Séminaire/Seminar Galaxies |
| « Little red dots -- JWST uncovers a new population of AGN at high redshifts » |
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Lukas Furtak |
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Active galactic nucleii (AGN) at high redshifts, observed when the Universe was only a few hundred Myr old, are crucial for our understanding of black hole growth in the early Universe. In particular, if gravitationally lensed and multiply imaged by an intervening strong lensing galaxy cluster, distant AGN can yield precious insight into AGN properties. We can even use them to constrain cosmological parameters by studying the time delay between the multiple images through the varying AGN activity. The advent of the JWST and its phenomenal near-infrared sensitivity and spatial resolution has initiated a new era in observations of strong lensing galaxy clusters and the lensed background sources. JWST observations allow us to push the frontier of observability towards fainter magnitudes and higher redshifts -- and thus uncovered a new population of dust-obscured red AGN at high redshifts.
In my talk I will present these red point-source objects observed with HST and JWST that represent new and hitherto unobserved populations of AGN. One case is even multiply-imaged by an intervening galaxy cluster in the foreground which opens fascinating prospects for future studies of its black hole properties and even cosmological parameters. |
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jeudi 19 octobre 2023 - 11:30 Salle 281 Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |