Discovery of Millisecond Pulsars toward the Galactic Bulge in an Image-based Survey with MeerKAT

Abstract We report on the follow-up observations of circularly polarized sources identified in the MeerKAT image-based survey of the Galactic bulge. Using the Parkes radio telescope, we observed 16 circularly polarized sources with the Ultra-Wideband Low receiver and detected nine pulsars, six of which are new discoveries. All pulsars are fast rotators with spin periods under 100 ms. Among the new discoveries, five are millisecond pulsars (MSPs), and one has a spin period of 53.6 ms. At least four new MSPs exhibit clear signs of binary motion in their discovery observations. The dispersion measures of these pulsars fall between 18 and 330 pc cm −3 , which are lower than expected for Galactic bulge members and indicate that these pulsars lie in the foreground along the line of sight rather than within the bulge itself. This is the first time such a large number of pulsars have been confirmed from candidates identified in an image-based survey. These discoveries underscore the exceptional efficacy of circular polarization selection in image-based pulsar surveys, demonstrate the powerful synergy between high-sensitivity imaging and targeted time-domain follow-up using wideband receivers, and strengthen prospects for future deep pulsation searches—e.g., with MeerKAT or the forthcoming SKA or DSA-2000—to uncover the true MSP population in the Galactic bulge.