Title:	Modelling of the spectral energy distribution of Fornax A: leptonic and hadronic production of high-energy emission from the radio lobes
Authors:	McKinley, B. Yang, R. Deshpande, A.A. Udaya Shankar, N. Srivani, K.S. Subrahmanyan, Ravi +40 Co-authors
Keywords:	active galaxies NGC1316 radio continuum
Issue Date:	4-Feb-2015
Publisher:	Oxford University Press for The Royal Astronomical Society
Citation:	Monthly Notices of the Royal Astronomical Society, 2015, Vol. 446, p3478-3491
Abstract:	We present new low-frequency observations of the nearby radio galaxy Fornax A at 154 MHz 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 1510 MHz 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:	Open Access
URI:	http://hdl.handle.net/2289/6184
ISSN:	0035-8711 1365-2966 - (online)
Alternative Location:	http://adsabs.harvard.edu/abs/2015MNRAS.446.3478M http://arxiv.org/abs/1411.1487 http://dx.doi.org/10.1093/mnras/stu2310
Copyright:	2015 The authors & the Royal Astronomical Society
Appears in Collections:	Research Papers (A&A)

Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.