J/MNRAS/446/3478 Fornax A MWA 154MHz image (McKinley+, 2015)
Modelling of the spectral energy distribution of Fornax A:
leptonic and hadronic production of high-energy emission from the radio lobes.
McKinley B., Yang R., Lopez-Caniego M., Briggs F., Hurley-Walker N.,
Wayth R.B., Offringa A.R., Crocker R., Bernardi G., Procopio P.,
Gaensler B.M., Tingay S.J., Johnston-Hollitt M., Mcdonald M., Bell M.,
Bhat N.D.R., Bowman J.D., Cappallo R.J., Corey B.E., Deshpande A.A.,
Emrich D., Ewall-wice A., Feng L., Goeke R., Greenhill L.J., Hazelton B.J.,
Hewitt J.N., Hindson L., Jacobs D., Kaplan D.L., Kasper J.C.,
Kratzenberg E., Kudryavtseva N., Lenc E., Lonsdale C.J., Lynch M.J.,
Mcwhirter S.R., Mitchell D.A., Morales M.F., Morgan E., Oberoi D.,
Ord S.M., Pindor B., Prabu T., Riding J., Rogers A.E.E., Roshi D.A.,
Udaya Shankar N., Srivani K.S., Subrahmanyan R., Waterson M., Webster R.L.,
Whitney A.R., Williams A., Williams C.L.
<Mon. Not. R. Astron. Soc., 446, 3478-3491 (2015)>
=2015MNRAS.446.3478M 2015MNRAS.446.3478M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio
Keywords: galaxies: active - galaxies: individual: NGC1316 -
radio continuum: galaxies
Abstract:
We present new low-frequency observations of the nearby radio galaxy
Fornax A at 154MHz with the Murchison Widefield Array, microwave
flux-density measurements obtained from WMAP and Planck
data, and γ-ray flux densities obtained from Fermi data.
We also compile a comprehensive list of previously published images
and flux-density measurements at radio, microwave and X-ray energies.
A detailed analysis of the spectrum of Fornax A between 154 and
1510MHz reveals that both radio lobes have a similar spatially
averaged spectral index, and that there exists a steep-spectrum bridge
of diffuse emission between the lobes. Taking the spectral index of
both lobes to be the same, we model the spectral energy distribution
of Fornax A across an energy range spanning 18 orders of magnitude, to
investigate the origin of the X-ray and γ-ray emission. A
standard leptonic model for the production of both the X-rays and
γ-rays by inverse-Compton scattering does not fit the
multiwavelength observations. Our results best support a scenario
where the X-rays are produced by inverse-Compton scattering and the
γ-rays are produced primarily by hadronic processes confined to
the filamentary structures of the Fornax A lobes.
Description:
Observations of Fornax A were made with the MWA on 2013 August 21,
comprising of seven snapshot observations, each of 112 s duration and
using the same beamformer delay settings.
Objects:
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RA (2000) DE Designation(s)
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03 22 41.79 -37 12 29.5 Fornax A = NGC 1316
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 109 1 Information on fits image
fits/* . 1 FITS image
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 50 A21 "datime" Obs.date Observation date
52- 58 F7.3 MHz Freq Observed frequency
60- 64 I5 Kibyte size Size of FITS file
66- 81 A16 --- FileName Name of FITS file, in subdirectory fits
83-109 A27 --- Title Title of the FITS file
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Acknowledgements:
Ben McKinley, ben.mckinley(at)curtin.edu.au
(End) Patricia Vannier [CDS] 07-Feb-2022