A High-frequency Search for Pulsars within the Central Parsec of Sgr A*
Abstract
We report results from a deep high-frequency search for pulsars within the central parsec of Sgr A* using the Green Bank Telescope. The observing frequency of 15 GHz was chosen to maximize the likelihood of detecting normal pulsars (i.e., with periods of ~500 ms and spectral indices of ~-1.7) close to Sgr A* that might be used as probes of gravity in the strong-field regime; this is the highest frequency used for such pulsar searches of the Galactic center (GC) to date. No convincing candidate was detected in the survey, with a 10σ detection threshold of ~10 μJy achieved in two separate observing sessions. This survey represents a significant improvement over previous searches for pulsars at the GC and would have detected a significant fraction (gsim5%) of the pulsars around Sgr A*, if they had properties similar to those of the known population. Using our best current knowledge of the properties of the Galactic pulsar population and the scattering material toward Sgr A*, we estimate an upper limit of 90 normal pulsars in orbit within the central parsec of Sgr A*.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2010
- DOI:
- 10.1088/0004-637X/715/2/939
- arXiv:
- arXiv:1004.1643
- Bibcode:
- 2010ApJ...715..939M
- Keywords:
-
- Galaxy: center;
- pulsars: general;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 10 pages, 7 figures, accepted for publication in the ApJ.