2019ApJ...876...20H

Recent analyses of the excess of gamma-ray radiation emanating from the Galactic center (GC) region suggest an origin in a population of thousands of undetected millisecond pulsars (MSPs). We have conducted a search for pulsar candidates using new high-sensitivity, wide-field radio observations of the GC covering 5 deg². We conducted the search at a low frequency of ∼320 MHz in order to take advantage of the very steep spectra typical of pulsars. Additional observations at 6 GHz of the most steep-spectrum, compact sources resulted in a list of seven candidate pulsars. No pulsations were detected for any of the candidates in a search conducted with the GBT at 1.5, 2, and 6 GHz, presumably due to severe temporal scattering in the GC region or along the line of sight. We discuss the implications of the nondetections on pulse period and distance estimates using two different models of the Galactic distribution of ionized gas. For our best candidate, C1748-2827, located 43' from Sgr A*, we estimate that pulsations from a normal pulsar would have been detected up to a distance of ∼8 kpc and from an MSP up to ∼4.5 kpc.