Circumgalactic Medium in X-ray emission
More results are coming soon ....
We investigate the super-virial phase of the Milky Way CGM using emission data from XMM-Newton, around a sightline where we detected this phase in absorption (Das et al. 2021, ApJ, 918, 83). For the first time, we have done "chemical tagging" of this phase to identify the element dominating the emission in this phase and its ionization states that are culprits to the discrepancy between the emission and absorption measurements. It can unambiguously reveal crucial information about different types of disk-wide stellar feedback in the past.
On-sky maps of the virial (left) and super-virial (right) phases of the Milky Way CGM probed in this paper (Bhattacharyya, Das, et al. 2023, ApJ, 952, 41)
Detection of the super-virial CGM of the Milky Way in X-ray emission using archival Suzaku data. The eROSITA bubble (the red ellipse in the figure) is not hotter but denser than the rest of the CGM. The chemical composition of the eROSITA Bubble is distinctly different from the interstellar medium of the Milky Way. It refutes the previous results in the literature (Gupta, Mathur, Kingsbury, Das & Krongold, 2023, NatAs, 4, 1)
Detection of the coexisting super-virial and virial phases of the Milky Way CGM in X-ray emission using Suzaku data along 10 sightlines (Gupta, Kingsbury, Mathur, Das, Krongold, Galeazzi, 2021, ApJ, 909, 2). It reinstates the discovery of the super-virial phase in Das et al. 2019, ApJ, 887, 257 using XMM-Newton data. The sightlines of Gupta et al. 2021 are away from the newly discovered eROSITA Bubble, confirming that the previous sightline of Das et al. 2019 that passes through the Bubble was not an outlier. A degeneracy between excess neon in the virial phase (bottom panel) and the presence of the super-virial phase (middle panel) is noted.
Cover image: Chandra News