大样本恒星演化研究组知识库

Calibrations of star formation rate (SFR) are affected by many factors, for example the metallicity, the initial mass function (IMF) and the evolutionary population synthesis (EPS) model used. In this paper we will discuss the effects of binary interactions, metallicity, EPS model and IMF on several widely used SFR calibrations based on the EPS models of Yunnan with and without binary interactions, BC03, SB99, PEGASE and POPSTAR. The inclusion of binary interactions makes these SFR conversion coefficients smaller (by less than 0.2 dex), and these differences increase with metallicity. The differences in the calibration coefficient between the SFR and the luminosity of the H alpha recombination line (C-H alpha) and that between the SFR and the ultraviolet (UV) fluxes at 1500 and 2800 angstrom (C-i,C- UV), caused by the IMF, are independent of metallicity (0.03-0.33 dex), except for Delta C-H alpha,C- IMF when using the POPSTAR and for Delta C-i,C- UV,C- IMF when using the PEGASE models. Moreover, we find that L-2800 is not suitable for the linear calibration of SFR at low metallicities. Finally, we compare the effects of these factors on the SFR calibrations considered in this paper. The effects of metallicity/IMF and EPS model on C-H alpha and C-FIR (the conversion coefficient between SFR and the far-infrared flux) are the largest among these factors, respectively. For the calibration between SFR and C-i,C- UV, the effects of these factors are comparable.