GBT25A-328

Searching for Radio Emission from the Four `Low B-Field' Magnetars

Abstract

Four of the 24 confirmed magnetars (CXOU\,J164710.2-455216, SGR\,J1822.3-1606, 3XMM\,J185246.6+003317, and SGR\,0418+5729) have been classified as `Low B-Field' based on their low magnetic field strengths ($B_{\rm surf}<10^{14}$\,G) which resemble those of radio pulsars. While these potentially provide an evolutionary link, no radio emission has been detected during the magnetars' transient outbursts, with $30-50\,\mu$Jy L-band upper limits placed on three of them. We propose new Green Bank Telescope observations of the `Low B-Field' magnetars in L-band and X-band to the $5\,\mu$Jy level. Detecting radio emission from this sample will not only allow for analysis of the connection between magnetars and radio pulsars, but also enable follow-up Very Long Baseline Interferometry (VLBI) observations to measure precise positions and proper motions. VLBI astrometry is a necessary step to more accurately identify infrared counterparts and confirm the unbound stellar companions proposed in Clark et al. 2014 and Sherman et al. 2024.

Investigators

Name	Institution
Myles Sherman *	California Institute of Technology
Vikram Ravi	California Institute of Technology
Alice Curtin	McGill University
Casey Law	California Institute of Technology

* indicates the PI