July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

VERITAS observations of exceptionally bright TeV flares from LS I +61 303

Aug 1, 2015, 2:48 PM
World Forum Theater (World Forum)

World Forum Theater

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Oral contribution GA-EX Parallel GA10 VERITAS


Anna O'Faolain de Bhroithe (DESY)


The very-high-energy (VHE; E > 100 GeV) gamma-ray observatory, VERITAS, detected exceptionally bright flares from the high mass X-ray binary LS I +61 303 during the period October - December 2014. LS I +61 303 is a known VHE gamma-ray source, the flux from which varies strongly with the orbital period of ~26.5 days. The maximum VHE flux is found around apastron (orbital phase ~0.6) at a level typically corresponding to 10-15% of the Crab Nebula flux (>350 GeV). During these most recent observations, relatively short (day scale), bright TeV flares were observed from the source around apastron in two orbital cycles (October and November). Both cases exhibited peak fluxes above 25% of the Crab Nebula flux (>350 GeV), making these the brightest VHE flares ever detected from this source. In the last orbital cycle observed (December), the source had returned to its historical level of activity. The results of these VERITAS observations from 2014 will be presented.
Registration number following "ICRC2015-I/" 316
Collaboration VERITAS

Primary author

Presentation materials