Evidence for Ultra-diffuse Galaxy “Formation” through Galaxy Interactions
Evidence for Ultra-diffuse Galaxy “Formation” through Galaxy Interactions
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DOI：
10.3847/2041-8213/aadedf
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
P. Bennet;D. Sand;D. Zaritsky;D. Crnojevi'c;K. Spekkens;A. Karunakaran
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文献类型：
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作者：
P. Bennet;D. Sand;D. Zaritsky;D. Crnojevi'c;K. Spekkens;A. Karunakaran
我们报告了在对加拿大-法国-夏威夷望远镜遗产调查的大范围搜索中发现的两个超扩散星系(UDG)，这两个星系显示出明显的证据表明与潮汐物质有关，并与一个更大的星系晕相互作用。这两个新的UDG，NGC2708-DW1和NGC5631-DW1，是微弱的(mg=−13.7和−11.8)，伸展的(Rh=2.60和2.15kpc)，具有较低的中心表面亮度(μ(g，0)=24.9和27.3mag弧秒−2)，而与它们相关的恒星流具有表面亮度μ(G)≳28.2mag弧秒−2。这些观测提供了一些UDG的起源可能与星系相互作用有关的证据，要么是通过扩展正常矮星系来转化它们，要么是通过扩展它们来转化正常的矮星系。或者是因为UDG可以从潮汐物质中坍塌出来(即它们是潮汐矮小星系)。还需要进一步的工作来了解通过星系相互作用而形成的UDG群体的比例，而对扩散矮星系的大范围搜索将为这些神秘的恒星系统的起源提供进一步的线索。
We report the discovery of two ultra-diffuse galaxies (UDGs) that show clear evidence of an association with tidal material and an interaction with a larger galaxy halo, found during a search of the Wide portion of the Canada–France–Hawaii Telescope Legacy Survey. The two new UDGs, NGC 2708-Dw1 and NGC 5631-Dw1, are faint (Mg = −13.7 and −11.8 mag), extended (rh = 2.60 and 2.15 kpc), and have low central surface brightness (μ(g, 0) = 24.9 and 27.3 mag arcsec−2), while the stellar stream associated with each has a surface brightness μ(g) ≳ 28.2 mag arcsec−2. These observations provide evidence that the origin of some UDGs may connect to galaxy interactions, either by transforming normal dwarf galaxies by expanding them, or because UDGs can collapse out of tidal material (i.e., they are tidal dwarf galaxies). Further work is needed to understand the fraction of the UDG population “formed” through galaxy interactions, and wide field searches for diffuse dwarf galaxies will provide further clues to the origin of these enigmatic stellar systems.