DESI 早期数据发布中的 GD-1 恒星流与胎儿
星系天体物理
2025-02-03 v2
摘要
我们报告了使用 5000 纤维的暗能量光谱仪（DESI）观测到的 115 颗新 spectroscopically 确认的 GD-1 恒星流成员。我们确认存在一个“胎儿”，其为宽的（FWHM~2.932 度 ~ 460 pc）且具有较高的速度分散（sigma ~ 5-8 km/s）的运动学热成分，包围着较窄的（FWHM~ 0.353 度 ~ 55）且具有较低温度（sigma = 3.09+/-0.76 km/s）的薄恒星流成分（基于每颗星的速度精度中值 2.7 km/s）。该胎儿在 DESI 观测到的该恒星流至少延伸覆盖 30 度。薄恒星流和胎儿成分的平均 [Fe/H] 值分别为 -2.54+/- 0.04 dex 和 -2.47+/- 0.06 dex，表明其源自同一天体。数据与以下 GD-1 恒星流胎儿起源的以下情景相符：（a）GD-1 恒星流的前体是被吸收的全球星团（GC），且胎儿在其仍位于其母星系内部时产生了气体层剥离；（b）胎儿来自母星系气体；（c）最初的薄 GC 恒星流因小鼠星系中的暗小卫星星体碰撞而受到加热；或（d）最初的薄 GC 恒星流因巨大的狮子座矮星系而受到加热；或上述某些情况的组合。未来的 DESI 光谱学和详细建模可能使我们能够区分这些可能的起源。
引用
@article{arxiv.2407.06336,
title = {GD-1 Stellar Stream and Cocoon in the DESI Early Data Release},
author = {Monica Valluri and Parker Fagrelius and Sergey. E. Koposov and Ting S. Li and Oleg Y. Gnedin and Eric F. Bell and Raymond G. Carlberg and Andrew P. Cooper and Jessia N. Aguilar and Carlos Allende Prieto and Vasily Belokurov and Leandro Beraldo e Silva and David Brooks and Amanda Byström and Todd Claybaugh and Kyle Dawson and Arjun Dey and Peter Doel and Jaime E. Forero-Romero and Enrique Gaztañaga and Satya Gontcho A Gontcho and Klaus Honscheid and T . Kisner and Anthony Kremin and A. Lambert and Martin Landriau and L. Le Guillou and Michael E. Levi and Axel de la Macorra and Mark Manera and Paul Martini and Gustavo E. Medina and Aaron Meisner and Ramon Miquel and John Moustakas and Adam D. Myer and Joan Najita and Claire Poppett and Francisco Prada and Mehdi Rezaie and Graziano Rossi and Alex H. Riley and Eusebio Sanchez and David Schlegel and Michael Schubnell and David Sprayberry and Gregory Tarlé and Guillaume Thomas and Benjamin A. Weaver and Risa H. Wechsler and Rongpu Zhou and Hu Zou},
journal= {arXiv preprint arXiv:2407.06336},
year = {2025}
}
备注
Accepted for publication in The Astrophysical Journal. 25 pages, 13 figures 4 tables; Minor changes to velocity spline fitted to the stream resulting in a small change in new GD1 stream members