We report the discovery of three pulsars whose large dispersion measures (DMs) and angular proximity to Sgr A* indicate the existence of a Galactic center population of neutron stars. The relatively long periods (0.98-1.48 s) most likely reflect strong selection against short-period pulsars from radio-wave scattering at the observation frequency of 2 GHz used in our survey with the Green Bank Telescope. One object (PSR J1746-2850I) has a characteristic spindown age of only 13 kyr along with a high surface magnetic field ~4 × 1013 G. It and a second object found in the same telescope pointing, PSR J1746-2850II (which has the highest known DM among pulsars), may have originated from recent star formation in the Arches or Quintuplet clusters given their angular locations. Along with a third object, PSR J1745-2910, and two similar high-dispersion, long-period pulsars reported by Johnston et al., the five objects found so far are 10-15 arcmin from Sgr A*, consistent with there being a large pulsar population in the Galactic center, most of whose members are undetectable in relatively low-frequency surveys because of pulse broadening from the same scattering volume that angularly broadens Sgr A* and OH/IR masers.
The Astrophysical Journal
- Pub Date:
- September 2009
- pulsars: general;
- pulsars: individual: J1746─2850I J1746─2850II J1745─2910;
- Astrophysics - Solar and Stellar Astrophysics
- Accepted to ApJ Letters