Very high energy γ -ray emission from RBS 0970

Brown, Anthony M.

Abstract

In this Letter I report the Fermi Large Area Telescope (LAT) detection of very high energy (VHE; E > 100 GeV) γ -ray emission from the BL Lac object RBS 0970. 5.3 years of LAT observations revealed the presence of three VHE photon events within 0. ◦1 of RBS 0970, with a subsequent unbinned likelihood analysis finding RBS 0970 to be a source of VHE photons at the 6.5σ level of confidence. The ≥1 GeV flux, binned in monthly periods, did not indicate any flux brightening of RBS 0970 accompanying the emission of the VHE photons. However, a likelihood analysis of the 0.1−100 GeV flux, binned in 28 d periods centred on detection of the VHE photons, revealed that the emission of the lowest energy VHE photons coincided with a hardening of the γ -ray spectrum. Interestingly, the same analysis did not find any significant γ -ray emission from RBS 0970 during the emission of the highest energy VHE event. The discovery of RBS 0970 as a VHE emitter, combined with the spectral variability, suggest RBS 0970 to be a good candidate for follow-up observations with ground-based γ -ray observatories.

Citation

Brown, A. M. (2014). Very high energy γ -ray emission from RBS 0970. Monthly Notices of the Royal Astronomical Society: Letters, 442(1), L56-L60. https://doi.org/10.1093/mnrasl/slu056

• Journal Article Type: Article
• Acceptance Date: Apr 13, 2014
• Publication Date: Jul 1, 2014
• Deposit Date: Apr 10, 2015
• Publicly Available Date: Apr 10, 2015
• Journal: Monthly Notices of the Royal Astronomical Society: Letters
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 442
• Issue: 1
• Pages: L56-L60
• DOI: https://doi.org/10.1093/mnrasl/slu056
• Keywords: Radiation mechanisms, Non-thermal galaxies, Active BL Lacertae object, Individual: RBS 0970 galaxies, Jets gamma rays, Galaxies
• Public URL: https://durham-repository.worktribe.com/output/1412701