Please use this identifier to cite or link to this item:
Title: Using HI to probe large scale structures at z ~ 3
Authors: Bharadwaj, Somnath
Nath, Biman B.
Sethi, S.K.
Keywords: Cosmology: theory, observations;
large scale structures- diffuse radiation,
Issue Date: 2001
Publisher: Indian Academy of Sciences, Bangalore, India.
Citation: Journal of Astrophysics and Astronomy, 2001, Vol.22, p21-34.
Abstract: The redshifted 1420 MHz emission from the HI in unresolved damped Lyman-α clouds at high z will appear as a background radiation in low frequency radio observations. This holds the possibility of a new tool for studying the universe at high-z, using the mean brightness temperature to probe the HI content and its fluctuations to probe the power spectrum. Existing estimates of the HI density at z~3 imply a mean brightness temperature of 1 mK at 320 Mhz. The cross-correlation between the temperature fluctuations across different frequencies and sight lines is predicted to vary from 10-7 K2 to 10-8 K2 over intervals corresponding to spatial scales from 10 Mpc to 40 Mpc for some of the currently favoured cosmological models. Comparing this with the expected sensitivity of the GMRT, we find that this can be detected with ~10 hrs of integration, provided we can distinguish it from the galactic and extragalactic foregrounds which will swamp this signal. We discuss a strategy based on the very distinct spectral properties of the foregrounds as against the HI emission, possibly allowing the removal of the foregrounds from the observed maps.
ISSN: 0250-6335
Copyright: Indian Academy of Sciences, Bangalore, India.
Appears in Collections:Research Papers (A&A)

Files in This Item:
File Description SizeFormat 
2001_JAA_V22_p21-34.pdf14p.740.91 kBAdobe PDFView/Open

Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.