论文标题
$ z \ sim0.2-0.9 $ clash最明亮的集群星系中的分子气体中的分子气
Molecular gas in CLASH brightest cluster galaxies at $z\sim0.2-0.9$
论文作者
论文摘要
最明亮的簇星系（BCG）是研究密集的MPC尺度环境中星系进化的出色实验室。我们已经在CO（1-0），CO（2-1），CO（3-2）或CO（4-3）中观察到，IRAM-30M，18 BCG的$ Z \ sim0.2-0.9 $从冲突调查中得出。我们的样本包括RX1532，这是我们的主要目标，是Clash样本中恒星形成率最高的BCG（SFR $ \ GTRSIM100〜M_ \ ODOT $/YR）。我们在RX1532中明确检测了CO（1-0）和CO（3-2），产生了大量的分子气储备，$ M_ {H_2} =（8.7 \ pM1.1）\ times10^{10} {10} 〜M_ \ m_ \ odot $，以及高度的激发$ r _ = 0.75} = 0.75。对RX1532的HST I波段图像的形态分析揭示了半光半径内外的块状子结构的存在，$ r_e =（11.6 \ pm0.3）$ kpc $ kpc，类似于在紫外线和先前工作中独立发现的H $_α$。我们在其他四个BCG中暂时检测到CO（1-0）或CO（2-1），分子气体储存量在$ M_ {H_2} = 2 \ times10^{10-11} m_ \ odot $。对于剩余的13个BCG，我们设置了$ M_ {H_2}/M_ \ Star'ssim0.1$的强大上限，这是针对遥远椭圆形和BCG的最低分子气与恒星质量比。与CO中观察到的遥远聚类星系相比，我们的研究表明，RX1532（$ M_ {H_2}/M_ \ Star = 0.40 \ PM0.05 $）属于遥远宇宙中罕见的恒星形成和富含气体的BCG。通过使用可用的X射线基于中央群集内介质熵的估计值，我们表明，检测大量分子气体$ M_ {H_2} \ GTRSIM10^{10} 〜M_ \ odot $在遥远的BCG中可能在两个条件上进行远处的bcgs，并在两个条件上进行cons and：I）高sfr and II），而ccel是高sfr and ii）ccel and topers and pers off and pers and portov and portover and portover and portover and cull off and pers off。 BCG本身与以前在某些本地BCG中找到的类似。
Brightest cluster galaxies (BCGs) are excellent laboratories to study galaxy evolution in dense Mpc-scale environments. We have observed in CO(1-0), CO(2-1), CO(3-2), or CO(4-3), with the IRAM-30m, 18 BCGs at $z\sim0.2-0.9$ that are drawn from the CLASH survey. Our sample includes RX1532, which is our primary target, being among the BCGs with the highest star formation rate (SFR$\gtrsim100~M_\odot$/yr) in the CLASH sample. We unambiguously detected both CO(1-0) and CO(3-2) in RX1532, yielding a large reservoir of molecular gas, $M_{H_2}=(8.7\pm1.1)\times10^{10}~M_\odot$, and a high level of excitation $r_{31}=0.75\pm0.12$. A morphological analysis of the HST I-band image of RX1532 reveals the presence of clumpy substructures both within and outside the half-light radius $r_e=(11.6\pm0.3)$ kpc, similarly to those found independently both in ultraviolet and in H$_α$ in previous work. We tentatively detected CO(1-0) or CO(2-1) in four other BCGs, with molecular gas reservoirs in the range $M_{H_2}=2\times10^{10-11} M_\odot$. For the remaining 13 BCGs we set robust upper limits of $M_{H_2}/M_\star\lesssim0.1$, which are among the lowest molecular gas to stellar mass ratios found for distant ellipticals and BCGs. By comparison with distant cluster galaxies observed in CO our study shows that RX1532 ($M_{H_2}/M_\star = 0.40\pm0.05$) belongs to the rare population of star forming and gas-rich BCGs in the distant universe. By using available X-ray based estimates of the central intra-cluster medium entropy, we show that the detection of large reservoirs of molecular gas $M_{H_2}\gtrsim10^{10}~M_\odot$ in distant BCGs is possible when the two conditions are met: i) high SFR and ii) low central entropy, which favors the condensation and the inflow of gas onto the BCGs themselves, similarly to what has been previously found for some local BCGs.
