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Free keywords:
Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE, Astrophysics, Galaxy Astrophysics, astro-ph.GA
Abstract:
The Sculptor Galaxy (NGC 253), located in the Southern Hemisphere, far off
the Galactic Plane, has a relatively high star-formation rate of about 7
M$_{\odot}$ yr$^{-1}$ and hosts a young and bright stellar population,
including several super star clusters and supernova remnants. It is also the
first galaxy, apart from the Milky Way Galaxy to be associated with two giant
magnetar flares. As such, it is a potential host of pulsars and/or fast radio
bursts in the nearby Universe. The instantaneous sensitivity and multibeam sky
coverage offered by MeerKAT therefore make it a favourable target. We searched
for pulsars, radio-emitting magnetars, and fast radio bursts in NGC 253 as part
of the TRAPUM large survey project with MeerKAT. We did not find any pulsars
during a four-hour observation, and derive a flux density limit of 4.4 $\mu$Jy
at 1400 MHz, limiting the pseudo-luminosity of the brightest putative pulsar in
this galaxy to 54 Jy kpc$^2$. Assuming universality of pulsar populations
between galaxies, we estimate that detecting a pulsar as bright as this limit
requires NGC 253 to contain a pulsar population of $\gtrsim$20 000. We also did
not detect any single pulses and our single pulse search flux density limit is
62 mJy at 1284 MHz. Our search is sensitive enough to have detected any fast
radio bursts and radio emission similar to the brighter pulses seen from the
magnetar SGR J1935+2154 if they had occurred during our observation.
