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Title: FERMI LARGE AREA TELESCOPE OBSERVATIONS OF MARKARIAN 421: THE MISSING PIECE OF ITS SPECTRAL ENERGY DISTRIBUTION

Journal Article · · Astrophysical Journal
 [1]; ; ; ; ; ; ; ;  [2]; ; ; ;  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10]
  1. National Research Council Research Associate, National Academy of Sciences, Washington, DC 20001 (United States)
  2. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
  3. Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
  4. Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France)
  5. Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
  6. Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
  7. Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy)
  8. Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)
  9. Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)
  10. Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France)
+ Show Author Affiliations

We report on the {gamma}-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk 421) during the first 1.5 years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) {gamma}-ray spectrum above 0.3 GeV can be well described by a power-law function with photon index {Gamma} = 1.78 {+-} 0.02 and average photon flux F(> 0.3 GeV) = (7.23 {+-} 0.16) x 10{sup -8} ph cm{sup -2} s{sup -1}. Over this time period, the Fermi-LAT spectrum above 0.3 GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor {approx}3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in {gamma}-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk 421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk 421 showed a low activity at all wavebands. The extensive multi-instrument (radio to TeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.

OSTI ID:
21578244
Journal Information:
Astrophysical Journal, Vol. 736, Issue 2; Other Information: DOI: 10.1088/0004-637X/736/2/131; ISSN 0004-637X
Country of Publication:
United States
Language:
English

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Optical polarization properties of February 2010 outburst of the blazar Mrk 421 journal May 2019
VLBA monitoring of Mrk 421 at 15 GHz and 24 GHz during 2011 journal September 2012
Discovery of high and very high-energy emission from the BL Lacertae object SHBL J001355.9–185406 journal June 2013
The TeV blazar Markarian 421 at the highest spatial resolution journal November 2013
The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies journal April 2015
Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010 journal May 2015
The F-GAMMA programme: multi-frequency study of active galactic nuclei in the Fermi era : Programme description and the first 2.5 years of monitoring⋆ journal November 2016
Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009 journal September 2016
The TANAMI Multiwavelength Program: Dynamic spectral energy distributions of southern blazars journal June 2016
Very high energy outburst of Markarian 501 in May 2009 journal October 2016
Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009 journal July 2017
Long-term optical monitoring of TeV emitting blazars: I. Data analysis⋆ journal December 2018
Broadband spectral fitting of blazars using XSPEC journal March 2018
A hadronic origin for ultra-high-frequency-peaked BL Lac objects journal February 2015
Photohadronic origin of $\boldsymbol {\gamma }$-ray BL Lac emission: implications for IceCube neutrinos journal March 2015
Particle diffusion and localized acceleration in inhomogeneous AGN jets – II. Stochastic variation journal March 2016
Brightness temperature – obtaining the physical properties of a non-equipartition plasma journal March 2017
Time-dependent spectral modelling of Markarian 421 during a violent outburst in 2010 journal May 2019
On the radiation energy density in the jet of high-energy-emitting BL Lac objects and its impact on their multimessenger role journal July 2019
Multiband optical flux density and polarization microvariability study of optically bright blazars journal December 2019
The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars journal November 2012
Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics journal July 2012
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MAGIC detection of very high energy γ-ray emission from the low-luminosity blazar 1ES 1741+196 text January 2017
The Correlation between the Total Magnetic Flux and the Total Jet Power journal December 2017
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X-Ray Flaring Activity of mrk 421 in the First half of 2013 journal October 2016
4.5 Years of Multi-Wavelength Observations of mrk 421 During the Argo-Ybj and Fermi Common Operation time journal January 2016
Kinematics of Parsec-scale Jets of Gamma-Ray Blazars at 43 GHz within the VLBA-BU-BLAZAR Program journal September 2017
General Physical Properties of CGRaBS Blazars journal December 2017
Swift Observations of Mrk 421 in Selected Epochs. I. The Spectral and Flux Variability in 2005–2008 journal February 2018
New High- z BL Lacs Using the Photometric Method with Swift and SARA journal May 2018
Blazar Spectra with Hard-sphere-like Acceleration of Electrons journal June 2018
The Properties of Parsec-scale Blazar Jets journal January 2019
Stable Radio Core of the Blazar Mrk 501 during High-energy Active State in 2012 journal October 2019
Long-term Optical Polarization Variability and Multiwavelength Analysis of Blazar Mrk 421 journal August 2017
New Hard-TeV Extreme Blazars Detected with the MAGIC Telescopes journal February 2020
Unraveling the Complex Behavior of Mrk 421 with Simultaneous X-Ray and VHE Observations during an Extreme Flaring Activity in 2013 April journal June 2020
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A compact radio source in the high-redshift soft gamma-ray blazar IGR J12319–0749 journal April 2013
THE SWIFT /BAT HARD X-RAY TRANSIENT MONITOR journal October 2013
Axion-like particle imprint in cosmological very-high-energy sources journal November 2011
Mrk 421 as a case study for TeV and X-ray variability in leptohadronic models journal July 2013
Bethe–Heitler emission in BL Lacs: filling the gap between X-rays and γ-rays journal December 2014
The accretion disc-jet connection in blazars journal March 2019
Discovery of high and very high-energy emission from the BL Lacertae object SHBL J001355.9–185406 text January 2013
Very high energy outburst of Markarian 501 in May 2009 text January 2016
Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009 text January 2017
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Leptonic and Hadronic Modeling of Fermi -LAT Hard Spectrum Quasars and Predictions for High-energy Polarization journal August 2018
Probing an X-Ray Flare Pattern in Mrk 421 Induced by Multiple Stationary Shocks: A Solution to the Bulk Lorentz Factor Crisis journal May 2019
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On the Jet Properties of γ -Ray-loud Active Galactic Nuclei journal April 2018
MAGIC detection of very high energy γ-ray emission from the low-luminosity blazar 1ES 1741+196 journal February 2017
Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009 text January 2016
Particle diffusion and localized acceleration in inhomogeneous AGN jets – II. Stochastic variation text January 2016
New Hard-TeV Extreme Blazars Detected with the MAGIC Telescopes text January 2020
Millimeter-Wave Monitoring of Active Galactic Nuclei with the Africa Millimetre Telescope journal June 2019
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Compton Dominance and the Blazar Sequence text January 2012
Mrk 421 as a case study for TeV and X-ray variability in leptohadronic models text January 2013
Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406 text January 2013
Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010 text January 2014
The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation text January 2015
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The F-GAMMA program: Multi-frequency study of Active Galactic Nuclei in the Fermi era. Program description and the first 2.5 years of monitoring text January 2016
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The correlation between the total magnetic flux and the total jet power text January 2018
Possible Accretion Disk Origin of the Emission Variability of a Blazar Jet text January 2018
Time dependent spectral modeling of Markarian 421 during a violent outburst in 2010 text January 2019
New hard-TeV extreme blazars detected with the MAGIC telescopes text January 2019
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Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BL LACERTAE OBJECTS
ENERGY SPECTRA
GALAXIES
GAMMA RADIATION
GAMMA SPECTRA
VARIATIONS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
RADIATIONS
SPECTRA