TY - JOUR
T1 - Discovery of transient high-energy γ-ray emission from the BL Lacertae object 5C 3.178
AU - Dickinson, H.
AU - Farnier, C.
PY - 2013
Y1 - 2013
N2 - We report the serendipitous discovery of transient, point-like high energy γ-ray emission coincident with the position of the suspected BL Lac object 5C 3.178. The source was detected using the Fermi Large Area Telescope (LAT) at a significance level of ~8σ during a 200 day period which began on November 17th 2011 (MJD 55 882). The observed γ-ray emission is characterised by a moderate 0.2-300 GeV flux F0.2-300 GeV = (8.22 ± 2.04) × 10-9 ph cm-2 s-1 and a hard power law spectrum with spectral index Γ = 1.76 ± 0.09. These properties appear consistent with the known sub-population of TeV γ-ray-emitting BL Lac objects, implying that the source may be detectable using atmospheric Cherenkov telescope arrays. Moreover, the temporal variability of the source suggests that real-time searches of the Fermi-LAT all-sky dataset for weak emission on ∼200 day timescales may represent a rewarding strategy.
AB - We report the serendipitous discovery of transient, point-like high energy γ-ray emission coincident with the position of the suspected BL Lac object 5C 3.178. The source was detected using the Fermi Large Area Telescope (LAT) at a significance level of ~8σ during a 200 day period which began on November 17th 2011 (MJD 55 882). The observed γ-ray emission is characterised by a moderate 0.2-300 GeV flux F0.2-300 GeV = (8.22 ± 2.04) × 10-9 ph cm-2 s-1 and a hard power law spectrum with spectral index Γ = 1.76 ± 0.09. These properties appear consistent with the known sub-population of TeV γ-ray-emitting BL Lac objects, implying that the source may be detectable using atmospheric Cherenkov telescope arrays. Moreover, the temporal variability of the source suggests that real-time searches of the Fermi-LAT all-sky dataset for weak emission on ∼200 day timescales may represent a rewarding strategy.
KW - Astroparticle physics
KW - BL Lacertae objects: individual: 5C 3.178
KW - Gamma rays: galaxies
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U2 - 10.1051/0004-6361/201321287
DO - 10.1051/0004-6361/201321287
M3 - Article
AN - SCOPUS:84876519275
VL - 552
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A134
ER -