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Title: How far do hot X-ray halos extend around Milky Way-mass galaxies?
Plain: Galaxies like ours should be wrapped in gas at a million degrees, which glows faintly in X-rays. Its density profile and how far out it reaches are only beginning to be measured.
Precise: Determine the electron density profile $n_{e}(r)$ and temperature of X-ray emitting gas ($T \sim 1e6\,\mathrm{K}$) around galaxies with $M_{*} \sim 3e10\text{ to }1e11\,M_{\mathrm{sun}}$ out to the virial radius (about 250 kpc), including the slope (for example a beta-model with $\beta \sim 0.5$) and the total hot gas mass.
Settled by: Stacked deep X-ray surface brightness profiles with resolved temperature and metallicity, combined with thermal Sunyaev-Zeldovich profiles for the same galaxies.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: partially-resolved
Status note: eROSITA All-Sky Survey stacking detected extended hot gas around Milky Way-mass galaxies (Zhang et al., A&A, 2024), with the total mass and its dependence on contamination by satellites and point sources debated.
Posed since: (empty)