Implications for galaxy formation models from observations of globular clusters around ultradiffuse galaxies
Implications for galaxy formation models from observations of globular clusters around ultradiffuse galaxies
复制标题
超漫射星系周围球状星团的观测对星系形成模型的影响
DOI：
10.1093/mnras/stac328
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发表时间：
2022
影响因子：
4.8
通讯作者：
Donnerstein, Richard
中科院分区：
文献类型：
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作者：
Saifollahi, Teymoor;Zaritsky, Dennis;Trujillo, Ignacio;Peletier, Reynier F;Knapen, Johan H;Amorisco, Nicola;Beasley, Michael A;Donnerstein, Richard
我们分析了哈勃太空望远镜对后发星团中六个超漫射星系（udg）中的球状星团（GCs）的观测结果，该样本代表了具有大有效半径（Re）的udg，并使用结果来评估相互竞争的形成模型。我们通过使用足够深的观测(i)达到球状星团亮度函数（GCLF）的周转率（ii）提供足够数量的GC来测量GC数的径向分布，从而消除了确定GC数的两个重要的系统不确定性来源，ngc。我们发现这些星系的ngc平均为~ 20，这意味着当应用ngcandmtotal之间的关系时，平均总质量Mtotal为~ 1011M⊙。ngclies的这个值位于相同恒星质量的矮星系观测到的范围的上端，大约比平均值大两倍。GCLF、径向轮廓和平均颜色与矮星系的观测结果比大质量（L*）星系的观测结果更一致，而径向和方位的GC分布与宿主星系的恒星分布密切相关。最后，我们讨论了为什么我们的观测结果，特别是这六个UDG周围的GC数量和GC分布，对目前一些受欢迎的UDG地层模型提出了挑战。
We present an analysis ofHubble Space Telescopeobservations of globular clusters (GCs) in six ultradiffuse galaxies (UDGs) in the Coma cluster, a sample that represents UDGs with large effective radii (Re), and use the results to evaluate competing formation models. We eliminate two significant sources of systematic uncertainty in the determination of the number of GCs,NGCby using sufficiently deep observations that (i) reach the turnover of the globular cluster luminosity function (GCLF) and (ii) provide a sufficient number of GCs with which to measure the GC number radial distribution. We find thatNGCfor these galaxies is on average ∼ 20, which implies an average total mass,Mtotal, ∼ 1011M⊙when applying the relation betweenNGCandMtotal. This value ofNGClies at the upper end of the range observed for dwarf galaxies of the same stellar mass and is roughly a factor of two larger than the mean. The GCLF, radial profile, and average colour are more consistent with those observed for dwarf galaxies than with those observed for the more massive (L*) galaxies, while both the radial and azimuthal GC distributions closely follow those of the stars in the host galaxy. Finally, we discuss why our observations, specifically the GC number and GC distribution around these six UDGs, pose challenges for several of the currently favoured UDG formation models.