Stellar Population Models
12/06/2020: UPDATE to version v0.2
The MaStar Stellar Population Models (Maraston et al 2020) use the new SDSS-based stellar library MaStar (Yan et al 2019) to predict the spectral energy distributions of stellar population models with various chemical composition and age.
MaStar is an empirical library containing around 9,000 stellar spectra acquired with the SDSS 2.5m telescope, hence spectral resolution and wavelength range are identical to SDSS data. The wavelength range is 3,600 to 10,300 A with a wavelength-dependent spectral resolution ranging from R=1,400 to R=2,200. The resolution array is provided with the model tables (see below). Wavelengths are in vacuum.
There are two model flavours with different stellar parameters for the MaStar sample, E-MaStar and Th-MaStar. In E-MaStar, stellar parameters are derived from fitting empirical stellar spectra from the MILES stellar library (Chen et al 2020, ApJ, submitted), while in Th-MaStar stellar parameters are derived from fitting stellar spectra of theoretical stellar atmospheres from MARCS and ATLAS (Hill et al 2020, in preparation).
The models are calculated for a wide range in age (t = 0.1 – 15 Gyr), metallicity ([Z/H] = -2.35 – 0.35 dex) and low-mass IMF slope (s = 0.3 – 3.8). These ranges are being extended through forthcoming releases thanks to the ongoing MaStar campaign. Please refer to the paper and in particular to Table 1 for a description of the confidence range of models.
The model data can be downloaded as gzipped fits file MaStar_SSP_v0.2.fits.gz (version v0.2). The models are stored in the third and fourth extensions as a 4-dimensional matrix. HDU3 contains the Th-MaStar models and HDU4 the E-MaStar models. In these, one dimension is model flux, the other three are the three model parameters age t, metallicity Z and low-mass IMF slope s. The equivalent 4-dimensional matrix of the model parameter arrays is stored in HDU1, while HDU2 contains the 1-dimensional wavelength array (linear in Angstrom, vacuum) and the array of spectral resolution R.
- 12/06/2020, v0.2: Bug fix to correct spectral resolution, resolution array added, artefact removed from metal-poor Th-MaStar model
- 14/11/2019, v0.1: First release based on SDSS/MaNGA data release DR16.