2015/08/27 by A. O’Faoláin de Bhróithe, de Bhroithe, Anna O'Faolain, collaboration, VERITAS
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.1508.06794
openalex publication_date 2015/08/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In 1989, the Whipple 10m telescope achieved the first indisputable detection of a TeV gamma-ray source, the Crab Nebula. Until its decommissioning in 2011, the Whipple telescope took regular measurements of the nebula. With the recent discovery of GeV gamma-ray flaring activity in the Crab Nebula, it is an opportune time to return to the Whipple telescope data set and search its extensive archive for evidence of TeV flares. A data set on the Crab Nebula spanning ten years, 2000 - 2010, is compiled and searched for day-scale flaring activity using a Bayesian-block binning algorithm. No evidence for significant flaring activity is found. Monte Carlo simulations show that low levels of flux increase on short timescales are difficult to detect. Assuming a flare duration of seven days, 99% confidence level upper limits are calculated for the possible frequency of five-fold, two-fold and 1.5-fold flares in the data set. An upper limit of 0.02 flares per year is found for the five-fold flare, and a limit of 0.27 flares per year is placed on the two-fold flare. The detection of the 1.5-fold flare is consistent with the false-positive rate of the method, and so cannot be excluded.