Modelling of the spectral energy distribution of fornax A: Leptonic and hadronic production of high-energy emission from the radio lobes

B. McKinley; R. Yang; M. López-Caniego; F. Briggs; N. Hurley-Walker; R. B. Wayth; A. R. Offringa; R. Crocker; G. Bernardi; P. Procopio; B. M. Gaensler; S. J. Tingay; M. Johnston-Hollitt; M. McDonald; M. Bell; N. D R Bhat; Judd Bowman; R. J. Cappallo; B. E. Corey; A. A. Deshpande; D. Emrich; A. Ewall-Wice; L. Feng; R. Goeke; L. J. Greenhill; B. J. Hazelton; J. N. Hewitt; L. Hindson; Daniel Jacobs; D. L. Kaplan; J. C. Kasper; E. Kratzenberg; N. Kudryavtseva; E. Lenc; C. J. Lonsdale; M. J. Lynch; S. R. McWhirter; D. A. Mitchell; M. F. Morales; E. Morgan; D. Oberoi; S. M. Ord; B. Pindor; T. Prabu; J. Riding; A. E E Rogers; D. A. Roshi; N. Udaya Shankar; K. S. Srivani; R. Subrahmanyan; M. Waterson; R. L. Webster; A. R. Whitney; A. Williams; C. L. Williams

doi:10.1093/mnras/stu2310

Modelling of the spectral energy distribution of fornax A: Leptonic and hadronic production of high-energy emission from the radio lobes

B. McKinley, R. Yang, M. López-Caniego, F. Briggs, N. Hurley-Walker, R. B. Wayth, A. R. Offringa, R. Crocker, G. Bernardi, P. Procopio, B. M. Gaensler, S. J. Tingay, M. Johnston-Hollitt, M. McDonald, M. Bell, N. D R Bhat, Judd Bowman, R. J. Cappallo, B. E. Corey, A. A. DeshpandeD. Emrich, A. Ewall-Wice, L. Feng, R. Goeke, L. J. Greenhill, B. J. Hazelton, J. N. Hewitt, L. Hindson, Daniel Jacobs, D. L. Kaplan, J. C. Kasper, E. Kratzenberg, N. Kudryavtseva, E. Lenc, C. J. Lonsdale, M. J. Lynch, S. R. McWhirter, D. A. Mitchell, M. F. Morales, E. Morgan, D. Oberoi, S. M. Ord, B. Pindor, T. Prabu, J. Riding, A. E E Rogers, D. A. Roshi, N. Udaya Shankar, K. S. Srivani, R. Subrahmanyan, M. Waterson, R. L. Webster, A. R. Whitney, A. Williams, C. L. Williams

Earth and Space Exploration, School of (SESE)

Research output: Contribution to journal › Article › peer-review

43 Scopus citations

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.

Original language	English (US)
Pages (from-to)	3478-3491
Number of pages	14
Journal	Monthly Notices of the Royal Astronomical Society
Volume	446
Issue number	4
DOIs	https://doi.org/10.1093/mnras/stu2310
State	Published - Feb 1 2015

Keywords

Galaxies: active
Galaxies: individual: NGC1316
Radio continuum: galaxies

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1093/mnras/stu2310

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McKinley, B., Yang, R., López-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., Cappallo, R. J., Corey, B. E., ... Williams, C. L. (2015). Modelling of the spectral energy distribution of fornax A: Leptonic and hadronic production of high-energy emission from the radio lobes. Monthly Notices of the Royal Astronomical Society, 446(4), 3478-3491. https://doi.org/10.1093/mnras/stu2310

McKinley, B, Yang, R, López-Caniego, M, Briggs, F, Hurley-Walker, N, Wayth, RB, Offringa, AR, Crocker, R, Bernardi, G, Procopio, P, Gaensler, BM, Tingay, SJ, Johnston-Hollitt, M, McDonald, M, Bell, M, Bhat, NDR, Bowman, J, Cappallo, RJ, Corey, BE, Deshpande, AA, Emrich, D, Ewall-Wice, A, Feng, L, Goeke, R, Greenhill, LJ, Hazelton, BJ, Hewitt, JN, Hindson, L, Jacobs, D, Kaplan, DL, Kasper, JC, Kratzenberg, E, Kudryavtseva, N, Lenc, E, Lonsdale, CJ, Lynch, MJ, McWhirter, SR, Mitchell, DA, Morales, MF, Morgan, E, Oberoi, D, Ord, SM, Pindor, B, Prabu, T, Riding, J, Rogers, AEE, Roshi, DA, Udaya Shankar, N, Srivani, KS, Subrahmanyan, R, Waterson, M, Webster, RL, Whitney, AR, Williams, A & Williams, CL 2015, 'Modelling of the spectral energy distribution of fornax A: Leptonic and hadronic production of high-energy emission from the radio lobes', Monthly Notices of the Royal Astronomical Society, vol. 446, no. 4, pp. 3478-3491. https://doi.org/10.1093/mnras/stu2310

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title = "Modelling of the spectral energy distribution of fornax A: Leptonic and hadronic production of high-energy emission from the radio lobes",

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.",

keywords = "Galaxies: active, Galaxies: individual: NGC1316, Radio continuum: galaxies",

author = "B. McKinley and R. Yang and M. L{\'o}pez-Caniego and F. Briggs and N. Hurley-Walker and Wayth, {R. B.} and Offringa, {A. R.} and R. Crocker and G. Bernardi and P. Procopio and Gaensler, {B. M.} and Tingay, {S. J.} and M. Johnston-Hollitt and M. McDonald and M. Bell and Bhat, {N. D R} and Judd Bowman and Cappallo, {R. J.} and Corey, {B. E.} and Deshpande, {A. A.} and D. Emrich and A. Ewall-Wice and L. Feng and R. Goeke and Greenhill, {L. J.} and Hazelton, {B. J.} and Hewitt, {J. N.} and L. Hindson and Daniel Jacobs and Kaplan, {D. L.} and Kasper, {J. C.} and E. Kratzenberg and N. Kudryavtseva and E. Lenc and Lonsdale, {C. J.} and Lynch, {M. J.} and McWhirter, {S. R.} and Mitchell, {D. A.} and Morales, {M. F.} and E. Morgan and D. Oberoi and Ord, {S. M.} and B. Pindor and T. Prabu and J. Riding and Rogers, {A. E E} and Roshi, {D. A.} and {Udaya Shankar}, N. and Srivani, {K. S.} and R. Subrahmanyan and M. Waterson and Webster, {R. L.} and Whitney, {A. R.} and A. Williams and Williams, {C. L.}",

note = "Publisher Copyright: {\textcopyright} 2014 The Authors.",

year = "2015",

month = feb,

day = "1",

doi = "10.1093/mnras/stu2310",

language = "English (US)",

volume = "446",

pages = "3478--3491",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

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TY - JOUR

T1 - Modelling of the spectral energy distribution of fornax A

T2 - Leptonic and hadronic production of high-energy emission from the radio lobes

AU - McKinley, B.

AU - Yang, R.

AU - López-Caniego, M.

AU - Briggs, F.

AU - Hurley-Walker, N.

AU - Wayth, R. B.

AU - Offringa, A. R.

AU - Crocker, R.

AU - Bernardi, G.

AU - Procopio, P.

AU - Gaensler, B. M.

AU - Tingay, S. J.

AU - Johnston-Hollitt, M.

AU - McDonald, M.

AU - Bell, M.

AU - Bhat, N. D R

AU - Bowman, Judd

AU - Cappallo, R. J.

AU - Corey, B. E.

AU - Deshpande, A. A.

AU - Emrich, D.

AU - Ewall-Wice, A.

AU - Feng, L.

AU - Goeke, R.

AU - Greenhill, L. J.

AU - Hazelton, B. J.

AU - Hewitt, J. N.

AU - Hindson, L.

AU - Jacobs, Daniel

AU - Kaplan, D. L.

AU - Kasper, J. C.

AU - Kratzenberg, E.

AU - Kudryavtseva, N.

AU - Lenc, E.

AU - Lonsdale, C. J.

AU - Lynch, M. J.

AU - McWhirter, S. R.

AU - Mitchell, D. A.

AU - Morales, M. F.

AU - Morgan, E.

AU - Oberoi, D.

AU - Ord, S. M.

AU - Pindor, B.

AU - Prabu, T.

AU - Riding, J.

AU - Rogers, A. E E

AU - Roshi, D. A.

AU - Udaya Shankar, N.

AU - Srivani, K. S.

AU - Subrahmanyan, R.

AU - Waterson, M.

AU - Webster, R. L.

AU - Whitney, A. R.

AU - Williams, A.

AU - Williams, C. L.

PY - 2015/2/1

Y1 - 2015/2/1

N2 - 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.

AB - 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.

KW - Galaxies: active

KW - Galaxies: individual: NGC1316

KW - Radio continuum: galaxies

UR - http://www.scopus.com/inward/record.url?scp=84984985988&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84984985988&partnerID=8YFLogxK

U2 - 10.1093/mnras/stu2310

DO - 10.1093/mnras/stu2310

M3 - Article

AN - SCOPUS:84984985988

SN - 0035-8711

VL - 446

SP - 3478

EP - 3491

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 4

ER -

Modelling of the spectral energy distribution of fornax A: Leptonic and hadronic production of high-energy emission from the radio lobes

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