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Pregled bibliografske jedinice broj: 492707


Autori: Abdo, A. A.; ...; Dominis Prester, Dijana; ...; Ferenc, Daniel; ...; Godinović, Nikola; ...; Hrupec, Dario; ...; Puljak, Ivica; ...; Surić, Tihomir; ...; Terzić, Tomislav; ...; Zook, A.
Naslov: Fermi-LAT Observations of Markarian 421: the Missing Piece of its Spectral Energy Distribution
Izvornik: The Astrophysical journal (0004-637X) 736 (2011), 131; 1-61
Vrsta rada: članak
Ključne riječi: acceleration of particles — radiation mechanisms: non-thermal — galaxies: active — BL Lacertae objects: general — BL Lacertae objects: individual (Mrk 421) — gamma rays: observations
We report on the gamma-ray activity of the high-synchrotron-peaked BL Lacertae object 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) 10^(-8) ph cm^(-2) s^(-1). Over this time period, the Fermi-LAT spectrum above 0.3 GeV was evaluated on 7-day-long time intervals, showing significant variations in the photon flux (up to a factor ~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 which 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 broad band 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.
Projekt / tema: 098-0982931-2875, HRZZ-02.01/12
Izvorni jezik: ENG
Rad je indeksiran u
bazama podataka:
Current Contents Connect (CCC)
Science Citation Index Expanded (SCI-EXP) (sastavni dio Web of Science Core Collectiona)
Kategorija: Znanstveni
Znanstvena područja:
Puni text rada: 492707.Mkn421_LAT_MAGIC_GASP.pdf
URL Internet adrese:
Broj citata:
DOI: 10.1088/0004-637X/736/2/131
URL cjelovitog teksta:
Google Scholar: Fermi-LAT Observations of Markarian 421: the Missing Piece of its Spectral Energy Distribution
Upisao u CROSBI: (, 26. Stu. 2010. u 11:27 sati
the Fermi-LAT collaboration, the MAGIC collaboration, the GASP-WEBT consortium.

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