论文标题
Arecibo Ultra-Deep调查
The Arecibo Ultra-Deep Survey
论文作者
论文摘要
Arecibo Ultra Deep调查（AUDS）是一项盲目的HI调查，旨在检测中性氢（HI）21厘米发射线以外的当地宇宙之外的星系。 Arecibo $ l $ -band Feed Array（Alfa）使用总计超过700小时的总源集成时间来对0.16的红移深度进行1.35〜DEG $^2 $的面积图像。长时间的集成时间和较小的观察区域使其成为最敏感的HI调查之一，噪声水平为$ \ sim 75 $〜$〜$ $ $ $ jy每21.4〜KHz（相当于4.5 〜km〜s $^s $^{ - 1} $，在红色SHSHIFT $ z = 0 $）。我们在调查中检测到247个星系，使AUDS60中已经检测到的数量增加了一倍以上。检测到的星系的质量范围为$ \ log（m _ {\ rm hi}〜[h_ {70}^{ - 2} {\ rm m} _ \ odot]）= 6.32-10.76 $。采用修改的最大似然方法来构建HI质量功能（HIMF）。最佳拟合Schechter参数是：低质量斜率$α= -1.37 \ pm 0.05 $，特征质量$ $ \ log（m^*〜[H_ {70}^{ - 2} {\ rm M} {\ rm M} _ \ odot]） 10^{ - 3} h_ {70}^3 $ 〜mpc $^{ - 3} $ 〜DEX $^{ - 1} $。将样品分为低红移和高红移箱，以研究HIMF的演变。低质量斜率$α$没有变化，但是在高红移样品中指出了特征质量$ m^*$。使用斯隆数字天空调查（SDSS）数据来定义相对星系数密度，在两个AUDS地区还研究了HIMF与环境的依赖性。我们发现$α$或$ m^*$没有显着变化。在被调查的区域中，我们测量了一个宇宙HI密度$ω_ {\ rm hi} =（3.55 \ pm 0.30）\ times 10^{ - 4} h_ {70}^{ - 1} $。 $ω_ {\ rm hi} $上的$2σ$上的$ω_ {\ rm hi}的进化趋势似乎没有进化趋势。
The Arecibo Ultra Deep Survey (AUDS) is a blind HI survey aimed at detecting galaxies beyond the local Universe in the 21-cm emission line of neutral hydrogen (HI). The Arecibo $L$-band Feed Array (ALFA) was used to image an area of 1.35~deg$^2$ to a redshift depth of 0.16, using a total on-source integration time of over 700 hours. The long integration time and small observation area makes it one of the most sensitive HI surveys, with a noise level of $\sim 75$~$μ$Jy per 21.4~kHz (equivalent to 4.5~km~s$^{-1}$ at redshift $z=0$). We detect 247 galaxies in the survey, more than doubling the number already detected in AUDS60. The mass range of detected galaxies is $\log(M_{\rm HI}~[h_{70}^{-2}{\rm M}_\odot]) = 6.32 - 10.76$. A modified maximum likelihood method is employed to construct an HI mass function (HIMF). The best fitting Schechter parameters are: low-mass slope $α= -1.37 \pm 0.05$, characteristic mass $\log(M^*~[h_{70}^{-2}{\rm M}_\odot]) = 10.15 \pm 0.09$, and density $Φ_* = (2.41 \pm 0.57) \times 10^{-3} h_{70}^3$~Mpc$^{-3}$~dex$^{-1}$. The sample was divided into low and high redshift bins to investigate the evolution of the HIMF. No change in low-mass slope $α$ was measured, but an increased characteristic mass $M^*$, was noted in the higher-redshift sample. Using Sloan Digital Sky Survey (SDSS) data to define relative galaxy number density, the dependence of the HIMF with environment was also investigated in the two AUDS regions. We find no significant variation in $α$ or $M^*$. In the surveyed region, we measured a cosmic HI density $Ω_{\rm HI} = (3.55 \pm 0.30) \times 10^{-4} h_{70}^{-1}$. There appears to be no evolutionary trend in $Ω_{\rm HI}$ above $2σ$ significance between redshifts of 0 and 0.16.
