Probing Individual Sources during Reionization and Cosmic Dawn using Square Kilometre Array HI 21-cm Observations
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Published version
Author(s)
Type
Journal Article
Abstract
Detection of individual luminous sources during the reionization epoch and cosmic dawn through their signatures in the HI 21-cm signal is one of the direct approaches to probe the epoch. Here, we summarize our previous works on this and present preliminary results on the prospects of detecting such sources using the SKA1-low experiment. We first discuss the expected HI 21-cm signal around luminous sources at different stages of reionization and cosmic dawn. We then introduce two visibility based estimators for detecting such signals: one based on the matched filtering technique and the other relies on simply combing the visibility signal from different baselines and frequency channels. We find that the SKA1-low should be able to detect ionized bubbles of radius Rb≳10Rb≳10 Mpc with ∼100 h of observations at redshift z∼8 provided that the mean outside neutral hydrogen fraction xHI≳0.5xHI≳0.5 . We also investigate the possibility of detecting HII regions around known bright QSOs such as around ULASJ1120+0641 discovered by Mortlock et al. (Nature474, 7353 (2011)). We find that a 5σ detection is possible with 600 h of SKA1-low observations if the QSO age and the outside xHI are at least ∼2×107 Myr and ∼0.2 respectively. Finally, we investigate the possibility of detecting the very first X-ray and Ly- α sources during the cosmic dawn. We consider mini-QSOs like sources which emits in X-ray frequency band. We find that with a total ∼ 1000 h of observations, SKA1-low should be able to detect those sources individually with a ∼ 9σ significance at redshift z=15. We summarize how the SNR changes with various parameters related to the source properties.
Date Issued
2016-11-04
Date Acceptance
2016-07-19
Citation
Journal of Astrophysics and Astronomy, 2016, 37 (4)
ISSN
0250-6335
Publisher
Indian Academy of Sciences
Journal / Book Title
Journal of Astrophysics and Astronomy
Volume
37
Issue
4
Copyright Statement
© 2016 Indian Academy of Sciences.
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Cosmology: cosmic reionization
21-cm signal
square kilometre array
LY-ALPHA EMITTERS
DETECTING IONIZED BUBBLES
REDSHIFT
MAPS
FLUCTUATIONS
GALAXIES
QUASAR
EPOCH
EVOLUTION
PROSPECTS
astro-ph.CO
0201 Astronomical And Space Sciences
Notes
archiveprefix: arXiv keywords: Cosmology: cosmic reionization, 21-cm signal, square kilometre array eid: 27 adsurl: http://adsabs.harvard.edu/abs/2016JApA...37...27D adsnote: Provided by the SAO/NASA Astrophysics Data System
Article Number
27