论文标题
两个高宽敞的HI 21厘米吸收剂的巨型射电望远镜检测$ z \大约1.2 $
Giant Metrewave Radio Telescope detections of two high-opacity HI 21cm absorbers at $z \approx 1.2$
论文作者
论文摘要
我们报告了针对低亮度活跃的银河系核（AGN）的两个显着的高宽敞HI 21厘米吸收剂，$ z = 1.2166 $ to j0229+0044，在$ z = 1.1630 $ to j02229+0053。在无偏见的巨型巨型射电望远镜调查中检测到吸收剂，该调查对HI 21cm吸收了Deep2调查场中的无线电源，覆盖$ Z \ yough $ z \约0.73-1.53 $，其中包括没有已知红移的来源。速度集成的HI 21厘米光学深度为$（74.2 \ pm 7.8）$ km s $^{ - 1} $（J0229+0044）和$（78.41 \ pm 0.81 \ pm 0.81）$ km S $ s $ s $^{-1} $（J0229+0053） 0.12 $，暗示高H {\ sc I}列密度，$> 10^{22} $ cm $^{ - 2} $。 J0229+0044的发射红移与HI 21cm的吸收红移一致，而对J0229+0053吸收的强度和速度扩散表明，它在AGN环境中也是由AGN环境中引起的：因此，两个吸收者都可能是“相关”的系统。这两个AGN的休息框架1.4 GHz无线电和1215个盎司紫外线仪（$ \ \ sillsim 10^{26.1} $ w hz $^{ - 1} $和$ \ $ \ ysim 10^{21.7} $ w hz $^hz $^{ - 1} $分别均较低。迄今为止以$ z \ gtrsim 1 $进行。在$ z \ gtrsim 1 $上，HI 21厘米吸收剂的稀少可能是由于高达$ z $ agn样品中的光度偏差引起的，这些样品已被搜索HI 21厘米吸收，高AGN紫外线亮度会影响其环境中的环境，因此使中性氢化了中性氢。
We report the discovery of two remarkable high-opacity HI 21cm absorbers against low-luminosity active galactic nuclei (AGNs), at $z = 1.2166$ towards J0229+0044 and at $z=1.1630$ towards J0229+0053. The absorbers were detected in an unbiased Giant Metrewave Radio Telescope survey for HI 21cm absorption against radio sources in the DEEP2 survey fields, covering $z \approx 0.73-1.53$, and including sources without known redshifts. The velocity-integrated HI 21cm optical depths are $(74.2 \pm 7.8)$ km s$^{-1}$ (J0229+0044) and $(78.41 \pm 0.81)$ km s$^{-1}$ (J0229+0053), higher than that of any known redshifted HI 21cm absorber at $z > 0.12$, and implying high H{\sc i} column densities, $> 10^{22}$ cm$^{-2}$. The emission redshift of J0229+0044 is consistent with the HI 21cm absorption redshift, while the strength and velocity spread of the absorption against J0229+0053 suggest that it too arises from gas in the AGN environment: both absorbers are thus likely to be "associated" systems. The two AGNs have low rest-frame 1.4 GHz radio and 1215 Angstrom ultraviolet luminosities ($\lesssim 10^{26.1}$ W Hz$^{-1}$ and $\lesssim 10^{21.7}$ W Hz$^{-1}$, respectively), both significantly lower than the typical luminosities of AGNs against which HI 21cm searches have hitherto been carried out at $z \gtrsim 1$. The paucity of HI 21cm absorbers at $z \gtrsim 1$ may be due to a luminosity bias in high-$z$ AGN samples that have been searched for HI 21cm absorption, where the high AGN ultraviolet luminosity affects physical conditions in its environment, ionizing the neutral hydrogen.
