Special Programs
Here we provide information on the targeting for the Special Programs in the APOGEE dataset. Each program has a brief description, targeting rationale, contact information for the leader of the program, and how to identify objects observed for the program.
Ancillary Programs in APOGEE
APOGEE-2N Ancillary Programs
Targets observed as part of APOGEE-2's approved ancillary science programs are indicated in APOGEE2_TARGET3 as "APOGEE2_ANCILLARY" (bit 8) in addition to a bit set in APOGEE2_TARGET3 for each individual program. See the list below for a summary. Note that not all programs may have targets in this data release, which depends on the date of the observation, but all are included here for completeness. The user should direct questions about targeting for these programs to the PIs.
QSOs APOGEE2_TARGET3 bit 10
PI: F. Albareti (UAM/CSIC)
A selection of high-redshift quasars (z=2-2.4) to detect H$\beta$-[OIII] emission shifted into the near-IR.
Starting with 297,301 quasars of the SDSS-III/BOSS-DR12Q catalog (Paris et al. 2017), we select 71,587 quasars that have an optical redshift in the range $2.06 \leq z \leq 2.38$. This sample is further restricted by requiring Vega H-band magnitudes < 20 mag. However, only 20,796 quasars have H-band flux measurements from UKIDSS. For the remaining ones, we studied the correlation between UKIDSS H-band measurements and z-band SDSS magnitudes using quasars with UKIDSS H-band magnitude < 21 mag (19,993 in total). Thus, for those quasars without H-band measurements, we require z-band SDSS magnitude < 21.27 mag. Alternatively, we demand the H-band magnitude obtained either from UKIDSS or estimated from z-band SDSS measurements to be $\lt 20$ mag. In this way, we obtain a sample of 61,075 quasars. The APOGEE-2N halo fields contain 971 quasars. Targets are prioritized by H-band magnitude.
A selection of high-redshift quasars (z=2-2.4) to detect H$\beta$-[OIII] emission shifted into the near-IR.
Starting with 297,301 quasars of the SDSS-III/BOSS-DR12Q catalog (Paris et al. 2017), we select 71,587 quasars that have an optical redshift in the range $2.06 \leq z \leq 2.38$. This sample is further restricted by requiring Vega H-band magnitudes < 20 mag. However, only 20,796 quasars have H-band flux measurements from UKIDSS. For the remaining ones, we studied the correlation between UKIDSS H-band measurements and z-band SDSS magnitudes using quasars with UKIDSS H-band magnitude < 21 mag (19,993 in total). Thus, for those quasars without H-band measurements, we require z-band SDSS magnitude < 21.27 mag. Alternatively, we demand the H-band magnitude obtained either from UKIDSS or estimated from z-band SDSS measurements to be $\lt 20$ mag. In this way, we obtain a sample of 61,075 quasars. The APOGEE-2N halo fields contain 971 quasars. Targets are prioritized by H-band magnitude.
Cepheids APOGEE2_TARGET3 bit 11
PI: R. Beaton (OCIS/Princeton)
A set of Galactic Cepheids throughout the disk, to obtain multi-species abundances.
Targets were selected by cross-matching the General Catalog of Variable Stars (GCVS; Samus et al. 2007-2012), restricted to those stars of normal Cepheid and delta Cepheid types (CEP and DCEP designations in the GCVS, respectively), to the APOGEE-2N field footprint. The GCVS Cepheid catalog is further restricted to those stars with H magnitudes between 6.5 and 11 to ensure that S/N of 100 is safely obtained in 1 hour (to avoid problems of co-adding spectra during different phases). While only those stars with periods longer than seven days are expected to show a MIR-color metallicity relationship, sources with periods less than seven days were included in the target selection to increase overlap with the Genovali et al. (2014, 2015).
A set of Galactic Cepheids throughout the disk, to obtain multi-species abundances.
Targets were selected by cross-matching the General Catalog of Variable Stars (GCVS; Samus et al. 2007-2012), restricted to those stars of normal Cepheid and delta Cepheid types (CEP and DCEP designations in the GCVS, respectively), to the APOGEE-2N field footprint. The GCVS Cepheid catalog is further restricted to those stars with H magnitudes between 6.5 and 11 to ensure that S/N of 100 is safely obtained in 1 hour (to avoid problems of co-adding spectra during different phases). While only those stars with periods longer than seven days are expected to show a MIR-color metallicity relationship, sources with periods less than seven days were included in the target selection to increase overlap with the Genovali et al. (2014, 2015).
Low Extinction Disk APOGEE2_TARGET3 bit 12
PI: J. Bovy (University of Toronto)
A sample of luminous giants in low-extinction windows, to sample the far reaches of the Milky Way's disk.
For each pointing, targets are selected in the region of the field for which $A_H(D=7{\rm\ kpc}) \le 1.4$ mag. This $A_H$ is computed from the 3D extinction map of Marshall et al. (2006), using linear interpolation in the distance and assuming $A_H/A_{Ks}=0.46/0.31$. Targets in this region are selected from the 2MASS catalog using the same 2MASS quality cuts and RJCE dereddening as the standard APOGEE disk targets. All potential targets are obtained by selecting stars with $(J-K_s)_0 \ge 0.8$ mag and $12 \le H \le 13$ mag. A random subset of these is observed. Targets at the top of the list were already observed as part of the regular disk sample in the $\ell = 34^{\circ}$, and $\ell = 64^{\circ}$ midplane fields are flagged, but not re-observed.
A sample of luminous giants in low-extinction windows, to sample the far reaches of the Milky Way's disk.
For each pointing, targets are selected in the region of the field for which $A_H(D=7{\rm\ kpc}) \le 1.4$ mag. This $A_H$ is computed from the 3D extinction map of Marshall et al. (2006), using linear interpolation in the distance and assuming $A_H/A_{Ks}=0.46/0.31$. Targets in this region are selected from the 2MASS catalog using the same 2MASS quality cuts and RJCE dereddening as the standard APOGEE disk targets. All potential targets are obtained by selecting stars with $(J-K_s)_0 \ge 0.8$ mag and $12 \le H \le 13$ mag. A random subset of these is observed. Targets at the top of the list were already observed as part of the regular disk sample in the $\ell = 34^{\circ}$, and $\ell = 64^{\circ}$ midplane fields are flagged, but not re-observed.
Emission Line Stars APOGEE2_TARGET3 bit 13
PI: S. D. Chojnowski (New Mexico State University)
This program obtains multi-epoch spectroscopy of a variety of B-type emission line stars, including several rare subtypes.
Our targets were selected according to straightforward and somewhat subjective criteria. First, we obtained comprehensive lists of known OBA emission-line stars via SIMBAD, VIZIER catalogs, and papers. Next, we identified the stars falling in planned APOGEE-2 fields and assembled additional data for them, including spectral types and 2MASS magnitudes. For stars with suitable H magnitudes, we checked the literature and attempted to sort by sub-type, e.g., classical Be star, B[e] star, unclassified emission star, etc. Rare and unusual Be subtypes were targeted first, followed by the six members of NGC 7419.
This program obtains multi-epoch spectroscopy of a variety of B-type emission line stars, including several rare subtypes.
Our targets were selected according to straightforward and somewhat subjective criteria. First, we obtained comprehensive lists of known OBA emission-line stars via SIMBAD, VIZIER catalogs, and papers. Next, we identified the stars falling in planned APOGEE-2 fields and assembled additional data for them, including spectral types and 2MASS magnitudes. For stars with suitable H magnitudes, we checked the literature and attempted to sort by sub-type, e.g., classical Be star, B[e] star, unclassified emission star, etc. Rare and unusual Be subtypes were targeted first, followed by the six members of NGC 7419.
Moving Groups APOGEE2_TARGET3 bit 14
PI: J. J. Downes (Universidad Nacional Autónoma de México)
Known members of Nearby Young Moving Groups, to characterize the groups and to generate high-quality young stellar spectral templates.
We made an all-sky catalog including all currently known members of Nearby Young Moving Groups, comprising more than 2000 stars across the sky. Of these, we selected stars with $7 \le H \le 12.2$ mag falling within planned APOGEE-2 fields, resulting in 9 stars with a variety of spectral types. We also selected 22 bright stars ($H \le 9.2$ mag) with $\delta \ge -10^{\circ}$, to span all spectral types, to be observed with the NMSU 1-m telescope.
Known members of Nearby Young Moving Groups, to characterize the groups and to generate high-quality young stellar spectral templates.
We made an all-sky catalog including all currently known members of Nearby Young Moving Groups, comprising more than 2000 stars across the sky. Of these, we selected stars with $7 \le H \le 12.2$ mag falling within planned APOGEE-2 fields, resulting in 9 stars with a variety of spectral types. We also selected 22 bright stars ($H \le 9.2$ mag) with $\delta \ge -10^{\circ}$, to span all spectral types, to be observed with the NMSU 1-m telescope.
Populations in NGC6791 APOGEE2_TARGET3 bit 15
PI: D. Geisler (Universidad de Concepcion)
A search for evidence of multiple stellar populations in the unusual open cluster NGC6791, by targeting several dozen member stars.
All of our targets lie in the existing APOGEE field K21_071+10 and have $H \le 12$. The target lists come from several sources. First, all of the stars observed optically by Geisler et al. (2012) that meet our $S/N$ requirements were included, excluding those that already have APOGEE-1 spectra from DR12 or earlier, as none of these show evidence for the Na-O anticorrelation. The three Na-poor stars from Geisler et al. (2012) have been given top priority on our target list. Additional candidates were drawn from literature studies that provide membership information (Platais et al. 2011, Tofflemire et al. 2014, Bragaglia et al. 2014), excluding all known non-members. The remaining targets were drawn from 2MASS point sources which fall on the cluster upper RGB or RC in the color-magnitude diagram (again excluding known non-members from the above studies), and these are sorted in order of increasing radius from the cluster center out to the approximate tidal radius of $\sim 24'$ (Dalessandro et al. 2015).
A search for evidence of multiple stellar populations in the unusual open cluster NGC6791, by targeting several dozen member stars.
All of our targets lie in the existing APOGEE field K21_071+10 and have $H \le 12$. The target lists come from several sources. First, all of the stars observed optically by Geisler et al. (2012) that meet our $S/N$ requirements were included, excluding those that already have APOGEE-1 spectra from DR12 or earlier, as none of these show evidence for the Na-O anticorrelation. The three Na-poor stars from Geisler et al. (2012) have been given top priority on our target list. Additional candidates were drawn from literature studies that provide membership information (Platais et al. 2011, Tofflemire et al. 2014, Bragaglia et al. 2014), excluding all known non-members. The remaining targets were drawn from 2MASS point sources which fall on the cluster upper RGB or RC in the color-magnitude diagram (again excluding known non-members from the above studies), and these are sorted in order of increasing radius from the cluster center out to the approximate tidal radius of $\sim 24'$ (Dalessandro et al. 2015).
External Cannon Calibrators APOGEE2_TARGET3 bit 16
PI: M. K. Ness (Columbia University)
A sample of stars that fill in parameter space for a Cannon training set and increase the calibration overlap with other surveys.
A sample of stars that fill in parameter space for a Cannon training set and increase the calibration overlap with other surveys.
Faint Asteroseismic Giants APOGEE2_TARGET3 bit 17
PI: M. Pinsonneault (The Ohio State University)
A sample of faint Kepler targets with asteroseismic measurements to probe stars at farther distances in the halo.
A sample of faint Kepler targets with asteroseismic measurements to probe stars at farther distances in the halo.
Star-Forming Complex in W3/4/5 APOGEE2_TARGET3 bit 18
PI: A. Roman-Lopes (Universidad de La Serena)
A study of embedded or massive stars in the W3, W4, and W5 star-forming regions.
The massive star sample was selected from a combination of near- to mid-infrared color-magnitude (CMD) and color-color (CCM) selection criteria, which are described in detail by Roman-Lopes (2016). The derived catalog was then cross-matched with known OB stars, using the SIMBAD database together with the catalogs of spectral classification of stars in the direction of W3-4-5.
The YSO sources were selected based on two different approaches. The first used Spitzer colors combined with X-ray detections, where available, to identify probable young star members. Traditionally, there are three categories of YSOs: Class I sources (deeply embedded protostars with large IR excesses), Class II sources (those with IR excesses typified by the presence of disks), and Class III sources (those lacking IR excesses, having had their disks dispersed). Targets were selected based on these criteria from the catalogues produced by Koenig et al. (2008), Koenig & Allen (2011), and Chauhan et al. (2011) for W5, and Rivera-Ingraham et al. (2011), Bik et al. (2012), and Roman-Zuniga et al. (2015) for W3-4.
A study of embedded or massive stars in the W3, W4, and W5 star-forming regions.
The massive star sample was selected from a combination of near- to mid-infrared color-magnitude (CMD) and color-color (CCM) selection criteria, which are described in detail by Roman-Lopes (2016). The derived catalog was then cross-matched with known OB stars, using the SIMBAD database together with the catalogs of spectral classification of stars in the direction of W3-4-5.
The YSO sources were selected based on two different approaches. The first used Spitzer colors combined with X-ray detections, where available, to identify probable young star members. Traditionally, there are three categories of YSOs: Class I sources (deeply embedded protostars with large IR excesses), Class II sources (those with IR excesses typified by the presence of disks), and Class III sources (those lacking IR excesses, having had their disks dispersed). Targets were selected based on these criteria from the catalogues produced by Koenig et al. (2008), Koenig & Allen (2011), and Chauhan et al. (2011) for W5, and Rivera-Ingraham et al. (2011), Bik et al. (2012), and Roman-Zuniga et al. (2015) for W3-4.
Evolved Stars APOGEE2_TARGET3 bit 19
PI: G. Stringfellow (University of Colorado, Boulder)
A study of the hottest, most massive, luminous evolved stars, to understand the variability of their emission line spectra.
The focus of this project is massive, high-luminosity stars with early spectral types. These spectral types include supergiant and emission line stars, along with other rare objects. We used Simbad and the online Wolf Rayet star catalog to select targets in APOGEE fields. A final subset of 15 stars in the range $6.5 \le H \le 12$ mag were selected, with an emphasis on observing all visits to study the spectral variability of the stars.
A study of the hottest, most massive, luminous evolved stars, to understand the variability of their emission line spectra.
The focus of this project is massive, high-luminosity stars with early spectral types. These spectral types include supergiant and emission line stars, along with other rare objects. We used Simbad and the online Wolf Rayet star catalog to select targets in APOGEE fields. A final subset of 15 stars in the range $6.5 \le H \le 12$ mag were selected, with an emphasis on observing all visits to study the spectral variability of the stars.
Reddening Evaluation APOGEE2_TARGET3 bit 20
PI: E. Schlafly (Lawrence Berkeley National Laboratory)
The APOGEE survey has delivered high-quality H-band spectroscopy of hundreds of thousands of stars covering a large fraction of the Galactic disk. Together with deep optical photometry from PS1, these data are ideal probes of the dust extinction law and its variation with the Galactic environment up to $A_{V} \gt 10$ mag. However, the APOGEE survey contains very few appropriate targets near (1) high-RV stars used to derive traditional extinction laws or (2) molecular clouds in the solar neighborhood. Consequently, the tremendous diagnostic power of the APOGEE reddening measurements cannot be connected to the few regions where the extinction law is known best, and, in consequence, the extinction law can best be interpreted in terms of dust properties. To overcome this shortcoming, we propose observing new stars near known high-RV stars and behind molecular clouds in the solar neighborhood. These data are crucial for the full exploitation of the APOGEE survey to study dust extinction and its variation in the Galaxy.
The APOGEE survey has delivered high-quality H-band spectroscopy of hundreds of thousands of stars covering a large fraction of the Galactic disk. Together with deep optical photometry from PS1, these data are ideal probes of the dust extinction law and its variation with the Galactic environment up to $A_{V} \gt 10$ mag. However, the APOGEE survey contains very few appropriate targets near (1) high-RV stars used to derive traditional extinction laws or (2) molecular clouds in the solar neighborhood. Consequently, the tremendous diagnostic power of the APOGEE reddening measurements cannot be connected to the few regions where the extinction law is known best, and, in consequence, the extinction law can best be interpreted in terms of dust properties. To overcome this shortcoming, we propose observing new stars near known high-RV stars and behind molecular clouds in the solar neighborhood. These data are crucial for the full exploitation of the APOGEE survey to study dust extinction and its variation in the Galaxy.
M dwarfs in Kepler APOGEE2_TARGET3 bit 21
PI: V. Smith (NOIR Lab)
A sample of M dwarfs, the most common stars in the Galaxy, to study their rich NIR spectra and extract stellar abundances.
The Kepler Exoplanet Archive was searched for all Kepler and Kepler Objects of Interest (KOI) systems having input catalog effective temperatures of $T_{eff} \le 4300$K. The primary emphasis for this project is to push abundance analyses to the M-dwarfs, but some overlap is allowed with late K-dwarfs. A $T_{eff}$ cut at 4300 K will include types K6 and K7, and these targets will provide overlap with abundance analyses from high-resolution optical spectra. SNRs were calculated for the number of planned visits given for each of the APOGEE-2 fields, and only those targets expected to yield an SNR $\ge 70$ were then included in the target list.
A sample of M dwarfs, the most common stars in the Galaxy, to study their rich NIR spectra and extract stellar abundances.
The Kepler Exoplanet Archive was searched for all Kepler and Kepler Objects of Interest (KOI) systems having input catalog effective temperatures of $T_{eff} \le 4300$K. The primary emphasis for this project is to push abundance analyses to the M-dwarfs, but some overlap is allowed with late K-dwarfs. A $T_{eff}$ cut at 4300 K will include types K6 and K7, and these targets will provide overlap with abundance analyses from high-resolution optical spectra. SNRs were calculated for the number of planned visits given for each of the APOGEE-2 fields, and only those targets expected to yield an SNR $\ge 70$ were then included in the target list.
AGB Stars APOGEE2_TARGET3 bit 22
PI: O. Zamora (IAC)
A study of the chemical abundances of a sample of galactic carbon-rich asymptotic giant branch (AGB) stars, post-AGB stars, and planetary nebulae (PNe).
The targets were selected using four different sources; these are (1) the General Catalogue of Galactic Carbon stars (Alknis et al. 2001), (2) the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker et al. 1992), (3) the Torun catalogue of Galactic post-AGB and related objects (Szczerba et al. 2007), and (4) the PhD thesis of Pedro Garcia-Lario (1992, unpublished). A cross-match with the APOGEE-2N fields was performed, finally selecting the targets with 2MASS H-band magnitude $7.0 \le H \le 13.5$ mag.
A study of the chemical abundances of a sample of galactic carbon-rich asymptotic giant branch (AGB) stars, post-AGB stars, and planetary nebulae (PNe).
The targets were selected using four different sources; these are (1) the General Catalogue of Galactic Carbon stars (Alknis et al. 2001), (2) the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker et al. 1992), (3) the Torun catalogue of Galactic post-AGB and related objects (Szczerba et al. 2007), and (4) the PhD thesis of Pedro Garcia-Lario (1992, unpublished). A cross-match with the APOGEE-2N fields was performed, finally selecting the targets with 2MASS H-band magnitude $7.0 \le H \le 13.5$ mag.
M33 Star Clusters APOGEE2_TARGET3 bit 23
PI: B. Anguiano (University of Virginia)
M33 has young and old Globular Clusters (GCs), spanning from 1 to 12 Gyr (Chandar et al. 2006; Beasley et al. 2015). We might expect both old and young GCs to show the CNO and Na/O anomalies; extragalactic GCs have been inferred to host Na/O anticorrelations because many have high integrated [Na/Fe] (Colucci et al. 2014, Sakari et al. 2015). The correlations are expected if this is related to the formation process of these clusters in contrast with the formation mechanisms observed in open clusters, which lack these anomalies. Surprisingly, abundance variations have not been observed in young-intermediate LMC GCs (Sakari et al. 2017). Thus we propose a detailed APOGEE IR integrated-light spectra analysis on young and old GCs in M33 to test this hypothesis.
M33 has young and old Globular Clusters (GCs), spanning from 1 to 12 Gyr (Chandar et al. 2006; Beasley et al. 2015). We might expect both old and young GCs to show the CNO and Na/O anomalies; extragalactic GCs have been inferred to host Na/O anticorrelations because many have high integrated [Na/Fe] (Colucci et al. 2014, Sakari et al. 2015). The correlations are expected if this is related to the formation process of these clusters in contrast with the formation mechanisms observed in open clusters, which lack these anomalies. Surprisingly, abundance variations have not been observed in young-intermediate LMC GCs (Sakari et al. 2017). Thus we propose a detailed APOGEE IR integrated-light spectra analysis on young and old GCs in M33 to test this hypothesis.
Milky Way Cepheid Calibrators
PI: R. Beaton (Princeton/OCIS)
The goal of this program is to provide a chemical characterization of Galactic Cepheids. The Cepheids were selected to have photometric characterizations across multiple wavelengths and also to have high-precision trigonometric-parallaxes from Gaia. This program uses the NMSU 1-meter fiber feed to obtain multiple epochs for each target. Chemical abundances will be used to calibrate the metallicity effects in the period-luminosity relationship for ten photometric bands and will provide high signal-to-noise templates over multiple phase points for other Cepheid-based programs in APOGEE-2.
The goal of this program is to provide a chemical characterization of Galactic Cepheids. The Cepheids were selected to have photometric characterizations across multiple wavelengths and also to have high-precision trigonometric-parallaxes from Gaia. This program uses the NMSU 1-meter fiber feed to obtain multiple epochs for each target. Chemical abundances will be used to calibrate the metallicity effects in the period-luminosity relationship for ten photometric bands and will provide high signal-to-noise templates over multiple phase points for other Cepheid-based programs in APOGEE-2.
This program used 1-meter targets only. All 1-meter targets are identified by TELESCOPE tag of 'apo1m'. Targets from this program will have a FIELD tag with "cepheid".
Lowest Mass Stars & Brown Dwarfs APOGEE2_TARGET3 bit 24
PI: A. Burgasser (University of California San Diego)
This program aims to build an APOGEE-based spectral library for late-M and L dwarf stars. There are two scientific goals. First, we will measure the spatial and rotational kinematics for the nearby populations. Second, we will extend spectral modeling for abundance analysis to temperatures below 2700 K. We select sources with spectral types later than M7 and 11 $\leq$ H mag (2MASS) < 14.5 mag. The desired scientific outcome is improved spectral models across the hydrogen-burning limit, with an eye toward improving the characterization of potential low-mass terrestrial exoplanet host systems.
This program aims to build an APOGEE-based spectral library for late-M and L dwarf stars. There are two scientific goals. First, we will measure the spatial and rotational kinematics for the nearby populations. Second, we will extend spectral modeling for abundance analysis to temperatures below 2700 K. We select sources with spectral types later than M7 and 11 $\leq$ H mag (2MASS) < 14.5 mag. The desired scientific outcome is improved spectral models across the hydrogen-burning limit, with an eye toward improving the characterization of potential low-mass terrestrial exoplanet host systems.
Distant Halo Giants APOGEE2_TARGET3 bit 25
PI: P. Harding (Case Western Reserve University)
Note that the strategy and targets for this program were absorbed into and expanded upon for the Bright Time Extension sub-program with the same aims.
Note that the strategy and targets for this program were absorbed into and expanded upon for the Bright Time Extension sub-program with the same aims.
Mapping the Inner Galaxy APOGEE2_TARGET3 bit 26
PI: L. Inno (Max-Planck-Institut für Astronomie)
The primary science goal of this program is to obtain a comprehensive map of Cepheids throughout the Galaxy, both to understand better the Galactic Cepheid population, and to make a map of the “young” stellar disk.
This program targets about 190 photometrically-selected candidate classical Cepheids, and it will allow us to a) spectroscopically validate our classification; b) trace the dynamics and the detailed chemical composition of the young Galactic disk with obscured/distant Cepheids.
The primary science goal of this program is to obtain a comprehensive map of Cepheids throughout the Galaxy, both to understand better the Galactic Cepheid population, and to make a map of the “young” stellar disk.
This program targets about 190 photometrically-selected candidate classical Cepheids, and it will allow us to a) spectroscopically validate our classification; b) trace the dynamics and the detailed chemical composition of the young Galactic disk with obscured/distant Cepheids.
Selected Area 57 APOGEE2_TARGET3 bit 27
PI: S. Majewski (University of Virginia)
Selected Area 57 (SA57) is the nearest of Kapteyn’s Selected Areas to the North Galactic Pole. SA57, therefore, is in a direction relatively free of reddening and where “in situ" halo stars can most easily be accessed. Because of its minimal stellar foreground, SA57 has traditionally played a significant role in a variety of astronomical studies, from probing the vertical density laws of the Galactic stellar populations to deep studies of galaxies and quasars. SA57 has received extensive observations, including extensive photometry, astrometry, and spectroscopy. To date, no high-resolution spectroscopy exists. The APOGEE observations here are intended to tie state-of-the-art chemistry of giant stars in this direction — selected with the same selection criteria as the main APOGEE survey — to the rich legacy of previous observations in this field. Four overlapping plate centers (N, S, E, W) were targeted, yielding three cohorts in a “wedding-cake” arrangement. First, 3-visit “short cohort” stars to H = 12.2 mag. Then, 6-visit “medium cohort” stars spanning H = 12.2 to 12.8 mag in areas where two plates overlap. Lastly, 12-visit “long cohort” stars that span H = 12.8 to 13.8 mag for the central area where all four plates overlap.
Selected Area 57 (SA57) is the nearest of Kapteyn’s Selected Areas to the North Galactic Pole. SA57, therefore, is in a direction relatively free of reddening and where “in situ" halo stars can most easily be accessed. Because of its minimal stellar foreground, SA57 has traditionally played a significant role in a variety of astronomical studies, from probing the vertical density laws of the Galactic stellar populations to deep studies of galaxies and quasars. SA57 has received extensive observations, including extensive photometry, astrometry, and spectroscopy. To date, no high-resolution spectroscopy exists. The APOGEE observations here are intended to tie state-of-the-art chemistry of giant stars in this direction — selected with the same selection criteria as the main APOGEE survey — to the rich legacy of previous observations in this field. Four overlapping plate centers (N, S, E, W) were targeted, yielding three cohorts in a “wedding-cake” arrangement. First, 3-visit “short cohort” stars to H = 12.2 mag. Then, 6-visit “medium cohort” stars spanning H = 12.2 to 12.8 mag in areas where two plates overlap. Lastly, 12-visit “long cohort” stars that span H = 12.8 to 13.8 mag for the central area where all four plates overlap.
M dwarf APOGEE2_TARGET3 bit 28
PI: V. Smith (NOIR Lab)
The targets for this program were absorbed into the K2 Science Program in the Bright Time Extension.
The targets for this program were absorbed into the K2 Science Program in the Bright Time Extension.
SubStellar Companions APOGEE2_TARGET3 bit 29
PI: N. Troup (Salisbury University)
This ancillary program expands upon the APOGEE Substellar Companion goal science program. The Substellar companion program is acquiring RV observations over a long temporal baseline for field stars. This ancillary program includes stars in a variety of star clusters, whose properties span a wide range of ages, metallicities, and stellar densities. With this data, we hope to determine the role of the stellar environment plays in the formation and evolution of stellar systems. Critically, this program extended the temporal baseline for targets observed in APOGEE-1 and increased the number of RV measurements to enable robust orbital fits.
This ancillary program expands upon the APOGEE Substellar Companion goal science program. The Substellar companion program is acquiring RV observations over a long temporal baseline for field stars. This ancillary program includes stars in a variety of star clusters, whose properties span a wide range of ages, metallicities, and stellar densities. With this data, we hope to determine the role of the stellar environment plays in the formation and evolution of stellar systems. Critically, this program extended the temporal baseline for targets observed in APOGEE-1 and increased the number of RV measurements to enable robust orbital fits.
M31 Integrated Starlight APOGEE2_TARGET3 bit 30
PI: G. Zasowski (University of Utah)
We aim to understand the universality of the MW's history that has resulted in the [alpha/Fe]-[Fe/H] patterns seen in its disk today. We are observing integrated light spectra of numerous positions in M31's disk, and will employ new methods to extract information about the chemical and dynamical complexity in our nearest large galactic neighbor.
We aim to understand the universality of the MW's history that has resulted in the [alpha/Fe]-[Fe/H] patterns seen in its disk today. We are observing integrated light spectra of numerous positions in M31's disk, and will employ new methods to extract information about the chemical and dynamical complexity in our nearest large galactic neighbor.
APOGEE-1 Ancillary Programs
Full descriptions of the Ancillary Programs from the APOGEE-1 Survey can be found here. For consistency, we provide the program name, targeting bit identifications, and contact scientists here.
Globular Clusters in M31 APOGEE_TARGET1 bit 18
PI: R. Schiavon (Liverpool John Moores University)
Link to Program Description
Link to Program Description
Ages of Red Giants in the Kepler and CoRoT Fields (APOGEE_TARGET1 bit 22 or 27)
PI: M. Pinsonneault (The Ohio State University)
Link to Program Description
Link to Program Description
Eclipsing Binaries APOGEE_TARGET1 bit 23
PI: S. Mahadevan (Penn State University) and S. Felming (STScI)
Link to Program Description
Link to Program Description
The Cluster Palomar 1 APOGEE_TARGET1 bit 24
PI: I. Ivans
Link to Program Description
Link to Program Description
Optical Calibrator Stars APOGEE_TARGET1 bit 20
PI: A. Herrero Davó (Instituto de Astrofısica de Canarias)
Link to Program Description
Link to Program Description
Massive Stars (APOGEE_TARGET1 bit 25)
PI: D. Fabbian (Instituto de Astrofısica de Canarias)
Link to Program Description
Link to Program Description
Embedded Young Stellar Clusters APOGEE_TARGET1 bit 13
PI: K. Covey (Western Washington University) and J. Tan (Chalmers University of Technology)
Link to Program Description
Link to Program Description
Galactic Long Bar APOGEE_TARGET1 bit 14
PI: G. Zasowski (University of Utah)
Link to Program Description
Link to Program Description
Emission Line Stars APOGEE_TARGET1 bit 15
PI: D. Chojnowski (New Mexico State University)
Link to Program Description
Link to Program Description
Kepler Cool Dwarfs APOGEE_TARGET1 bit 16
PI: J. van Saders (University of Hawaii)
Link to Program Description
Link to Program Description
MIR-Discovered Open Clusters APOGEE_TARGET1 bit 17
PI: R. Beaton (Princeton/OCIS) and G. Zasowski (University of Utah)
Link to Program Description
Link to Program Description
RV Variability in the IC 348 field APOGEE_TARGET1 bit 18
PI: D. Nidever (Montana State University) and K. Covey (Western Washington University)
Link to Program Description
Link to Program Description
RV Variability in Kepler APOGEE_TARGET1 bit 19
PI: S. Mahadevan (Penn State University)
Link to Program Description
Link to Program Description
Other Special Programs
While many SDSS surveys have Ancillary programs, the APOGEE survey contains several other modes by which the survey implements special programs. These programs are listed below.
Bright Time Extension Programs
APOGEE implemented some special programs in the last two years of Bright Time in SDSS-IV. The programs were allocated competitively among all SDSS-IV surveys as well as for SDSS-V preparatory projects. All fields observed for the Bright Time Extension have "_btx" appended to their FIELD tag. The majority of the programs using the APOGEE instrument were expansions of existing programs to meet their science goals at a higher level. Programs distinct from existing programs in APOGEE are listed below.
California Cloud APOGEE2_TARGET2 bit 1
The California GMC is a nearby (400 pc), quiescent, massive ($10^5 M_{Sun}$), isolated GMC with a large reservoir of surrounding dust and gas. Gaia DR2 will provide distances accurate to 10 pc to ~1200 stars within about 50 pc of California. By obtaining APOGEE spectra of these stars, we can measure the velocity of the $1.53 \mu m$ DIB to directly observe the flow of material along the line of sight in 3D onto or away from the molecular cloud. These stars are split among F stars and red giants and have $H$ < 11.5 mag, making 1-visit adequate to provide S/N ~ 100 spectra suitable for measuring the DIB in $A_V$ ~ 1 material. Seven plates centered on the California GMC ($\ell,b$ = 162.5$^{\circ}$, 8.5$^{\circ}$) are needed to observe these 1200 stars, providing a final density of > 1 star / (10 pc)$^3$.
APOGEE-2S Contributed Programs
Targets observed as part of APOGEE-2's Contributed Science programs are indicated by APOGEE2_TARGET3 as APOGEE2_CIS (bit 24) for programs awarded by the Observatories Carnegie Institution for Science (OCIS) Telescope Allocation Committee (TAC) and by APOGEE2_TARGET3 as APOGEE2_CNTAC (bit 25) for the programs allocated by the Chilean National Telescope Allocation Committee (CNTAC). Fields for OCIS programs have "-O" appended to the FIELD and for CNTAC programs "-C" is appended to FIELD.
Brief descriptions, contact scientists, and the awarding TAC are indicated for each of the programs. Note that not all programs may have targets in this data release, but all programs currently implemented are included here for completeness. Questions about the targeting for these programs should be directed to the contact scientist(s) for that program. The titles of each section below refer to the PROGRAMNAME, which is the most direct means of identifying individual programs, and PROGRAMNAME is typically the last name of the lead contact scientist and the first semester of observations.
The contributed programs are scheduled classically, with specific nights assigned to each PI. Because of this, many programs obtained observations over multiple semesters (e.g., 18A and 19B), but the same PROGRAMNAME is maintained. Thus, if a single contact scientist has led multiple programs, then the programs are scientifically distinct.
Borissova_17a (CNTAC)
CPI: J. Borissova (Universidad de Valparaíso)
The relatively nearby star-forming complex G305 is one of the most luminous H II regions in the Galaxy, and it contains several sites and epochs of star formation. This project combination of near-infrared photometry from “Vista Variables in Via Lactea” ESO Large Public Survey, SDSS-IV APOGEE-2 spectra, and Gaia DR2 photometry and astrometry to classify stars in this complex.
Please see Borissova et al. (2019).
Teske_17a (OCIS)
PI: J. van Saders (University of Hawaii) and J. Teske (OCIS)
We propose to collect APOGEE spectra of bright, cool dwarf stars monitored with the K2 ecliptic survey, including stars found via the K2 light curves to host planet candidates and M dwarf stars. These APOGEE data will be used to measure stellar parameters and chemical abundances for low-mass stars in the K2 fields. The scientific goals are: (1) to determine rotation-based ages, (2) to constrain the age-metallicity relation, and (3) look for a correlation between exoplanet architecture and host-star composition. In particular, M dwarf spectra are of high value in the development of an analysis method for extracting reliable, detailed abundances of $T_{eff} \lt$ 4000 K stars.
We propose to collect APOGEE spectra of bright, cool dwarf stars monitored with the K2 ecliptic survey, including stars found via the K2 light curves to host planet candidates and M dwarf stars. These APOGEE data will be used to measure stellar parameters and chemical abundances for low-mass stars in the K2 fields. The scientific goals are: (1) to determine rotation-based ages, (2) to constrain the age-metallicity relation, and (3) look for a correlation between exoplanet architecture and host-star composition. In particular, M dwarf spectra are of high value in the development of an analysis method for extracting reliable, detailed abundances of $T_{eff} \lt$ 4000 K stars.
Weinberger_17a (OCIS)
PI: A. Weinberger (Carnegie Institution for Science - Department of Terrestrial Magnetism)
We will survey the young, about 10 Myr old, Upper Scorpius cluster to measure the properties of a large, homogenous population of young stars. We primarily target stars included in the K2 survey of the cluster. We will measure effective temperatures, surface gravities, and radial velocities.
We will survey the young, about 10 Myr old, Upper Scorpius cluster to measure the properties of a large, homogenous population of young stars. We primarily target stars included in the K2 survey of the cluster. We will measure effective temperatures, surface gravities, and radial velocities.
Zoccali_17a (CNTAC)
PI: M. Zoccali (PUC-MAS)
This project aims to extend the GIRAFFE Inner Bulge Survey (GIBS, Zoccali et al. 2014, 2016, Gonzalez et al. 2015) to the inner $\pm 1^{\circ}$ about the Galactic plane with the final objective of constraining the bulge formation scenario. The observation of red giant branch (RGB) stars within a small range of reddening $E(J-K_s)$ in five Galactic bulge fields will allow us to derive the metallicity distribution function (MDF) to firmly establish whether the metal-poor bulge component is indeed dominant in the central region.
This project aims to extend the GIRAFFE Inner Bulge Survey (GIBS, Zoccali et al. 2014, 2016, Gonzalez et al. 2015) to the inner $\pm 1^{\circ}$ about the Galactic plane with the final objective of constraining the bulge formation scenario. The observation of red giant branch (RGB) stars within a small range of reddening $E(J-K_s)$ in five Galactic bulge fields will allow us to derive the metallicity distribution function (MDF) to firmly establish whether the metal-poor bulge component is indeed dominant in the central region.
Schlaufman_17a (OCIS)
PI: K. Schlaufmam (Johns Hopkins University)
The oldest stars in the Milky Way are thought to be very metal-poor stars (i.e., [Fe/H] $\lt -2.0$) in the inner Galaxy. However, extreme reddening, extinction, and crowding in the inner bulge have made finding metal-poor stars there impossible with traditional techniques. In Schlaufman & Casey (2014), we published an efficient metal-poor star selection that uses only infrared photometry, thereby overcoming all barriers to the identification of metal-poor stars in the inner Galaxy. We have applied this selection to dereddened 2MASS and Spitzer/IRAC photometry in the inner bulge to identify a sample of 9,208 candidates metal-poor K giants with H <= 12.5 mag. We expect APOGEE-2S observations of that sample to discover and characterize more than 1,000 K giants with [Fe/H] < -2.0 dex.
The oldest stars in the Milky Way are thought to be very metal-poor stars (i.e., [Fe/H] $\lt -2.0$) in the inner Galaxy. However, extreme reddening, extinction, and crowding in the inner bulge have made finding metal-poor stars there impossible with traditional techniques. In Schlaufman & Casey (2014), we published an efficient metal-poor star selection that uses only infrared photometry, thereby overcoming all barriers to the identification of metal-poor stars in the inner Galaxy. We have applied this selection to dereddened 2MASS and Spitzer/IRAC photometry in the inner bulge to identify a sample of 9,208 candidates metal-poor K giants with H <= 12.5 mag. We expect APOGEE-2S observations of that sample to discover and characterize more than 1,000 K giants with [Fe/H] < -2.0 dex.
Kollmeier_17a (OCIS)
PI: J. Kollmeier (OCIS)
This external program collects single-phase spectra for RR Lyrae variables in the Galactic Bulge.
This external program collects single-phase spectra for RR Lyrae variables in the Galactic Bulge.
TeskeVanSaders_17b (OCIS)
PI: J. Teske (OCIS) and J. Van Saders (University of Hawaii)
We propose to collect APOGEE spectra of bright, cool dwarf stars monitored with the K2 ecliptic survey, including stars found via the K2 light curves to host planet candidates and M dwarf stars. These APOGEE data will be used to measure stellar parameters and chemical abundances for low-mass stars in the K2 campaign fields. The science goals are (1) estimating rotation-based ages, (2) deriving the age-metallicity relation, and (3) looking for correlations between exoplanet architectures and host-star compositions. In particular, M dwarf spectra are of high value in the development of an analysis method for extracting reliable, detailed abundances of $T_{eff} \lt 4000$ K stars.
We propose to collect APOGEE spectra of bright, cool dwarf stars monitored with the K2 ecliptic survey, including stars found via the K2 light curves to host planet candidates and M dwarf stars. These APOGEE data will be used to measure stellar parameters and chemical abundances for low-mass stars in the K2 campaign fields. The science goals are (1) estimating rotation-based ages, (2) deriving the age-metallicity relation, and (3) looking for correlations between exoplanet architectures and host-star compositions. In particular, M dwarf spectra are of high value in the development of an analysis method for extracting reliable, detailed abundances of $T_{eff} \lt 4000$ K stars.
Beaton_18a (OCIS)
PI: R. Beaton (Princeton/OCIS)
This CIS External Program has collected single-phase APOGEE spectroscopy for the brightest and well-studied Cepheids in the LMC and SMC, which can be combined with literature multi-band optical to mid-infrared photometry, to study the dispersion of these stars against the mean Leavitt Law. Additional fainter Cepheids were also targeted.
This CIS External Program has collected single-phase APOGEE spectroscopy for the brightest and well-studied Cepheids in the LMC and SMC, which can be combined with literature multi-band optical to mid-infrared photometry, to study the dispersion of these stars against the mean Leavitt Law. Additional fainter Cepheids were also targeted.
TeskeVanSaders_18a (OCIS)
PI: J. Teske (OCIS), J. van Saders (University of Hawaii), and R. Beaton (Princeton/OCIS)
We propose to collect APOGEE-2S spectra of bright (7 $\lt$ H $\lt$ 11 mag) stars that fall within the 450 deg$^{2}$ of the Southern Ecliptic Pole. NASA's Transiting Exoplanet Survey Satellite (TESS) will have continuous coverage in this region of the sky. These APOGEE data will be used to measure stellar parameters and chemical abundances. When combined with the precise TESS photometric light curves, these data enable investigations of open questions about exoplanets, stellar astrophysics, and distance ladder calibration.
We propose to collect APOGEE-2S spectra of bright (7 $\lt$ H $\lt$ 11 mag) stars that fall within the 450 deg$^{2}$ of the Southern Ecliptic Pole. NASA's Transiting Exoplanet Survey Satellite (TESS) will have continuous coverage in this region of the sky. These APOGEE data will be used to measure stellar parameters and chemical abundances. When combined with the precise TESS photometric light curves, these data enable investigations of open questions about exoplanets, stellar astrophysics, and distance ladder calibration.
RomanLopes_18a (CNTAC)
PI: A. Roman-Lopes (Universidad de La Serena)
As part of SDSS-IV, the APOGEE-2 survey is leading a revolution in our understanding of the Milky Way. The Carina star-forming complexes (CSFCs) contain some of the most massive star-forming regions in the Galaxy. It is an ideal laboratory to test theories of the spatially segregated formation of stars and triggering mechanisms. This program takes advantage of the huge FOV and multiplexing of the APOGEE2-S spectrograph to confirm the massive nature of selected samples of hot star candidates in the Galactic plane, both in the vicinity and in the periphery of the regions forming massive stars that are found in the CSFCs. The project also uses the excellent spectral resolution provided by the APOGEE2-S instrument, using the high signal-to-noise radial velocity measurements to obtain spectroscopic information of about 1750 candidate massive stars, a task virtually impossible to be done by using single-object NIR spectrograph facilities.
As part of SDSS-IV, the APOGEE-2 survey is leading a revolution in our understanding of the Milky Way. The Carina star-forming complexes (CSFCs) contain some of the most massive star-forming regions in the Galaxy. It is an ideal laboratory to test theories of the spatially segregated formation of stars and triggering mechanisms. This program takes advantage of the huge FOV and multiplexing of the APOGEE2-S spectrograph to confirm the massive nature of selected samples of hot star candidates in the Galactic plane, both in the vicinity and in the periphery of the regions forming massive stars that are found in the CSFCs. The project also uses the excellent spectral resolution provided by the APOGEE2-S instrument, using the high signal-to-noise radial velocity measurements to obtain spectroscopic information of about 1750 candidate massive stars, a task virtually impossible to be done by using single-object NIR spectrograph facilities.
Stutz_18a (CNTAC)
PI: A. Stutz (Universidad de Concepcion)
We propose to measure the radial velocities of the young stellar cluster population in Corona Australis with APOGEE-2S in order to study the radial velocity distribution of young stars at different evolutionary stages. Targets for this program were selected from the Spitzer-based catalog of Corona Australis members assembled by Peterson et al. (2011). We prioritize all young stellar objects (Classes 0, I, II, and III) with $H \lt 14$
mag, comprising a high-priority sample of 50 objects that are distributed across two plates to cover the full stellar population.
We propose to measure the radial velocities of the young stellar cluster population in Corona Australis with APOGEE-2S in order to study the radial velocity distribution of young stars at different evolutionary stages. Targets for this program were selected from the Spitzer-based catalog of Corona Australis members assembled by Peterson et al. (2011). We prioritize all young stellar objects (Classes 0, I, II, and III) with $H \lt 14$
mag, comprising a high-priority sample of 50 objects that are distributed across two plates to cover the full stellar population.
Geisler_18a (CNTAC)
PI: D. Geisler (Universidad de Concepcion)
The Galactic Bulge hosts a large number of globular clusters (GCs). These objects are powerful cosmological probes to investigate the formation and chemical evolution of this key Galactic component. Unfortunately, until recently, we have not been able to unleash the full power of the bulge GCs to help unravel its mysteries due to their high extinction, which strongly limits optical observations. However, we minimize extinction effects are minimized by observing in the near IR, allowing us to exploit the bulge GC's extraordinary archaeological attributes fully. CAPOS (bulge Cluster APOgee Survey) will observe a number of the GCs that are left off the Survey. The goal of CAPOS is to observe ALL of the missing GCs, amounting to fully 80% of the total sample, to obtain a complete sample, which will become part of SDSS-IV. These observations will allow us to perform a definitive study of the Bulge GC system, as well as investigate many salient details concerning chemistry, multiple populations, orbits, etc.
The Galactic Bulge hosts a large number of globular clusters (GCs). These objects are powerful cosmological probes to investigate the formation and chemical evolution of this key Galactic component. Unfortunately, until recently, we have not been able to unleash the full power of the bulge GCs to help unravel its mysteries due to their high extinction, which strongly limits optical observations. However, we minimize extinction effects are minimized by observing in the near IR, allowing us to exploit the bulge GC's extraordinary archaeological attributes fully. CAPOS (bulge Cluster APOgee Survey) will observe a number of the GCs that are left off the Survey. The goal of CAPOS is to observe ALL of the missing GCs, amounting to fully 80% of the total sample, to obtain a complete sample, which will become part of SDSS-IV. These observations will allow us to perform a definitive study of the Bulge GC system, as well as investigate many salient details concerning chemistry, multiple populations, orbits, etc.
Drout_18b (OCIS)
PI: M. Drout (University of Toronto)
Our goal was to conduct a wide and shallow survey of the evolved massive star populations (e.g. yellow supergiants, red supergiants, and luminous blue variables) of the Large and Small Magellanic Clouds (LMC and SMC) with APOGEE-S. For targeting, we followed a procedure similar to that outlined in Neugent et al. (2010) and Neugent et al. (2012), who study the red and yellow supergiants (RSGs and YSGs) of the LMC and SMC. To separate likely LMC/SMC supergiants from foreground dwarfs in the FOV we use a combination of Gaia DR2 proper motions/parallax values and radial velocities/spectroscopic classifications, when available. We assign probabilities of membership based on Gaia DR2 kinematics by the procedure described in O’Grady et al. (2020), which is based on that outlined in Helmi et al. (2018). In total 16 LMC fields and 5 SMC fields were constructed and observed. Field centers were chosen to optimize the number of confirmed RSG, YSGs, and LBVs.
Our goal was to conduct a wide and shallow survey of the evolved massive star populations (e.g. yellow supergiants, red supergiants, and luminous blue variables) of the Large and Small Magellanic Clouds (LMC and SMC) with APOGEE-S. For targeting, we followed a procedure similar to that outlined in Neugent et al. (2010) and Neugent et al. (2012), who study the red and yellow supergiants (RSGs and YSGs) of the LMC and SMC. To separate likely LMC/SMC supergiants from foreground dwarfs in the FOV we use a combination of Gaia DR2 proper motions/parallax values and radial velocities/spectroscopic classifications, when available. We assign probabilities of membership based on Gaia DR2 kinematics by the procedure described in O’Grady et al. (2020), which is based on that outlined in Helmi et al. (2018). In total 16 LMC fields and 5 SMC fields were constructed and observed. Field centers were chosen to optimize the number of confirmed RSG, YSGs, and LBVs.
Stutz_18b (CNTAC)
PI: A. Stutz (Universidad de Concepcion)
This program will obtain radial velocity measurements of young stars of the protocluster in the Rosette molecular cloud. Targets were selected from the WISE-selected catalog of cluster members assembled by Cambresy et al (2013). Sources with $H \lt 12.2$ were assigned to a bright plate planned for a single 1-hour visit. Members with $13.3 \gt H \gt $12.2, or suffering from a fiber collision with a brighter neighbor in the bright plate, were assigned to a 'dim' plate planned for 3 hours of integration time.
This program will obtain radial velocity measurements of young stars of the protocluster in the Rosette molecular cloud. Targets were selected from the WISE-selected catalog of cluster members assembled by Cambresy et al (2013). Sources with $H \lt 12.2$ were assigned to a bright plate planned for a single 1-hour visit. Members with $13.3 \gt H \gt $12.2, or suffering from a fiber collision with a brighter neighbor in the bright plate, were assigned to a 'dim' plate planned for 3 hours of integration time.
Stutz_19a (CNTAC)
PI: A. Stutz (Universidad de Concepcion)
These data will measure the radial velocities (RV) of the young star protocluster population in the Carina cloud complex (d ~ 2.3 kpc, gas mass ~ 6.3 $\times$ 10$^{5}$ M$_{Sun}$). Carina's morphology and high-mass star content both stand in sharp contrast to the well studied Orion-A cluster. One of the major differences is that Carina samples the complete initial mass function. With ~90 massive stars, Carina is a cosmologically relevant protocluster cloud at solar metallicity. The RV data from the Gaia-ESO program are not of sufficient precision to allow for detailed scrutiny of the dynamics of the protocluster by self-consistent modeling of the stellar and gas kinematics. APOGEE-2S provides the required RV precision for this, and the Gaia-ESO data will be highly complementary. This survey of the recently formed stars (ages $\sim$ 2 Myr) will provide the required observational basis, in combination with Gaia, for theoretical dynamical modeling of this representative protocluster-forming region.
These data will measure the radial velocities (RV) of the young star protocluster population in the Carina cloud complex (d ~ 2.3 kpc, gas mass ~ 6.3 $\times$ 10$^{5}$ M$_{Sun}$). Carina's morphology and high-mass star content both stand in sharp contrast to the well studied Orion-A cluster. One of the major differences is that Carina samples the complete initial mass function. With ~90 massive stars, Carina is a cosmologically relevant protocluster cloud at solar metallicity. The RV data from the Gaia-ESO program are not of sufficient precision to allow for detailed scrutiny of the dynamics of the protocluster by self-consistent modeling of the stellar and gas kinematics. APOGEE-2S provides the required RV precision for this, and the Gaia-ESO data will be highly complementary. This survey of the recently formed stars (ages $\sim$ 2 Myr) will provide the required observational basis, in combination with Gaia, for theoretical dynamical modeling of this representative protocluster-forming region.
Kollmeier_19b (OCIS)
PI: J. Kollmeier (OCIS) and A. Tkachenko (KU Leuven)
Using high-resolution spectroscopy for intermediate- to high-mass stars (O and B spectral types), our program exploits the synergy between asteroseismology and stellar binarity. Our ultimate goal is to obtain precise observational constraints on angular momentum transport inside these stars by combining asteroseismic inferences of interior structure properties through the interpretation of their gravity-mode oscillations, and high-precision radial velocity measurements along with the determination of atmospheric properties of our stars. We have selected our sample based on the type of variability imprinted in high-precision TESS light-curves of the proposed targets, and the sample itself is a healthy mix between single and binary star systems. The APOGEE instrument plays critical role in this project by offering 1) preliminary orbital phase coverage for known binary stars which will ultimately enable disentangling of individual spectral contributions and determination of atmospheric properties of stars; 2) a check for binarity for stars that are currently believed to be single and determination of their atmospheric properties should they proved to be single.
Using high-resolution spectroscopy for intermediate- to high-mass stars (O and B spectral types), our program exploits the synergy between asteroseismology and stellar binarity. Our ultimate goal is to obtain precise observational constraints on angular momentum transport inside these stars by combining asteroseismic inferences of interior structure properties through the interpretation of their gravity-mode oscillations, and high-precision radial velocity measurements along with the determination of atmospheric properties of our stars. We have selected our sample based on the type of variability imprinted in high-precision TESS light-curves of the proposed targets, and the sample itself is a healthy mix between single and binary star systems. The APOGEE instrument plays critical role in this project by offering 1) preliminary orbital phase coverage for known binary stars which will ultimately enable disentangling of individual spectral contributions and determination of atmospheric properties of stars; 2) a check for binarity for stars that are currently believed to be single and determination of their atmospheric properties should they proved to be single.
Monachesi_19b (CNTAC)
PI: Antonela Monachesi (Universidad de La Serena)
The Large and Small Magellanic Clouds (LMC and SMC) are important systems to study. Thanks to their proximity, we can investigate in great detail their formation, interaction, and evolution and put constraints on dwarf galaxy formation models. During the last decade, an increasing number of photometric surveys covering the main bodies of the MCs as well as their surroundings have uncovered many substructures extending out to several degrees from their galactic centers (e.g., Mackey et al., 2016, 2018; Pieres et al., 2017; Nidever et al., 2019), especially around the LMC. More recently, Belokurov & Erkal (2019) using Gaia Data Release 2 (DR2) data have detected several substructures around the LMC out to a radius of 20 deg. All these discoveries provide new insights into the picture that we have of the MCs and are fundamental to understand their formation and evolution. The high-resolution spectra of these newly discovered features and the large field of view of APOGEE-2S are crucial to understanding the origin of the detected substructures; thus APOGEE is well-positioned to make crucial insights on this field.
The Large and Small Magellanic Clouds (LMC and SMC) are important systems to study. Thanks to their proximity, we can investigate in great detail their formation, interaction, and evolution and put constraints on dwarf galaxy formation models. During the last decade, an increasing number of photometric surveys covering the main bodies of the MCs as well as their surroundings have uncovered many substructures extending out to several degrees from their galactic centers (e.g., Mackey et al., 2016, 2018; Pieres et al., 2017; Nidever et al., 2019), especially around the LMC. More recently, Belokurov & Erkal (2019) using Gaia Data Release 2 (DR2) data have detected several substructures around the LMC out to a radius of 20 deg. All these discoveries provide new insights into the picture that we have of the MCs and are fundamental to understand their formation and evolution. The high-resolution spectra of these newly discovered features and the large field of view of APOGEE-2S are crucial to understanding the origin of the detected substructures; thus APOGEE is well-positioned to make crucial insights on this field.
Stutz_20a (CNTAC)
PI: A. Stutz (Universidad de Concepcion)
This program consists of two parts: an Orion program and a Vela C program. The later was developed to fill the telescope time after our original Orion program becomes unobservable.
The Orion Nebula Cluster (ONC) and the Integral Shaped Filament (ISF) within which it is forming, are a central laboratory for star and cluster formation physics. Recently we proposed the Slingshot model based on APOGEE data; here, the stars and cluster form on the oscillating ISF. Previous APOGEE data have been pivotal to the development of this model. However, a large fraction of the young stars (470 stars with $H \gt 14$ mag) still do not have radial velocities (RVs), and a substantial fraction of these do not have Gaia detections. The kinematics of these young stars remains unexplored, but one thing is clear: our current view of the ONC is biased. We propose to obtain APOGEE-2S RVs, the only means to obtain kinematic information for this young population.
This program consists of two parts: an Orion program and a Vela C program. The later was developed to fill the telescope time after our original Orion program becomes unobservable.
The Orion Nebula Cluster (ONC) and the Integral Shaped Filament (ISF) within which it is forming, are a central laboratory for star and cluster formation physics. Recently we proposed the Slingshot model based on APOGEE data; here, the stars and cluster form on the oscillating ISF. Previous APOGEE data have been pivotal to the development of this model. However, a large fraction of the young stars (470 stars with $H \gt 14$ mag) still do not have radial velocities (RVs), and a substantial fraction of these do not have Gaia detections. The kinematics of these young stars remains unexplored, but one thing is clear: our current view of the ONC is biased. We propose to obtain APOGEE-2S RVs, the only means to obtain kinematic information for this young population.
Medina_20a (CNTAC)
PI: N. Medina (Universidad de Valparaíso)
Using the automated tool from Medina et al. (2018), we searched the Carina region for variable young stellar objects in $K_{s}$ and created a catalog of candidate targets. APOGEE-2 spectroscopy complements photometric variability studies that identify candidate young stellar objects. The project will collect spectroscopy of ~1000 young stellar objects, covering the whole projected area of the Carina Nebula Complex. Spectroscopy will validate the photometric classification as young stellar objects, removing the AGB stars, novae, and long-period variables, which show similar light curve behavior, especially for high amplitude variables.
Using the automated tool from Medina et al. (2018), we searched the Carina region for variable young stellar objects in $K_{s}$ and created a catalog of candidate targets. APOGEE-2 spectroscopy complements photometric variability studies that identify candidate young stellar objects. The project will collect spectroscopy of ~1000 young stellar objects, covering the whole projected area of the Carina Nebula Complex. Spectroscopy will validate the photometric classification as young stellar objects, removing the AGB stars, novae, and long-period variables, which show similar light curve behavior, especially for high amplitude variables.
Fernandez_20a (CNTAC)
PI: José G. Fernández-Trincado (Universidad de Atacama).
NGC6362 is a nearby, low-mass, old stellar system with an intermediate metallicity; as such, it is a perfect tool to study the phenomenon of multiple stellar populations to a large projected radius. Measurements from APOGEE-2S will place constraints on the extra-tidal population and, thus, will provide insight into its formation, evolution, chemistry, and kinematics, all of which are poorly understood at present. This program aims to observe the bulk of the Gaia-DR2 extra-tidal candidates from Kundu et al. (2019).
NGC6362 is a nearby, low-mass, old stellar system with an intermediate metallicity; as such, it is a perfect tool to study the phenomenon of multiple stellar populations to a large projected radius. Measurements from APOGEE-2S will place constraints on the extra-tidal population and, thus, will provide insight into its formation, evolution, chemistry, and kinematics, all of which are poorly understood at present. This program aims to observe the bulk of the Gaia-DR2 extra-tidal candidates from Kundu et al. (2019).
NMSU-1m Programs
The science programs that use the NMSU 1-meter generally require observations of stars that are brighter than the bright limit for the primary survey on the 2.5-meter. Generally, these programs augment Core or Goal science with APOGEE observations of bright, nearby, and, often, well-studied stars or by obtaining multiple epoch observations for variable sources. These programs are executed in a single-object observing mode and require slightly different data processing, as is described by Holtzman et al. (2015). All targets observed with the NMSU 1-meter have 1-m target flag (APOGEE2_TARGET2 bit 22) set, as well as any other relevant targeting flags. The programs are organized by the program title instead of the field name.
Per the Targeting Caveat, in DR17 the best way to identify 1-meter targets is to select on 'apo1m' for the telescope tag and then use the field tag as specified below.
RRL
A small number of RR Lyrae (RRL) observations were made by APOGEE-2 and are available in this release. These stars were selected as bright sources accessible with the 1-m telescope at APO and observed for a varying number of epochs.
All pre-selected RRL stars have the
All pre-selected RRL stars have the
APOGEE2_TARGET1 bit 24 set and others, if applicable.
These targets have FIELD of 'rrlyr'.
M dwarf
This program targets previously identified M Dwarf stars to establish an empirical metallicity scale and spectral atlas for M-dwarfs in the APOGEE spectral range.
These targets have FIELD of 'Mdwarfs'.
Calibration
This program targets several stars with known parameters drawn from a variety of sources, such as those with angular diameters, asteroseismic measurements, Gaia targets, and optical abundance measurements.
These targets have FIELD of 'calibration'.
Be Stars
Be stars that are observable from the Northern hemisphere and too bright for the 2.5m are observed in this program.
These targets have FIELD of 'Bestars'.
Cepheid
Cepheid stars that are observable from the Northern hemisphere and too bright for the 2.5m are observed in this program.
These targets have FIELD of 'cepheid'.
Hipparcos
This program obtains APOGEE spectra for stars with parallaxes in Hipparcos and complimentary high-resolution optical spectroscopy.
These targets have FIELD of 'hip'.
Moving Groups
This program targets known stars in nearby moving groups.
These targets have FIELD of 'moving_group'.
RCB
This program targets known hydrogen deficient carbon (HdC) and R Coronae Borealis (RCB) stars.
These targets have FIELD of 'RCB'.
DQ Tau
This program targets a T Tauri binary system.
Other Programs
Data also exists with the
field tag of 'misc' and 'rv'.
