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arXiv · 0912.4229

HESS J1507-622: an unique unidentified source off the Galactic Plane

O. Tibolla·W. Domainko·W. Hofmann·O. de Jager·S. Kaufmann·N. Komin·K. Kosack
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Abstract

Galactic very high energy (VHE, > 100 GeV) gamma ray sources in the inner Galaxy H.E.S.S. survey tend to cluster within 1 degree in latitude around the Galactic plane. HESS J1507-622 instead is unique, since it is located at latitude of ~3.5 degrees. HESS J1507-622 is slightly extended over the PSF of the instrument and hence its Galactic origin is clear. The search for counterparts in other wavelength regimes (radio, infrared and X-rays) failed to show any plausible counterparts; and given its position off the Galactic plane and hence the absorption almost one order of magnitude lower, it is very surprising to not see any counterparts especially at X-rays wavelengths (by ROSAT, XMM Newton and Chandra). Its latitude implies that it is either rather close, within about 1 kpc, or is located well off the Galactic plane. And also the models reflect the uniqueness of this object: a leptonic PWN scenario would place this source due to its quite small extension to multi-kpc distance whereas a hadronic scenario would preferentially locate this object at distances of < 1 kpc where the density of target material is higher.

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O. Tibolla, W. Domainko, W. Hofmann, O. de Jager, S. Kaufmann, N. Komin, K. Kosack. 2009-12-21. HESS J1507-622: an unique unidentified source off the Galactic Plane. https://arxiv.org/abs/0912.4229

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