2008A&A...478..111L


Query : 2008A&A...478..111L

2008A&A...478..111L - Astronomy and Astrophysics, volume 478, 111-120 (2008/1-4)

A synchrotron self-Compton scenario for the very high energy γ-ray emission of the radiogalaxy M87. Unifying the TeV emission of blazars and other AGNs?

LENAIN J.-P., BOISSON C., SOL H. and KATARZYNSKI K.

Abstract (from CDS):

M87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Cerenkov telescopes, we can now probe the variability in the γ-ray flux on small timescales, thus putting strong constraints on the size of the emitting zone. The large scale jet of M87 is misaligned with respect to the line of sight. A modification of standard emission models of TeV blazars appears necessary to account for the γ-ray observations despite this misalignment. We explain TeV γ-ray spectra and the fast variability of M87 by invoking an emission zone close to the central supermassive black hole, which is filled with several plasma blobs moving in the large opening angle of the jet formation zone. We develop a new multi-blob synchrotron self-Compton (SSC) model with emitting blobs set on a cap beyond the Alfven surface in the jet, at a distance of ∼100rg from the central engine to interpret the high energies inferred by new TeV observations. We present an SSC model that is explicitly adapted to dealing with large viewing angles and moderate values of the Lorentz factor inferred from (general relativistic) magnetohydrodynamic models of jet formation. This scenario can account for the recent γ-ray observations of M87 made by the High Energy Stereoscopic System (HESS) telescope array. We find individual blob radii of about 1014cm, that is compatible with the variability on timescales of days recently reported by the HESS collaboration and is close to the black hole gravitational radius. Predictions of the very high-energy emission for three other sources with extended optical or X-ray jet that could be misaligned blazars still with moderate beaming are presented for one Seyfert 2 radiogalaxy, namely Cen A, one peculiar BL Lac, PKS 0521-36, and one quasar, 3C 273.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: individual: M87 - gamma rays: theory - radiation mechanisms: non-thermal

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 ESO 362-21 Sy1 05 22 57.98464178 -36 27 30.8512953   15.26 14.62 14.48   ~ 843 2
2 Mrk 421 BLL 11 04 27.3140835504 +38 12 31.798495872   13.50 12.90 8.31   ~ 2691 1
3 NAME Virgo Cluster ClG 12 26 32.1 +12 43 24           ~ 6683 0
4 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5824 2
5 NAME Knot in M87 Jet PoG 12 30 49.355 +12 23 28.32           ~ 206 0
6 M 87 AGN 12 30 49.42338414 +12 23 28.0436859 10.16 9.59 8.63   7.49 ~ 7251 3
7 NAME Centaurus A Sy2 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4508 3
8 7C 165211.80+395026.00 BLL 16 53 52.21668403 +39 45 36.6088754 14.09 14.15 13.29 8.26   ~ 2179 2

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