The 2009 Fermi Symposium

PSR J1907+0602, A Gamma-Ray Pulsar Powering a Bright TeV PWN

Aous Abdo

Abstract:

The Fermi-LAT collaboration recently reported the discovery of the gamma-ray pulsar PSR J1907+06 at energies > 100 MeV near the TeV source MGRO J1908+06. Here we report a more detailed analysis of the Fermi data and discuss multi-wavelength observations of the region containing the pulsar. Pulsed emission from this pulsar is clearly visible at energies from 100 MeV to greater than 10 GeV. We present the energy dependent gamma-ray pulsed light curve as well as limits on off-pulse emission associated with the TeV source. We performed radio observations at 1.4 GHz with the Arecibo radio telescope and detect very faint (flux density of 2 µJy) radio pulsations at a dispersion measure DM = (82.1 1.1) cm^-3 pc. Using the latest electron model of the Galaxy we derive a distance of ~3 kpc and a pseudo-luminosity of ~0.02 d_3.0² mJy kpc² i.e., this might be the faintest radio pulsar ever detected. A Chandra ACIS Observation revealed an absorbed, possibly extended, compact (< 4 arcsec) x-ray source with significant non-thermal emission at the location of the pulsar. Upper limits on arcminute scale 2-10 keV X-ray emission of ~10^-13 erg cm^-2 s^-1 from archival ASCA observations from the pulsar and compact X-ray nebula imply a distance > 3 kpc, which is consistent with the distance derived from the DM of the pulsar. This is also compatible with the distance to the supernova remnant G40.5-0.5, located on the far side of the TeV nebula from PSR J1907+0602, and the S74 molecular cloud on the near side of the TeV nebula. We discuss these as potential birth sites for the pulsar.