A tale of a tail: a tidally disrupting ultra-diffuse galaxy in the M81 group
A tale of a tail: a tidally disrupting ultra-diffuse galaxy in the M81 group
复制标题
尾巴的故事：M81群中潮汐扰动的超漫射星系
DOI：
10.1093/mnras/stac3133
复制
发表时间：
2022
影响因子：
4.8
通讯作者：
Irwin Mike J
中科院分区：
文献类型：
--
作者：
Zemaitis Rokas;Ferguson Annette M N;Okamoto Sakurako;Cuillandre Jean-Charles;Stone Connor J;Arimoto Nobuo;Irwin Mike J
我们发现了与 F8D1 相关的巨大恒星潮汐尾，F8D1 是已知最接近的超漫射星系 (UDG) 的例子。 F8D1 位于天空中被银河卷云严重污染的区域，自二十年前被发现以来，对其进行的研究很少。利用我们对 M81 群的 Subaru Hyper Suprime-Cam 巡天数据构建的红巨星分支恒星深度图揭示了潮汐特征。它的平均表面亮度为 μg∼ 32 mag arcsec−2，并且可以用我们当前的图像在天空上追踪超过一度（在 F8D1 距离处为 60 kpc）。我们使用 MegaCam 在 CFHT 上获取的深层多波段图像重新审视了 F8D1 的主体特性，并测量了 1.7–1.9 kpc 的有效半径、24.7–25.7 星等的中心表面亮度以及 ∼7 × 107M⊙ 的恒星质量。假设银河系的另一侧具有对称特征，我们计算出 F8D1 目前光度的 30-36% 包含在尾部。我们认为，F8D1 破坏的最可能起源是最近靠近 M81，这会剥离其气体并终止其恒星形成。作为迄今为止唯一被研究到如此微弱的表面亮度深度的 UDG，F8D1 潮汐破坏的揭秘非常重要。它留下了一种可能性，即许多其他 UDG 可能是类似过程的结果，其中最明显的特征潜伏在当前的检测极限以下。
We present the discovery of a giant tidal tail of stars associated with F8D1, the closest known example of an ultra-diffuse galaxy (UDG). F8D1 sits in a region of the sky heavily contaminated by Galactic cirrus and has been poorly studied since its discovery two decades ago. The tidal feature was revealed in a deep map of resolved red giant branch stars constructed using data from our Subaru Hyper Suprime-Cam survey of the M81 Group. It has an average surface brightness of μg∼ 32 mag arcsec−2and can be traced for over a degree on the sky (60 kpc at the distance of F8D1) with our current imagery. We revisit the main body properties of F8D1 using deep multiband imagery acquired with MegaCam on CFHT and measure effective radii of 1.7–1.9 kpc, central surface brightnesses of 24.7–25.7 mag, and a stellar mass of ∼7 × 107M⊙. Assuming a symmetric feature on the other side of the galaxy, we calculate that 30–36 per cent of F8D1’s present-day luminosity is contained in the tail. We argue that the most likely origin of F8D1’s disruption is a recent close passage to M81, which would have stripped its gas and quenched its star formation. As the only UDG that has so far been studied to such faint surface brightness depths, the unveiling of F8D1’s tidal disruption is important. It leaves open the possibility that many other UDGs could be the result of similar processes, with the most telling signatures of this lurking below current detection limits.