Asymmetric eROSITA bubbles as the evidence of a circumgalactic medium wind

The eROSITA bubbles are detected via the instrument with the same name. The northern bubble shows noticeable asymmetric features, including distortion to the west and enhancement in the eastern edge, while the southern counterpart is significantly dimmer. Their origins are debated. Here, we performe...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2023-02
Main Authors: Mou, Guobin, Sun, Dongze, Fang, Taotao, Wang, Wei, Zhang, Ruiyu, Yuan, Feng, Sofue, Yoshiaki, Wang, Tinggui, He, Zhicheng
Format: Article
Language:English
Subjects:
Asymmetry
Bubbles
Deposition
Metallicity
Outflow
Surface brightness
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The eROSITA bubbles are detected via the instrument with the same name. The northern bubble shows noticeable asymmetric features, including distortion to the west and enhancement in the eastern edge, while the southern counterpart is significantly dimmer. Their origins are debated. Here, we performed hydrodynamic simulations showing that asymmetric eROSITA bubbles favor a dynamic, circumgalactic medium wind model, but disfavor other mechanisms such as a non-axisymmetric halo gas or a tilted nuclear outflow. The wind from the east by north direction in Galactic coordinates blows across the northern halo with a velocity of about 200 km s\(^{-1}\), and part of it enters the southern halo. This creates a dynamic halo medium and redistributes both density and metallicity within. This naturally explains the asymmetric bubbles in both the morphology and surface brightness. Our results suggest that our Galaxy is accreting low-abundance circumgalactic medium from one side while providing outflow feedback.
ISSN:2331-8422
DOI:10.48550/arxiv.2212.02270