论文标题
$ \ mathbf {z \ sim 0.35} $的星形星系的HI质量功能
The HI mass function of star-forming galaxies at $\mathbf{z \sim 0.35}$
论文作者
论文摘要
中性原子氢（HI）质量函数（HIMF）描述了任何时期星系的HI含量的分布；它的进化提供了对星系形成和进化模型的重要探测。在这里，我们报告了巨大的Metrewave射电望远镜HI 21cm蓝色星形星系的光谱$ z \ yourted Groth Strip中的$ Z \ of Z \大约0.20-0.42 $，这使我们能够确定平均HI质量的扩展关系（$ \ rm {m_ {m_ {hi}} $ _ $ _ $ _ $ _ $ _ $ \）在$ z \大约0.35 $上，通过将Galaxy子样本的HI 21厘米排放信号堆叠在不同的$ \ rm {M_b} $范围内。我们将此$ \ rm {m_ {hi} -m_b} $缩放关系（假定在本地宇宙中等于本地宇宙的散点）与已知的b频段亮度函数在这些redshifts上的已知B波段亮度函数，以确定$ z \ z \ y himf at $ z \ of z \ of0.35 $。我们表明，在$ \ rm {m_ {hi} -m_b} $缩放关系中使用正确的散布对于准确估计HIMF至关重要。我们发现，HIMF已从$ z \ of的大约0.35 $变为$ z \ oft of0 $，即在最后四个回旋中，尤其是在高质量末端。具有$ \ rm {m_ {hi} \ gtrsim10^{10} \ m_ \ odot} $的高质量星系是一个$ \ y of $ z \ of y of $ z \大约0 $。相反，有$ \ rm {m_ {hi} \ oft10^9 \ {m} _ \ odot} $，$ z \ oid0.35 $比本地宇宙中的$ \ rm {m_ {hi} \ oid10^9 \ {m} _ \ odot} $。尽管我们的结果可能受宇宙方差的影响，但我们发现，在过去的四个GYR中，大量的星系已通过合并事件获得了大量的HI或从海洋层次培养基中获得的增值。
The neutral atomic hydrogen (HI) mass function (HIMF) describes the distribution of the HI content of galaxies at any epoch; its evolution provides an important probe of models of galaxy formation and evolution. Here, we report Giant Metrewave Radio Telescope HI 21cm spectroscopy of blue star-forming galaxies at $z\approx0.20-0.42$ in the Extended Groth Strip, which has allowed us to determine the scaling relation between the average HI mass ($\rm{M_{HI}}$) and the absolute B-band magnitude ($\rm{M_B}$) of such galaxies at $z \approx 0.35$, by stacking the HI 21cm emission signals of galaxy subsamples in different $\rm{M_B}$ ranges. We combine this $\rm{M_{HI}-M_B}$ scaling relation (with a scatter assumed to be equal to that in the local Universe) with the known B-band luminosity function of star-forming galaxies at these redshifts to determine the HIMF at $z\approx0.35$. We show that the use of the correct scatter in the $\rm{M_{HI}-M_B}$ scaling relation is critical for an accurate estimate of the HIMF. We find that the HIMF has evolved significantly from $z\approx0.35$ to $z\approx0$, i.e. over the last four Gyr, especially at the high-mass end. High-mass galaxies, with $\rm{M_{HI}\gtrsim10^{10}\ M_\odot}$, are a factor of $\approx3.4$ less prevalent at $z\approx0.35$ than at $z \approx 0$. Conversely, there are more low-mass galaxies, with $\rm{M_{HI} \approx10^9\ {M}_\odot}$, at $z\approx0.35$ than in the local Universe. While our results may be affected by cosmic variance, we find that massive star-forming galaxies have acquired a significant amount of HI through merger events or accretion from the circumgalactic medium over the past four Gyr.
