Revisiting the Chandra Observation on the Region of PSR J1809-193: Indication of the Existence of an X-Ray Halo and Implication for the Origin of HESS J1809-193
Abstract
HESS J1809-193 is an extended TeV γ-ray source and the origin of its γ-ray emission remains ambiguous. The pulsar wind nebula (PWN) of PSR J1J1809-193 lying inside the extended γ-ray emission is a possible candidate. Powered by the central pulsar, ultrarelativistic electrons in the PWN can produce radio to X-ray emission through synchrotron and γ-ray emission by inverse Compton (IC) scattering. To check whether this PWN is the counterpart of HESS J1809-193, we analyzed the Chandra X-ray radial intensity profile and spectral index profile of this PWN. We then adopted a one-zone isotropic diffusion model to fit the keV and TeV data. We found diffuse nonthermal X-ray emission extending beyond the PWN, which is likely an X-ray halo radiated by escaping electron/positron pairs from the PWN. A relatively strong magnetic field of ~20 μG is required to explain the spatial evolution of the X-ray spectrum (i.e., the significant softening of the spectrum with increasing distance from the pulsar), which, however, would suppress the IC radiation of pairs. Our result implies that a hadronic component may be needed to explain HESS J1809-193.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2023
- DOI:
- 10.3847/1538-4357/acc7a0
- arXiv:
- arXiv:2303.14946
- Bibcode:
- 2023ApJ...949...90L
- Keywords:
-
- High energy astrophysics;
- Pulsar wind nebulae;
- X-ray astronomy;
- Gamma-ray sources;
- Non-thermal radiation sources;
- 739;
- 2215;
- 1810;
- 633;
- 1119;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 20 pages, 8 figures, accepted by APJ. Comments are welcome