Constraining Neutrino mass using the large scale HI distribution in the   Post-reionization epoch
  The neutral intergalactic medium in the post reionization epoch allows us to study cosmological structure formation through the observation of the redshifted 21 cm signal and the Lyman-alpha forest. We investigate the possibility of measuring the total neutrino mass through the suppression of power in the matter power spectrum. We investigate the possibility of measuring the neutrino mass through its imprint on the cross-correlation power spectrum of the 21-cm signal and the Lyman-alpha forest. We consider a radio-interferometric measurement of the 21 cm signal with a SKA1-mid like radio telescope and a BOSS like Lyman-alpha forest survey. A Fisher matrix analysis shows that at the fiducial redshift z = 2.5, a 10,000 hrs 21-cm observation distributed equally over 25 radio pointings and a Lyman-alpha forest survey with 30 quasars lines of sights in 1 {deg}^2, allows us to measure \Omega_{\nu} at a 3.25 % level. A total of 25,000 hrs radio-interferometric observation distributed equally over 25 radio pointings and a Lyman-alpha survey with \bar n = 60 {\rm deg}^{-2} will allow \Omega_{\nu} to be measured at a 2.26 % level. This corresponds to an idealized measurement of \sum m_{\nu} at the precision of (100 \pm 2.26) meV and f_{\nu}= \Omega_{\nu}/ \Omega_{m} at 2.49 % level. 
Ashis Kumar Pal, Tapomoy Guha Sarkar
astro-ph.CO