Bibliographic Details
| Title: |
The warm-hot circumgalactic medium of the Milky Way as seen by eROSITA |
| Authors: |
Locatelli, N., Ponti, G., Zheng, X., Merloni, A., Becker, W., Comparat, J., Dennerl, K., Freyberg, M. J., Sasaki, M., Yeung, M. C. H. |
| Source: |
A&A 681, A78 (2024) |
| Publication Year: |
2023 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies |
| More Details: |
The first all-sky maps of the diffuse emission of high ionization lines observed in X-rays by SRG/eROSITA, provide an excellent probe for the study of the warm-hot phase (T~10^6 K) of the circumgalactic medium (CGM) of the Milky Way (MW). In this work we analyse the O VIII line detected in the first eROSITA All-Sky Survey data (eRASS1). We fit a sky map made in a narrow energy bin around this line, with physical emission models embedded in a 3D geometry to constrain the density distribution of the warm-hot gas around our Galaxy, with a focus on mid and high (absolute) Galactic latitudes. By masking out the eROSITA bubbles and other bright extended foreground sources, we find that an oblate geometry of the warm-hot gas (T~0.15-0.17 keV), flattened around the Galactic disk with scale height z_h~1-3 kpc, best describes the eRASS1 O VIII map, with most of the observed emission resulting to be produced within a few kpc from the Sun. The additional presence of a large scale warm-hot spherical halo, while providing a minor contribute to the X-ray emission, accounts for the high O VII absorption column densities detected with XMM-Newton, as well as most of the baryon budget of the CGM of the MW. The eROSITA data carry the largest amount of information and detail of O VIII CGM intensities to date, allowing for a significant reduction of the statistical uncertainties of the inferred physical parameters.
Comment: Accepted for publication in Astronomy & Astrophysics |
| Document Type: |
Working Paper |
| DOI: |
10.1051/0004-6361/202347061 |
| Access URL: |
http://arxiv.org/abs/2310.10715 |
| Accession Number: |
edsarx.2310.10715 |
| Database: |
arXiv |
