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The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

Aleksić, Jelena; ...; Babić, Ana; ...; Dominis Prester, Dijana; ...; Ferenc, Daniel; ...; Godinović, Nikola; ... et al.
The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies // Astronomy and astrophysics, 576 (2015), A126-1 doi:10.1051/0004-6361/201424216 (međunarodna recenzija, članak, znanstveni)

The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

Aleksić, Jelena ; ... ; Babić, Ana ; ... ; Dominis Prester, Dijana ; ... ; Ferenc, Daniel ; ... ; Godinović, Nikola ; ... ; Hrupec, Dario ; ... ; Lelas, Damir ; ... ; Puljak, Ivica ; ... ; Surić, Tihomir ; ... ; Šnidarić, Iva ; ... ; Terzić, Tomislav ; ...

Astronomy and astrophysics (0004-6361) 576 (2015); A126-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Galaxies: BL Lacertae objects: individual: Markarian 421

We performed a 4.5-month multi-instrument campaign (from radio to VHE gamma rays) on Mrk421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical/UV and X-rays extending over the duration of the campaign. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multi-wavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk421 during non-flaring activity. Such a temporally extended X-ray/VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies.

Izvorni jezik

Znanstvena područja


Projekt / tema
HRZZ-09/176 - Visokoenergijska astronomija gama zraka teleskopima MAGIC (Nikola Godinović, )

Fakultet elektrotehnike, strojarstva i brodogradnje, Split,
Institut "Ruđer Bošković", Zagreb,
Sveučilište u Rijeci - Odjel za fiziku

Časopis indeksira:

  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus