Existence of tidal tails for the globular cluster NGC 5824

作者：Yong Yang, Jingkun Zhao, Miho N. Ishigaki, Masashi Chiba, Chengqun Yang, Xiang-Xiang Xue, Xianhao Ye, Gang Zhao · 发表于：Astronomy and Astrophysics · 年份：2022 · DOI：10.1051/0004-6361/202243976 · 被引用次数：6 · 研究领域：Stellar, planetary, and galactic studies、Astronomy and Astrophysical Research、Astrophysics and Star Formation Studies

Context. Several dynamically cold streams have been associated with certain globular clusters (GCs) based on orbital energies and angular momenta. Some of these streams are surprisingly far apart from their progenitors and one such pair is Triangulum and NGC 5824. Triangulum can be considered as a piece of the leading tail of NGC 5824 since the cluster’s future orbit matches well with the stream’s track. The existence of the leading tail of NGC 5824 is the motivation behind the search for its trailing tail. Aims. Our goal is to confirm the connection between Triangulum and NGC 5824. We also search for the trailing tail of the cluster. Methods. The selection of member stars of Triangulum is made through various cuts in metallicity, proper motions (PMs), radial velocity and a color–magnitude diagram (CMD). The selected members are compared in phase space to a mock stream that models the disruption of NGC 5824. We then try to detect the trailing tail of the cluster based on a modified matched-filter technique. Stars are assigned weights using their color differences from the cluster’s locus in the CMD. These weights are further scaled, based on the stars’ departures from expected PMs of the model stream. Results. A total of 26 member stars for Triangulum are obtained, 16 of which are newly identified. These members are consistent with the mock stream in the phase space, and their metalicity and position on the CMD are in good agreement with NGC 5824. By applying the matched filt...