Virgo filaments: I. Processing of gas in cosmological filaments around the Virgo cluster
Virgo filaments: I. Processing of gas in cosmological filaments around the Virgo cluster
复制标题
处女座细丝：I. 处女座星团周围宇宙细丝中气体的处理
DOI：
10.1051/0004-6361/202040141
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发表时间：
2022
影响因子：
6.5
通讯作者：
Salomé, P.
中科院分区：
文献类型：
--
作者：
Castignani, G.;Combes, F.;Jablonka, P.;Finn, R. A.;Rudnick, G.;Vulcani, B.;Desai, V.;Zaritsky, D.;Salomé, P.
现在已经确定的是，在像星系团这样的致密环境中，星系具有不同的形态、气体含量和星星形成率（SFR）。环境密度的影响延伸到几个维里半径，星系似乎在落入星系团之前被预处理成细丝和集团。我们的目标是根据气体含量和SFR来量化这种预处理，作为宇宙细丝密度的函数。我们用IRAM-30 m望远镜在163个星系中观测到了两次首次CO跃迁，并从文献中增加了82个测量值，从而形成了室女座星系团周围暗条中245个星系的样本。我们从文献中收集了HI-21 cm测量数据，并使用Nançay望远镜观察了69个星系以完成我们的样本。我们比较我们的丝状星系与室女座星系团的可比样本和AMIGA样本的孤立星系。我们发现一个明确的进展，从场星系的丝状和星系团的减少SFR，增加比例的星系在淬火阶段，早期型星系的比例增加，并减少气体含量。根据局部星系密度，在孤立样本中，猝灭相的星系密度（SFR低于主序星（MS）的1/3）仅在0%-20%之间，而在暗条星系中，猝灭相的星系密度为20%-60%，在室女座星系团中，猝灭相的星系密度为30%-80%。导致星星形成淬灭的过程已经在暗条中发挥作用;它们主要取决于局部星系密度，而到暗条脊的距离是次要参数。虽然HI-恒星质量比随着局部密度的降低而降低，在细丝中降低一个数量级，在室女座星系团中降低两个数量级，但H2-恒星质量比的降低要小得多。随着环境密度的增加，气体耗尽时间缩短，因为气体含量比SFR减少得更快。这表明气体耗尽先于星星的形成淬火。
It is now well established that galaxies have different morphologies, gas contents, and star formation rates (SFR) in dense environments like galaxy clusters. The impact of environmental density extends to several virial radii, and galaxies appear to be pre-processed in filaments and groups before falling into the cluster. Our goal is to quantify this pre-processing in terms of gas content and SFR, as a function of density in cosmic filaments. We have observed the two first CO transitions in 163 galaxies with the IRAM-30 m telescope, and added 82 more measurements from the literature, thus forming a sample of 245 galaxies in the filaments around the Virgo cluster. We gathered HI-21cm measurements from the literature and observed 69 galaxies with the Nançay telescope to complete our sample. We compare our filament galaxies with comparable samples from the Virgo cluster and with the isolated galaxies of the AMIGA sample. We find a clear progression from field galaxies to filament and cluster galaxies for decreasing SFR, increasing fraction of galaxies in the quenching phase, an increasing proportion of early-type galaxies, and decreasing gas content. Galaxies in the quenching phase, defined as having a SFR below one-third of that of the main sequence (MS), are only between 0% and 20% in the isolated sample, according to local galaxy density, while they are 20%–60% in the filaments and 30%–80% in the Virgo cluster. Processes that lead to star formation quenching are already at play in filaments; they depend mostly on the local galaxy density, while the distance to the filament spine is a secondary parameter. While the HI-to-stellar-mass ratio decreases with local density by an order of magnitude in the filaments, and two orders of magnitude in the Virgo cluster with respect to the field, the decrease is much less for the H2-to-stellar-mass ratio. As the environmental density increases, the gas depletion time decreases, because the gas content decreases faster than the SFR. This suggests that gas depletion precedes star formation quenching.