The giant lobes of centaurus a observed at 118MHz with the murchison widefield array

B. McKinley; F. Briggs; B. M. Gaensler; I. J. Feain; G. Bernardi; R. B. Wayth; M. Johnston-Hollitt; A. R. Offringa; W. Arcus; D. G. Barnes; J. D. Bowman; J. D. Bunton; R. J. Cappallo; B. E. Corey; A. A. Deshpande; L. deSouza; D. Emrich; R. Goeke; L. J. Greenhill; B. J. Hazelton; D. Herne; J. N. Hewitt; D. L. Kaplan; J. C. Kasper; B. B. Kincaid; R. Koenig; E. Kratzenberg; C. J. Lonsdale; M. J. Lynch; S. R. McWhirter; D. A. Mitchell; M. F. Morales; E. Morgan; D. Oberoi; S. M. Ord; J. Pathikulangara; T. Prabu; R. A. Remillard; A. E.E. Rogers; D. A. Roshi; J. E. Salah; R. J. Sault; N. Udaya Shankar; K. S. Srivani; J. Stevens; R. Subrahmanyan; S. J. Tingay; M. Waterson; R. L. Webster; A. R. Whitney; A. Williams; C. L. Williams; J. S.B. Wyithe

doi:10.1093/mnras/stt1662

The giant lobes of centaurus a observed at 118MHz with the murchison widefield array

B. McKinley^*, F. Briggs, B. M. Gaensler, I. J. Feain, G. Bernardi, R. B. Wayth, M. Johnston-Hollitt, A. R. Offringa, W. Arcus, D. G. Barnes, J. D. Bowman, J. D. Bunton, R. J. Cappallo, B. E. Corey, A. A. Deshpande, L. deSouza, D. Emrich, R. Goeke, L. J. Greenhill, B. J. HazeltonD. Herne, J. N. Hewitt, D. L. Kaplan, J. C. Kasper, B. B. Kincaid, R. Koenig, E. Kratzenberg, C. J. Lonsdale, M. J. Lynch, S. R. McWhirter, D. A. Mitchell, M. F. Morales, E. Morgan, D. Oberoi, S. M. Ord, J. Pathikulangara, T. Prabu, R. A. Remillard, A. E.E. Rogers, D. A. Roshi, J. E. Salah, R. J. Sault, N. Udaya Shankar, K. S. Srivani, J. Stevens, R. Subrahmanyan, S. J. Tingay, M. Waterson, R. L. Webster, A. R. Whitney, A. Williams, C. L. Williams, J. S.B. Wyithe

^*Corresponding author for this work

Research School of Astronomy & Astrophysics

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Abstract

We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A's giant radio lobes.We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature-temperature plots and spectral tomography. We find that the morphologies at 118MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr.

Original language	English
Pages (from-to)	1286-1301
Number of pages	16
Journal	Monthly Notices of the Royal Astronomical Society
Volume	436
Issue number	2
DOIs	https://doi.org/10.1093/mnras/stt1662
Publication status	Published - Dec 2013

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McKinley, B., Briggs, F., Gaensler, B. M., Feain, I. J., Bernardi, G., Wayth, R. B., Johnston-Hollitt, M., Offringa, A. R., Arcus, W., Barnes, D. G., Bowman, J. D., Bunton, J. D., Cappallo, R. J., Corey, B. E., Deshpande, A. A., deSouza, L., Emrich, D., Goeke, R., Greenhill, L. J., ... Wyithe, J. S. B. (2013). The giant lobes of centaurus a observed at 118MHz with the murchison widefield array. Monthly Notices of the Royal Astronomical Society, 436(2), 1286-1301. https://doi.org/10.1093/mnras/stt1662

@article{e6cbd2b72283428e9a64488c45681d3c,

title = "The giant lobes of centaurus a observed at 118MHz with the murchison widefield array",

abstract = "We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A's giant radio lobes.We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature-temperature plots and spectral tomography. We find that the morphologies at 118MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr.",

keywords = "Active-galaxies, Galaxies, Individual, Interferometric-galaxies, NGC 5128-radio continuum, Techniques",

author = "B. McKinley and F. Briggs and Gaensler, {B. M.} and Feain, {I. J.} and G. Bernardi and Wayth, {R. B.} and M. Johnston-Hollitt and Offringa, {A. R.} and W. Arcus and Barnes, {D. G.} and Bowman, {J. D.} and Bunton, {J. D.} and Cappallo, {R. J.} and Corey, {B. E.} and Deshpande, {A. A.} and L. deSouza and D. Emrich and R. Goeke and Greenhill, {L. J.} and Hazelton, {B. J.} and D. Herne and Hewitt, {J. N.} and Kaplan, {D. L.} and Kasper, {J. C.} and Kincaid, {B. B.} and R. Koenig and E. Kratzenberg 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 J. Pathikulangara and T. Prabu and Remillard, {R. A.} and Rogers, {A. E.E.} and Roshi, {D. A.} and Salah, {J. E.} and Sault, {R. J.} and {Udaya Shankar}, N. and Srivani, {K. S.} and J. Stevens and R. Subrahmanyan and Tingay, {S. J.} and M. Waterson and Webster, {R. L.} and Whitney, {A. R.} and A. Williams and Williams, {C. L.} and Wyithe, {J. S.B.}",

year = "2013",

month = dec,

doi = "10.1093/mnras/stt1662",

language = "English",

volume = "436",

pages = "1286--1301",

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

issn = "0035-8711",

publisher = "Oxford University Press ",

number = "2",

}

McKinley, B, Briggs, F, Gaensler, BM, Feain, IJ, Bernardi, G, Wayth, RB, Johnston-Hollitt, M, Offringa, AR, Arcus, W, Barnes, DG, Bowman, JD, Bunton, JD, Cappallo, RJ, Corey, BE, Deshpande, AA, deSouza, L, Emrich, D, Goeke, R, Greenhill, LJ, Hazelton, BJ, Herne, D, Hewitt, JN, Kaplan, DL, Kasper, JC, Kincaid, BB, Koenig, R, Kratzenberg, E, Lonsdale, CJ, Lynch, MJ, McWhirter, SR, Mitchell, DA, Morales, MF, Morgan, E, Oberoi, D, Ord, SM, Pathikulangara, J, Prabu, T, Remillard, RA, Rogers, AEE, Roshi, DA, Salah, JE, Sault, RJ, Udaya Shankar, N, Srivani, KS, Stevens, J, Subrahmanyan, R, Tingay, SJ, Waterson, M, Webster, RL, Whitney, AR, Williams, A, Williams, CL & Wyithe, JSB 2013, 'The giant lobes of centaurus a observed at 118MHz with the murchison widefield array', Monthly Notices of the Royal Astronomical Society, vol. 436, no. 2, pp. 1286-1301. https://doi.org/10.1093/mnras/stt1662

TY - JOUR

T1 - The giant lobes of centaurus a observed at 118MHz with the murchison widefield array

AU - McKinley, B.

AU - Briggs, F.

AU - Gaensler, B. M.

AU - Feain, I. J.

AU - Bernardi, G.

AU - Wayth, R. B.

AU - Johnston-Hollitt, M.

AU - Offringa, A. R.

AU - Arcus, W.

AU - Barnes, D. G.

AU - Bowman, J. D.

AU - Bunton, J. D.

AU - Cappallo, R. J.

AU - Corey, B. E.

AU - Deshpande, A. A.

AU - deSouza, L.

AU - Emrich, D.

AU - Goeke, R.

AU - Greenhill, L. J.

AU - Hazelton, B. J.

AU - Herne, D.

AU - Hewitt, J. N.

AU - Kaplan, D. L.

AU - Kasper, J. C.

AU - Kincaid, B. B.

AU - Koenig, R.

AU - Kratzenberg, 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 - Pathikulangara, J.

AU - Prabu, T.

AU - Remillard, R. A.

AU - Rogers, A. E.E.

AU - Roshi, D. A.

AU - Salah, J. E.

AU - Sault, R. J.

AU - Udaya Shankar, N.

AU - Srivani, K. S.

AU - Stevens, J.

AU - Subrahmanyan, R.

AU - Tingay, S. J.

AU - Waterson, M.

AU - Webster, R. L.

AU - Whitney, A. R.

AU - Williams, A.

AU - Williams, C. L.

AU - Wyithe, J. S.B.

PY - 2013/12

Y1 - 2013/12

N2 - We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A's giant radio lobes.We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature-temperature plots and spectral tomography. We find that the morphologies at 118MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr.

AB - We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A's giant radio lobes.We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature-temperature plots and spectral tomography. We find that the morphologies at 118MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr.

KW - Active-galaxies

KW - Galaxies

KW - Individual

KW - Interferometric-galaxies

KW - NGC 5128-radio continuum

KW - Techniques

UR - http://www.scopus.com/inward/record.url?scp=84888020502&partnerID=8YFLogxK

U2 - 10.1093/mnras/stt1662

DO - 10.1093/mnras/stt1662

M3 - Article

SN - 0035-8711

VL - 436

SP - 1286

EP - 1301

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 2

ER -

The giant lobes of centaurus a observed at 118MHz with the murchison widefield array

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