COS B observation of high-energy γ radiation from 3C273

Swanenburg, B. N.; Bennett, K.; Bignami, G. F.; Caraveo, P. A.; Hermsen, W.; Kanbach, G.; Masnou, J. L.; Mayer‐Hasselwander, H. A.; Paul, J.; Sacco, B.; Scarsi, L.; Wills, R. D.

doi:10.1038/275298a0

Cited by 167 publications

(62 citation statements)

References 4 publications

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“…The unusual high-energy properties of the quasar 3C 273 were suggested by the COS B detection of this source at energies above 50 MeV (Swanenburg et al 1978). Interpolation between the available hard X-ray data up to 1120 keV (Primini et al 1979;Ricker et al 1980;Pietsch et al 1981;Bezler et al 1984) and the COS B data indicated that the peak in the power output of 3C 273 occurs in the soft gamma-ray regime.…”

Section: Introductionmentioning

confidence: 99%

Time Variability Detected in the Gamma-Ray Emission of 3C 273 by OSSE

McNaron-Brown

Johnson

Dermer

et al. 1997

The Astrophysical Journal

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We report results of a 3 week observation of the quasar 3C 273 with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (CGRO). During the observation between 1994 August 31 and September 20, 3C 273 exhibited variability on timescales as short as 3-4 days in the 0.05-0.15 MeV energy range. This is the shortest measured variability of 3C 273 in this energy range. The measured flux at 100 keV is 2.40 H 0.06 (ϫ10 Ϫ2 ph cm Ϫ2 s Ϫ1 MeV Ϫ1 ), which is the highest recorded flux for 3C 273 by OSSE in 5 years of monitoring and nearly twice as great as the previously recorded peak flux measured in 1991 June. While the flux varied by a factor of 41.7, no significant gamma-ray spectral evolution in the OSSE band was observed throughout the viewing period. The data for the full viewing period are described better with a broken power law than a single power law, with photon spectral index ⌫ ϭ 1.62 H 0.08 below a break at 300 H 100 keV, and with a spectral index change of ⌬⌫ ϭ 0.9 Ϫ0.6 ϩ1.6 . This break energy is significantly lower than the 1 MeV break reported by Johnson et al. in 1991 June.

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Section: Introductionmentioning

confidence: 99%

Time Variability Detected in the Gamma-Ray Emission of 3C 273 by OSSE

McNaron-Brown

Johnson

Dermer

et al. 1997

The Astrophysical Journal

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“…It was the first discovered quasar (Schmidt 1963), and the first extragalactic source detected in γ-ray band, by COS-B (Swanenburg et al 1978). The source is categorized as a low synchrotron peaked blazar (LSP) by Abdo et al (2010a).…”

Section: Introductionmentioning

confidence: 99%

Constraining the location of rapid gamma-ray flares in the flat spectrum radio quasar 3C 273

Rani¹,

Lott²,

Krichbaum³

et al. 2013

A&A

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We present a γ-ray photon flux and spectral variability study of the flat-spectrum radio quasar 3C 273 over a rapid flaring activity period between September 2009 to April 2010. Five major flares were observed in the source during this period. The most rapid flare observed in the source has a flux doubling time of 1.1 hr. The rapid γ-ray flares allow us to constrain the location and size of the γ-ray emission region in the source. The γγ-opacity constrains the Doppler factor δ γ ≥ 10 for the highest energy (15 GeV) photon observed by the Fermi-Large Area Telescope (LAT). Causality arguments constrain the size of the emission region to 1.6 × 10 15 cm. The γ-ray spectra measured over this period show clear deviations from a simple power law with a break in the 1−2 GeV energy range. We discuss possible explanations for the origin of the γ-ray spectral breaks. Our study suggests that the γ-ray emission region in 3C 273 is located within the broad line region (<1.6 pc). The spectral behavior and temporal characteristics of the individual flares indicate the presence of multiple shock scenarios at the base of the jet.

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“…The QSO 3C273 is the only detected extragalactic source at E > 30 MeV (Swanenberg, 1978). As discussed earlier, the spectrum must exhibit a steepening or break in a power-law form between ^ 30 keV and 30 MeV.…”

Section: Diffuse Galactic Emissionmentioning

confidence: 82%

44. Astronomy From Space

1982

Trans. Int. Astron. Union

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The coming of age of space astronomy is evident from the ever increasing involvement of astronomers with space observatories. In the last years we have witnessed a tremendous growth of papers in the literature on the interpretation of results from space observations. The range of astronomical topics affected by space observations is very wide, covering the gammut from stellar birth to cosmology. Chapters following this brief introductions amply illustrate this encouraging development. Space astronomy is no longer a field exploited only by a few specialists.

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COS B observation of high-energy γ radiation from 3C273

Cited by 167 publications

References 4 publications

Time Variability Detected in the Gamma-Ray Emission of 3C 273 by OSSE

Time Variability Detected in the Gamma-Ray Emission of 3C 273 by OSSE

Constraining the location of rapid gamma-ray flares in the flat spectrum radio quasar 3C 273

44. Astronomy From Space

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