AGC 226178 and NGVS 3543: Two Deceptive Dwarfs toward Virgo
AGC 226178 and NGVS 3543: Two Deceptive Dwarfs toward Virgo
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DOI：
10.3847/2041-8213/ac51dc
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Michael G. Jones;D. Sand;M. Bellazzini;K. Spekkens;J. Cannon;B. Mutlu-Pakdil;A. Karunakaran;G. Be
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文献类型：
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作者：
Michael G. Jones;D. Sand;M. Bellazzini;K. Spekkens;J. Cannon;B. Mutlu-Pakdil;A. Karunakaran;G. Be
两个光源AGC 226178和NGVS 3543，一个极暗的蓝色星团系统和一个低表面亮度的矮椭球体，是室女座星系团方向上的相邻系统。这两个星系之前都被详细研究过，有人认为它们是不相关的正常矮星系，或者NGVS 3543最近通过冲压压力剥离失去了气体，AGC 226178就是由这些剥离的气体形成的。然而，利用哈勃太空望远镜高级巡天照相机成像，我们证明NGVS 3543的恒星数量与室女座星团的距离不一致，它可能是一个大约10 Mpc的前景天体，而AGC 226178的恒星数量与室女座星团中一个非常年轻（10- 1亿年）的天体一致。通过重新分析原来的阿尔法H i检测，我们表明，AGC 226178可能是从附近的矮星系VCC 2034剥离的气体形成的，这一假设得到了MUSE VLT观测测量的高金属丰度的加强。然而，目前还不清楚是否冲压压力或潮汐相互作用是负责剥离的气体。AGC 226178是目前已知的至少五个与室女座相似的天体之一。这些天体都很年轻，不太可能在超过1.5亿年的时间里保持可见，这表明它们在星团中不断产生。
The two sources AGC 226178 and NGVS 3543, an extremely faint, clumpy, blue stellar system and a low surface brightness dwarf spheroidal, are adjacent systems in the direction of the Virgo cluster. Both have been studied in detail previously, with it being suggested that they are unrelated normal dwarf galaxies or that NGVS 3543 recently lost its gas through ram pressure stripping and AGC 226178 formed from this stripped gas. However, with Hubble Space Telescope Advanced Camera for Surveys imaging, we demonstrate that the stellar population of NGVS 3543 is inconsistent with being at the distance of the Virgo cluster and that it is likely a foreground object at approximately 10 Mpc, whereas the stellar population of AGC 226178 is consistent with it being a very young (10–100 Myr) object in the Virgo cluster. Through a reanalysis of the original ALFALFA H i detection, we show that AGC 226178 likely formed from gas stripped from the nearby dwarf galaxy VCC 2034, a hypothesis strengthened by the high metallicity measured with MUSE VLT observations. However, it is unclear whether ram pressure or a tidal interaction is responsible for stripping the gas. Object AGC 226178 is one of at least five similar objects now known toward Virgo. These objects are all young and unlikely to remain visible for over ∼500 Myr, suggesting that they are continually produced in the cluster.