Issue |
A&A
Volume 523, November-December 2010
|
|
---|---|---|
Article Number | A4 | |
Number of page(s) | 16 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/201014347 | |
Published online | 10 November 2010 |
Reionization by UV or X-ray sources
1
LERMA, Observatoire de Paris,
61 Av. de l’Observatoire,
75014
Paris,
France
2
Scuola Normale Superiore,
Piazza dei Cavalieri 7,
56126
Pisa,
Italy
e-mail: sunghye.baek@sns.it
3
Université Pierre et Marie Curie,
4 place Jussieu, 75005
Paris,
France
4
GEPI, Observatoire de Paris, 5 place Jules Janssen, 92195
Meudon Cedex,
France
5
Laboratoire d’Astrophysique, École Polytechnique Fédérale de
Lausanne (EPFL), Swizerland
Received:
3
March
2010
Accepted:
3
August
2010
We present simulations of the 21-cm signal during the epoch of reionization. We focus on properly modeling the absorption regime in the presence of inhomogeneous Wouthuysen-Field effect and X-ray heating. We ran radiative transfer simulations for three bands in the source spectrum (Lyman, UV, and X-ray) to fully account for these processes. We find that the brightness temperature fluctuation of the 21 cm signal has an amplitude greater than 100 mK during the early reionization, up to 10 times greater than the typical amplitude of a few 10 mK obtained during the later emission phase. More importantly, we find that even a rather high contribution from QSO-like sources only damps the absorption regime without erasing it. Heating the IGM with X-ray takes time. Our results show that observations of the early reionization will probably benefit from a higher signal-to-noise value than during later stages. After analyzing the statistical properties of the signal (power spectrum and PDF) we find three diagnostics to constrain the level of X-ray, hence the nature of the first sources.
Key words: dark ages, reionization, first stars / radiative transfer / HII regions / quasars: general / intergalactic medium / early Universe
© ESO, 2010
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.