arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.04675astro-ph.GA
收藏

在$z\approx 2$巨大的Ly $α$星云中寻找尘埃和分子气体

A search for dust and molecular gas in enormous Ly$α$ nebulae at $z\approx 2$

Roberto Decarli, Fabrizio Arrigoni-Battaia, Joseph F. Hennawi, Fabian Walter, Jason X. Prochaska, Sebastiano Cantalupo

摘要:

巨大的Ly $α$星云,围绕类星体延伸超过300- 500 kpc,代表了星系和星团形成的顶峰。这里我们介绍IRAM Plateau de Bure干涉仪对巨大的Ly $α$星云“Slug”($z$ = $2.282$)和“Jackpot”($z$ = $2.041$)的观测。我们的数据揭示了明亮的同步辐射,与嵌入目标星云的两个无线电响亮的活动星系核有关,以及分子气体,通过CO(3-2)线追踪,在三个星系中(两个源在鼻涕虫,一个在头奖)。所有的CO发射与星系在其静止帧UV恒星发射检测。这三个星系[ $\sim (3-5)\times10^{10}$ M $_\odot$ ]的分子气体总质量与弥漫星云发射的电离气体总质量相当。我们的观测结果限制了星云中分子气体的排放:蛞蝓星云的分子气体表面密度为$Σ_{\rm H2}<12-25$ M $_\odot$ pc $^{-2}$,而头奖星云的分子气体表面密度为$Σ_{\rm H2}<34-68$ M $_\odot$ pc $^{-2}$。这些都是符合预期的分子气体表面密度,预测通过光电离模型的休息帧紫外线发射的星云,并通过Ly $α$吸收的头奖星云。与其他射电大声类星体在$z>1$,高红移射电大声星系相比,我们没有发现任何强烈的趋势有关的分子气体水库,无线电功率,和这些系统的Ly $α$光度。如果星云中存在分子气体的话,要实现对星云中分子气体的探测,需要在灵敏度上迈出重要的一步,这将需要对JVLA、NOEMA或ALMA进行大量的时间投资。

英文摘要:

Enormous Ly$α$ nebulae, extending over 300-500\,kpc around quasars, represent the pinnacle of galaxy and cluster formation. Here we present IRAM Plateau de Bure Interferometer observations of the enormous Ly$α$ nebulae `Slug' ($z$=$2.282$) and `Jackpot' ($z$=$2.041$). Our data reveal bright, synchrotron emission associated with the two radio-loud AGN embedded in the targeted nebulae, as well as molecular gas, as traced via the CO(3-2) line, in three galaxies (two sources in the Slug, and one in the Jackpot). All of the CO emission is associated with galaxies detected in their rest-frame UV stellar emission. The total mass in molecular gas of these three galaxies [$\sim (3-5)\times10^{10}$ M$_\odot$] is comparable with the total ionized gas mass responsible for the diffuse nebular emission. Our observations place limits on the molecular gas emission in the nebulae: The molecular gas surface density is $Σ_{\rm H2}<12-25$ M$_\odot$ pc$^{-2}$ for the Slug nebula and $Σ_{\rm H2}<34-68$ M$_\odot$ pc$^{-2}$ for the Jackpot nebula. These are consistent with the expected molecular gas surface densities, as predicted via photoionization models of the rest-frame UV line emission in the nebulae, and via Ly$α$ absorption in the Jackpot nebula. Compared to other radio--loud quasars at $z>1$, and high-redshift radio--loud galaxies, we do not find any strong trends relating the molecular gas reservoirs, the radio power, and the Ly$α$ luminosities of these systems. The significant step in sensitivity required to achieve a detection of the molecular gas from the nebulae, if present, will require a substantial time investment with JVLA, NOEMA, or ALMA.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑