Discovery of >350 GeV Gamma Rays from the BL Lacertae Object 1ES 2344+514
/ Authors
M. Catanese, C. Akerlof, H. Badran, S. Biller, I. Bond, P. Boyle, S. Bradbury, J. Buckley, A. Burdett, J. Gordo
and 24 more authors
D. Carter-Lewis, M. Cawley, V. Connaughton, D. Fegan, J. Finley, J. Gaidos, T. Hall, A. Hillas, F. Krennrich, R. Lamb, R. Lessard, C. Masterson, J. Mcenery, G. Mohanty, J. Quinn, A. Rodgers, H. Rose, F. Samuelson, M. Schubnell, G. Sembroski, R. Srinivasan, T. Weekes, C. Wilson, J. Zweerink
/ Abstract
We present the discovery of >350 GeV gamma-ray emission from the BL Lacertae object 1ES 2344+514 with the Whipple Observatory 10m gamma-ray telescope. This is the third BL Lac object detected at gamma-ray energies above 300 Gev, the other two being Markarian 421 (Mrk 421) and Mrk501. These three active galactic nuclei are all X-ray selected and have the lowest known redshifts of any BL Lac objects currently identified. The evidence for emission derives primarily from an apparent flare on December 20, 1995 when a 6 sigma excess was detected with a flux approximately 63% of the very high energy gamma-ray emission from the Crab Nebula, the standard candle for TeV gamma-ray sources. Excluding the flare, observations between October 1995 and January 1996 yield a 4 sigma detection corresponding to 11% of the VHE Crab Nebula flux. Observations spanning September 1996 to January 1997 failed to yield a significant detection of a steady flux or any flaring. For this period, the 99.9% confidence level upper limit is <8% of the Crab Nebula. The low baseline emission level and variations in nightly and yearly flux of 1ES 22344+514 are the same as the VHE emission characteristics of Mrk 421 and Mrk 501
Journal: arXiv: Astrophysics
DOI: 10.1086/305857