Discovery of transient high-energy gamma-ray emission from the BL Lacertae object 5C 3.178
2013 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 552, A134- p.Article in journal (Refereed) Published
We report the serendipitous discovery of transient, point-like high energy gamma-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 similar to 8 sigma during a 200 day period which began on November 17th 2011 (MJD 55 882). The observed gamma-ray emission is characterised by a moderate 0.2-300 GeV flux F0.2-300 (GeV) = (8.22 +/- 2.04) x 10(-9) ph cm(-2) s(-1) and a hard power law spectrum with spectral index Gamma = 1.76 +/- 0.09. These properties appear consistent with the known sub-population of TeV gamma-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 similar to 200 day timescales may represent a rewarding strategy.
Place, publisher, year, edition, pages
2013. Vol. 552, A134- p.
astroparticle physics, BL Lacertae objects: individual: 5C 3.178, gamma rays: galaxies
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:su:diva-90374DOI: 10.1051/0004-6361/201321287ISI: 000317912000133OAI: oai:DiVA.org:su-90374DiVA: diva2:627684