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Krauss, F.; Wilms, J.; Kadler, Matthias; Ojha, R.; Schulz, R.; Trüstedt, J.; Edwards, P.G.; Stevens, J.; Ros Ibarra, Eduardo
Perfil; Baumgartner, W.; Beuchert, T.; Blanchard, J.; Buson, S.; Carpenter, B.; Dauser, T.; Falkner, S.; Gehrels, N.; Gräfe, C.; Gulyaev, S.; Hase, H.; Horiuchi, S.; Kreikenbohm, A.; Kreykenbohm, I.; Langejahn, M.; Leiter, K.; Lovell, J.E.J.; Müller, C.; Natusch, T.; Nesci, R.; Pursimo, T.; Phillips, C.; Plötz, C.; Quick, J.; Tzioumis, A.K.; Weston, S.
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This document is a artículoDate2016
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Este documento está disponible también en :
http://hdl.handle.net/10550/59347
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Context. Simultaneous broadband spectral and temporal studies of blazars are an important tool in investigating AGN jet physics. Aims. We study the spectral evolution between quiescent and flaring periods of 23 radio loud active galactic nuclei through multiepoch quasi-simultaneous broadband spectra. For many of these sources these are the first broadband studies. From these SEDs we study the blazar sequence in low, intermediate, and high states, the Compton dominance, the fundamental plane of black holes and the thermal excess called the 'Big Blue Bump'. Methods. We use a Bayesian block analysis of Fermi/LAT light curves in order to determine time ranges of constant flux for constructing quasi-simultaneous SEDs, and are therefore limited by the -ray flux. The shape of the humps are characterized using an empirical model consisting of logarithmic parabolas and a blackbody if necessary. Results. For low states the observed peak frequencies and luminosities agree well with the blazar sequence - a SED peak at a higher luminosity is found at lower frequencies - however, this is not true for sources in a high state. The photon index in Fermi/LAT shows a correlation with the synchrotron peak frequency in low, and intermediate states, however, this is not true for the high state, where the scatter seems much larger.We confirm previous findings about the Compton dominance and show that the black hole mass can not be determined from the SEDs. Surprisingly, we find that all 'big blue bumps' (the thermal excess often found in FSRQs at optical/UV wavelengths) can be described by a single temperature blackbody. We confirm previous findings that the temperature is below what is expected of an accretion disk. Conclusions. We construct multi-epoch quasi-simultaneous broadband SEDs for 22 sources, yielding 81 SEDs. We show that the 'harder-when-brighter-trend', typically seen in X-ray spectra of flaring blazars, is visible in the blazar sequence. Our results for low and intermediate states, as well as the Compton dominance, are in agreement with previous results. We further find that black hole mass estimates using the parameters from Bonchi et al. (2013) are in agreement with some of the measurements. For a few sources, all estimates disagree with the measurement by more than four orders of magnitude. This might be due to boosting effects. The temperature and blackbody shape of the thermal excess seen predominantely in flat spectrum radio quasars are inconsistent with a direct accretion disk origin.
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Krauss, F. Wilms, J. Kadler, Matthias Ojha, R. Schulz, R. Trüstedt, J. Edwards, P.G. Stevens, J. Ros Ibarra, Eduardo Baumgartner, W. Beuchert, T. Blanchard, J. Buson, S. Carpenter, B. Dauser, T. Falkner, S. Gehrels, N. Gräfe, C. Gulyaev, S. Hase, H. Horiuchi, S. Kreikenbohm, A. Kreykenbohm, I. Langejahn, M. Leiter, K. Lovell, J.E.J. Müller, C. Natusch, T. Nesci, R. Pursimo, T. Phillips, C. Plötz, C. Quick, J. Tzioumis, A.K. Weston, S. 2016 The TANAMI Multiwavelength Program: Dynamic spectral energy distributions of southern blazars Astronomy and Astrophysics 591 A130 1 26 |
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https://doi.org/10.1051/0004-6361/201628595
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