Journal-club Postdoc |
| « Using quasar eclipses to reveal quasar host galaxies » |
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Hassan Fathivavsari |
| Luminous high-redshift quasars consist of supermassive black holes residing at the center of massive galaxies and growing through mass accretion of gas into an accretion disk. Bright quasars play an important role in shaping their host galaxies through the emission of ionizing flux but also through launching powerful and high-velocity outflows of gas. These outflows bring energy and material to the disk of the galaxy and even to larger distances. It has remained unclear however what are the mechanisms that drive energy from the very center of the active galactic nuclei (AGN) to the outskirts of the galaxy. If outflows are observed both on small and large scales, how the small scale outflows are transported at larger distances remains unclear. This is however a crucial question as these outflows are massive and energetic enough to significantly influence the formation of the host galaxy, providing significant metal enrichment to the interstellar and intergalactic medium. Very recently, we searched quasar spectra from the SDSS-III BOSS database for the rare occurrences where a strong damped Lyman- absorber (DLA) blocks the Broad Line Region emission from the quasar and acts as a natural coronagraph to reveal narrow Lyman-alpha emission from the host galaxy. In this search, we found one object SDSS J0823+0529 where the DLA does not cover entirely the broad line region. We show here that this is a unique opportunity to study the link between the properties of the central regions of the AGN to that of the gas in the halo of the quasar. |
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mardi 23 juin 2015 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
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