This paper presents the analysis of candidate quiescent low mass xray binarie (qLMXBs) observed during a short Chandra/ACIS observation of the globular cluster (GC) NGC 6304. Two out of the three candidate qLMXBs of this cluster, XMMU 171433-292747 and XMMU 171421-292917, lie within the field of view. This permits comparison with the discovery observation of these sources. The one in the GC core -- XMMU 171433-292747 -- is spatially resolved into two separate X-ray sources, one of which is consistent with a pure H-atmosphere qLMXB, and the other is an X-ray power-law spectrum source. These two spectral components separately account for those observed from XMMU 171433-292747 in its discovery observation. We find that the observed flux and spectral parameters of the H-atmosphere spectral components are consistent with the previous observation, as expected from a qLMXB powered by deep crustal heating. XMMU 171421-292917 also has neutron star atmosphere spectral parameters consistent with those in the XMM-Newton observation and the observed flux has decreased by a factor 0.54^{+0.30}_{-0.24}.
AstroSat UVIT Detections of Chandra X-ray Sources in M31
在2017-19年期间，利用AstroSat天文台上的UVIT仪器对M31进行了紫外线调查。在这里，我们将M31 UVIT源目录（Leahy et al. 2020）与Chandra源目录（Vulic et al. 2016）进行了匹配。我们发现67 UVIT/钱德拉源检测到不同数量的紫外线和X射线波段。用幂律模型和黑体模型分析了紫外和X射线光度学。X射线类型包括15个LMXB和5个活动星系核。与恒星、星团和其他源类型的目录交叉匹配产生以下结果。其中20个UVIT/Chandra源与M31球状星团匹配，9个与前景星匹配。另外3个球状星团和2个前景星与紫外线源位置一致，尽管在钱德拉匹配半径1角秒之外。与球状星团相关的UVIT/Chandra源的紫外辐射与蓝色水平分支星的辐射一致，而不是来自X射线源。球状星团中的LMXB是M31中最明亮的球状星团之一。与恒星演化轨迹的比较表明，具有高紫外黑体温度的UVIT/Chandra源与M31中的大质量（10 ~ 30 M $_{\odot}$）恒星是一致的。
Discovery of Ancient Globular Cluster Candidates in the Relic, a Quiescent Galaxy at $z=2.5$
University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Department of Physics & Astronomy, Tufts University（塔夫茨大学物理与天文学系）；Ritter Astrophysical Research Center, University of Toledo（托莱多大学里特天体物理研究中心）；Department of Astrophysical Sciences, Princeton University（普林斯顿大学天体物理科学系）；Department of Physics, Ben-Gurion University of the Negev（内盖夫本-古里安大学物理系）；Department of Physics & Astronomy and PITT PACC, University of Pittsburgh（匹兹堡大学物理与天文学系及PITT PACC）；Centre for Astrophysics and Supercomputing, Swinburne University of Technology（斯威本科技大学天体物理与超级计算中心）
