标题： 0.7<z<1.9的全球恒星形成率密度 显示英文标题

标题： Global Star Formation Rate Density over 0.7<z<1.9

摘要： 我们利用哈勃太空望远镜近红外相机和多目标光谱仪（HST-NICMOS）光栅光谱观测中识别出的发射线选择星系，在0.7<z<1.9范围内确定了宇宙恒星形成率密度。在整个哈勃空间望远镜第12周期和第13周期中以纯平行模式观测，我们的巡天覆盖了约104平方角分区域，从中选出了80个可能具有红移Ha发射线的星系。在若干情况下，还检测到相对较弱的[OIII]双线发射。发射线星系样本的Ha亮度范围为4.4 x 10^41 < L(Ha) < 1.5 x 10^43 erg/s。在这个范围内，亮度函数可以用一个Schechter函数很好地描述，其中phi* = (4.24\pm 3.55) x 10^-3 Mpc^-3，L* = (2.88\pm 1.58) x 10^42 erg/s，alpha = -1.39\pm 0.43。未考虑消光校正的情况下，在z=1.4时得到的体积平均恒星形成率密度为0.138\pm 0.058 Msun/yr/Mpc3。将红移范围细分后，我们在z=1.1处发现恒星形成率密度为0.088\pm 0.056 Msun/yr/Mpc3，在z=1.6处发现为0.265\pm 0.174 Msun/yr/Mpc3。当应用相同的平均消光校正时，总体恒星形成率密度与以往使用Ha的研究结果一致，证实了宇宙恒星形成的峰值出现在z>1.5。 显示英文摘要

摘要： We determine the global star formation rate density at 0.7<z<1.9 using emission-line selected galaxies identified in Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrograph (HST-NICMOS) grism spectroscopy observations. Observing in pure parallel mode throughout HST Cycles 12 and 13, our survey covers ~104 arcmin2 from which we select 80 galaxies with likely redshifted Ha emission lines. In several cases, a somewhat weaker [OIII] doublet emission is also detected. The Ha luminosity range of the emission-line galaxy sample is 4.4 x 10^41 < L(Ha) < 1.5 x 10^43 erg/s. In this range, the luminosity function is well described by a Schechter function with phi* = (4.24\pm3.55) x 10^-3 Mpc^-3, L* = (2.88\pm1.58) x 10^42 erg/s, and alpha = -1.39\pm0.43. We derive a volume-averaged star formation rate density of 0.138\pm0.058 Msun/yr/Mpc3 at z=1.4 without an extinction correction. Subdividing the redshift range, we find star formation rate densities of 0.088\pm0.056 Msun/yr/Mpc3 at z=1.1 and 0.265\pm0.174 Msun/yr/Mpc3 at z=1.6. The overall star formation rate density is consistent with previous studies using Ha when the same average extinction correction is applied, confirming that the cosmic peak of star formation occurs at z>1.5.