Brown, Anthony M. and Chadwick, Paula M. and Landt, Hermine (2014) 'Very high energy γ-ray emission from RBS 0679.', Monthly notices of the Royal Astronomical Society., 445 (4). pp. 4345-4350.
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.
|Keywords:||Radiation mechanisms: non-thermal galaxies: Active BL Lacertae objects: Individual: RBS 0679 galaxies: Jets gamma rays: galaxies|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1093/mnras/stu2321|
|Publisher statement:||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.|
|Date accepted:||25 September 2015|
|Date deposited:||10 April 2015|
|Date of first online publication:||December 2014|
|Date first made open access:||No date available|
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