论文标题
局部宇宙学量中星系星的恒星形成历史的约束
Constraints on the star formation histories of galaxies in the Local Cosmological Volume
论文作者
论文摘要
在局部宇宙学量中，大多数具有当前恒星形成速率（SFRS）的星系，SFRO> = 10^-3 msun/yr，在局部宇宙学量中，观察值应该是可靠的，其性质的性质比其平均星形形成率大。这与延迟的TAU模型描述的星系的演变有关，根据这一模型，这相反。张力很明显，因为局部星系意味着恒星形成时间尺度tau约6.7 Gyr，比使用几个红移的经验确定的主序列获得的3.5-4.5 GYR长得多。使用模型，其中sfr是形式的propto（t -t -t1）^eta的幂定律，用于t1 = 1.8 gyr（在T1之前没有恒星形成）意味着ETA = 0.18 +-0.03。这表明，随着时间的流逝，银河系的SFR的近构态引起了星系的进化和形成时间的非平凡问题，但与观察到的随着宇宙年龄的增长而观察到的主要序列降低。
The majority of galaxies with current star-formation rates (SFRs), SFRo >= 10^-3 Msun/yr, in the Local Cosmological Volume where observations should be reliable, have the property that their observed SFRo is larger than their average star formation rate. This is in tension with the evolution of galaxies described by delayed-tau models, according to which the opposite would be expected. The tension is apparent in that local galaxies imply the star formation timescale tau approx 6.7 Gyr, much longer than the 3.5-4.5 Gyr obtained using an empirically determined main sequence at several redshifts. Using models where the SFR is a power law in time of the form propto (t - t1)^eta for t1 = 1.8 Gyr (with no stars forming prior to t1) implies that eta = 0.18 +- 0.03. This suggested near-constancy of a galaxy's SFR over time raises non-trivial problems for the evolution and formation time of galaxies, but is broadly consistent with the observed decreasing main sequence with increasing age of the Universe.
