Bibcode
Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Clapson, A. C.; Coignet, G.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Häffner, S.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khangulyan, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R. et al.
Referencia bibliográfica
The Astrophysical Journal, Volume 746, Issue 2, article id. 151 (2012).
Fecha de publicación:
2
2012
Revista
Número de citas
176
Número de citas referidas
133
Descripción
The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and
very massive black hole ((3 - 6) × 109 M
&sun;) provides a unique opportunity to investigate the
origin of very high energy (VHE; E > 100 GeV) γ-ray emission
generated in relativistic outflows and the surroundings of supermassive
black holes. M 87 has been established as a VHE γ-ray emitter
since 2006. The VHE γ-ray emission displays strong variability on
timescales as short as a day. In this paper, results from a joint VHE
monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010
are reported. During the campaign, a flare at VHE was detected
triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and
radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of
the VHE γ-ray light curve enables one to derive a precise temporal
characterization of the flare: the single, isolated flare is well
described by a two-sided exponential function with significantly
different flux rise and decay times of τrise d
= (1.69 ± 0.30) days and τdecay d =
(0.611 ± 0.080) days, respectively. While the overall variability
pattern of the 2010 flare appears somewhat different from that of
previous VHE flares in 2005 and 2008, they share very similar timescales
(~day), peak fluxes (Φ>0.35 TeV ~= (1-3) ×
10-11 photons cm-2 s-1), and VHE
spectra. VLBA radio observations of 43 GHz of the inner jet regions
indicate no enhanced flux in 2010 in contrast to observations in 2008,
where an increase of the radio flux of the innermost core regions
coincided with a VHE flare. On the other hand, Chandra X-ray
observations taken ~3 days after the peak of the VHE γ-ray
emission reveal an enhanced flux from the core (flux increased by factor
~2; variability timescale <2 days). The long-term (2001-2010)
multi-wavelength (MWL) light curve of M 87, spanning from radio to VHE
and including data from Hubble Space Telescope, Liverpool Telescope,
Very Large Array, and European VLBI Network, is used to further
investigate the origin of the VHE γ-ray emission. No unique,
common MWL signature of the three VHE flares has been identified. In the
outer kiloparsec jet region, in particular in HST-1, no enhanced MWL
activity was detected in 2008 and 2010, disfavoring it as the origin of
the VHE flares during these years. Shortly after two of the three flares
(2008 and 2010), the X-ray core was observed to be at a higher flux
level than its characteristic range (determined from more than 60
monitoring observations: 2002-2009). In 2005, the strong flux dominance
of HST-1 could have suppressed the detection of such a feature.
Published models for VHE γ-ray emission from M 87 are reviewed in
the light of the new data.
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