We report on the detection of radio bursts from the Galactic bulge using the real-time transient detection and localization system, realfast. The pulses were detected commensally on the Karl G. Jansky Very Large Array during a survey of unidentified Fermi γ-ray sources. The bursts were localized to subarcsecond precision using realfast fast-sampled imaging. Follow-up observations with the Green Bank Telescope detected additional bursts from the same source. The bursts do not exhibit periodicity in a search up to periods of 480 s, assuming a duty cycle of < 20%. The pulses are nearly 100% linearly polarized, showing circular polarization up to 12%, and exhibit variable scattering on timescales of months. The arcsecond-level realfast localization links the source confidently with the Fermi γ-ray source and places it nearby (though not coincident with) an XMM-Newton X-ray source. Based on the source's overall properties, we discuss various options for the nature of this object and propose that it could be a young pulsar, a magnetar, or a binary pulsar system.
@article{arxiv.2401.02498,
title = {An unidentified Fermi source emitting radio bursts in the Galactic bulge},
author = {Reshma Anna-Thomas and Sarah Burke-Spolaor and Casey J. Law and F. K. Schinzel and Kshitij Aggarwal and Geoffrey C. Bower and Liam Connor and Paul B. Demorest},
journal= {arXiv preprint arXiv:2401.02498},
year = {2024}
}