TY - JOUR
T1 - Discovery of PSR J0523-7125 as a Circularly Polarized Variable Radio Source in the Large Magellanic Cloud
AU - Wang, Yuanming
AU - Murphy, Tara
AU - Kaplan, David L.
AU - Klinner-Teo, Teresa
AU - Ridolfi, Alessandro
AU - Bailes, Matthew
AU - Crawford, Fronefield
AU - Dai, Shi
AU - Dobie, Dougal
AU - Gaensler, B. M.
AU - Graber, Vanessa
AU - Heywood, Ian
AU - Lenc, Emil
AU - Lorimer, Duncan R.
AU - McLaughlin, Maura A.
AU - O'Brien, Andrew
AU - Pintaldi, Sergio
AU - Pritchard, Joshua
AU - Rea, Nanda
AU - Ridley, Joshua P.
AU - Ronchi, Michele
AU - Shannon, Ryan M.
AU - Sivakoff, Gregory R.
AU - Stewart, Adam
AU - Wang, Ziteng
AU - Zic, Andrew
N1 - 17 pages, 7 figures; accepted by ApJ
PY - 2022/5/2
Y1 - 2022/5/2
N2 - We report the discovery of a highly circularly polarized, variable, steep-spectrum pulsar in the Australian Square Kilometre Array Pathfinder (ASKAP) Variables and Slow Transients (VAST) survey. The pulsar is located about $1^\circ$ from the center of the Large Magellanic Cloud, and has a significant fractional circular polarization of $\sim$20%. We discovered pulsations with a period of 322.5 ms, dispersion measure (DM) of 157.5 pc cm$^{-3}$, and rotation measure (RM) of $+456$ rad m$^{-2}$ using observations from the MeerKAT and the Parkes telescopes. This DM firmly places the source, PSR J0523$-$7125, in the Large Magellanic Cloud (LMC). This RM is extreme compared to other pulsars in the LMC (more than twice that of the largest previously reported one). The average flux density of $\sim$1 mJy at 1400 MHz and $\sim$25 mJy at 400 MHz places it among the most luminous radio pulsars known. It likely evaded previous discovery because of its very steep radio spectrum (spectral index $\alpha \approx -3$, where $S_\nu \propto \nu^\alpha$) and broad pulse profile (duty cycle $\gtrsim35$%). We discuss implications for searches for unusual radio sources in continuum images, as well as extragalactic pulsars in the Magellanic Clouds and beyond. Our result highlighted the possibility of identifying pulsars, especially extreme pulsars, from radio continuum images. Future large-scale radio surveys will give us an unprecedented opportunity to discover more pulsars and potentially the most distant pulsars beyond the Magellanic Clouds.
AB - We report the discovery of a highly circularly polarized, variable, steep-spectrum pulsar in the Australian Square Kilometre Array Pathfinder (ASKAP) Variables and Slow Transients (VAST) survey. The pulsar is located about $1^\circ$ from the center of the Large Magellanic Cloud, and has a significant fractional circular polarization of $\sim$20%. We discovered pulsations with a period of 322.5 ms, dispersion measure (DM) of 157.5 pc cm$^{-3}$, and rotation measure (RM) of $+456$ rad m$^{-2}$ using observations from the MeerKAT and the Parkes telescopes. This DM firmly places the source, PSR J0523$-$7125, in the Large Magellanic Cloud (LMC). This RM is extreme compared to other pulsars in the LMC (more than twice that of the largest previously reported one). The average flux density of $\sim$1 mJy at 1400 MHz and $\sim$25 mJy at 400 MHz places it among the most luminous radio pulsars known. It likely evaded previous discovery because of its very steep radio spectrum (spectral index $\alpha \approx -3$, where $S_\nu \propto \nu^\alpha$) and broad pulse profile (duty cycle $\gtrsim35$%). We discuss implications for searches for unusual radio sources in continuum images, as well as extragalactic pulsars in the Magellanic Clouds and beyond. Our result highlighted the possibility of identifying pulsars, especially extreme pulsars, from radio continuum images. Future large-scale radio surveys will give us an unprecedented opportunity to discover more pulsars and potentially the most distant pulsars beyond the Magellanic Clouds.
KW - astro-ph.HE
U2 - 10.3847/1538-4357/ac61dc
DO - 10.3847/1538-4357/ac61dc
M3 - Article
SN - 0004-637X
VL - 930
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
ER -