On the Properties of Spectroscopically Confirmed Ultra-diffuse Galaxies across Environments
On the Properties of Spectroscopically Confirmed Ultra-diffuse Galaxies across Environments
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DOI：
10.3847/1538-4357/ac2948
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发表时间：
2021-09
期刊：
影响因子：
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通讯作者：
J. Kadowaki;D. Zaritsky;R. Donnerstein;Pranjal Rs;A. Karunakaran;K. Spekkens
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文献类型：
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作者：
J. Kadowaki;D. Zaritsky;R. Donnerstein;Pranjal Rs;A. Karunakaran;K. Spekkens
在用大双筒望远镜对23个候选星系进行了长缝光谱跟踪活动后，我们给出了系统测量超扩散星系(污点)调查中19个候选超扩散星系(UDG)的新红移测量结果。我们将这些结果与来自其他来源的29个污点和20个非污点候选UDG的红移测量结合在一起。这个样本总共产生了44个光谱确认的UDG(Re≥1.5kpc和μg(0)≥24 MAg arcsec−2，在不确定范围内)，并跨越星系团和野外环境，除了一个外，所有的UDG都投射到彗星团和环境上。我们发现团簇和非团簇确认的UDG的结构参数没有统计上的显著差异，尽管轴比分布之间有迹象的差异。同样，我们发现在局部密集或稀疏环境中的那些人之间没有显著的结构性差异。然而，我们观察到投影的星团中心半径在颜色上的显著差异，证实了以前在UDG统计样本中观察到的趋势。当考虑到UDG是否驻留在星团或局部密集环境中时，这一趋势进一步加强，这表明驻留在高密度环境和低密度环境中的UDG的恒星形成历史截然不同。在我们的样本中的16个大的(Re≥3.5kpc)UDG中，只有一个是落入早期类型星系红色序列附近的场星系。在低密度环境中没有发现其他野外UDG落在红色序列附近。这一发现，再加上我们对稀疏环境中近一半UDG中的星系演化探测器NUV通量的检测，表明场域UDG是一群缓慢演化的星系。
We present new redshift measurements for 19 candidate ultra-diffuse galaxies (UDGs) from the Systematically Measuring Ultra-Diffuse Galaxies (SMUDGes) survey after conducting a long-slit spectroscopic follow-up campaign on 23 candidates with the Large Binocular Telescope. We combine these results with redshift measurements from other sources for 29 SMUDGes and 20 non-SMUDGes candidate UDGs. Together, this sample yields 44 spectroscopically confirmed UDGs (r e ≥ 1.5 kpc and μ g (0) ≥ 24 mag arcsec−2 within uncertainties) and spans cluster and field environments, with all but one projected on the Coma cluster and environs. We find no statistically significant differences in the structural parameters of cluster and noncluster confirmed UDGs, although there are hints of differences among the axis ratio distributions. Similarly, we find no significant structural differences among those in locally dense or sparse environments. However, we observe a significant difference in color with respect to projected clustercentric radius, confirming trends observed previously in statistical UDG samples. This trend strengthens further when considering whether UDGs reside in either cluster or locally dense environments, suggesting starkly different star formation histories for UDGs residing in high- and low-density environments. Of the 16 large (r e ≥ 3.5 kpc) UDGs in our sample, only one is a field galaxy that falls near the early-type galaxy red sequence. No other field UDGs found in low-density environments fall near the red sequence. This finding, in combination with our detection of Galaxy Evolution Explorer NUV flux in nearly half of the UDGs in sparse environments, suggests that field UDGs are a population of slowly evolving galaxies.