Discovery of a Pulsar Wind Nebula Candidate in the Cygnus Loop
Abstract
We report on a discovery of a diffuse nebula containing a pointlike source in the southern blowout region of the Cygnus Loop supernova remnant, based on Suzaku and XMM-Newton observations. The X-ray spectra from the nebula and the pointlike source are well represented by an absorbed power-law model with photon indices of 2.2 ± 0.1 and 1.6 ± 0.2, respectively. The photon indices as well as the flux ratio of F nebula/F pointlike ~ 4 lead us to propose that the system is a pulsar wind nebula, although pulsations have not yet been detected. If we attribute its origin to the Cygnus Loop supernova, then the 0.5-8 keV luminosity of the nebula is computed to be 2.1 × 1031 (d/540 pc)2 erg s-1, where d is the distance to the Loop. This implies a spin-down loss-energy \dot{E}\sim 2.6\times 10^{35} (d/540 pc)2 erg s-1. The location of the neutron star candidate, ~2° away from the geometric center of the Loop, implies a high transverse velocity of ~1850 (θ/2°) (d/540 pc) (t/10 kyr)-1 km s-1, assuming the currently accepted age of the Cygnus Loop.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2012
- DOI:
- 10.1088/2041-8205/754/1/L7
- arXiv:
- arXiv:1206.4367
- Bibcode:
- 2012ApJ...754L...7K
- Keywords:
-
- ISM: individual objects: Cygnus Loop;
- ISM: supernova remnants;
- pulsars: general;
- stars: neutron;
- stars: winds;
- outflows;
- X-rays: ISM;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 6 pages, 3 figures, accepted for publication in The Astrophysical Journal Letters