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Detection of significant cm to sub-mm band radio and γ-ray correlated variability in Fermi bright blazars

Fuhrmann, L. and Larsson, S. and Chiang, J. and Angelakis, E. and Zensus, J. A. and Nestoras, I. and Krichbaum, T. P. and Ungerechts, H. and Sievers, A. and Pavlidou, V. and Readhead, A. C. S. and Max-Moerbeck, W. and Pearson, T. J. (2014) Detection of significant cm to sub-mm band radio and γ-ray correlated variability in Fermi bright blazars. Monthly Notices of the Royal Astronomical Society, 441 (3). pp. 1899-1909. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20140811-080157933

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Abstract

The exact location of the γ-ray emitting region in blazars is still controversial. In order to attack this problem we present first results of a cross-correlation analysis between radio (11 cm to 0.8 mm wavelength, F-GAMMA programme) and γ-ray (0.1–300 GeV) ∼3.5 yr light curves of 54 Fermi-bright blazars. We perform a source stacking analysis and estimate significances and chance correlations using mixed source correlations. Our results reveal: (i) the first highly significant multiband radio and γ-ray correlations (radio lagging γ rays) when averaging over the whole sample, (ii) average time delays (source frame: 76 ± 23 to 7 ± 9 d), systematically decreasing from cm to mm/sub-mm bands with a frequency dependence τ_(r, γ)(ν) ∝ ν^(−1), in good agreement with jet opacity dominated by synchrotron self-absorption, (iii) a bulk γ-ray production region typically located within/upstream of the 3 mm core region (τ_(3mm, γ) = 12 ± 8 d), (iv) mean distances between the region of γ-ray peak emission and the radio ‘τ = 1 photosphere’ decreasing from 9.8 ± 3.0 pc (11 cm) to 0.9 ± 1.1 pc (2 mm) and 1.4 ± 0.8 pc (0.8 mm), (v) 3 mm/γ-ray correlations in nine individual sources at a significance level where one is expected by chance (probability: 4 × 10^(−6)), (vi) opacity and ‘time lag core shift’ estimates for quasar 3C 454.3 providing a lower limit for the distance of the bulk γ-ray production region from the supermassive black hole (SMBH) of ∼0.8–1.6 pc, i.e. at the outer edge of the broad-line region (BLR) or beyond. A 3 mm τ = 1 surface at ∼2–3 pc from the jet base (i.e. well outside the ‘canonical BLR’) finally suggests that BLR material extends to several parsec distances from the SMBH.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://mnras.oxfordjournals.org/content/441/3/1899.abstractPublisherArticle
http://dx.doi.org/10.1093/mnras/stu540DOIArticle
http://mnras.oxfordjournals.org/content/441/3/1899/suppl/DC1Related ItemSupporting Information
ORCID:
AuthorORCID
Pearson, T. J.0000-0001-5213-6231
Additional Information:© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 March 7. Received 2014 March 4; in original form 2013 November 20. This research is based on observations with the 100-m telescope of the Max-Planck-Institut für Radioastronomie (MPIfR) at Effelsberg. This work has made use of observations with the IRAM 30-m telescope. IRAMis supported by INSU/CNRS (France),MPG (Germany) and IGN (Spain). Part of this work was supported by the COST Action MP0905 ‘Black Holes in a Violent Universe’. SL also acknowledges support by a grant from the Royal Swedish Academy Crafoord Foundation. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the USA, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A.Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’ Études Spatiales in France. IN is supported for this research through a stipend from the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne. We thank Charles Dermer, Andrei Lobanov and the referee for valuable comments and suggestions.
Funders:
Funding AgencyGrant Number
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Max-Planck-GesellschaftUNSPECIFIED
Instituto Geográfico Nacional (IGN)UNSPECIFIED
COST ActionMP0905
Royal Swedish Academy Crafoord FoundationUNSPECIFIED
NASAUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Commissariat à l’Energie Atomique (CEA)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
High Energy Accelerator Research Organization (KEK)UNSPECIFIED
Japan Aerospace Exploration Agency (JAXA)UNSPECIFIED
K. A. Wallenberg FoundationUNSPECIFIED
Swedish Research CouncilUNSPECIFIED
Swedish National Space Board (SNSB)UNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Centre National d’ Études Spatiales (CNES)UNSPECIFIED
International Max Planck Research School (IMPRS) for Astronomy and AstrophysicsUNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Subject Keywords:galaxies: active galaxies: jets galaxies: nuclei quasars: general gamma-rays: galaxies radio continuum: galaxies
Issue or Number:3
Record Number:CaltechAUTHORS:20140811-080157933
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140811-080157933
Official Citation:L. Fuhrmann, S. Larsson, J. Chiang, E. Angelakis, J. A. Zensus, I. Nestoras, T. P. Krichbaum, H. Ungerechts, A. Sievers, V. Pavlidou, A. C. S. Readhead, W. Max-Moerbeck, and T. J. Pearson Detection of significant cm to sub-mm band radio and γ-ray correlated variability in Fermi bright blazars MNRAS (July 1, 2014) Vol. 441 1899-1909 First published online May 12, 2014, doi:10.1093/mnras/stu540
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48275
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:11 Aug 2014 16:17
Last Modified:03 Oct 2019 07:02

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