Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a cen...

Full description

Bibliographic Details
Main Authors:	Kapinska, A., Staveley-Smith, L., Crocker, R., Meurer, G., Bhandari, S., Hurley-Walker, Natasha, Offringa, A., Hanish, D., Seymour, Nick, Ekers, R., Bell, M., Callingham, J., Dwarakanath, K., For, B., Gaensler, B., Hancock, Paul, Hindson, L., Johnston-Hollitt, M., Lenc, E., McKinley, B., Morgan, John, Procopio, P., Wayth, Randall, Wu, C., Zheng, Q., Barry, N., Beardsley, A., Bowman, J., Briggs, F., Carroll, P., Dillon, J., Ewall-Wice, A., Feng, L., Greenhill, L., Hazelton, B., Hewitt, J., Jacobs, D., Kim, H., Kittiwisit, P., Line, J., Loeb, A., Mitchell, D., Morales, M., Neben, A., Paul, S., Pindor, B., Pober, J., Riding, J., Sethi, S., Shankar, N., Subrahmanyan, R., Sullivan, I., Tegmark, M., Thyagarajan, N., Tingay, Steven, Trott, Cathryn, Webster, R., Wyithe, S., Cappallo, R., Deshpande, A., Kaplan, D., Lonsdale, C., McWhirter, S., Morgan, E., Oberoi, D., Ord, S., Prabu, T., Srivani, K., Williams, Andrew, Williams, C.
Format:	Journal Article
Published:	Institute of Physics Publishing 2017
Online Access:	http://hdl.handle.net/20.500.11937/52356

_version_	1848758908433203200
author	Kapinska, A. Staveley-Smith, L. Crocker, R. Meurer, G. Bhandari, S. Hurley-Walker, Natasha Offringa, A. Hanish, D. Seymour, Nick Ekers, R. Bell, M. Callingham, J. Dwarakanath, K. For, B. Gaensler, B. Hancock, Paul Hindson, L. Johnston-Hollitt, M. Lenc, E. McKinley, B. Morgan, John Procopio, P. Wayth, Randall Wu, C. Zheng, Q. Barry, N. Beardsley, A. Bowman, J. Briggs, F. Carroll, P. Dillon, J. Ewall-Wice, A. Feng, L. Greenhill, L. Hazelton, B. Hewitt, J. Jacobs, D. Kim, H. Kittiwisit, P. Line, J. Loeb, A. Mitchell, D. Morales, M. Neben, A. Paul, S. Pindor, B. Pober, J. Riding, J. Sethi, S. Shankar, N. Subrahmanyan, R. Sullivan, I. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, Cathryn Webster, R. Wyithe, S. Cappallo, R. Deshpande, A. Kaplan, D. Lonsdale, C. McWhirter, S. Morgan, E. Oberoi, D. Ord, S. Prabu, T. Srivani, K. Williams, Andrew Williams, C.
author_facet	Kapinska, A. Staveley-Smith, L. Crocker, R. Meurer, G. Bhandari, S. Hurley-Walker, Natasha Offringa, A. Hanish, D. Seymour, Nick Ekers, R. Bell, M. Callingham, J. Dwarakanath, K. For, B. Gaensler, B. Hancock, Paul Hindson, L. Johnston-Hollitt, M. Lenc, E. McKinley, B. Morgan, John Procopio, P. Wayth, Randall Wu, C. Zheng, Q. Barry, N. Beardsley, A. Bowman, J. Briggs, F. Carroll, P. Dillon, J. Ewall-Wice, A. Feng, L. Greenhill, L. Hazelton, B. Hewitt, J. Jacobs, D. Kim, H. Kittiwisit, P. Line, J. Loeb, A. Mitchell, D. Morales, M. Neben, A. Paul, S. Pindor, B. Pober, J. Riding, J. Sethi, S. Shankar, N. Subrahmanyan, R. Sullivan, I. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, Cathryn Webster, R. Wyithe, S. Cappallo, R. Deshpande, A. Kaplan, D. Lonsdale, C. McWhirter, S. Morgan, E. Oberoi, D. Ord, S. Prabu, T. Srivani, K. Williams, Andrew Williams, C.
author_sort	Kapinska, A.
building	Curtin Institutional Repository
collection	Online Access
description	We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free-free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154-231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ~8 kpc in the z-direction (from the major axis).
first_indexed	2025-11-14T09:51:28Z
format	Journal Article
id	curtin-20.500.11937-52356
institution	Curtin University Malaysia
institution_category	Local University
last_indexed	2025-11-14T09:51:28Z
publishDate	2017
publisher	Institute of Physics Publishing
recordtype	eprints
repository_type	Digital Repository
spelling	curtin-20.500.11937-523562018-03-05T08:48:06Z Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies Kapinska, A. Staveley-Smith, L. Crocker, R. Meurer, G. Bhandari, S. Hurley-Walker, Natasha Offringa, A. Hanish, D. Seymour, Nick Ekers, R. Bell, M. Callingham, J. Dwarakanath, K. For, B. Gaensler, B. Hancock, Paul Hindson, L. Johnston-Hollitt, M. Lenc, E. McKinley, B. Morgan, John Procopio, P. Wayth, Randall Wu, C. Zheng, Q. Barry, N. Beardsley, A. Bowman, J. Briggs, F. Carroll, P. Dillon, J. Ewall-Wice, A. Feng, L. Greenhill, L. Hazelton, B. Hewitt, J. Jacobs, D. Kim, H. Kittiwisit, P. Line, J. Loeb, A. Mitchell, D. Morales, M. Neben, A. Paul, S. Pindor, B. Pober, J. Riding, J. Sethi, S. Shankar, N. Subrahmanyan, R. Sullivan, I. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, Cathryn Webster, R. Wyithe, S. Cappallo, R. Deshpande, A. Kaplan, D. Lonsdale, C. McWhirter, S. Morgan, E. Oberoi, D. Ord, S. Prabu, T. Srivani, K. Williams, Andrew Williams, C. We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free-free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154-231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ~8 kpc in the z-direction (from the major axis). 2017 Journal Article http://hdl.handle.net/20.500.11937/52356 10.3847/1538-4357/aa5f5d Institute of Physics Publishing fulltext
spellingShingle	Kapinska, A. Staveley-Smith, L. Crocker, R. Meurer, G. Bhandari, S. Hurley-Walker, Natasha Offringa, A. Hanish, D. Seymour, Nick Ekers, R. Bell, M. Callingham, J. Dwarakanath, K. For, B. Gaensler, B. Hancock, Paul Hindson, L. Johnston-Hollitt, M. Lenc, E. McKinley, B. Morgan, John Procopio, P. Wayth, Randall Wu, C. Zheng, Q. Barry, N. Beardsley, A. Bowman, J. Briggs, F. Carroll, P. Dillon, J. Ewall-Wice, A. Feng, L. Greenhill, L. Hazelton, B. Hewitt, J. Jacobs, D. Kim, H. Kittiwisit, P. Line, J. Loeb, A. Mitchell, D. Morales, M. Neben, A. Paul, S. Pindor, B. Pober, J. Riding, J. Sethi, S. Shankar, N. Subrahmanyan, R. Sullivan, I. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, Cathryn Webster, R. Wyithe, S. Cappallo, R. Deshpande, A. Kaplan, D. Lonsdale, C. McWhirter, S. Morgan, E. Oberoi, D. Ord, S. Prabu, T. Srivani, K. Williams, Andrew Williams, C. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies
title	Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies
title_full	Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies
title_fullStr	Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies
title_full_unstemmed	Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies
title_short	Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies
title_sort	spectral energy distribution and radio halo of ngc 253 at low radio frequencies
url	http://hdl.handle.net/20.500.11937/52356

Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

Similar Items