George Djorgovski
California Inst. Technology (Caltech) (Pasadena, California, Etats-Unis d'Amérique)
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
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| « Black Holes From the Dark Ages: Probing the Reionization Era With Quasars and Gamma-Ray Bursts » |
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George Djorgovski |
| Exploration of the cosmic reionization era - from the appearance of the first luminous sources to the end of the phase transition when the intergalactic hydrogen becomes fully reionized and transparent to the UV light - is now rapidly becoming an active frontier of cosmological research. Luminous sources at redshifts z > 6 can be used to probe this fundamental era. High-z QSOs can be used both as markers of sites of early massive galaxy formation, and as absorption probes of the IGM along the line sight. Such objects are very rare; we will describe a large new survey, Palomar-Quest, in which one of the science goals is to discover a statistically significant samples of high-z QSOs to be used as cosmological probes. Gamma-ray bursts from the first generations of massive stars may be used to probe even higher redshifts, yielding the information on the formation of first stars, early chemical enrichment, and the early history of IGM. We will describe some prospects for the detection of such events in the next few years. |
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vendredi 11 juin 2004 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |