MaStar Overview


Example spectra from the MaStar library (click to enlarge).
Example spectra from the MaStar library (click to enlarge).

MaNGA Stellar Library (MaStar) is a stellar spectral library with a wide coverage of stellar parameters, high quality calibration, and identical observing setup as the MaNGA survey.

DR16 contains no new data from MaStar, and data products are identical to those release in DR15. New MaStar data products will be released in DR17.

The spectra cover 3,622-10,354 Angstrom with a spectral resolution around R~1800. The final version will include approximately 10,000 stars. In DR15, we released the first version of the library containing 8646 good quality individual visit spectra for 3321 unique stars, which is only a subset of the final version.

The library is described in detail by Yan et al. (2019). Please cite this paper when using the library, and please also follow the general guide to citing SDSS.

MaStar Observations

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.

MaStar Data in DR17

Color-Luminosity Diagram for the DR15 version of the MaStar Library, color-coded by metallicity.
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.

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 DR17, see the list of links on this page.

MaStar Data Access

Several interfaces are available to access the data (see MaStar Data Access for more details).

Science Archive Server (SAS)

MaStar individual epoch spectra, individual exposure spectra, and MaStar summary tables are available as FITS files through the Science Archive Server (SAS), which can return FITS spectra either individually or in bulk. For more information on retrieving MaStar data from the SAS, see MaStar Data Access page.

The Science Archive Webapp provides a searchable interface for MaStar spectra, and includes an interactive view of spectra, and a data download facility (supports both rsync and wget).

Sky Server

Information for individual MaStar targets are now shown in the SkyServer Explore tool, such as for this sample MaStar target star.

You can search for MaStar data using Structured Query Language (SQL) with the SkyServer SQL Search tool. MaStar summary data are in the mastar-goodstars table and the mastar-goodvisits table.

CasJobs

You can search for MaStar data within the mastar summary table more flexibly with the CasJobs data access tool. You can save results into a personal MyDB database for later analysis.

MaStar data are part of the DR16 context - don't forget to change to the DR16 context when you want to find MaStar data. MaStar summary data are in the mastar-goodstars table and the mastar-goodvisits table.

MaStar Twitter

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Follow us on twitter! MaStar tweets as @MaStar_library, and tweets includes observing updates and science results.