Searching for Pulsars, Magnetars, and Fast Radio Bursts in the Sculptor Galaxy using MeerKAT

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.

6 pages, 3 figures, added citation in section 3, corrected values in section 4, published in MNRAS

References in corpus (15)

• A bright millisecond radio burst of extragalactic origin
• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• Transient pulsed radio emission from a magnetar
• The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime
• Discovery of 14 radio pulsars in a survey of the Magellanic Clouds
• A bright gamma-ray flare interpreted as a giant magnetar flare in NGC 253
• Spatially Resolving a Starburst Galaxy at Hard X-ray Energies: NuSTAR, Chandra, AND VLBA Observations of NGC 253
• The Thousand-Pulsar-Array programme on MeerKAT III: Giant pulse characteristics of PSR J0540$-$6919
• Interplanetary Scintillation studies with the Murchison Wide-field Array II: Properties of sub-arcsecond compact sources at low radio frequencies
• PulsarX: a new pulsar searching package -I. A high performance folding program for pulsar surveys
• Targeted search for young radio pulsars in the SMC: Discovery of two new pulsars
• Arecibo Pulsar Survey Using ALFA. III. Precursor Survey and Population Synthesis
• A search for supernova-like optical counterparts to ASKAP-localised Fast Radio Bursts
• Distance and mass of the NGC 253 galaxy group
• A Parkes "Murriyang" Search for Pulsars and Transients in the Large Magellanic Cloud