Astrophysics Webinar
First direct detection of the neutral hydrogen intensity mapping
Speaker: Sourabh Paul (McGill University, Canada.)
Intensity mapping with neutral hydrogen is a promising avenue to probe the large-scale structure of the Universe at radio frequencies and probe the underlying Cosmology. However, the inherent weakness of the signal, presence of strong foregrounds and extraordinary calibration challenges have limited the detection of this signal only in cross-correlations with galaxy surveys. We present the first direct detection of the cosmological power spectrum using the intensity signal from 21-cm emission of neutral hydrogen (HI), derived from interferometric observations with the L-band receivers of the new MeerKAT radio telescope. The independent measurements of the HI power spectrum at redshifts 0.32 and 0.44 are estimated with high statistical significance using a foreground avoidance method. These results are a significant step towards precision cosmology with HI intensity mapping using the new generation of radio telescopes.