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

Abstract

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 hours 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 0.446$\pm$0.008 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.

arXiv comment29 pages, 15 figures. Accepted for publication in Astroparticle Physics

References in corpus (22)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• An Exceptional VHE Gamma-Ray Flare of PKS 2155-304
• First Results from the All-Sky Monitor on the Rossi X-ray Timing Explorer
• Variable VHE gamma-ray emission from Markarian 501
• Gamma-ray flares from the Crab Nebula
• VERITAS: the Very Energetic Radiation Imaging Telescope Array System
• Discovery of Powerful Gamma-Ray Flares from the Crab Nebula
• MOJAVE: Monitoring of Jets in AGN with VLBA Experiments - I. First-Epoch 15 GHz Linear Polarization Images
• A Multi-wavelength View of the TeV Blazar Markarian 421: Correlated Variability, Flaring, and Spectral Evolution
• Multiwavelength Observations of Markarian 421 in March 2001: an Unprecedented View on the X-ray/TeV Correlated Variability
• Gamma-ray Activity in the Crab Nebula: The Exceptional Flare of April 2011
• Discovery of >350 GeV Gamma Rays from the BL Lacertae Object 1ES 2344+514
• When A Standard Candle Flickers
• TeV and Multi-wavelength Observations of Mrk 421 in 2006-2008
• Detection of TeV Gamma Rays from the BL Lac Object 1ES1959+650 with the Whipple 10m Telescope
• Simultaneous X-Ray and TeV Gamma-Ray Observations of the TeV Blazar Markarian 421 during February and May 2000
• Discovery of Spectral Variability of Markarian 421 at TeV Energies
• Detection of the BL Lac Object H1426+428 at TeV Gamma Ray Energies
• Measurement of the Multi-TeV gamma-ray Flare-Spectra of Markarian 421 and Markarian 501
• Observations of Mkn 421 in 2004 with H.E.S.S. at large zenith angles
• Mid-Infrared Fine Structure Line Ratios in Active Galactic Nuclei Observed with Spitzer IRS: Evidence for Extinction by the Torus
• Multiwavelength Observations of the Blazar Mrk 421 in December 2002 and January 2003

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• The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies
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• 4.5 years multi-wavelength observations of Mrk 421 during the ARGO-YBJ and Fermi common operation time
• Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC
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• Connecting steady emission and Very High Energy flaring states in blazars: the case of Mrk 421
• FACT - Monitoring Blazars at Very High Energies
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• Blazar variability power spectra from radio up to TeV photon energies: Mrk 421 and PKS 2155-304
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