Observation of Markarian 421 in TeV gamma rays over a 14-year time span

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• 作者：V.A. Acciari ; T. Arlen ; T. Aune ; W. Benbow ; R. Bird ; A. Bouvier ; S.M. Bradbury ; J.H. Buckley ; V. Bugaev ; I. de la Calle Perez ; D.A. Carter-Lewis ; A. Cesarini ; L. Ciupik ; E. Collins-Hughes ; M.P. Connolly ; W. Cui ; C. Duke ; J. Dumm ; A. Falcone ; S. Federici ; D.J. Fegan ; et al.
• 关键词：AGN ; TeV gamma rays ; Markarian 421
• 刊名：Astroparticle Physics
• 出版年：February, 2014
• 年：2014
• 卷：54
• 期：Complete
• 页码：1-10
• 全文大小：736 K

文摘

The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with the Whipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation between the X-ray and TeV energy bands is observed during some bright flares and when the complete data sets are binned on long timescales. The main database consists of 878.4 h of observation with the Whipple telescope, spread over 783 nights. The peak energy response of the telescope was 400 GeV with 20% uncertainty. This is the largest database of any TeV-emitting active galactic nucleus (AGN) and hence was used to explore the variability profile of Markarian 421. The time-averaged flux from Markarian 421 over this period was  Crab flux units. The flux exceeded 10 Crab flux units on three separate occasions. For the 2000-2001 season the average flux reached 1.86 Crab units, while in the 1996-1997 season the average flux was only 0.23 Crab units.