I will discuss some recent progress in 21cm line intensity mapping within the SKA cosmology science working group. In particular, we report the first direct detection of the cosmological power spectrum using 21cm line (2301.11943), derived from interferometric observations with the L-band receivers of the MeerKAT radio telescope. I review the challenges in analysing the MeerKAT data and present the power spectrum measurements as well as various tests of the robustness of our detection. The information contained in the power spectrum measurements allows us to probe the parameters of the HI mass function and HI halo model. I will also talk about simulations of 21cm observations in preparation for SKA-Low (2302.11504), which we use to test foreground mitigation methods. We find that the integration time of one field needs to be larger than 250 hours to provide large enough signal-to-noise ratio to accurately model the data covariance for foreground cleaning. Images within the primary beam field-of-view give measurements of the HI power spectrum at scales k∼0.02-0.3 Mpc-1 with signal-to-noise ratio ∼2−5 assuming an integration time of 600 hours. Our result validates using the SKA-Low array for measuring BAO at z~5-6.
BIO
Zhaoting Chen is currently a final-year PhD student at the Jodrell Bank Centre for Astrophysics (JBCA) in Manchester, under the supervision of Dr. Laura Wolz and Prof. Richard Battye. He obtained his B.Sc. from USTC working with Prof. Yi-Fu Cai and M.Sc. from JBCA with Dr. Wolz. From Sept. 2023, he will be a postdoctoral researcher at Institute for Astronomy (IfA) in Edinburgh, working with Dr. Alkistis Pourtsidou.
Host: Yi Mao
