论文标题
一个尾巴的故事：M81组中的潮汐干扰超扩散星系
A Tale of a Tail: A Tidally-Disrupting Ultra-Diffuse Galaxy in the M81 Group
论文作者
论文摘要
我们介绍了与F8D1相关的恒星的巨大潮汐尾巴，这是最接近的超扩散星系（UDG）的示例。 F8D1坐落在被银河卷心菜严重污染的天空区域中，自二十年前发现以来，它的研究很差。潮汐特征在已解决的红色巨型分支星星的深度图中显示出，该星星使用我们的Subaru Hyper Soprime-Cam调查的M81组构建的数据构建。它的平均表面亮度为$μ_g\ sim 32 $ mag arcsec $^{ - 2} $，可以通过我们当前的图像追溯到天空（60 kpc of F8d1的60 kpc）上。我们使用用Megacam在CFHT上获得的深层多播图像重新访问F8D1的主体性能，并测量有效半径为$ 1.7-1.9 $ kpc，中央表面亮度为$ 24.7-25.7 $ mag和$ \ sim7 \ sim7 \ sim7 \ sim7 \ times 10^7 m_ _ _ _ _ {假设银河系的另一侧具有对称特征，我们计算出F8D1当今的亮度的$ 30-36美元。我们认为，F8D1中断的最有可能起源是最近通往M81的近距离通道，这将剥夺其气体并淬灭其恒星形成。作为迄今为止研究到如此微弱的表面亮度深度的唯一UDG，F8D1潮汐破坏的揭幕很重要。它打开了许多其他UDG可能是类似过程的结果的可能性，而这种潜伏在当前检测限的可能性最有可能。
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 $μ_g \sim 32$ mag arcsec$^{-2}$ and 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 $\sim7 \times 10^7 M_{\odot}$. Assuming a symmetric feature on the other side of the galaxy, we calculate that $30-36$% 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.
