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High-energy properties of the high-redshift flat spectrum radio quasar PKS 2149−306

D'Ammando, F. and Orienti, M. (2016) High-energy properties of the high-redshift flat spectrum radio quasar PKS 2149−306. Monthly Notices of the Royal Astronomical Society, 455 (2). pp. 1881-1891. ISSN 0035-8711. http://resolver.caltech.edu/CaltechAUTHORS:20160204-183823009

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Abstract

We investigate the γ-ray and X-ray properties of the flat spectrum radio quasar PKS 2149−306 at redshift z = 2.345. A strong γ-ray flare from this source was detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope satellite in 2013 January, reaching on January 20 a daily peak flux of (301 ± 36) × 10^(−8) ph cm^(−2) s^(−1) in the 0.1–100 GeV energy range. This flux corresponds to an apparent isotropic luminosity of (1.5 ± 0.2) × 10^(50) erg s^(−1), comparable to the highest values observed by a blazar so far. During the flare the increase of flux was accompanied by a significant change of the spectral properties. Moreover significant flux variations on a 6-h time-scale were observed, compatible with the light crossing time of the event horizon of the central black hole. The broad-band X-ray spectra of PKS 2149−306 observed by Swift-XRT and NuSTAR are well described by a broken power-law model, with a very hard spectrum (Γ_1 ∼ 1) below the break energy, at E_(break) = 2.5–3.0 keV, and Γ_2 ∼ 1.4–1.5 above the break energy. The steepening of the spectrum below ∼3 keV may indicate that the soft X-ray emission is produced by the low-energy relativistic electrons. This is in agreement with the small variability amplitude and the lack of spectral changes in that part of the X-ray spectrum observed between the two NuSTAR and Swift joint observations. As for the other high-redshift FSRQ detected by both Fermi-LAT and Swift-BAT, the photon index of PKS 2149−306 in hard X-ray is 1.6 or lower and the average γ-ray luminosity higher than 2 × 10^(48) erg s^(−1).


Item Type:Article
Related URLs:
URLURL TypeDescription
http://mnras.oxfordjournals/content/455/2/1881.abstractPublisherArticle
http://dx.doi.org/10.1093/mnras/stv2452DOIArticle
Additional Information:© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 October 20. Received 2015 October 14. In original form 2015 August 10. First published online November 19, 2015. 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 United States, 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. Part of this work was done with the contribution of the Italian Ministry of Foreign Affairs and Research for the collaboration project between Italy and Japan. We thank the Swift team for making these observations possible, the duty scientists, and science planners. This research has made use of the NuSTAR Data Analysis Software (NUSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). We thank Eugenio Bottacini, Luca Baldini, and Jeremy Perkins for useful comments and suggestions.
Group:NuSTAR
Funders:
Funding AgencyGrant Number
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
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Italian Ministry of Foreign Affairs and ResearchUNSPECIFIED
Record Number:CaltechAUTHORS:20160204-183823009
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160204-183823009
Official Citation:F. D'Ammando and M. Orienti High-energy properties of the high-redshift flat spectrum radio quasar PKS 2149−306 MNRAS (January 11, 2016) Vol. 455 1881-1891 doi:10.1093/mnras/stv2452 First published online November 19, 2015
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64255
Collection:CaltechAUTHORS
Deposited By: Joy Painter
Deposited On:05 Feb 2016 17:04
Last Modified:05 Feb 2016 17:04

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