on bright star plates |
The MANGA_TARGET1, MANGA_TARGET2, and MANGA_TARGET3 integers are used to track the target type (e.g., primary sample galaxies, F-standard stars, etc). Loosely speaking, all galaxy targets have a non-zero bit set for MANGA_TARGET1, all non-galaxy targets (e.g., MaStar) have a non-zero bit set for MANGA_TARGET2, and all ancillary program targets have a non-zero bit set for MANGA_TARGET3.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| NONE | 0 | 1 | Unused. |
| AGN_BAT | 1 | 2 | |
| AGN_OIII | 2 | 4 | |
| AGN_WISE | 3 | 8 | |
| AGN_PALOMAR | 4 | 16 | |
| VOID | 5 | 32 | |
| EDGE_ON_WINDS | 6 | 64 | |
| PAIR_ENLARGE | 7 | 128 | |
| PAIR_RECENTER | 8 | 256 | |
| PAIR_SIM | 9 | 512 | |
| PAIR_2IFU | 10 | 1024 | |
| LETTERS | 11 | 2048 | |
| MASSIVE | 12 | 4096 | |
| MWA | 13 | 8192 | |
| DWARF | 14 | 16384 | |
| RADIO_JETS | 15 | 32768 | |
| DISKMASS | 16 | 65536 | |
| BCG | 17 | 131072 | |
| ANGST | 18 | 262144 | |
| DEEP_COMA | 19 | 524288 | |
| IC342 | 20 | 1048576 | |
| M31 | 21 | 2097152 | |
| SN_ENV | 22 | 4194304 | |
| MW_ANALOG | 23 | 8388608 | |
| POST-STARBURST | 24 | 16777216 | |
| GLSB | 25 | 33554432 | |
| SN1A_HOST | 26 | 67108864 |
The 2d section of the MaNGA/MaStar DRP (i.e., reducing a single exposure of an entire plate through to the flux calibrated stage) uses the MANGA_DRP2PIXMASK maskbits. These maskbits apply to individual pixels in these images, and are used to determine (e.g.) where the extraction quality is bad due to hot pixels, cosmic ray hits, etc. These masks are contained in the MASK extensions to data produced by the 2d DRP.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| The following mask bits are for fibers: | |||
| NOPLUG | 0 | 1 | Fiber not listed in plugmap file. |
| BADTRACE | 1 | 2 | Bad trace. |
| BADFLAT | 2 | 4 | Low counts in fiberflat. |
| BADARC | 3 | 8 | Bad arc solution. |
| MANYBADCOLUMNS | 4 | 16 | More than 10% of pixels are bad columns. |
| MANYREJECTED | 5 | 32 | More than 10% of pixels are rejected in extraction. |
| LARGESHIFT | 6 | 64 | Large spatial shift between flat and object position. |
| BADSKYFIBER | 7 | 128 | Sky fiber shows extreme residuals. |
| NEARWHOPPER | 8 | 256 | Within 2 fibers of a whopping fiber (exclusive). |
| WHOPPER | 9 | 512 | Whopping fiber, with a very bright source. |
| SMEARIMAGE | 10 | 1024 | Smear available for red and blue cameras. |
| SMEARHIGHSN | 11 | 2048 | S/N sufficient for full smear fit. |
| SMEARMEDSN | 12 | 4096 | S/N only sufficient for scaled median fit. |
| DEADFIBER | 13 | 8192 | Broken fiber according to metrology files. |
| The following mask bits are for a pixel: | |||
| SATURATION | 14 | 16384 | Pixel considered saturated. |
| BADPIX | 15 | 32768 | Pixel flagged in badpix reference file. |
| COSMIC | 16 | 65536 | Pixel flagged as cosmic ray. |
| NEARBADPIXEL | 17 | 131072 | Bad pixel within 3 pixels of trace. |
| LOWFLAT | 18 | 262144 | Flat field less than 0.5. |
| FULLREJECT | 19 | 524288 | Pixel fully rejected in extraction model fit (INVVAR=0). |
| PARTIALREJECT | 20 | 1048576 | Some pixels rejected in extraction model fit. |
| SCATTEREDLIGHT | 21 | 2097152 | Scattered light significant. |
| CROSSTALK | 22 | 4194304 | Cross-talk significant. |
| NOSKY | 23 | 8388608 | Sky level unknown at this wavelength (INVVAR=0). |
| BRIGHTSKY | 24 | 16777216 | Sky level > flux + 10*(flux_err) AND sky > 1.25 * median(sky,99 pixels). |
| NODATA | 25 | 33554432 | No data available in combine B-spline (INVVAR=0). |
| COMBINEREJ | 26 | 671108864 | Rejected in combine B-spline. |
| BADFLUXFACTOR | 27 | 134217728 | Low flux-calibration or flux-correction factor. |
| BADSKYCHI | 28 | 268435456 | Relative chi2 > 3 in sky residuals at this wavelength. |
| REDMONSTER | 29 | 536870912 | Contiguous region of bad chi2 in sky residuals (with threshhold of relative chi2 > 3). |
| 3DREJECT | 30 | 1073741824 | Used in RSS file, indicates should be rejected when making 3D cube. |
Since the RSS files combining all exposures for specific IFUs have the same data format as the 2d pipeline, they retain the MANGA_DRP2PIXMASK mask bits. These are informative, in the sense that they tell the end user why a given pixel was masked at the detector level (e.g., cosmic ray, full rejection of the model fit during spectral extraction, etc.).
The combined 3d data cubes use the MANGA_DRP3PIXMASK mask bits that describe whether a given spaxel should be used for science analyses. For instance, it tells where dead fibers are, low relative exposure depth (e.g. at the edges of the frame), no coverage (beyond the borders of the IFU hexagon but within the rectilinear data cube frame, etc. The most generally useful mask bit though is the 'DONOTUSE' bit, which should be self explanatory, and is a distillation of all of the relevant reasons why not to trust particular values.
There is also a FORESTAR bit that indicates where a foreground star has been noted, and should probably be masked out for galaxy analyses. Since the spectra in these regions are still valid, having the FORESTAR bit set does not automatically set the DONOTUSE bit.
The combined 3d data cubes use the MANGA_DRP3PIXMASK mask bits that describe whether a given spaxel should be used for science analyses. For instance, it tells where dead fibers are, low relative exposure depth (e.g. at the edges of the frame), no coverage (beyond the borders of the IFU hexagon but within the rectilinear data cube frame, etc. The most generally useful mask bit though is the 'DONOTUSE' bit, which should be self explanatory, and is a distillation of all of the relevant reasons why not to trust particular values.
There is also a FORESTAR bit that indicates where a foreground star has been noted, and should probably be masked out for galaxy analyses. Since the spectra in these regions are still valid, having the FORESTAR bit set does not automatically set the DONOTUSE bit.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| NOCOV | 0 | 1 | No coverage in cube. |
| LOWCOV | 1 | 2 | Low coverage depth in cube. |
| DEADFIBER | 2 | 4 | Major contributing fiber is dead. |
| FORESTAR | 3 | 8 | Foreground star. |
| DONOTUSE | 10 | 1024 | Do not use this spaxel for science. |
MANGA_DAPPIXMASK is the 2d image bitmap used to describe the quality of individual pixel measurements in the DAP MAPS file. In addition to reproducing some entries from the MANGA_DRP3PIXMASK for the data cubes (e.g., flagging foreground stars, low coverage, etc) it also adds some new entries indicating spaxels for which the fitting algorithms failed in some manner (e.g., by reaching the bounds of allowable values, failing to derive a fit, etc). The most important flags are incorporated into the
DONOTUSE bit, which indicates that a given pixel should not be used for science.
The NEARBOUND flag is used to signify that a returned parameter is likely biased by an imposed boundary on the allowed parameter space. These are specifically relevant to the kinematics (both for stars and ionized-gas) from pPXF. pPXF imposes a ±2000 km/s limit relative to the input guess velocity (set to cz as given by the SCINPVEL header keyword and most often identical to the NSA redshift) on the returned velocity and dv/100 < σ < 1000 limit on the velocity dispersion, where dv is the size of the MaNGA LOGCUBE wavelength channel (~70 km/s; given by VSTEP header keyword). The returned velocity is determined to be NEARBOUND if the "best-fit" value is within 100th of the width of the allowed range of either boundary; i.e., NEARBOUND is triggered if the velocity is -2000 < v < -1980 or 1980 < v < 2000. For the velocity dispersion, NEARBOUND is triggered by the same criterion but geometrically; i.e., if the velocity dispersion is 0.69 < σ < 0.74 or 929.8 < σ < 1000.
The UNRELIABLE flag is not incorporated into the DONOTUSE flag. This flag is intended to act as a warning to users that the data may be biased in some way, based on a set of criteria developed by the data pipeline team. You are strongly encouraged to understand the implications of this flag on the data and how to properly make the distinction between the DONOTUSE and UNRELIABLE flags for your science application. For DR15, the UNRELIABLE flag is only set if there are masked pixels in any of the wavelength passbands used when calculating the emission-line equivalent widths or the spectral indices (extensions EMLINE_SEW, EMLINE_GEW, and SPECINDEX in the MAPS file).
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| NOCOV | 0 | 1 | No coverage in cube. |
| LOWCOV | 1 | 2 | Low coverage depth in cube. |
| DEADFIBER | 2 | 4 | Major contributing fiber is dead. |
| FORESTAR | 3 | 8 | Foreground star. |
| NOVALUE | 4 | 16 | Spaxel was not fit because it did not meet selection criteria. |
| UNRELIABLE | 5 | 32 | Value is deemed unreliable. |
| MATHERROR | 6 | 64 | Mathematical error in computing value. |
| FITFAILED | 7 | 128 | Attempted fit for property failed. |
| NEARBOUND | 8 | 256 | Fitted value is too near an imposed boundary. |
| NOCORRECTION | 9 | 512 | Appropriate correction not available. |
| MULTICOMP | 10 | 1024 | Multi-component velocity features present (placeholder, not used in DR15). |
| DONOTUSE | 30 | 1073741824 | Do not use this spaxel for science. |
MANGA_DAPSPECMASK is the 3d cube bitmap used to describe the quality of individual spaxel fits in the DAP model data cube file.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| IGNORED | 0 | 1 | Ignored because of DRP flags or stacking parameters. |
| FORESTAR | 1 | 2 | There is a foreground star within the data cube. |
| FLUXINVALID | 2 | 4 | Ignored because (stacked) flux not valid. |
| IVARINVALID | 3 | 8 | Ignored because inverse variance not valid. |
| ARTIFACT | 4 | 16 | Contains a designated artifact. |
| FITIGNORED | 5 | 32 | Ignored during fit. |
| FITFAILED | 6 | 64 | Fit failed in this region. |
| ELIGNORED | 7 | 128 | Ignored during emission-line fit. |
| ELFAILED | 8 | 256 | Emission-line fit failed. |
The quality of DRP-2d products is tracked using the integer DRP2QUAL that is contained in the output FITS headers of all 2d DRP products (and in the OBSINFO extensions of all 3d DRP products). This uses the bitmask values MANGA_DRP2QUAL. These provide information to the pipeline about failure points that need to be addressed in quality control. For instance, a detected failure in sky subtraction will trigger a mask bit SKYSUBBAD to be set; the flux calibration routine will detect this, and not try to flux calibrate data that has failed the sky subtraction stage.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| RETIRED | 0 | 1 | Retired bit; do not use. |
| EXTRACTBAD | 1 | 2 | Many bad values in extracted frame. |
| EXTRACTBRIGHT | 2 | 4 | Extracted spectra abnormally bright. |
| LOWEXPTIME | 3 | 8 | Exposure time less than 10 minutes. |
| BADIFU | 4 | 16 | One or more IFUs missing/bad in this frame. |
| HIGHSCAT | 5 | 32 | High scattered light levels. |
| SCATFAIL | 6 | 64 | Failure to correct high scattered light levels. |
| BADDITHER | 7 | 128 | Bad dither location information. |
| ARCFOCUS | 8 | 256 | Bad focus on arc frames. |
| RAMPAGINGBUNNY | 9 | 512 | Rampaging dust bunnies in IFU flats. |
| SKYSUBBAD | 10 | 1024 | Bad sky subtraction. |
| SKYSUBFAIL | 11 | 2048 | Failed sky subtraction. |
| FULLCLOUD | 12 | 4096 | Completely cloudy exposure. |
| BADFLEXURE | 13 | 8192 | Abnormally high flexure LSF correction. |
| VGROOVEFAIL | 14 | 16384 | Possible V-groove glue failure. |
| NOGUIDER | 15 | 32768 | No guider data available. |
| NOSPEC1 | 16 | 65536 | No data from spec1. |
| NOSPEC2 | 17 | 131072 | No data from spec2. |
The quality of DRP-3d products is tracked using the integer DRP3QUAL that is contained in the output FITS headers of all 3d DRP products. This uses the bitmask values MANGA_DRP3QUAL. These provide information to end-users and the DAP about final cubes and RSS files that do not meet quality standards (e.g., this ifu dropped out of the plate for some observations, so the data are not as deep as for other IFUs on the plate).
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| RETIRED | 0 | 1 | Bit retired from use; do not use. |
| BADDEPTH | 1 | 2 | IFU does not reach target depth. |
| SKYSUBBAD | 2 | 4 | Bad sky subtraction in one or more frames. |
| HIGHSCAT | 3 | 8 | High scattered light in one or more frames. |
| BADASTROM | 4 | 16 | Bad astrometry in one or more frames. |
| VARIABLELSF | 5 | 32 | LSF varies signif. between component spectra. |
| BADOMEGA | 6 | 64 | Omega greater than threshhold in one or more sets. |
| BADSET | 7 | 128 | One or more sets are bad. |
| BADFLUX | 8 | 256 | Bad flux calibration. |
| BADPSF | 9 | 512 | PSF estimate may be bad. |
| MANYDEAD | 10 | 1024 | Many dead fibers. |
| RETIRED2 | 11 | 2048 | Bit retired, moved into MASTAR_QUAL instead. |
| CRITICAL | 30 | 1073741824 | Critical failure in one or more frames . |
The overall quality of DAP data products is tracked using
MANGA_DAPQUAL bit contained in the headers of the DAP output fits files. This bit provides information to end-users about DAP maps and model data cubes that do not meet quality standards (e.g., a bad NSA redshift, ppxf failures, etc.). Anything with the CRITICAL bit set in MANGA_DAPQUAL should generally not be used for scientific purposes.
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| FORESTAR | 0 | 1 | There is a foreground star within the data cube. |
| BADZ | 1 | 2 | NSA redshift does not match derived redshift. |
| LINELESS | 2 | 4 | No emission lines in data cube. |
| PPXFFAIL | 3 | 8 | PPXF fails to fit this object. |
| SINGLEBIN | 4 | 16 | Voronoi binning resulted in all spectra in a single bin. |
| BADGEOM | 5 | 32 | Invalid input geometry; elliptical coordinates and effective radius are meaningless. |
| DRPCRIT | 28 | 268435456 | Critical failure in DRP. |
| DAPCRIT | 29 | 536870912 | Critical failure in DAP. |
| CRITICAL | 30 | 1073741824 | Critical failure in DRP or DAP. |
The overall quality of summary MaStar spectra is tracked using the integers MJDQUAL, EXPQUAL, and MSTRQUAL that are contained in the output FITS headers and/or binary tables of all MaStar data products. These all use the bitmask values MASTAR_QUAL (see further info at MaStar spectra). These provide information to end-users about spectra that do not meet quality standards (e.g., bad flux calibration, high variance in radial velocity estimates, problematic visual inspection, etc.).
| Bit name | Binary digit | Value | Description |
|---|---|---|---|
| NODATA | 0 | 1 | No Data. |
| SKYSUBBAD | 1 | 2 | Bad sky subtraction in one or more frames. |
| HIGHSCAT | 2 | 4 | High scattered light in one or more frames. |
| BADFLUX | 3 | 8 | Bad flux calibration. |
| LOWCOV | 4 | 16 | PSF-covering fraction by fiber is too small (<10%). |
| POORCAL | 5 | 32 | Poor throughput. |
| BADHELIORV | 6 | 64 | High variance between stellar RVs. |
| MANUAL | 7 | 128 | Flagged as problematic by visual inspection. |
| EMLINE | 8 | 256 | Spectrum contain emission lines. |
| LOWSN | 9 | 512 | Per-MJD Spectrum has median S/N <= 15. |
| CRITICAL | 30 | 1073741824 | Critical failure in one or more frames. |
