Very high energy γ-ray emission from RBS 0679

Brown, Anthony M.; Chadwick, Paula M.; Landt, Hermine

doi:10.1093/mnras/stu2321

Very high energy γ-ray emission from RBS 0679

Brown, Anthony M.; Chadwick, Paula M.; Landt, Hermine

Authors

Dr Anthony Brown anthony.brown@durham.ac.uk
Assistant Professor

Professor Paula Chadwick p.m.chadwick@durham.ac.uk
Head Of Department

Hermine Landt

Abstract

In this paper, we report the Fermi Large Area Telescope (LAT) detection of Very High Energy (VHE; Eγ > 100 GeV) γ-ray emission from the BL Lac object RBS 0679. 5.3 years of LAT observations revealed the presence of three VHE photon events within 0 ∘.1 of RBS 0679, with a subsequent unbinned likelihood analysis finding RBS 0679 to be a source of VHE photons at 6.9 standard deviations (σ). An unbinned likelihood analysis of the 0.1–100 GeV data, binned in 28-d periods, finds both the flux and spectral index to be variable, with a ‘softer-when-brighter’ trend in the global γ-ray characteristics. On the other hand, the 28-d periods in which the VHE photons were detected have spectral indices that are consistent with the 5.3 year average suggesting that the observed VHE emission is not associated with a spectral hardening event. The discovery of RBS 0679 in the 100–300 GeV energy range, combined with the non-detection above 390 GeV with the H.E.S.S. telescope array, suggest RBS 0679 to be an intriguing source that requires further follow-up observations with ground-based γ-ray observatories.

Citation

Brown, A. M., Chadwick, P. M., & Landt, H. (2014). Very high energy γ-ray emission from RBS 0679. Monthly Notices of the Royal Astronomical Society, 445(4), 4345-4350. https://doi.org/10.1093/mnras/stu2321

Journal Article Type	Article
Acceptance Date	Sep 25, 2015
Publication Date	Dec 21, 2014
Deposit Date	Apr 10, 2015
Publicly Available Date	Apr 10, 2015
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	445
Issue	4
Pages	4345-4350
DOI	https://doi.org/10.1093/mnras/stu2321
Keywords	Radiation mechanisms: non-thermal galaxies: Active BL Lacertae objects: Individual: RBS 0679 galaxies: Jets gamma rays: galaxies

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This article has been published in Monthly Notices of the Royal Astronomical Society © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.