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| Title: |
| Constraining cosmic reionization with quasar, gamma ray burst, and Lyalpha emitter observations |
| Authors: |
| Gallerani, S.; Ferrara, A.; Choudhury, T. Roy; Fan, X.; Salvaterra, R.; Dayal, P. |
| Affiliation: |
| AA( INAF-Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone, Italy, gallerani@oa-roma.inaf.it), AB(Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy), AC(Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad 211 019, India), AD(Steward Observatory, 933 N. Cherry Ave, Tucson, AZ 85721-0065, US), AE(INAF-Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy), AF(Scuola Internazionale Superiore di Studi Avanzati, via Beirut 2-4, 34151 Trieste, Italy) |
| Publication: |
| Memorie della Società Astronomica Italiana Supplement, v.14, p.47 (2010) |
| Publication Date: |
| 00/2010 |
| Origin: |
| MmSAI |
| Keywords: |
| cosmology: large scale structure, intergalactic medium, quasars: absorption lines, gamma-ray: bursts, galaxies: high redshift, luminosity function |
| Abstract Copyright: |
| (c) 2010: SAIt |
| Bibliographic Code: |
| 2010MSAIS..14...47G |
Abstract
We investigate the cosmic reionization history by comparing semi-analytical models of the Lyalpha forest with observations of high-z quasars and gamma ray bursts absorption spectra. In order to constrain the reionization epoch z_rei, we consider two physically motivated scenarios in which reionization ends either early (ERM, z_reigtrsim 7) or late (LRM, z_rei≈ 6). We analyze the transmitted flux in a sample of 17 QSOs spectra at 5.7< z_em< 6.4 and in the spectrum of the GRB 050904 at z=6.3, studying the wide dark portions (gaps) in the observed absorption spectra. By comparing the statistics of these spectral features with our models, we conclude that current observational data do not require any sudden change in the ionization state of the IGM at z≈ 6, favouring indeed a highly ionized Universe at these epochs, as predicted by the ERM. Moreover, we test the predictions of this model through Lyalpha emitters observations, finding that the ERM provide a good fit to the evolution of the luminosity function of Lyalpha emitting galaxies in the redshift range z=5.7-6.5. The overall result points towards an extended reionization process which starts at zgtrsim 11 and completes at z_reigtrsim 7, in agreement with the recent WMAP5 data.
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