Résumé / Abstract Journal-club_Galaxies

Journal-club Galaxies

« Outbursts from supermassive black holes seen in the hot atmospheres of early-type galaxies, galaxy groups, and rich clusters »

Bill Forman
Harvard-Smithsonian Center Astroph. (CfA) (Cambridge, Massachusetts, Etats-Unis d'Amérique)

We discuss the effects of supermassive black hole (SMBH) outbursts on the hot atmospheres of early type galaxies, galaxy groups, and galaxy clusters whose atmospheres are only seen through X-ray observations. The discussion is motivated by the need to understand the separation of galaxies into their two fundamental classes - the red and "dead" early type galaxies with little star formation and the blue clound (spiral, actively star forming galaxies). We show the detailed effects of the outbursts from the supermassive black hole in M87 at the center of the Virgo cluster using Chandra and XMM-Newton observations including buoyant bubbles of relativistic plasma produced by the central SMBH, uplifted filaments of X-ray emitting gas, and the Mach 1.2 shock. We present the results from a large survey of more than 100 early type galaxies observed with Chandra. From the X-ray images, we identify the sample of hot coronae that show gas cavities, estimate cavity ages, and compute the mechanical power needed to inflate the cavities. From the X-ray luminosities, we derive Eddington ratios and briefly discuss the accretion mode for these low-luminosity actice galactic nuclei. We compare the early-type galaxy AGN to their more powerful counterparts in rich clusters. Finally, we show the dramatic effects that SMBH outbursts can have on galaxy-scale hot coronae.
jeudi 2 février 2012 - 11:30
Salle 281, Institut d'Astrophysique
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