2006A&A...451..797O


Query : 2006A&A...451..797O

2006A&A...451..797O - Astronomy and Astrophysics, volume 451, 797-807 (2006/6-1)

Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71. I. Simultaneous broadband observations during November 2003.

OSTORERO L., WAGNER S.J., GRACIA J., FERRERO E., KRICHBAUM T.P., BRITZEN S., WITZEL A., NILSSON K., VILLATA M., BACH U., BARNABY D., BERNHART S., CARINI M.T., CHEN C.W., CHEN W.P., CIPRINI S., CRAPANZANO S., DOROSHENKO V., EFIMOVA N.V., EMMANOULOPOULOS D., FUHRMANN L., GABANYI K., GILTINAN A., HAGEN-THORN V., HAUSER M., HEIDT J., HOJAEV A.S., HOVATTA T., HROCH F., IBRAHIMOV M., IMPELLIZZERI V., IVANIDZE R.Z., KACHEL D., KRAUS A., KURTANIDZE O., LAEHTEENMAEKI A., LANTERI L., LARIONOV V.M., LIN Z.Y., LINDFORS E., MUNZ F., NIKOLASHVILI M.G., NUCCIARELLI G., O'CONNOR A., OHLERT J., PASANEN M., PULLEN C., RAITERI C.M., RECTOR T.A., ROBB R., SIGUA L.A., SILLANPAEAE A., SIXTOVA L., SMITH N., STRUB P., TAKAHASHI S., TAKALO L.O., TAPKEN C., TARTAR J., TORNIKOSKI M., TOSTI G., TROELLER M., WALTERS R., WILKING B.A., WILLS W., AGUDO I., ALLER H.D., ALLER M.F., ANGELAKIS E., KLARE J., KOERDING E., STROM R.G., TERAESRANTA H., UNGERECHTS H. and VILA-VILARO B.

Abstract (from CDS):

Some intra-day variable, compact extra-galactic radio sources show brightness temperatures severely exceeding 1012K, the limit set by catastrophic inverse-Compton (IC) cooling in sources of incoherent synchrotron radiation. The violation of the IC limit, actually possible under non-stationary conditions, would lead to IC avalanches in the soft-γ-ray energy band during transient periods. For the first time, broadband signatures of possible IC catastrophes were searched for in a prototypical source, S5 0716+71. A multifrequency observing campaign targetting S5 0716+71 was carried out during November 06-20, 2003. The observations, organized under the framework of the European Network for the Investigation of Galactic nuclei through Multifrequency Analysis (ENIGMA) together with a campaign by the Whole Earth Blazar Telescope (WEBT), involved a pointing by the soft-γ-ray satellite INTEGRAL, optical, near-infrared, sub-millimeter, millimeter, radio, as well as Very Long Baseline Array (VLBA) monitoring. S5 0716+71 was very bright at radio frequencies and in a rather faint optical state (R=14.17-13.64) during the INTEGRAL pointing; significant inter-day and low intra-day variability was recorded in the radio regime, while typical fast variability features were observed in the optical band. No obvious correlation was found between the radio and optical emission. The source was not detected by INTEGRAL, neither by the X-ray monitor JEM-X nor by the γ-ray imager ISGRI, but upper limits to the source emission in the 3-200keV energy band were estimated. A brightness temperature Tb>2.1x1014K (violating the IC limit) was inferred from the variability observed in the radio regime, but no corresponding signatures of IC avalanches were recorded at higher energies. In the most plausible scenario of negligible contribution of the interstellar scintillation to the observed radio variability, the absence of the signatures of IC catastrophes provides either a lower limit δ>8 to the Doppler factor affecting the radio emission or strong constraints for modelling of the Compton-catastrophe scenario in S5 0716+71.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: BL Lacertae objects: general - galaxies: BL Lacertae objects: individual: S5 0716+71 - galaxies: quasars: general - gamma-rays: observations - 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 - 2022
#notes
1 3C 84 Sy2 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 3769 3
2 V* CM Tau Psr 05 34 31.9474694616 +22 00 52.153698024           ~ 5028 0
3 M 1 SNR 05 34 32 +22 00.8           ~ 5904 1
4 8C 0716+714 BLL 07 21 53.4482942664 +71 20 36.363846516   15.5 14.17 14.27   ~ 1207 1
5 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4065 2
6 3C 295 Sy2 14 11 20.467 +52 12 09.52   22.34 20.80 18.54   ~ 946 5
7 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 1001 0
8 NGC 7027 PN 21 07 01.571952 +42 14 10.47120   10.358 8.831 10.157   ~ 2402 1

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2022.05.27-04:56:43

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