Long-term lightcurves from combined unified very high energy $\gamma$-ray data

Abstract

Very high-energy (VHE, E\,$>$\,100\,GeV) $\gamma$-ray data are a valuable input for multi-wavelength and multi-messenger (e.g. combination with neutrino data) studies. We aim at the conservation and homogenization of historical, current, and future {VHE $\gamma$-ray-data} on active galactic nuclei (AGN). We have collected lightcurve data taken by major VHE experiments since 1991 and combined them into long-term lightcurves for several AGN, and now provide our collected datasets for further use. Due to the lack of common data formats in VHE $\gamma$-ray astronomy, we have defined relevant datafields to be stored in standard data formats. The time variability of the combined VHE lightcurve data was investigated, and correlation with archival X-ray data collected by {{\em RXTE}/ASM} tested. The combination of data on the prominent blazar Mrk\,421 from different experiments yields a lightcurve spanning more than a decade. From this combined dataset we derive an integral baseline flux from Mrk\,421 that must be lower than 33\,% of the Crab Nebula flux above 1\,TeV. The analysis of the time variability yields log-normal flux variations in the VHE-data on Mrk\,421. Existing VHE data contain valuable information concerning the variability of AGN and can be an important ingredient for multi-wavelength or multi-messenger studies. In the future, upcoming and planned experiments will provide more data from many transient objects, and the interaction of VHE astronomy with classical astronomy will intensify. In this context a unified and exchangeable data format will become increasingly important. Our data collection is available at the url: {\tt {http://nuastro-zeuthen.desy.de/magic\_experiment/projects/light\_curve\_archive/index\_eng.html}}.

arXiv comment6 pages, 4 figures. Accepted for publication in A&A, 11/10/2010

References in corpus (24)

• On characterising the variability properties of X-ray light curves from active galaxies
• Observations of the Crab Nebula with H.E.S.S
• An Exceptional VHE Gamma-Ray Flare of PKS 2155-304
• BL Lac Objects in the Synchrotron Proton Blazar Model
• TeV Gamma Rays from BL Lac Objects due to Synchrotron Radiation of Extremely High Energy Protons
• VHE Gamma-Ray Observation of the Crab Nebula and its Pulsar with the MAGIC telescope
• Teraelectronvolt Astronomy
• The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA stereoscopic air Cherenkov telescopes
• Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope
• Temporal and spectral gamma-ray properties of Mkn421 above 250 GeV from CAT observations between 1996 and 2000
• Variations of the TeV energy spectrum at different flux levels of Mkn 421 observed with the HEGRA system of Cherenkov telescopes
• The June 2008 flare of Markarian 421 from optical to TeV energies
• Simultaneous X-Ray and TeV Gamma-Ray Observations of the TeV Blazar Markarian 421 during February and May 2000
• Observations of Mkn 421 in 2004 with H.E.S.S. at large zenith angles
• Correlation between the TeV and X-ray emission in high--energy peaked BL Lac objects
• Multi-TeV Gamma-Ray Flares from Markarian 421 in 2000 and 2001 Observed with the Tibet Air Shower Array
• The TeV Energy Spectrum of Mkn 501 Measured with the Stereoscopic Telescope System of HEGRA during 1998 and 1999
• Lognormal variability in BL Lacertae
• Multiwavelength Observations of the Blazar Mrk 421 in December 2002 and January 2003
• Very High Energy Gamma-Ray Emission from the Blazar Markarian 421
• Correlated variability of Mkn 421 at X-ray and TeV wavelengths on timescales of hours
• TeV Gamma-ray Astronomy: The Story So Far
• Simultaneous multi-wavelength observations of the TeV Blazar Mrk 421 during February - March 2003: X-ray and NIR correlated variability
• High-(Energy)-Lights -- The Very High Energy Gamma-Ray Sky

Cited by in corpus (30)

• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• Characterizing the Gamma-Ray Variability of the Brightest Flat Spectrum Radio Quasars Observed with the Fermi LAT
• Long-term monitoring of the TeV emission from Mrk 421 with the ARGO-YBJ experiment
• 4.5 years multi-wavelength observations of Mrk 421 during the ARGO-YBJ and Fermi common operation time
• Log-normal flux distribution of bright Fermi blazars
• Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC
• Multiwavelength study of TeV Blazar Mrk421 during giant flare
• Characterizing the gamma-ray long-term variability of PKS 2155-304 with H.E.S.S. and Fermi-LAT
• Long-term study of Mkn 421 with the HAGAR Array of Telescopes
• Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009
• Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and $\gamma$-ray activity in 2015$-$2016
• Gamma-ray Cosmology and Tests of Fundamental Physics
• Flux Distribution of Gamma-Ray Emission in Blazars: The Example of Mrk 501
• Variability studies and modeling of the blazar PKS 2155-304 in the light of a decade of multi-wavelength observations
• The Study of TeV Variability and Duty Cycle of Mrk 421 from 3 Years of Observations with the Milagro Observatory
• Multi-band Variability Analysis of Mrk 421
• Study of long-term flux and photon Index distributions of blazars using RXTE observations
• Probing an X-ray flare pattern in Mrk 421 induced by multiple stationary shocks: a solution to the bulk Lorentz factor crisis
• Search for Blazar Flux-Correlated TeV Neutrinos in IceCube 40-String Data
• A time dependent approach to model X-ray and $\gamma$--ray light curves of Mrk 421 observed during the flare in February 2010
• Broadband study of OQ 334 during its flaring state
• Galactic and Extragalactic Sources of Very High Energy Gamma-rays
• Study of short term enhanced TeV $\gamma$- ray emission from Mrk 421 observed with TACTIC on December 28, 2014
• Open high-level data formats and software for gamma-ray astronomy
• Correlated Short-Timescale Hard-Soft X-ray Variability of the Blazars Mrk 421 and 1ES 1959+650 using $\text{AstroSat}$
• Observations of very high energy gamma-ray emission from AGNs with the ground-based EAS arrays
• Estimation of the TeV gamma-ray duty cycle of Mrk 421 with the Milagro observatory
• Study of Intra-Day Flux Distributions of Blazars Using XMM-Newton Satellite
• Optimal strategies for observation of active galactic nuclei variability with Imaging Atmospheric Cherenkov Telescopes