A Measurement of Circumgalactic Gas around Nearby Galaxies Using Fast Radio Bursts
A Measurement of Circumgalactic Gas around Nearby Galaxies Using Fast Radio Bursts
复制标题
DOI：
10.3847/1538-4357/acbc7d
复制
发表时间：
2022-09
期刊：
影响因子：
--
通讯作者：
Xiaohan Wu;M. McQuinn
中科院分区：
文献类型：
--
作者：
Xiaohan Wu;M. McQuinn
气体在所有类型星系的环星系介质(CGM)中的分布受到很差的限制。前台CGMS对快速射电暴(FRB)的频散测量(DM)有额外的贡献。我们使用CHINE/FRB First数据发布测量了1011-1013M⊙晕的CGM的DM过剩，这是一个用任何其他方式都难以探测的晕质量范围。由于FRB角坐标的不确定性，只有对于附近的星系，定位才足以自信地将它们与任何前景光晕相交。因此，我们在80MPC以内的星系上进行堆叠，优化堆叠方案以近似最小化堆叠的方差，并将FRB位置的不确定性排除在外。样品有20-30个FRB相交，质量分别为1011-1012M⊙和1012M-1013M⊙，这些相交允许边缘1σ-2σ检测两个质量盒中的DM过剩。1011-1012M⊙晕盒在1-2维里半径处也显示出DM过剩。通过比较CGM气体剖面不同模型的数据，我们发现，与没有DM过剩的零假设相比，所有模型都被高达2σ水平的数据所支持。随着未来CHINE数据发布的3000多个突发，我们预计CGM的检测将达到4σ。通过将FRB堆叠成钟状的局部化来区分可行的CGM模型需要数万次爆发。
The distribution of gas in the circumgalactic medium (CGM) of galaxies of all types is poorly constrained. Foreground CGMs contribute an extra amount to the dispersion measure (DM) of fast radio bursts (FRBs). We measure this DM excess for the CGMs of 1011–1013 M ⊙ halos using the CHIME/FRB first data release, a halo mass range that is challenging to probe in any other way. Because of the uncertainty in the FRBs’ angular coordinates, only for nearby galaxies is the localization sufficient to confidently associate them with intersecting any foreground halo. Thus we stack on galaxies within 80 Mpc, optimizing the stacking scheme to approximately minimize the stack’s variance and marginalize over uncertainties in FRB locations. The sample has 20–30 FRBs intersecting halos with masses of 1011–1012 M ⊙ and also of 1012–1013 M ⊙, and these intersections allow a marginal 1σ–2σ detection of the DM excess in both mass bins. The bin of 1011–1012 M ⊙ halos also shows a DM excess at 1–2 virial radii. By comparing data with different models for the CGM gas profile, we find that all models are favored by the data up to 2σ level compared to the null hypothesis of no DM excess. With 3000 more bursts from a future CHIME data release, we project a 4σ detection of the CGM. Distinguishing between viable CGM models by stacking FRBs with CHIME-like localization would require tens of thousands of bursts.