Galactic sources of E>100 GeV gamma-rays seen by Fermi telescope

Abstract

We perform a search for sources of gamma-rays with energies E>100 GeV at low Galactic latitudes |b|<10 deg using the data of Fermi telescope. To separate compact gamma-ray sources from the diffuse emission from the Galaxy, we use the Minimal Spanning Tree method with threshold of 5 events in inner Galaxy (Galactic longitude |l|<60 deg) and of 3 events in outer Galaxy. Using this method, we identify 22 clusters of very-high-energy (VHE) gamma-rays, which we consider as "source candidates". 3 out of 22 event clusters are expected to be produced in result of random coincidences of arrival directions of diffuse background photons. To distinguish clusters of VHE events produced by real sources from the background we perform likelihood analysis on each source candidate. We present a list of 19 higher significance sources for which the likelihood analysis in the energy band E>100 GeV gives Test Statistics (TS) values above 25. Only 10 out of the 19 high-significance sources can be readily identified with previously known VHE gamma-ray sources. 4 sources could be parts of extended emission from known VHE gamma-ray sources. Five sources are new detections in the VHE band. Among these new detections we tentatively identify one source as a possible extragalactic source PMN J1603-4904 (a blazar candidate), one as a pulsar wind nebula around PSR J1828-1007. High significance cluster of VHE events is also found at the position of a source coincident with the Eta Carinae nebula. In the Galactic Center region, strong VHE gamma-ray signal is detected from Sgr C molecular cloud, but not from the Galactic Center itself.

6 pages, 2 figures

References in corpus (5)

• Fermi Large Area Telescope Observation of a Gamma-ray Source at the Position of Eta Carinae
• Revisiting the Westerlund 2 Field with the H.E.S.S. Telescope Array
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• H.E.S.S. observations of massive stellar clusters
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Cited by in corpus (5)

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• Fermi-LAT constraints on the Pulsar Wind Nebula nature of HESS J1857+026
• Discovery of new X-ray sources near the unidentified gamma-ray source HESS J1841-055
• Producing baryons from neutralinos in small H2 clumps over cosmological ages