Presentation #110.08 in the session LEM.
The circum-galactic medium (CGM) of the Milky Way exhibits a prominent, large-scale feature. Namely, the Fermi and the eROSITA bubbles, two bipolar cocoon-like structures emerging from the Galactic Center, extending below and above the Galaxy’s disk up to 7-14 kpc, and emitting in gamma-ray and X-ray, respectively. What are the physical mechanisms that inflated such structures? Feedback from star-formation or energy injections from the super-massive black hole (SMBH) at the center of our Galaxy? And are such CGM features unique to our Milky Way? According to the cosmological magnetohydrodynamical simulation of galaxies TNG50, X-ray bubbles similar to (or more extended than) the ones (already) seen in the Milky Way could be a frequent feature of disk-like galaxies prior to, or on the verge of, being quenched in their star formation. In the TNG50 model, these are the manifestations of episodic kinetic energy injections by low-luminosity SMBHs. In this poster, we quantify the potential discovery of possible eROSITA-like features in the CGM of external disk-like, edge-on galaxies by focusing on the Line Emission Mapper (LEM), a NASA probe-class mission concept. Thanks to its spectral resolution and large grasp, LEM will offer unprecedented opportunities — it will allow to separate the CGM of external galaxies from the one of our own foreground Galaxy, to map the entire gaseous haloes of galaxies in the local Universe, and to distinguish and capitalize upon the individual contributions of narrow X-ray bands around emission lines such as OVII, OVIII and FeXVII, in which eROSITA-like bubbles are predicted to be particularly prominent.