Juan Uson
Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères, Observatoire de Paris (Paris, France)
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
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| « Living on the Edge: Superthin Galaxies and the Cosmic UV Background » |
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Juan Uson |
| Superthin galaxies are bulgeless, late-type spiral galaxies seen edge-on. HI synthesis observations probe the kinematic structure of their interstellar medium. Observations of these isolated, quiescent galaxies have reached column densities as low as few x 10^18 atoms.cm^-2. The simple structure of the superthins makes them ideal cosmological laboratories. The strength of the cosmic UV background has a strong influence on the formation of structure in the Universe, from the inhibition of the collapse of small haloes to the ionizing escape fraction in galaxies to the global star formation history. Recent (2010) H-alpha observations of UGC7321 and UGC1281 limit the strength of the local UV background below theoretical expectations (Adams et al., Astrophys. J., 728, 107, 2011). New observations (March 2011) have improved the sensitivity significantly (there's no substitute for a few photometric nights!) yielding a measurement of the cosmic UV background at z ~ 0. |
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vendredi 15 avril 2011 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |