What's New in DR15

The MaNGA Data Reduction Pipeline (DRP; v2_4_3) and Data Analysis Pipeline (DAP; 2.2.1) are living pipelines that are constantly evolving based on the MaNGA team analysis of the data. As such, there are some substantial differences between the DR15 data products and previous data releases. Most obvious for this release is that the DAP products are entirely new, and we're providing a new way of interacting with MaNGA data via our Marvin python package. Finally, a new set of MaNGA value added catalogs is available here.

Change Logs

We maintain detailed change logs for all of our software products. Locations of detailed change logs are found at the following locations.

Data Reduction Pipeline (DRP) RELEASE_NOTES
Data Analysis Pipeline (DAP) CHANGES.md
Marvin CHANGELOG

Flux Calibration

DR15 introduces some significant changes in the overall flux calibration relative to DR13/DR14. Foremost among these is the use of BOSZ templates instead of Kurucz templates, which slightly increases the overall flux blueward of 4000 Angstroms. Additionally, the calibration vector applied to the data is now smoother at many wavelengths; high-frequency basis spline fits are still used in telluric regions, but the spline has a much lower frequency outside the telluric regions to avoid introducing wiggles due to slight template mismatches. This significantly reduces the amount of artificially high frequency low level (a few percent) variations seen in the resulting spectra from earlier versions. The list of telluric regions is also updated.

Spectral LSF Estimates

Many aspects of the spectral line-spread function (LSF) estimation in the DRP have changed in DR15 in order to improve the level of agreement with independent estimates (e.g., observations of bright stars that have been observed at significantly higher spectral resolution). These changes include the use of a gaussian comb method to propagate LSF estimates through wavelength rectification, computation of both pre-pixellized and post-pixellized LSF estimates, improved interpolation over masked regions, and a modified arclamp reference line list to improve LSF estimation in the far blue by rejecting poor-quality lines.

Spectral LSF Extensions

Additional information regarding the LSF has been added to the DRP data files. New extensions in the CUBE-format files are:

  • DISP: Instrumental LSF cube, combined across exposures along with the individual spectra to give the estimated LSF at each location in the data cubes.
  • PREDISP: As DISP, but for the pre-pixellized estimate of the LSF
  • PRESPECRES: As previous SPECRES extension (i.e, a 1d vector of mean spectral resolution at each wavelength) but for pre-pixellized estimate of the resolution
  • PRESPECRESD: As previous SPECRESD extension (i.e, a 1d vector of standard deviation about the mean spectral resolution at each wavelength) but for pre-pixellized estimate of the resolution

New extensions in the RSS-format files are:

  • PREDISP: As DISP (RSS-format LSF for each fiber), but for the pre-pixellized estimate of the LSF
  • PRESPECRES: As SPECRES (i.e, a 1d vector of mean spectral resolution at each wavelength) but for pre-pixellized estimate of the resolution
  • PRESPECRESD: As SPECRESD (i.e, a 1d vector of standard deviation about the mean spectral resolution at each wavelength) but for pre-pixellized estimate of the resolution

Data Cube Covariance

The DRP data cubes now contain extensions describing the covariance introduced into the data cubes by the cube-building process. See Working with the MaNGA Data for details.

No Minibundle Data Cubes

Data cubes are no longer being produced for the 7-fiber minibundles targeting flux calibration stars during MaNGA operations. In a future data release these will instead be processed with the MaStar pipeline. Since cubes are no longer being produced for these objects, they are no longer listed in the drpall summary file.

Additional columns in DRPall summary file

The DRPall summary file in DR15 contains 10 additional columns compared to DR14. These columns are:

  • z: The targeting redshift (identical to nsa_z for those targets in the NSA Catalog. For others, it is the redshift provided by the Ancillary programs)
  • probs: The probability that a Secondary sample galaxy is included after down-sampling. For galaxies not in the Secondary sample PROBS is set to the mean down-sampling probability
  • pweight: The volume weight for the Primary sample. Corrects the MaNGA selection to a volume limited sample.
  • psweight: The volume weight for the combined Primary and full Secondary samples. Corrects the MaNGA selection to a volume limited sample.
  • psrweight: The volume weight for the combined Primary and down-sampled Secondary samples. Corrects the MaNGA selection to a volume limited sample.
  • sweight: The volume weight for the full Secondary sample. Corrects the MaNGA selection to a volume limited sample.
  • srweight: The volume weight for the down-sampled Secondary sample. Corrects the MaNGA selection to a volume limited sample.
  • eweight: The volume weight for the Primary+ sample. Corrects the MaNGA selection to a volume limited sample.
  • esweight: The volume weight for the combined Primary+ and full Secondary samples. Corrects the MaNGA selection to a volume limited sample.
  • esrweight: The volume weight for the combined Primary+ and down-sampled Secondary samples. Corrects the MaNGA selection to a volume limited sample.

Under-the-hood DRP changes

Numerous additional under-the-hood changes have been made in DR15. These include modifications to the pixel flatfields, biases, and bad pixel reference masks, updates to the algorithms governing weights near ultra-bright emission lines, minor adjustments to the far-blue (below 3900 Angstrom) wavelength solution, etc.