Simultaneous observations of the continuum emission of the quasar 3C 273 from radio to γ-ray energies

Lichti, G.; Montigny, C. von; Balonek, T. J.; Courvoisier, T. J. L.; Johnson, N.; McConnell, M.; Pačiesas, W. S.; Robson, E. I.; Sadun, A. C.; Schalinski, C. J.; Steppe, H.; Smith, Alex; Staubert, R.; Swanenburg, B. N.; Turner, Martin; Ulrich, M. H.; Williams, O. R.

doi:10.1063/1.45659

Cited by 3 publications

(10 citation statements)

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“…It has been found in several blazar sources that their SEDs have more than two peaks. Particularly, in some cases a peak frequency of ∼ 10 15 Hz (e.g., Lichti et al 1995;Pian et al 1999) is seen (a UV bump), which is assumed to come purely from the optically thick accretion disk (OTAD) and from the Broad Line Region (BLR). In recent works, thermal radiation from both OTAD and BLR are considered separately in order to classify blazars (Giommi et al , 2013.…”

Section: Comparison With Observationsmentioning

confidence: 99%

The influence of the magnetic field on the spectral properties of blazars

Rueda-Becerril¹,

Mimica²,

Aloy³

2013

Monthly Notices of the Royal Astronomical Society

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We explore the signature imprinted by dynamically relevant magnetic fields on the spectral energy distribution (SED) of blazars. It is assumed that the emission from these sources originates from the collision of cold plasma shells, whose magnetohydrodynamic evolution we compute by numerically solving Riemann problems. We compute the SEDs including the most relevant radiative processes and scan a broad parameter space that encompasses a significant fraction of the commonly accepted values of not directly measurable physical properties. We reproduce the standard double hump SED found in blazar observations for unmagnetized shells, but show that the prototype double hump structure of blazars can also be reproduced if the dynamical source of the radiation field is very ultrarelativistic both, in a kinematically sense (namely, if it has Lorentz factors 50) and regarding its magnetization (e.g., with flow magnetizations σ ≃ 0.1). A fair fraction of the blazar sequence could be explained as a consequence of shell magnetization: negligible magnetization in FSRQs, and moderate or large (and uniform) magnetization in BL Lacs. The predicted photon spectral indices (Γ ph ) in the γ−ray band are above the observed values (Γ ph,obs 2.6 for sources with redshifts 0.4 z 0.6) if the magnetization of the sources is moderate (σ ≃ 10 −2 ). W: weakly magnetized, σ L = 10 −6 , σ R = 10 −6 , M: moderately magnetized, σ L = 10 −2 , σ R = 10 −2 , S: strongly magnetized, σ L = 1, σ R = 10 −1 , S1: strongly and equally magnetized, σ L = 10 −1 , σ R = 10 −1 , and S2: strongly magnetized, σ L = 10 −1 , σ R = 1.

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Section: Comparison With Observationsmentioning

confidence: 99%

The influence of the magnetic field on the spectral properties of blazars

Rueda-Becerril¹,

Mimica²,

Aloy³

2013

Monthly Notices of the Royal Astronomical Society

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“…Several observational campaigns have been carried out on 3C 273, starting from the broad multiwavelength campaign by Lichti et al (1995), which made use of data spanning from radio to γ rays, to more recent observations in X-rays. Courvoisier et al (2003) described simultaneous observation of IN-TEGRAL, XMM-Newton, and RXTE performed in January 2003.…”

Section: Introductionmentioning

confidence: 99%

“…The aim of this work is to use contemporaneous X-ray to γray observations obtained with INTEGRAL and Fermi for the first time since the CGRO campaign (Lichti et al 1995) to study the origin of the non-thermal spectral components. In Sect.…”

Section: Introductionmentioning

confidence: 99%

The high energy spectrum of 3C 273

Esposito

Walter

Jean

et al. 2015

A&A

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Aims. The high energy spectrum of 3C 273 is usually understood in terms of inverse-Compton emission in a relativistic leptonic jet. This model predicts variability patterns and delays that could be tested with simultaneous observations from the radio to the GeV range. Methods. The instruments IBIS, SPI, JEM-X on board INTEGRAL, PCA on board RXTE, and LAT on board Fermi have enough sensitivity to follow the spectral variability of 3C 273 from the keV to the GeV. We looked for correlations between the different energy bands, including radio data at 37 GHz collected at the Metsähovi Radio Observatory and built quasi-simultaneous multiwavelength spectra in the high energy domain when the source is flaring either in the X-rays or in the γ rays. Results. Both temporal and spectral analysis suggest a two-component model to explain the complete high energy spectrum. X-ray emission is likely dominated by a Seyfert-like component while the γ-ray emission is dominated by a blazar-like component produced by the relativistic jet. The variability of the blazar-like component is discussed, comparing the spectral parameters in the two different spectral states. Changes of the electron Lorentz factor are found to be the most likely source of the observed variability.

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“…Cas-A, Cyg X-1). [Adapted from Lichti et al [104]] is an all-sky map of the COMPTEL and EGRET sources. This map is derived from Fig.…”

Section: Synergy Between Cgro Instrumentsmentioning

confidence: 99%

“…A nice example is 3C 273 (Fig. 26, [104]). In addition, COMPTEL found indications for an unexpected class of so-called MeV blazars among the nine AGN, which occasionally show bumps in the 1-10 MeV range above a simple extrapolation of the simultaneously measured EGRET-spectra to lower gamma-ray energies [18,19].…”

Section: Synergy Between Cgro Instrumentsmentioning

confidence: 99%

Half-a-century of gamma-ray astrophysics at the Max-Planck Institute for Extraterrestrial Physics

Schönfelder

Greiner

2021

EPJ H

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Gamma-ray astronomy has been one of the prime scientific research fields of the Max-Planck Institute for Extraterrestrial Physics (MPE) from its beginning. Over the years, the entire gamma-ray energy range accessible from space was explored. The purpose of this review article is to summarise the achievements of the gamma-ray group at MPE during the last 50+ years. This covers a substantial part of the general history of space-based gamma-ray astronomy, for which both, general review articles (e.g. Pinkau in Exp Astron 5: 157, 2009; Schönfelder in AN 323: 524, 2002; Trimble in AIP Conf Proc 304: 40, 1994) and a detailed tabular list of events and missions (Leonard and Gehrels in https://heasarc.gsfc.nasa.gov/docs/history, version 1.0.8, 2009), have been compiled. Here, we describe the gamma-ray activities at MPE from the beginning till the present, reviewing the tight interplay between new technological developments towards new instruments and scientific progress in understanding gamma-ray sources in the sky. This covers (i) the early development of instruments and their tests on half a dozen balloon flights, (ii) the involvement in the most important space missions at the time, i.e. ESA’s COS-B satellite, NASA’s Compton Gamma-ray Observatory and Fermi Space Telescope, as well as ESA’s INTEGRAL observatory, (iii) the participation in several other missions such as TD-1, Solar Maximum Mission, or Ulysses, and (iv) the complementary ground-based optical instruments OPTIMA and GROND to enhance selected science topics (pulsars, gamma-ray bursts). With the gradual running-out of institutional support since 2010, gamma-ray astrophysics as a main research field has now come to an end at MPE.

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Simultaneous observations of the continuum emission of the quasar 3C 273 from radio to γ-ray energies

Cited by 3 publications

References 1 publication

The influence of the magnetic field on the spectral properties of blazars

The influence of the magnetic field on the spectral properties of blazars

The high energy spectrum of 3C 273

Half-a-century of gamma-ray astrophysics at the Max-Planck Institute for Extraterrestrial Physics

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