High-Energy Gamma-Ray Emission from Active Galaxies: EGRET Observations and Their Implications

Montigny, C. von; Bertsch, D. L.; Chiang, J.; Dingus, B. L.; Esposito, J. A.; Fichtel, C. E.; Fierro, J. M.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.; Kniffen, D. A.; Lin, Y. C.; Mattox, J. R.; Mayer‐Hasselwander, H. A.; Michelson, P. F.; Nolan, P. L.; Radecke, H. D.; Schneid, E. J.; Sreekumar, P.; Thompson, D. J.; Willis, T. D.

doi:10.1086/175294

Cited by 362 publications

(231 citation statements)

References 0 publications

Supporting

Mentioning

220

Contrasting

Unclassified

Order By: Relevance

“…Correlated intraday variations in optical and radio frequencies have been reported for this source (Quirrenbach et al 1991). It is also a gamma-ray emitting object associated with an FR II radio source (Wagner et al 1996;von Montigny et al 1995;Chen et al 2008;Villata et al 2008). Observations over a period of ten years indicate it experiences nearly continuous micro-variability activity (Humrickhouse & Webb 2008;Webb et al 2010), with duty cycle of about 95.3%.…”

Section: Introductionmentioning

confidence: 76%

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

Bhatta

Webb

Hollingsworth

et al. 2013

A&A

View full text Add to dashboard Cite

Context. The international Whole Earth Blazar Telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due to its bright apparent magnitude range, its high declination, and its very large duty cycle for micro-variations. Aims. We report here on the long continuous optical micro-variability light curve of 0716+714 obtained during the multi-site observing campaign during which the Blazar showed almost constant variability over a 0.5 mag range. The resulting light curve is presented here for the first time.Observations from participating observatories were corrected for instrumental differences and combined to construct the overall smoothed light curve. Methods. Thirty-six observatories in sixteen countries participated in this continuous monitoring program and twenty of them submitted data for compilation into a continuous light curve. The light curve was analyzed using several techniques including Fourier transform, Wavelet and noise analysis techniques. Those results led us to model the light curve by attributing the variations to a series of synchrotron pulses. Results. We have interpreted the observed microvariations in this extended light curve in terms of a new model consisting of individual stochastic pulses due to cells in a turbulent jet which are energized by a passing shock and cool by means of synchrotron emission. We obtained an excellent fit to the 72-hour light curve with the synchrotron pulse model.

show abstract

Section: Introductionmentioning

confidence: 76%

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

Bhatta

Webb

Hollingsworth

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…For broadband spectra of blazars see, e.g., von Montigny et al (1995) and Fossati et al (1998) ; for timescales of rapid (daily) c-ray variability see, e.g., Michelson et al (1994), Mattox et al (1997), and Wehrle et al (1998).…”

Section: Modeling Of the Radiation Spectramentioning

confidence: 99%

Comptonization of Infrared Radiation from Hot Dust by Relativistic Jets in Quasars

Błażejowski

Sikora

Moderski

et al. 2000

ApJ

405

300

View full text Add to dashboard Cite

We demonstrate the importance of near-infrared radiation from hot dust for Compton cooling of electrons/positrons in quasar jets. In our model, we assume that the nonthermal radiation spectra observed in optically violent variable (OVV) quasars are produced by relativistic electrons/positrons accelerated in thin shells that propagate down the jet with relativistic speeds. We show that the Comptonization of the near-IR Ñux is likely to dominate the radiative output of OVV quasars in the energy range from tens of keV up to hundreds of MeV, where it exceeds that produced by Comptonization of the UV radiation reprocessed and rescattered in the broad emission line (BEL) region. The main reason for this lies in the fact that the jet encounters the ambient IR radiation over a relatively large distance as compared to the distance where the energy density of the BEL light peaks. In the soft to mid-energy X-ray band, the spectral component resulting from Comptonization of the near-IR radiation joins smoothly with the synchrotron self-Compton component, which may be responsible for the soft X-ray Ñux. At the highest observed c-ray energies, in the GeV range, Comptonization of broad emission lines dominates over other components.

show abstract

“…It came as a surprise when, a decade ago, EGRET aboard the Compton Gamma Ray Observatory detected many blazars as strong and variable γ-ray emitters (von Montigny et al 1995;Mukherjee et al 1997). More recently, observations with ground-basedČerenkov telescopes have shown that at least for BL Lacertae objects the γ-ray spectrum can be traced to more than a TeV observed photon energy (Punch et al 1992;Quinn et al 1996;Catanese et al 1998;Krennrich et al 1997).…”

Section: Introductionmentioning

confidence: 99%

The influence of dust on the inverse Compton emission from jets in Active Galactic Nuclei

Arbeiter

Pohl

Schlickeiser

2002

A&A

View full text Add to dashboard Cite

Abstract. The recently observed high energy γ-ray emission from more than sixty blazars is most likely caused by inverse Compton scattering of soft ambient photons, the source of which is a subject of extensive debate. We investigate the influence of a dust torus on the inverse Compton emission of the relativistic electrons in the jets of Active Galactic Nuclei. This is an extension of previous studies, in which the main focus had been on target photons emitted by the accretion disk. We show that due to the different angular distribution of the two photon fields, the beaming pattern of the respective scattered inverse Compton gamma rays are different. We also calculate the bolometric luminosity, the beaming pattern and the spectral distribution of the emitted gamma rays for the dust torus as well as for the accretion disk as the target photon source. The results show that the relative contributions of both to the gamma ray emission depend sensitively on the observer's viewing angle and the distance of the jet plasmoids from the accretion disk and the dust torus, respectively.

show abstract

High-Energy Gamma-Ray Emission from Active Galaxies: EGRET Observations and Their Implications

Cited by 362 publications

References 0 publications

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

The 72-h WEBT microvariability observation of blazar S5 0716 + 714 in 2009

Comptonization of Infrared Radiation from Hot Dust by Relativistic Jets in Quasars

The influence of dust on the inverse Compton emission from jets in Active Galactic Nuclei

Contact Info

Product

Resources

About