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arXiv 1702.00495astro-ph.GA
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SG1120-1202:在z=0.37时,在群环境中通过UV发射跟踪的质量淬火

SG1120-1202: Mass-Quenching as Tracked by UV Emission in the Group Environment at z=0.37

Jonathan T. Monroe, Kim-Vy H. Tran, Anthony H. Gonzalez

摘要:

我们使用哈勃太空望远镜获得了z=0.37的超群SG 1120 -1202的WFC 3/F390 W图像,映射了138个光谱确认成员的紫外发射。我们测量总(F390 W-F814 W)的颜色和视觉分类的紫外线形态的个别星系为“cloudly”或“平滑”。“大约30%的成员有紫外线发射口袋(cloudspot),我们第一次在群环境中识别出具有类似于在大质量星系团中观察到的水母星系的紫外线形态的星系。我们堆叠的cloud-UV成员和测量浅的内部颜色梯度,这表明清晰的恒星形成发生在这些星系。我们还堆叠的四个星系群,并测量一个强烈的趋势,减少紫外线发射减少投影组距离($R_{proj}$)。我们发现,紫外辐射减少和恒星质量增加之间的强相关性可以完全解释在(F390 W-F814 W)- $R_{proj}$中观察到的趋势,即,质量猝灭是星系群中紫外辐射熄灭的主要机制。我们对SG 1120 -1202进行的广泛的多波长分析表明,恒星质量是紫外线辐射的主要预测因子,但在$R_{proj}$ < 2 $R_{200}$处大质量(红色/光滑)星系的比例增加以及水母候选者的存在是由于群体环境。

英文摘要:

We use the Hubble Space Telescope to obtain WFC3/F390W imaging of the supergroup SG1120-1202 at z=0.37, mapping the UV emission of 138 spectroscopically confirmed members. We measure total (F390W-F814W) colors and visually classify the UV morphology of individual galaxies as "clumpy" or "smooth." Approximately 30% of the members have pockets of UV emission (clumpy) and we identify for the first time in the group environment galaxies with UV morphologies similar to the jellyfish galaxies observed in massive clusters. We stack the clumpy UV members and measure a shallow internal color gradient, which indicates unobscured star formation is occurring throughout these galaxies. We also stack the four galaxy groups and measure a strong trend of decreasing UV emission with decreasing projected group distance ($R_{proj}$). We find that the strong correlation between decreasing UV emission and increasing stellar mass can fully account for the observed trend in (F390W-F814W) - $R_{proj}$, i.e., mass-quenching is the dominant mechanism for extinguishing UV emission in group galaxies. Our extensive multi-wavelength analysis of SG1120-1202 indicates that stellar mass is the primary predictor of UV emission, but that the increasing fraction of massive (red/smooth) galaxies at $R_{proj}$ < 2$R_{200}$ and existence of jellyfish candidates is due to the group environment.

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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