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Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE
Abstract:
The Small and Large Magellanic Clouds are the only galaxies outside our own
in which radio pulsars have been discovered to date. The sensitivity of the
MeerKAT radio interferometer offers an opportunity to search for a population
of more distant extragalactic pulsars. The TRAPUM (TRansients And PUlsars with
MeerKAT) collaboration has performed a radio-domain search for pulsars and
transients in the dwarf star-forming galaxies Sextans A and B, situated at the
edge of the local group 1.4 Mpc away. We conducted three 2-hour multi-beam
observations at L-band (856-1712 MHz) with the full array of MeerKAT. No
pulsars were found down to a radio pseudo-luminosity upper limit of 7.9$\pm$0.4
Jy kpc$^{2}$ at 1400 MHz, which is 28 times more sensitive than the previous
limit from the Murriyang telescope. This luminosity is 30 per cent greater than
that of the brightest known radio pulsar and sets a cut-off on the luminosity
distributions of the entire Sextans A and B galaxies for unobscured radio
pulsars beamed in our direction. A Fast Radio Burst was detected in one of the
Sextans A observations at a Dispersion Measure (DM) of 737 pc cm$^{-3}$. We
believe this is a background event not associated with the dwarf galaxy due to
its large DM and its S/N being strongest in the wide-field incoherent beam of
MeerKAT.
