AlgoSCR: An algorithm for Solar Contamination Removal from radio interferometric data – on May 14, 2021 at 7:43 pm

Hydrogen intensity mapping is a new field in astronomy that promises to make
three-dimensional maps of the matter distribution of the Universe using the
redshifted $21,textrm{cm}$ line of neutral hydrogen gas (HI). Several ongoing
and upcoming radio interferometers, such as Tianlai, CHIME, HERA, HIRAX, etc.
are using this technique. These instruments are designed to map large swaths of
the sky by drift scanning over periods of many months. One of the challenges of
the observations is that the daytime data is contaminated by strong radio
signals from the Sun. In the case of Tianlai, this results in almost half of
the measured data being unusable. We try to address this issue by developing an
algorithm for solar contamination removal (AlgoSCR) from the radio data. The
algorithm is based on an eigenvalue analysis of the visibility matrix, and
hence is applicable only to interferometers. We apply AlgoSCR to simulated
visibilities, as well as real daytime data from the Tianlai dish array. The
algorithm can remove most of the solar contamination without seriously
affecting other sky signals and thus makes the data usable for certain
applications.
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