Fermi-LAT Detection of a Hard Spectrum Flare from the Gravitationally Lensed Blazar B0218+357

Abstract

The Fermi-LAT has observed new gamma-ray flares from the blazar B0218+357 during July 2014. While no significant change in the gamma-ray spectrum has been previously observed through the flaring phase in late-2012, during this recent high activity the source displayed an exceptionally hard spectrum. The latter led to the detection of very high energy (VHE, E > 100 GeV) gamma-rays from B0218+357 by the MAGIC telescopes, establishing this source as the most distant TeV emitter known to date. In addition to the detection of VHE emission, this blazar is of particular interest since it is known to be a double-image gravitationally lensed system with a lens delay of 11.46 +/- 0.16 days measured in gamma-rays. We present the Fermi-LAT study of the July 2014 flares and discuss them in the context of previous measurements.

arXiv comment2014 Fermi Symposium proceedings - eConf C14102.1

References in corpus (1)

• Fermi Large Area Telescope First Source Catalog

Cited by in corpus (5)

• Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes
• Microlensing constraint on the size of the gamma-ray emission region in blazar B0218+357
• Multiwavelength study of the gravitationally lensed blazar QSO B0218+357 between 2016 and 2020
• Variability of GeV gamma-ray emission in QSO B0218+357 due to microlensing on intermediate size structures
• Detection of very-high-energy gamma rays from the most distant and gravitationally lensed blazar QSO B0218+357 using the MAGIC telescope system