论文标题
长伽马射线爆发宿主星系的恒星质量功能
The Stellar-mass Function of Long Gamma-Ray Burst Host Galaxies
论文作者
论文摘要
长时间讨论了长时间的伽马射线爆发（GRB），作为长期探测宇宙恒星形成速率（SFR）的潜在工具。一些研究发现，在高红移处，相对于星系延续的SFR的GRB速率有所提高，这表明GRB可能不是恒星形成的好示踪剂。但是，在这些研究中，在任何红移下测得的GRB速率是该时期所有星系的平均值。对GRB生产与环境之间的联系的深入了解也需要直接表征GRB宿主星系的人群。基于GRB宿主的完整样本，我们限制了GRB宿主的恒星质量函数（SMF），并检查GRB宿主种群中的红移演化。我们的结果证实了能量的强烈红移演化（$δ= 2.47^{+0.73} _ { - 0.89} $）或密度（$δ= 1.82^{+0.22} _ { - 0.22} _ { - 0.59} $）是为了考虑观察的序列。 Schechter功能可以很好地描述GRB主机SMF，并具有幂律索引$ξ\ of-1.10 $，而断裂质量$ m_ {b，0} \ oft4.9 \ times10^{10} $ {\ rm m} _ \ rm m} _ \ odot $，独立于假定的进化效果。这是GRB主机SMF的第一个公式。观察到的GRB速率和星系冠军SFR之间的差异也可以通过不断发展的SMF来解释。
Long gamma-ray bursts (GRBs) have been discussed as a potential tool to probe the cosmic star formation rate (SFR) for a long time. Some studies found an enhancement in the GRB rate relative to the galaxy-inferred SFR at high redshifts, which indicates that GRBs may not be good tracers of star formation. However, in these studies, the GRB rate measured at any redshift is an average over all galaxies at that epoch. A deep understanding of the connection between GRB production and environment also needs to characterize the population of GRB host galaxies directly. Based on a complete sample of GRB hosts, we constrain the stellar-mass function (SMF) of GRB hosts, and examine redshift evolution in the GRB host population. Our results confirm that a strong redshift evolution in energy (with an evolution index of $δ=2.47^{+0.73}_{-0.89}$) or in density ($δ=1.82^{+0.22}_{-0.59}$) is needed in order to account for the observations. The GRB host SMF can be well described by the Schechter function with a power-law index $ξ\approx-1.10$ and a break mass $M_{b,0}\approx4.9\times10^{10}$ ${\rm M}_\odot$, independent of the assumed evolutionary effects. This is the first formulation of the GRB host SMF. The observed discrepancy between the GRB rate and the galaxy-inferred SFR may also be explained by an evolving SMF.
