High-Energy Gamma Rays from PKS 1406−076 and the Observation of Correlated Gamma-Ray and Optical Emission

Wagner, S. J.; Mattox, J. R.; Hopp, U.; Bock, Heike; Heidt, J.; Bertsch, D. L.; Dingus, B. L.; Fichtel, C. E.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.; Kniffen, D. A.; Lin, Y. C.; Mayer‐Hasselwander, H. A.; Michelson, P. F.; Montigny, C. von; Nolan, P. L.; Sreekumar, P.; Thompson, D. J.

doi:10.1086/309776

Cited by 39 publications

(5 citation statements)

References 12 publications

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“…Simultaneous observations at a higher cadence would be required to test the hypothesis. A correlated optical -γ-ray flare with optical leading γ-rays by ∼22 hrs was previously observed for PKS 1406−076 (Wagner et al 1995). Such correlations seem not to be consistent with simple versions of high-energy emissions models, where one expects to see either high-energy flares followed by lowenergy flares or simultaneous variations.…”

Section: Gamma-ray Vs Opticalmentioning

confidence: 74%

Probing the gamma-ray variability in 3C 279 using broad-band observations

Rani

Krichbaum

Lee

et al. 2016

Mon. Not. R. Astron. Soc.

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We present the results of a broadband radio-to-GeV observing campaign organized to get a better understanding of the radiation processes responsible for the γ-ray flares observed in 3C 279. The total intensity and polarization observations of the source were carried out between December 28, 2013 and January 03, 2014 using the Fermi-LAT, Swift-XRT, Swift-UVOT, and KVN telescopes. A prominent flare observed in the optical/near-UV passbands was found to be correlated with a concurrent γ-ray flare at a confidence level >95%, which suggests a co-spatial origin of the two. Moreover, the flaring activity in the two regimes was accompanied by no significant spectral variations. A peak in the X-ray light curve coincides with the peaks of the fractional polarization curves at 43 and 86 GHz radio bands. No prominent variation was noticed for the total intensity and the electric vector position angle (EVPA) observations at radio bands during this period. We noticed a possible hint of steepening of the radio spectrum with an increase in percentage polarization, which suggests that the radio polarization variations could be simply due to a spectral change. In a simple scenario, the correlated optical/γ-ray flares could be caused by the same population of emitting particles. The coincidence of the increase in radio polarization with the X-ray flux supports the picture that X-rays are produced via inverse-Compton scattering of radio photons. The observed fractional variability for the γ-ray flare ∼0.23 does not exceed that in the optical regime, which is inconsistent with what we usually observe for 3C 279; it could be due to different dependencies of the magnetic field and the external radiation field energy density profiles along the jet.

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Section: Gamma-ray Vs Opticalmentioning

confidence: 74%

Probing the gamma-ray variability in 3C 279 using broad-band observations

Rani

Krichbaum

Lee

et al. 2016

Mon. Not. R. Astron. Soc.

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“…OPTICAL-GAMMA RAY Despite the obvious importance, it has proved very difficult to obtain simultaneous coverage of gamma-ray flares at optical wavelengths. In one case, PKS 1406-076, the optical flux rises by about 60% while the gamma rays increase by a factor of ∼3, with the optical flare apparently leading the gamma-ray flare by about a day (Wagner et al 1995b). In another case, PKS 0420-014, gamma-ray high states correspond to optical flares, while gamma-ray nondetections coincide with optically faint states (Wagner et al 1995a).…”

Section: Multiwavelength Light Curves and Correlationsmentioning

confidence: 99%

Variability of Active Galactic Nuclei

Ulrich

Maraschi

Urry

1997

Annu. Rev. Astron. Astrophys.

834

645

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A large collective effort to study the variability of active galactic nuclei (AGN) over the past decade has led to a number of fundamental results on radioquiet AGN and blazars. In radio-quiet AGN, the ultraviolet (UV) bump in low-luminosity objects is thermal emission from a dense medium, very probably an accretion disk, irradiated by the variable X-ray source. The validity of this model for high-luminosity radio-quiet AGN is unclear because the relevant UV and X-ray observations are lacking. The broad-line gas kinematics appears to be dominated by virialized motions in the gravity field of a black hole, whose mass can be derived from the observed motions. The "accretion disk plus wind" model explains most of the variability (and other) data and appears to be the most appropriate model at present. Future investigations are outlined. In blazars, rapid variability at the highest energies (gamma-rays) implies that the whole continuum is relativistically boosted along the line of sight. The general correlation found between variations in TeV gamma rays and in X rays for Mrk 421, and between variations in GeV gamma rays and in the IR-optical-UV bands for 3C 279, two prototype objects, supports models in which the same population of relativistic electrons radiates the low-frequency continuum via synchrotron and the high frequency continuum via inverse Compton scattering of soft photons.

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“…The ultimate confirmation of such gamma-ray sources as blazars came with multiwavelength campaigns that found correlated variability of gamma-ray flares with flares seen at other wavelengths. The first example was a flare seen in PKS 1406−076 in January 1993, shown in figure 11, where an optical flare was seen nearly simultaneous with the gammaray flare (Wagner et al 1995). Such correlated variability is a valuable source of information about how such jets are formed, how they are collimated and how they carry energy.…”

Section: Blazarsmentioning

confidence: 99%

Gamma ray astrophysics: the EGRET results

Thompson¹

2008

Rep. Prog. Phys.

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Cosmic gamma rays provide insight into some of the most dynamic processes in the Universe. At the dawn of a new generation of gamma-ray telescopes, this review summarizes results from the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the principal predecessor mission studying high-energy photons in the 100 MeV energy range. EGRET viewed a gammaray sky dominated by prominent emission from the Milky Way, but featuring an array of other sources, including quasars, pulsars, gamma-ray bursts, and many sources that remain unidentified. A central feature of the EGRET results was the high degree of variability seen in many gamma-ray sources, indicative of the powerful forces at work in objects visible to gamma-ray telescopes.PACS numbers: 95.55. Ka, 95.85.Pw, 98.70.Rz

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High-Energy Gamma Rays from PKS 1406−076 and the Observation of Correlated Gamma-Ray and Optical Emission

Cited by 39 publications

References 12 publications

Probing the gamma-ray variability in 3C 279 using broad-band observations

Probing the gamma-ray variability in 3C 279 using broad-band observations

Variability of Active Galactic Nuclei

Gamma ray astrophysics: the EGRET results

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