Lazaros Souvaitzis | AUTH - Academia.edu (original) (raw)
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Papers by Lazaros Souvaitzis
Epj Web of Conferences, 2022
A di↵erent chemistry of the interstellar medium (ISM) is expected in the circumgalactic medium (C... more A di↵erent chemistry of the interstellar medium (ISM) is expected in the circumgalactic medium (CGM) gas where high-energetic particles (i.e. cosmic rays) seem to be produced in-situ by the hot X-ray gas, as it is observed in the Perseus cluster. This very di↵erent astrochemistry, where extreme gas-dust thermal decoupling is expected, and where CO can be destroyed over large massscales, is the subject of the investigation briefly reported here. We introduce an ongoing project aiming at studying the properties of the CGM of two clusters at low and high redshift using their molecular gas tracers and thermal emission from dust. 1 Circumgalactic Medium in Galaxy clusters: Why? The circumgalactic medium (CGM) is the site where galaxies exchange their gas with the surrounding environment via inflows from the CGM to the galaxy and/or outflows powered by AGN and star formation which may deposit chemically enriched material in the CGM. The CGM therefore represents a site where physical conditions might be di↵erent from the less extreme interstellar medium of galaxy discs. It is expected that in galaxy clusters (GCs) with intense SF and/or AGN activities the CGM (and intracluster medium, ICM) contain large amounts of lower-density, galaxy-expelled, molecular gas and dust, which would then be subjected to a high-energy particle-dominated chemistry [see, 4-7, 13, 21, 22]. Strong H 2 winds are expected from galaxy cluster members with SFR ⇠ 150-250 M � yr −1 , injecting gas and dust into the CGM/ICM [7]. In these media, dust is very efficiently cooled by thermal emission while no longer heated by the far-UV photons (from the distant SF inside the BCG) nor by ambient CRs.
Epj Web of Conferences, 2022
A di↵erent chemistry of the interstellar medium (ISM) is expected in the circumgalactic medium (C... more A di↵erent chemistry of the interstellar medium (ISM) is expected in the circumgalactic medium (CGM) gas where high-energetic particles (i.e. cosmic rays) seem to be produced in-situ by the hot X-ray gas, as it is observed in the Perseus cluster. This very di↵erent astrochemistry, where extreme gas-dust thermal decoupling is expected, and where CO can be destroyed over large massscales, is the subject of the investigation briefly reported here. We introduce an ongoing project aiming at studying the properties of the CGM of two clusters at low and high redshift using their molecular gas tracers and thermal emission from dust. 1 Circumgalactic Medium in Galaxy clusters: Why? The circumgalactic medium (CGM) is the site where galaxies exchange their gas with the surrounding environment via inflows from the CGM to the galaxy and/or outflows powered by AGN and star formation which may deposit chemically enriched material in the CGM. The CGM therefore represents a site where physical conditions might be di↵erent from the less extreme interstellar medium of galaxy discs. It is expected that in galaxy clusters (GCs) with intense SF and/or AGN activities the CGM (and intracluster medium, ICM) contain large amounts of lower-density, galaxy-expelled, molecular gas and dust, which would then be subjected to a high-energy particle-dominated chemistry [see, 4-7, 13, 21, 22]. Strong H 2 winds are expected from galaxy cluster members with SFR ⇠ 150-250 M � yr −1 , injecting gas and dust into the CGM/ICM [7]. In these media, dust is very efficiently cooled by thermal emission while no longer heated by the far-UV photons (from the distant SF inside the BCG) nor by ambient CRs.