WEBT and XMM-Newton observations of 3C 454.3  during the post-outburst phase

Raiteri, C. M.; Villata, M.; Larionov, V. M.; Pursimo, T.; Ibrahimov, M.; Nilsson, K.; Aller, M. F.; Kurtanidze, O. M.; Foschini, L.; Ohlert, J.; Papadakis, I. E.; Sumitomo, N.; Volvach, A. E.; Aller, H. D.; Arkharov, A. A.; Bach, U.; Berdyugin, A.; Böttcher, M.; Buemi, C. S.; Calcidese, P.; Charlot, P.; Sánchez, A.; Paola, Andrea; Djupvik, A. A.; Dolci, M.; Ефимова, Н. В.; Fan, J. H.; Forné, E.; Gómez, César; Gupta, Alok C.; Hagen-Thorn, V. A.; Hooks, L.; Hovatta, T.; Ishii, Yuko; Kamada, M.; Константинова, Т. С.; Kopatskaya, E. N.; Kovalev, Yu. A.; Kovalev, Y. Y.; Lähteenmäki, A.; Lanteri, L.; Campion, J.-F. Le; Lee, Chung-Uk; Leto, P.; Lin, H. C.; Lindfors, E.; Мингалиев, М. Г.; Mizoguchi, Shigeru; Nicastro, F.; Nikolashvili, M. G.; Nishiyama, Shinji; Östman, L.; Ovcharov, E.; Pääkkönen, Pertti; Pasanen, M.; Pian, E.; Rector, T. A.; Ros, Javier; Sadakane, Kozo; Selj, Josefine; Semkov, E.; Sharapov, D.; Somero, A.; Stanev, I. S.; Strigachev, A.; Takalo, L. O.; Tanaka, K.; Tavani, M.; Torniainen, I.; Tornikoski, M.; Trigilio, C.; Umana, G.; Vercellone, S.; Valcheva, A.; Volvach, L. N.; Yamanaka, Masahito

doi:10.1051/0004-6361:20078289

Cited by 100 publications

(98 citation statements)

References 40 publications

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“…For instance, 3C 454.3 shows approximately the same spectral slope in different brightness states (see e.g. Raiteri et al 2007;Raiteri et al 2008). …”

Section: Swift/xrt Datamentioning

confidence: 97%

AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

D’Ammando

Pucella²,

Raiteri

et al. 2009

A&A

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Aims. We report the detection by the AGILE satellite of a rapid γ-ray flare from the source 1AGL J1511−0908, associated with the powerful γ-ray quasar PKS 1510−089, during a pointing centered on the Galactic center region from 1 March to 30 March 2008. This source has been continuosly monitored in the radio-to-optical bands by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT). Moreover, the γ-ray flaring episode triggered three ToO observations by the Swi f t satellite in three consecutive days, starting from 20 March 2008. The quasisimultaneous radio-to-optical, UV, X-ray and γ-ray coverage allows us to make a detailed study of the multifrequency time evolution, the spectral energy distribution of this source, and its theoretical interpretation based on the synchrotron and inverse Compton (IC) emission mechanisms. Methods. During the radio-to-optical monitoring provided by the GASP-WEBT, AGILE observed the source with its two co-aligned imagers, the gamma-ray imaging detector (GRID) and the hard X-ray imager (SuperAGILE), which are sensitive in the 30 MeV-30 GeV and 18-60 keV energy bands, respectively. Results. In the period 1-16 March 2008, AGILE detected γ-ray emission from PKS 1510−089 at a significance level of 6.2-σ with an average flux over the entire period of (84 ± 17) × 10 −8 photons cm −2 s −1 for photon energies above 100 MeV. After a predefined satellite re-pointing, between 17 and 21 March 2008, AGILE detected the source at a significance level of 7.3-σ, with an average flux (E > 100 MeV) of (134 ± 29) × 10 −8 photons cm −2 s −1 and a peak level of (281 ± 68) × 10 −8 photons cm −2 s −1 with daily integration. During the observing period January-April 2008, the source also showed an intense and variable optical activity, with several flaring episodes and a significant increase in the flux was observed at millimetric frequencies. Moreover, in the X-ray band, the Swi f t/XRT observations seem to show a harder-when-brighter behavior of the source spectrum. Conclusions. The flat spectrum radio quasar PKS 1510−089 showed strong activity between January and April 2008, with episodes of rapid variability from radio to γ-ray energy bands, in particular with a rapid γ-ray flaring episode. The spectral energy distribution of mid-March 2008 is modeled with a homogeneous one-zone synchrotron self Compton (SSC) emission plus contributions from inverse Compton scattering of external photons from both the accretion disk and the broad line region. Indeed, some features in the optical-UV spectrum seem to indicate Seyfert-like components such as the little and the big blue bumps.

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“…For instance, 3C 454.3 shows approximately the same spectral slope in different brightness states (see e.g. Raiteri et al 2007;Raiteri et al 2008). …”

Section: Swift/xrt Datamentioning

confidence: 97%

AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

D’Ammando

Pucella²,

Raiteri

et al. 2009

A&A

Self Cite

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show abstract

“…Through the analysis of low-energy data from the Whole Earth Blazar Telescope 1 (WEBT) and highenergy data from the XMM-Newton satellite, Raiteri et al (2007) were able to recognise both a little blue bump in the optical, possibly due to emission lines from the BLR, and a UV excess, suggesting a big blue bump likely due to thermal radiation from the accretion disc. Moreover, they argue that the X-ray spectrum may be concave, with spectral softening at lower energies becoming more evident when the source is fainter, maybe revealing the high-frequency tail of the big blue bump.…”

Section: Introductionmentioning

confidence: 99%

The long-lasting activity of 3C 454.3

Raiteri

Villata

Aller

et al. 2011

A&A

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Context. The blazar 3C 454.3 is one of the most active sources from the radio to the γ-ray frequencies observed in the past few years. Aims. We present multiwavelength observations of this source from April 2008 to March 2010. The radio to optical data are mostly from the GASP-WEBT, UV and X-ray data from Swift, and γ-ray data from the AGILE and Fermi satellites. The aim is to understand the connection among emissions at different frequencies and to derive information on the emitting jet. Methods. Light curves in 18 bands were carefully assembled to study flux variability correlations. We improved the calibration of optical-UV data from the UVOT and OM instruments and estimated the Lyα flux to disentangle the contributions from different components in this spectral region. Results. The observations reveal prominent variability above 8 GHz. In the optical-UV band, the variability amplitude decreases with increasing frequency due to a steadier radiation from both a broad line region and an accretion disc. The optical flux reaches nearly the same levels in the 2008-2009 and 2009-2010 observing seasons; the mm one shows similar behaviour, whereas the γ and X-ray flux levels rise in the second period. Two prominent γ-ray flares in mid 2008 and late 2009 show a double-peaked structure, with a variable γ/optical flux ratio. The X-ray flux variations seem to follow the γ-ray and optical ones by about 0.5 and 1 d, respectively. Conclusions. We interpret the multifrequency behaviour in terms of an inhomogeneous curved jet, where synchrotron radiation of increasing wavelength is produced in progressively outer and wider jet regions, which can change their orientation in time. In particular, we assume that the long-term variability is due to this geometrical effect. By combining the optical and mm light curves to fit the γ and X-ray ones, we find that the γ (X-ray) emission may be explained by inverse-Comptonisation of synchrotron optical (IR) photons by their parent relativistic electrons (SSC process). A slight, variable misalignment between the synchrotron and Comptonisation zones would explain the increased γ and X-ray flux levels in 2009-2010, as well as the change in the γ/optical flux ratio during the outbursts peaks. The time delays of the X-ray flux changes after the γ, and optical ones are consistent with the proposed scenario.

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“…3C 454.3: This source is studied by Donato et al (2005) and found that it is well described by simple power law with Γ=1.34. XMM−Newton observations are analyzed by Raiteri et al (2007); 2008 in its post outburst and outburst states, respectively. We analysed four observations of XMM−Newton and found that all are well described by the power law model.…”

Section: S4 0954+65mentioning

confidence: 99%

Signature of inverse Compton emission from blazars

Gaur

Mohan

Wierzcholska

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Blazars are classified into high, intermediate and low energy peaked sources based on the location of their synchrotron peak. This lies in infra-red/optical to ultra-violet bands for low and intermediate peaked blazars. The transition from synchrotron to inverse Compton emission falls in the X-ray bands for such sources. We present the spectral and timing analysis of 14 low and intermediate energy peaked blazars observed with XMMNewton spanning 31 epochs. Parametric fits to X-ray spectra helps constrain the possible location of transition from the high energy end of the synchrotron to the low energy end of the inverse Compton emission. In seven sources in our sample, we infer such a transition and constrain the break energy in the range 0.6 10 keV. The Lomb-Scargle periodogram is used to estimate the power spectral density (PSD) shape. It is well described by a power law in a majority of light curves, the index being flatter compared to general expectation from AGN, ranging here between 0.01 and 1.12, possibly due to short observation durations resulting in an absence of long term trends. A toy model involving synchrotron self-Compton (SSC) and external Compton (EC; disk, broad line region, torus) mechanisms are used to estimate magnetic field strength 0.03 -0.88 G in sources displaying the energy break and infer a prominent EC contribution. The timescale for variability being shorter than synchrotron cooling implies steeper PSD slopes which are inferred in these sources.

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WEBT and XMM-Newton observations of 3C 454.3 during the post-outburst phase

Cited by 100 publications

References 40 publications

AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

The long-lasting activity of 3C 454.3

Signature of inverse Compton emission from blazars

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