The Stellar Spectra Factory (SSF) Based On SLAM

In this work, we present Stellar Spectra Factory (SSF), a tool to generate empirical-based stellar spectra from arbitrary stellar atmospheric parameters. The relative flux-calibrated empirical spectra can be predicted by SSF given arbitrary effective temperature, surface gravity, and metallicity. SSF constructs the interpolation approach based on the SLAM, using ATLAS-A library as the training dataset. SSF is composed of 4 data-driven sub-models to predict empirical stellar spectra. SSF-N can generate spectra from A to K type and some M giant stars, covering 3700 < Teff < 8700 K, 0 < logg < 6 dex, and -1.5 < [M/H] < 0.5 dex. SSF-gM is mainly used to predict M giant spectra with 3520 < Teff < 4000K and -1.5 < [M/H] < 0.4 dex. SSF-dM is for generating M dwarf spectra with 3295 < Teff < 4040K, -1.0 < [M/H] < 0.1 dex. And SSF-B can predict B-type spectra with 9000 < Teff < 24000K and -5.2< MG < 1.5 mag. The accuracy of the predicted spectra is validated by comparing the flux of predicted spectra to those with same stellar parameters selected from the known spectral libraries, MILES and MaStar. The averaged difference of flux over optical wavelength between the predicted spectra and the corresponding ones in MILES and MaStar is less than 5%. More verification is conducted between the magnitudes calculated from the integration of the predicted spectra and the observations in PS1 and APASS bands with the same stellar parameters. No significant systematic difference is found between the predicted spectra and the photomatric observations. The uncertainty is 0.08mag in r band for SSF-gM when comparing with the stars with the same stellar parameters selected from PS1. And the uncertainty becomes 0.31mag in i band for SSF-dM when comparing with the stars with the same stellar parameters selected from APASS.