Three basic ingredients are required to generate a simple stellar population (SSP) library, i.e. an initial mass function (IMF), a stellar evolution model/isochrones, and an empirical/theoretical stellar spectral library. However, there are still some uncertainties to the determination and understanding of these ingredients. We perform the spectral fitting to test the relative parameter offsets between these uncertainties using two different stellar population models, two different empirical stellar libraries, two different isochrones, and the Salpeter and Chabrier IMFs. Based on these setups, we select five SSP libraries generated with the Galaxev/STELIB and Vazdekis/MILES models, and apply them to the pPXF full-spectrum fitting of both MaNGA and mock spectra. We find that: (1) Compared to the Galaxev/STELIB model, spectral fitting qualities with the Vazdekis/MILES model have significant improvements for those metal-rich (especially oversolar) spectra, which cause better reduced χ2 distributions and more precisely fitted absorption lines. This might due to the lack of metal-rich stars in the empirical STELIB library, or code improvement of the Vazdekis model. (2) When applying the Vazdekis/MILES model for spectral fitting, the IMF variation will lead to not only a systematic offset in M∗/Lr, but also offsets in age and metallicity, and these offsets increase with increasing stellar population ages. However, the IMF variation caused metallicity offsets disappear in the case of Galaxev/STELIB based libraries. (3) The Padova2000 model provides a better match to the MaNGA galaxy spectra at [M/H]L < −1.0, while the BaSTI model match the local galaxy spectra better at [M/H]L > −1.0. Current tests suggest that spectral fitting with the Vazdekis/MILES + BaSTI combination would be a better choice for local galaxies.
|Number of pages||19|
|Journal||Monthly Notices of the Royal Astronomical Society|
|State||Published - Feb 15 2019|
Bibliographical noteFunding Information:
We would like to thank to the anonymous referee for the suggestions that helped to improve this paper. This work is supported by the National Key Basic Research and Development Program of China (No. 2018YFA0404501 to SM), by the National Natural Science Foundation of China (NSFC) under grant number 11473032 (JG), 11333003 and 11761131004 (SM), 11390372 (SM, YL), and 11690024 (YL), and by the National Key Program for Science and Technology Research and Development (Grant No. 2016YFA0400704 to YL). MC acknowledges support from a Royal Society University Research Fellowship. RY acknowledges support by National Science Foundation grant AST-1715898.
This work makes use of data from SDSS-IV. Funding for SDSS has been provided by the Alfred P. Sloan Foundation and Participating Institutions. Additional funding towards SDSS-IV has been provided by the U.S. Department of Energy Office of Science. SDSS-IV acknowledges support and resources from the Centre for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org.
© 2019 The Author(s).
- Galaxies: evolution
- Galaxies: fundamental parameters
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science