作为2MRS星系群的大型eROSITA X射线源
Large eROSITA X-ray sources as 2MRS galaxy groups
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中文总结 AI 辅助
本研究利用eROSITA数据开发新型识别方法，得到619个80%纯度的X射线星系群目录，其光度函数与以往研究一致，可用于重子分布的宇宙学研究。
中文摘要 AI 辅助
本研究旨在利用eROSITA的大面积覆盖、良好灵敏度及低仪器背景，探测来自2微米全天巡天红移巡天（2MRS）的星系群的微弱面亮度发射。我们使用eROSITA-DE数据发布1的数据，包括图像、曝光图和本地背景图，对0.6-2.3 keV波段的图像拼接图进行了角尺度为1/8-16'的小波分解。我们采用8-16'尺度进行源检测，采用2-4'尺度提高目录纯度。一种基于排序部分豪斯多夫距离的新型识别方法充分利用了X射线图像和群成员信息。我们使用随机目录控制匹配纯度，并选择识别阈值以在固定纯度下最大化目录规模。我们提出了一个包含619个X射线星系群、纯度为80%的目录，并定义了纯度为90%和97%的子样本。亮源与AXES-2MRS目录（该目录基于ROSAT全天天图在12-24'空间尺度上的数据分析）高度匹配。我们的星系群的X射线光度函数与以往研究在低至5×10^41 erg/s的范围内一致。利用动力学质量估计，我们发现成员数≥4的星系群的X射线对应体完整性在质量>2×10^13 Msun时超过60%。我们对2MRS星系群目录进行了建模，并证明将双成员群纳入识别是合理的。本研究表明，利用邻近星系群目录可以可靠地检测和识别与重子分布宇宙学研究相关的空间尺度上的大型X射线源。
英文摘要
We aim to exploit the large area coverage, good sensitivity, and low instrumental background of eROSITA to detect the faint surface brightness emission of galaxy groups from the Two Micron All Sky Survey Redshift Survey (2MRS). Using the data from eROSITA-DE Data Release 1, including images, exposure maps, and local background maps, we performed a wavelet decomposition of image mosaics in the 0.6--2.3 keV band at angular scales of 1/8-16'. We adopted 8-16' scales for source detection and 2-4' scales to improve catalog purity. A novel identification method based on the ranked partial Hausdorff distance fully exploits the X-ray image and group membership information. Random catalogs were used to control match purity, and the identification threshold was chosen to maximize the catalog size at a fixed purity. {We present a catalog of 619 X-ray galaxy groups with 80% purity, and define subsamples with 90% and 97% purity. Bright sources closely match the AXES-2MRS catalog (which is based on ROSAT All Sky Survey data analysis on spatial scales of 12-24'). The X-ray luminosity function of our groups agrees with previous studies down to 5.e41 erg/s. Using dynamical mass estimates, we find that the X-ray counterpart completeness for groups with >=4 members exceeds 60% for masses >2e13 Msun. We modeled the 2MRS group catalog and justify the inclusion of two-member groups in the identification. This study demonstrates that large X-ray sources on spatial scales relevant for cosmological studies of baryonic distributions can be reliably detected and identified using nearby galaxy group catalogs.
