HI Fluctuations at Large Redshifts: II – the Signal Expected for the GMRT

Journal of astrophysics and astronomy

Somnath Bharadwaj1¹  Sanjay K. Pandey2² 

[1] Department of Physics and Meteorology & Center for Theoretical Studies, I.I.T. Kharagpur 721 302, India.$$;Department of Mathematics, L.B.S. College, Gonda 271 001, India.$$

关键词: Cosmology: theory;    observations;    large scale structures;    diffuse radiation.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

For the GMRT, we calculate the expected signal from redshifted HI emission at two frequency bands centered at 610 and 325MHz. The study focuses on the visibility-visibility cross-correlations, proposed earlier as the optimal statistical estimator for detecting and analyzing this signal. These correlations directly probe the power spectrum of density fluctuations at the redshift where the radiation originated, and thereby provide a method for studying the large scale structures at large redshifts. We present detailed estimates of the correlations expected between the visibilities measured at different baselines and frequencies. Analytic fitting formulas representing the salient features of the expected signal are also provided. These will be useful in planning observations and deciding an optimal strategy for detecting this signal.

【 授权许可】

Unknown