论文标题
CGM $^{2} $ i：中性氢所追踪的环境培养基的程度
CGM$^{2}$ I: The Extent of the Circumgalactic Medium Traced by Neutral Hydrogen
论文作者
论文摘要
我们从\ textIt {cos和gemini映射圆形培养基}（\ mbox {cgmcgm} $ \ equiv $ cgm $^{2} $调查中，我们提供了初始结果。 CGM $^{2} $调查由1689个星系组成，所有星系都有高质量的双子座GMOS光谱，在1 MPC 22 $ $ Z \ Lessim 1 $ Quasars以内，所有这些都有S/N $ \ sim $ \ sim $ 10 {\ emph {\ emph {hst/cos}} g130m $ $ $+g130m $+g160m specedra。在这些星系中，有572个具有恒星质量的星系$ 10^{7} m _ {\ odot} <m _ {\ star} <10^{11} {11} m _ {\ odot} $和$ z \ limssim 0.5 $，我们表明\ ion {h} hh} \ nhi $> 10^{14} $ cm $^{ - 2} $ is $ \ gtrsim 0.5 $在1.5 virial radii（$ r _ {\ rm vir} \ sim r_ r_ {200m {200m} $）中。我们检查了\ ion {h} {1}运动学，发现大部分吸收位于$ \ pm $ \ pm $ 250 km s $^{ - 1} $的$^{ - 1} $。我们检查\ ion {h} {1}覆盖一系列影响参数的分数，以推断CGM的特征大小，$ r^{14} _ {\ rm cgm} $，作为星系质量的函数。 $ r^{14} _ {\ rm cgm} $是影响参数，在该参数中，观察具有\ nhi $> $ 10 $> $ 10 $^{14} $ cm $^{ - 2} $的概率是$ 50 \％。在此框架内，CGM的径向范围为$ m _ {\ star}> 10^{9.9} m _ {\ odot} $ GALAXIES是$ r^{14} _ {\ rm cgm cgm} = 346^{+57} {+57} _ {+57} _ { - 53} _ {-53} $ kpc or^{14 CGM} \ simeq 1.2r _ {\ rm vir} $。 $ 10^{9.2} <m _ {\ star}/m _ {\ odot} <10^{9.9} $具有$ r^{14} _ {\ rm cgm cgm} = 353^{+64} = 353^{+64} _ {+64} _ {+64} _ {+64} _ {+64} $ $ r^{14} _ {\ rm cgm} \ simeq 2.4r _ {\ rm vir} $。低质量星系，$ m _ {\ star} <10^{9.2} m _ {\ odot} $，显示一个较小的物理比例$ r^{14} _ {\ rm cgm} = 177 _ { - 65} \ simeq 1.6r _ {\ rm vir} $。我们的分析表明，使用$ r _ {\ rm vir} $作为CGM特征半径的代理可能会低估其范围。
We present initial results from the \textit{COS and Gemini Mapping the Circumgalactic Medium} (\mbox{CGMCGM} $\equiv$ CGM$^{2}$) survey. The CGM$^{2}$ survey consists of 1689 galaxies, all with high-quality Gemini GMOS spectra, within 1 Mpc of twenty-two $z \lesssim 1$ quasars, all with S/N$\sim$10 {\emph{HST/COS}} G130M$+$G160M spectra. For 572 of these galaxies having stellar masses $10^{7} M_{\odot} < M_{\star} < 10^{11} M_{\odot}$ and $z \lesssim 0.5$, we show that the \ion{H}{1} covering fraction above a threshold of \NHI$>10^{14} $cm$^{-2}$ is $\gtrsim 0.5$ within 1.5 virial radii ($R_{\rm vir} \sim R_{200m}$). We examine the \ion{H}{1} kinematics and find that the majority of absorption lies within $\pm$ 250 km s$^{-1}$ of the galaxy systemic velocity. We examine \ion{H}{1} covering fractions over a range of impact parameters to infer a characteristic size of the CGM, $R^{14}_{\rm CGM}$, as a function of galaxy mass. $R^{14}_{\rm CGM}$ is the impact parameter at which the probability of observing an absorber with \NHI $>$ 10$^{14}$ cm$^{-2}$ is $>$ 50\%. In this framework, the radial extent of the CGM of $M_{\star} > 10^{9.9} M_{\odot}$ galaxies is $R^{14}_{\rm CGM} = 346^{+57}_{-53}$ kpc or $R^{14}_{\rm CGM} \simeq 1.2R_{\rm vir}$. Intermediate-mass galaxies with $10^{9.2} < M_{\star}/M_{\odot} < 10^{9.9}$ have an extent of $R^{14}_{\rm CGM} = 353^{+64}_{-50}$ kpc or $R^{14}_{\rm CGM} \simeq 2.4R_{\rm vir}$. Low-mass galaxies, $M_{\star} < 10^{9.2} M_{\odot}$, show a smaller physical scale $R^{14}_{\rm CGM} = 177_{-65}^{+70}$ kpc and extend to $R^{14}_{\rm CGM} \simeq 1.6R_{\rm vir}$. Our analysis suggests that using $R_{\rm vir}$ as a proxy for the characteristic radius of the CGM likely underestimates its extent.
