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arXiv 2402.14909astro-ph.GA
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不再黑暗:室女座星系团中一片暗云的低光度恒星对应体

Dark no more: The low luminosity stellar counterpart of a dark cloud in the Virgo cluster

Michael G. Jones, Steven Janowiecki, Swapnaneel Dey, David J. Sand, Paul Bennet, Denija Crnojevic, Catherine E. Fielder, Ananthan Karunakaran, Brian R. Kent, Ni… 展开作者

Michael G. Jones, Steven Janowiecki, Swapnaneel Dey, David J. Sand, Paul Bennet, Denija Crnojevic, Catherine E. Fielder, Ananthan Karunakaran, Brian R. Kent, Nicolas Mazziotti, Burcin Mutlu-Pakdil, Kristine Spekkens

AI总结:

本研究发现了此前被认为光学暗弱、几乎无恒星的ALFALFA Virgo 7云复合体的低光度恒星对应体BC6,证实其富气、正在产星,可能源于极端冲压剥离,并计划通过公民科学搜索同类天体。

摘要:

我们发现了ALFALFA Virgo 7(阿尔法法室女座7号)云复合体的恒星对应体,该复合体自2007年被发现以来,一直被认为是光学暗弱且几乎不含恒星的。这条长约190千秒差距的巨型原子气体云链(中性氢质量$M_\text{HI} \sim 10^9 \\\\; \mathrm{M_\odot}$)嵌入室女座星系团的高温星系团内介质中,但与任何星系都相互隔绝。其暗弱的蓝色恒星对应体BC6,是在对存档光学和紫外观测图像进行目视搜索时识别出来的。\n\n通过绿岸望远镜(Green Bank Telescope)、霍比-埃伯利望远镜(Hobby-Eberly Telescope)和哈勃空间望远镜(Hubble Space Telescope)的后续观测证实,这一暗弱对应体的运动速度与原子气体一致,正处于活跃的恒星形成阶段,且金属丰度较高($12 + \mathrm{(O/H)} = 8.58 \pm 0.25$)。我们估算其恒星质量仅为$\log ( M_\ast/\mathrm{M_\odot}) \sim 4.4$,使其成为目前已知富气程度最高的恒星系统之一。\n\n除了极高的气体含量外,BC6的各项性质与近期发现的一类室女座年轻、小质量、孤立的恒星形成云完全相符,这类云被认为是通过极端冲压剥离事件形成的。我们拓展了关于该结构起源的现有讨论,并提出NGC 4522是可能的前身星系候选体,但目前的证据与我们提出的所有前身星系假设都不能完全吻合。我们推测室女座中其他“暗”气体云可能也存在类似的暗弱恒星形成对应体,计划通过针对整个星系团的公民科学搜索来识别这些天体。

英文摘要:

We have discovered the stellar counterpart to the ALFALFA Virgo 7 cloud complex, which has been thought to be optically dark and nearly star-free since its discovery in 2007. This ~190 kpc long chain of enormous atomic gas clouds ($M_\mathrm{HI} \sim 10^9 \; \mathrm{M_\odot}$) is embedded in the hot intracluster medium of the Virgo galaxy cluster but is isolated from any galaxy. Its faint, blue stellar counterpart, BC6, was identified in a visual search of archival optical and UV imaging. Follow-up observations with the Green Bank Telescope, Hobby-Eberly Telescope, and Hubble Space Telescope demonstrate that this faint counterpart is at the same velocity as the atomic gas, is actively forming stars, and is metal-rich ($12 + \mathrm{(O/H)} = 8.58 \pm 0.25$). We estimate its stellar mass to be only $\log ( M_\ast/\mathrm{M_\odot}) \sim 4.4$, making it one of the most gas-rich stellar systems known. Aside from its extraordinary gas content, the properties of BC6 are entirely consistent with those of a recently identified class of young, low-mass, isolated, and star-forming clouds in Virgo, that appear to have formed via extreme ram pressure stripping events. We expand the existing discussion of the origin of this structure and suggest NGC 4522 as a likely candidate, however, the current evidence is not fully consistent with any of our proposed progenitor galaxies. We anticipate that other "dark" gas clouds in Virgo may have similarly faint, star-forming counterparts. We aim to identify these through the help of a citizen science search of the entire cluster.

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。

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