The Hα Luminosity Function and Star Formation Rate at z ~ 0.2
The Hα Luminosity Function and Star Formation Rate at z ~ 0.2
复制标题
DOI：
10.1086/305331
复制
发表时间：
1997-09
期刊：
影响因子：
--
通讯作者：
L. Tresse;S. Maddox
中科院分区：
文献类型：
--
作者：
L. Tresse;S. Maddox
我们测量了红移z小于0.3的加法红移巡天（CFRS）星系的Hα ~+ [N Ⅱ]通量，并由此导出了Hα光度函数。CFRS的星等限制意味着只有MB = 21等的星系才能在这些红移下被观测到。我们获得了静止坐标系EW（Hα + [N II]）= 10 π的星系在平均z = 0.2时的总Hα光度密度至少为1039.44±0.04 ergs-1 Mpc-3。这是Gallego等人在当地宇宙中发现的值的两倍。我们的Hα星星形成率，来自Madau，高于相同z的紫外观测，这意味着紫外尘埃消光~1 mag. We发现Hα光度和B波段的绝对星等之间有很强的相关性：M（BA B）= 46.7 - 1.6 log L（Hα）。这项工作将作为未来研究Hα光度分布的基础，这些光度分布是从遥远宇宙的光学选择光谱测量中测量的，它将提供对所观察到的星系演化的物理过程的更好理解。
We have measured the Hα + [N II] fluxes of the I-selected Canada-France Redshift Survey (CFRS) galaxies lying at a redshift z below 0.3 and hence derived the Hα luminosity function. The magnitude limits of the CFRS mean that only the galaxies with MB ≳ -21 mag were observed at these redshifts. We obtained a total Hα luminosity density of at least 1039.44±0.04 ergs s-1 Mpc-3 at a mean z = 0.2 for galaxies with rest-frame EW(Hα + [N II]) ≳ 10 Å. This is twice the value found in the local universe by Gallego et al. Our Hα star formation rate, derived from Madau, is higher than the UV observations at the same z, implying a UV dust extinction of ~1 mag. We found a strong correlation between the Hα luminosity and the absolute magnitude in the B band: M(BAB) = 46.7 - 1.6 log L(Hα). This work will serve as a basis of future studies of Hα luminosity distributions measured from optically selected spectroscopic surveys of the distant universe, and it will provide a better understanding of the physical processes responsible for the observed galaxy evolution.