DR16 MaStar Overview

The observations are obtained by piggybacking on the APOGEE-2 survey during bright time, using MaNGA fiber bundles and the BOSS optical spectrographs. The use of fiber bundles allow us to obtain much more accurate flux calibration than previous SDSS surveys of stars that use single fibers; see the Observing Strategy page for details of our observations.

For detailed information about the instruments, please see the MaNGA Instrument page.

Extinction-corrected color-luminosity diagram for the DR16 version of the MaStar Library, color-coded by metallicity (click to enlarge). The photometry in this figure are in SDSS bands. The derivation of the absolute magnitudes are based on distances computed by Bailer-Jones et al. (2018) using parallax from Gaia DR2 .

The DR16 version of the MaStar Library is identical to DR15, and is not the final version of the library. We are still accumulating more data and are working on improving the data reduction. This version includes all data obtained in the first three years of observation. Of all the stars observed, we have selected a subset of stars, termed 'good stars', with good quality visit spectra, termed 'good visits'. Each 'visit' is defined as the observation obtained for a star on a single night. This is the primary product of this release. It includes 8,646 good quality single visit spectra for 3,321 unique good stars.

The DR16 release includes a summary file called 'mastarall-(version).fits' and a spectra file called 'mastar-goodspec-(version).fits'. The summary file contains a 'GOODSTARS' table and a 'GOODVISITS' table. The 'GOODSTARS' table lists the ID, location, photometry, input stellar parameters, etc. for all stars with good quality visit spectra. The 'GOODVISITS' table lists the information needed to locate all good quality visits for each star, the radial velocity used to shift each spectrum to restframe, and spectral quality information. The spectra file contains all the good quality single visits spectra, matching the order of entries in the 'GOODVISITS' table.

• The MaStar Catalog page provides the details about the summary file -- 'mastarall'.
• The MaStar Spectra page provides the details about the spectra file -- 'mastar-goodspec'.
• The MaStar Data Access page provides information about ways to access the data.
• The MaStar Caveats page lists important usage caveats for the data. You are strongly encouraged to read this.
• The MaStar Tutorial page provides tutorials for using the MaStar data.

In addition, DR16 also contains the raw data from the first three years of the observations, the intermediate data reduction pipeline (DRP) products, and the combined, flux-calibrated, individual visit and individual exposure spectra.

For more detailed information on the MaStar survey in DR16, see the list of links on this page.