skip to main content

SciTech ConnectSciTech Connect

Title: The blob crashes into the mirror: modeling the exceptional γ-ray flaring activity of 3C 454.3 in 2010 November

3C 454.3 is a prominent flat-spectrum radio quasar that in recent years attracted considerable attention because of its variable high-energy emissions. In this paper, we focus on the exceptional flaring activity of 3C 454.3 that was detected by AGILE and by Fermi-LAT in 2010 November. In the light of the time-varying data ranging from the radio, optical, and X-ray up to GeV γ-ray bands, we discuss a theoretical framework addressing all data in their overall evolution. For two weeks, the source has shown a plateau of enhanced GeV emission preceding a sudden major flare lasting about three days before decaying. The γ-ray flare onset is abrupt (about six hours), and is characterized by a prominent 'Compton dominance' with the GeV flux exceeding the pre-flare values by a factor of four to five. During this episode, the optical and X-ray fluxes increased by a factor of around two. Within the standard framework of a jet launched with a Lorentz bulk factor Γ ∼ 10 from a central black hole, we explore the yields of two alternatives. Case 1, with high-energy emission originating within the broad line region (BLR); and Case 2, with most of it produced outside at larger distances ofmore » a few parsecs. We show that Case 1 has considerable problems in explaining the whole set of multifrequency data. Case 2, instead, leads to a consistent and interesting interpretation based on the enhanced inverse Compton radiation that is produced as the jet crashes onto a mirror cloud positioned at parsec scales. This model explains the γ-ray versus optical/X-ray behavior of 3C 454.3, including the otherwise puzzling phenomena such as the prominent 'rphan' optical flare, and the enhanced line emission with no appreciable γ-ray counterpart that preceded the GeV γ-ray flare. It also accounts for the delayed onset of the latter on top of the long plateau. Our modeling of the exceptional 3C 454.3 γ-ray flare shows that while emission inside the canonical BLR is problematic, major and rapid variations can be produced at parsec scales with moderate bulk Lorentz factors Γ ≈ 15. Our 'crashed mirror' model is also applicable to other blazar flares marked by large Compton dominance of the emitted radiation such as the flare of PKS 1830–211 in 2010 October.« less
Authors:
;  [1] ; ;  [2] ;  [3]
  1. INAF/IASF-Roma, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy)
  2. Universite "Tor Vergata," Via della Ricerca Scientifica 1, I-00133 Roma (Italy)
  3. INAF/IASF-Palermo, Via Ugo La Malfa 153, I-90146 Palermo (Italy)
Publication Date:
OSTI Identifier:
22370575
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 793; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; COMPTON EFFECT; COSMIC RADIO SOURCES; DISTANCE; EMISSION; EVOLUTION; FLARING; GALAXIES; GAMMA RADIATION; GEV RANGE; MIRRORS; QUASARS; SIMULATION; SPECTRA; STELLAR FLARES; VISIBLE RADIATION; X RADIATION