Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

High-energy sources at low radio frequency: the Murchison Widefield Array view of Fermi blazars

Journal Article · · Astronomy and Astrophysics
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. In this paper, we characterize the spectral properties of the blazar population at low radio frequency, compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. We cross-correlated the 6100 deg2 Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by Fermi-LAT. When available, we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue. We find low-frequency counterparts for 186 out of 517 (36%) blazars, 79 out of 174 (45%) gamma-ray blazars, and 8 out of 73 (11%) gamma-ray blazar candidates. The mean low-frequency (120–180 MHz) blazar spectral index is (αlow) = 0.57 ± 0.02: blazar spectra are flatter than the rest of the population of low-frequency sources, but are steeper than at ~GHz frequencies. Low-frequency radio flux density and gamma-ray energy flux display a mildly significant and broadly scattered correlation. Ten unidentified gamma-ray sources have a (probably fortuitous) positional match with low radio frequency sources. Low-frequency radio astronomy provides important information about sources with a flat radio spectrum and high energy. However, the relatively low sensitivity of the present surveys still misses a significant fraction of these objects. Finally, upcoming deeper surveys, such as the GaLactic and Extragalactic All-Sky MWA (GLEAM) survey, will provide further insight into this population.
Research Organization:
National Inst. for Astrophysics (INAF), Bologna (Italy); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Organization:
USDOE; National Inst. for Astrophysics (INAF) (Italy)
Contributing Organization:
Fermi-LAT Collaboration
OSTI ID:
1355690
Journal Information:
Astronomy and Astrophysics, Journal Name: Astronomy and Astrophysics Vol. 588; ISSN 0004-6361
Publisher:
EDP SciencesCopyright Statement
Country of Publication:
United States
Language:
English

References (49)

The VLA Low-frequency Sky Survey journal March 2006
The 5th edition of the Roma-BZCAT. A short presentation journal April 2015
The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies journal January 2013
The Murchison Widefield Array Commissioning Survey: A Low-Frequency Catalogue of 14 110 Compact Radio Sources over 6 100 Square Degrees journal January 2014
GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey journal January 2015
A unifying view of the spectral energy distributions of blazars journal September 1998
SUMSS: a wide-field radio imaging survey of the southern sky - II. The source catalogue journal July 2003
LOFAR: The LOw-Frequency ARray journal July 2013
The LOFAR Multifrequency Snapshot Sky Survey (MSSS): I. Survey description and first results journal October 2015
Roma-BZCAT: a multifrequency catalogue of blazars journal December 2008
Unified Schemes for Radio-Loud Active Galactic Nuclei journal June 1995
The NRAO VLA Sky Survey journal May 1998
SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. I. Science Goals, Survey Design, and Instrumentation journal March 1999
The VLA Low-Frequency Sky Survey journal July 2007
HIGH-FREQUENCY RADIO PROPERTIES OF SOURCES IN THE FERMI -LAT 1 YEAR POINT SOURCE CATALOG journal July 2010
From the Blazar Sequence to the Blazar Envelope: Revisiting the Relativistic jet Dichotomy in Radio-Loud Active Galactic Nuclei journal October 2011
THE RADIO/GAMMA-RAY CONNECTION IN ACTIVE GALACTIC NUCLEI IN THE ERA OF THE FERMI LARGE AREA TELESCOPE journal October 2011
THE SECOND CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE journal December 2011
Assessing the Significance of Apparent Correlations Between Radio and Gamma-Ray Blazar Fluxes journal May 2012
THE THIRD CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE journal August 2015
FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: COSMOLOGICAL INTERPRETATION journal February 2009
FERMI LARGE AREA TELESCOPE FIRST SOURCE CATALOG journal May 2010
FERMI LARGE AREA TELESCOPE SECOND SOURCE CATALOG journal March 2012
Unveiling the Nature of the Unidentified Gamma-Ray Sources. iii. Gamma-Ray Blazar-Like Counterparts at low Radio Frequencies journal June 2013
BLAZAR SPECTRAL PROPERTIES AT 74 MHz journal September 2013
Unveiling the Nature of Unidentified γ-Ray Sources. vi. γ-Ray Blazar Candidates in the wish Survey and Their Radio Properties journal April 2014
The Low-Frequency Radio Catalog of Flat-Spectrum Sources journal June 2014
FERMI LARGE AREA TELESCOPE THIRD SOURCE CATALOG journal June 2015
Synchrotron and inverse-Compton emission from blazar jets – IV. BL Lac type blazars and the physical basis for the blazar sequence journal October 2013
The Planck –ATCA Co-eval Observations project: analysis of radio source properties between 5 and 217 GHz journal November 2015
A simplified view of blazars: contribution to the X-ray and γ-ray extragalactic backgrounds journal May 2015
The Australia Telescope 20 GHz Survey: the source catalogue journal March 2010
Correlation of Fermi Large Area Telescope sources with the 20-GHz Australia Telescope Compact Array radio survey: AT20G-1FGL journal July 2010
The radio-γ-ray connection in Fermi blazars: γ-ray-radio flux correlation in blazars journal March 2011
Spectral properties and the effect on redshift cut-off of compact active galactic nuclei from the AT20G survey: Spectral properties and z cut-off of AGNs journal April 2012
From the Blazar Sequence to the Blazar Envelope: Revisiting the Relativistic jet Dichotomy in Radio-Loud Active Galactic Nuclei collection January 2011
The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope text January 2015
The VLA Low-frequency Sky Survey text January 2007
The Australia Telescope 20 GHz Survey: The Source Catalogue text January 2009
High-frequency radio properties of sources in the Fermi-LAT 1-year Point Source Catalogue text January 2010
The radio/gamma-ray connection in Active Galactic Nuclei in the era of the Fermi Large Area Telescope text January 2011
The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies text January 2012
Blazars spectral properties at 74 MHz text January 2013
Unveiling the nature of the unidentified gamma-ray sources VI: gamma-ray blazar candidates in the WISH survey and their radio properties text January 2015
GLEAM: The GaLactic and Extragalactic All-sky MWA survey text January 2015
The LOFAR Multifrequency Snapshot Sky Survey (MSSS) I. Survey description and first results text January 2015
The Planck-ATCA Co-eval Observations (PACO) project: analysis of radio source properties between 5 and 217 GHz text January 2015
SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. II. The Source Catalogue text January 2003
SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. I. Science goals, survey design and instrumentation text January 1998

Cited By (12)

Blazars in the LOFAR Two-Metre Sky Survey first data release journal February 2019
The γ -ray sky seen at X-ray energies: I. Searching for the connection between X-rays and γ -rays in Fermi BL Lac objects journal November 2019
Fermi Large Area Telescope Fourth Source Catalog collection January 2020
Fermi Large Area Telescope Fourth Source Catalog text January 2020
Radio Luminosity Function of Flat-spectrum Radio Quasars journal June 2017
The Radio/Gamma Connection of Blazars from High to Low Radio Frequencies journal December 2018
Jet Power of Jetted Active Galactic Nuclei: Implications for Evolution and Unification journal July 2019
Two New Catalogs of Blazar Candidates in the WISE Infrared Sky journal May 2019
Fermi Large Area Telescope Fourth Source Catalog journal March 2020
Blazars in the LOFAR Two-Metre Sky Survey First Data Release text January 2018
Jet Power of Jetted Active Galactic Nuclei: Implication for Evolution and Unification text January 2019
Blazars in the LOFAR Two-Metre Sky Survey First Data Release audiovisual January 2018

Similar Records

THE LOW-FREQUENCY RADIO CATALOG OF FLAT-SPECTRUM SOURCES
Journal Article · Tue Jul 01 00:00:00 EDT 2014 · Astrophysical Journal, Supplement Series · OSTI ID:22340209
Gamma-Ray Emission From Two Blazars Behind The Galactic Plane: B2013+370 And B2023+336
Journal Article · Wed Feb 01 23:00:00 EST 2012 · The Astrophysical Journal · OSTI ID:1356760
UNVEILING THE NATURE OF THE UNIDENTIFIED GAMMA-RAY SOURCES. III. GAMMA-RAY BLAZAR-LIKE COUNTERPARTS AT LOW RADIO FREQUENCIES
Journal Article · Mon Jul 01 00:00:00 EDT 2013 · Astrophysical Journal, Supplement Series · OSTI ID:22118723

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BL Lacertae objects
catalogs
gamma rays: galaxies
non-thermal radiation mechanisms
quasars
radio continuum: galaxies