A multifrequency radio continuum study of the Magellanic Clouds - I. Overall structure and star formation rates

B. Q. For, L. Staveley-Smith, N. Hurley-Walker, T. Franzen, A. D. Kapińska, M. D. Filipović, J. D. Collier, C. Wu, K. Grieve, J. R. Callingham, M. E. Bell, G. Bernardi, J. D. Bowman, F. Briggs, R. J. Cappallo, A. A. Deshpande, K. S. Dwarakanath, B. M. Gaensler, L. J. Greenhill, P. Hancock & 26 others B. J. Hazelton, L. Hindson, M. Johnston-Hollitt, D. L. Kaplan, E. Lenc, C. J. Lonsdale, B. McKinley, S. R. McWhirter, D. A. Mitchell, M. F. Morales, E. Morgan, J. Morgan, D. Oberoi, A. Offringa, S. M. Ord, T. Prabu, P. Procopio, N. Udaya Shankar, K. S. Srivani, R. Subrahmanyan, S. J. Tingay, R. B. Wayth, R. L. Webster, A. Williams, C. L. Williams, Q. Zheng

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We present the first low-frequency Murchison Widefield Array (MWA) radio continuum maps of the Magellanic Clouds (MCs), usingmosaics from the GaLactic Extragalactic All-SkyMWA (GLEAM) survey. In this paper, we discuss the overall radio continuum morphology between 76 and 227 MHz and compare them with neutral hydrogen maps, 1.4 GHz continuum maps and optical images. Variation of diffuse emission is noticeable across the Large Magellanic Cloud (LMC) but absent across the bar of the Small Magellanic Cloud (SMC). We also measure the integrated flux densities and derive the spectral indices for the MCs. A double power-law model with fixed α1 = -0.1 fit between 19.7 MHz and 8.55 GHz yields α0 = -0.66 ± 0.08 for the LMC. A power-law model yields α8.55GHz 85.5MHz = -0.82 ± 0.03 for the SMC. The radio spectral index maps reveal distinctive flat and steep spectral indices for the HII regions and supernova remnants, respectively. We find strong correlation between HII regions and Ha emission. Using a new 150 MHz-Hα relation as a star formation rate indicator, we estimate global star formation rates of 0.068-0.161 M yr-1 and 0.021-0.050 M yr-1 for the LMC and SMC, respectively. Images in 20 frequency bands, and wideband averages are made available via the GLEAM virtual observatory server.

Original languageEnglish
Pages (from-to)2743-2756
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume480
Issue number2
DOIs
Publication statusPublished - 1 Oct 2018

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Magellanic clouds
star formation rate
radio
continuums
power law
observatory
hydrogen
rate
supernova remnants
index
observatories
flux density
low frequencies
broadband
estimates

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For, B. Q. ; Staveley-Smith, L. ; Hurley-Walker, N. ; Franzen, T. ; Kapińska, A. D. ; Filipović, M. D. ; Collier, J. D. ; Wu, C. ; Grieve, K. ; Callingham, J. R. ; Bell, M. E. ; Bernardi, G. ; Bowman, J. D. ; Briggs, F. ; Cappallo, R. J. ; Deshpande, A. A. ; Dwarakanath, K. S. ; Gaensler, B. M. ; Greenhill, L. J. ; Hancock, P. ; Hazelton, B. J. ; Hindson, L. ; Johnston-Hollitt, M. ; Kaplan, D. L. ; Lenc, E. ; Lonsdale, C. J. ; McKinley, B. ; McWhirter, S. R. ; Mitchell, D. A. ; Morales, M. F. ; Morgan, E. ; Morgan, J. ; Oberoi, D. ; Offringa, A. ; Ord, S. M. ; Prabu, T. ; Procopio, P. ; Udaya Shankar, N. ; Srivani, K. S. ; Subrahmanyan, R. ; Tingay, S. J. ; Wayth, R. B. ; Webster, R. L. ; Williams, A. ; Williams, C. L. ; Zheng, Q. / A multifrequency radio continuum study of the Magellanic Clouds - I. Overall structure and star formation rates. In: Monthly Notices of the Royal Astronomical Society. 2018 ; Vol. 480, No. 2. pp. 2743-2756.
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abstract = "We present the first low-frequency Murchison Widefield Array (MWA) radio continuum maps of the Magellanic Clouds (MCs), usingmosaics from the GaLactic Extragalactic All-SkyMWA (GLEAM) survey. In this paper, we discuss the overall radio continuum morphology between 76 and 227 MHz and compare them with neutral hydrogen maps, 1.4 GHz continuum maps and optical images. Variation of diffuse emission is noticeable across the Large Magellanic Cloud (LMC) but absent across the bar of the Small Magellanic Cloud (SMC). We also measure the integrated flux densities and derive the spectral indices for the MCs. A double power-law model with fixed α1 = -0.1 fit between 19.7 MHz and 8.55 GHz yields α0 = -0.66 ± 0.08 for the LMC. A power-law model yields α8.55GHz 85.5MHz = -0.82 ± 0.03 for the SMC. The radio spectral index maps reveal distinctive flat and steep spectral indices for the HII regions and supernova remnants, respectively. We find strong correlation between HII regions and Ha emission. Using a new 150 MHz-Hα relation as a star formation rate indicator, we estimate global star formation rates of 0.068-0.161 M⊙ yr-1 and 0.021-0.050 M⊙ yr-1 for the LMC and SMC, respectively. Images in 20 frequency bands, and wideband averages are made available via the GLEAM virtual observatory server.",
keywords = "Magellanic Clouds, Radiation mechanisms: non-thermal, Radiation mechanisms: thermal, Radio continuum: galaxies",
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For, BQ, Staveley-Smith, L, Hurley-Walker, N, Franzen, T, Kapińska, AD, Filipović, MD, Collier, JD, Wu, C, Grieve, K, Callingham, JR, Bell, ME, Bernardi, G, Bowman, JD, Briggs, F, Cappallo, RJ, Deshpande, AA, Dwarakanath, KS, Gaensler, BM, Greenhill, LJ, Hancock, P, Hazelton, BJ, Hindson, L, Johnston-Hollitt, M, Kaplan, DL, Lenc, E, Lonsdale, CJ, McKinley, B, McWhirter, SR, Mitchell, DA, Morales, MF, Morgan, E, Morgan, J, Oberoi, D, Offringa, A, Ord, SM, Prabu, T, Procopio, P, Udaya Shankar, N, Srivani, KS, Subrahmanyan, R, Tingay, SJ, Wayth, RB, Webster, RL, Williams, A, Williams, CL & Zheng, Q 2018, 'A multifrequency radio continuum study of the Magellanic Clouds - I. Overall structure and star formation rates' Monthly Notices of the Royal Astronomical Society, vol. 480, no. 2, pp. 2743-2756. https://doi.org/10.1093/MNRAS/STY1960

A multifrequency radio continuum study of the Magellanic Clouds - I. Overall structure and star formation rates. / For, B. Q.; Staveley-Smith, L.; Hurley-Walker, N.; Franzen, T.; Kapińska, A. D.; Filipović, M. D.; Collier, J. D.; Wu, C.; Grieve, K.; Callingham, J. R.; Bell, M. E.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Dwarakanath, K. S.; Gaensler, B. M.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Zheng, Q.

In: Monthly Notices of the Royal Astronomical Society, Vol. 480, No. 2, 01.10.2018, p. 2743-2756.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A multifrequency radio continuum study of the Magellanic Clouds - I. Overall structure and star formation rates

AU - For, B. Q.

AU - Staveley-Smith, L.

AU - Hurley-Walker, N.

AU - Franzen, T.

AU - Kapińska, A. D.

AU - Filipović, M. D.

AU - Collier, J. D.

AU - Wu, C.

AU - Grieve, K.

AU - Callingham, J. R.

AU - Bell, M. E.

AU - Bernardi, G.

AU - Bowman, J. D.

AU - Briggs, F.

AU - Cappallo, R. J.

AU - Deshpande, A. A.

AU - Dwarakanath, K. S.

AU - Gaensler, B. M.

AU - Greenhill, L. J.

AU - Hancock, P.

AU - Hazelton, B. J.

AU - Hindson, L.

AU - Johnston-Hollitt, M.

AU - Kaplan, D. L.

AU - Lenc, E.

AU - Lonsdale, C. J.

AU - McKinley, B.

AU - McWhirter, S. R.

AU - Mitchell, D. A.

AU - Morales, M. F.

AU - Morgan, E.

AU - Morgan, J.

AU - Oberoi, D.

AU - Offringa, A.

AU - Ord, S. M.

AU - Prabu, T.

AU - Procopio, P.

AU - Udaya Shankar, N.

AU - Srivani, K. S.

AU - Subrahmanyan, R.

AU - Tingay, S. J.

AU - Wayth, R. B.

AU - Webster, R. L.

AU - Williams, A.

AU - Williams, C. L.

AU - Zheng, Q.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - We present the first low-frequency Murchison Widefield Array (MWA) radio continuum maps of the Magellanic Clouds (MCs), usingmosaics from the GaLactic Extragalactic All-SkyMWA (GLEAM) survey. In this paper, we discuss the overall radio continuum morphology between 76 and 227 MHz and compare them with neutral hydrogen maps, 1.4 GHz continuum maps and optical images. Variation of diffuse emission is noticeable across the Large Magellanic Cloud (LMC) but absent across the bar of the Small Magellanic Cloud (SMC). We also measure the integrated flux densities and derive the spectral indices for the MCs. A double power-law model with fixed α1 = -0.1 fit between 19.7 MHz and 8.55 GHz yields α0 = -0.66 ± 0.08 for the LMC. A power-law model yields α8.55GHz 85.5MHz = -0.82 ± 0.03 for the SMC. The radio spectral index maps reveal distinctive flat and steep spectral indices for the HII regions and supernova remnants, respectively. We find strong correlation between HII regions and Ha emission. Using a new 150 MHz-Hα relation as a star formation rate indicator, we estimate global star formation rates of 0.068-0.161 M⊙ yr-1 and 0.021-0.050 M⊙ yr-1 for the LMC and SMC, respectively. Images in 20 frequency bands, and wideband averages are made available via the GLEAM virtual observatory server.

AB - We present the first low-frequency Murchison Widefield Array (MWA) radio continuum maps of the Magellanic Clouds (MCs), usingmosaics from the GaLactic Extragalactic All-SkyMWA (GLEAM) survey. In this paper, we discuss the overall radio continuum morphology between 76 and 227 MHz and compare them with neutral hydrogen maps, 1.4 GHz continuum maps and optical images. Variation of diffuse emission is noticeable across the Large Magellanic Cloud (LMC) but absent across the bar of the Small Magellanic Cloud (SMC). We also measure the integrated flux densities and derive the spectral indices for the MCs. A double power-law model with fixed α1 = -0.1 fit between 19.7 MHz and 8.55 GHz yields α0 = -0.66 ± 0.08 for the LMC. A power-law model yields α8.55GHz 85.5MHz = -0.82 ± 0.03 for the SMC. The radio spectral index maps reveal distinctive flat and steep spectral indices for the HII regions and supernova remnants, respectively. We find strong correlation between HII regions and Ha emission. Using a new 150 MHz-Hα relation as a star formation rate indicator, we estimate global star formation rates of 0.068-0.161 M⊙ yr-1 and 0.021-0.050 M⊙ yr-1 for the LMC and SMC, respectively. Images in 20 frequency bands, and wideband averages are made available via the GLEAM virtual observatory server.

KW - Magellanic Clouds

KW - Radiation mechanisms: non-thermal

KW - Radiation mechanisms: thermal

KW - Radio continuum: galaxies

UR - http://www.scopus.com/inward/record.url?scp=85055159832&partnerID=8YFLogxK

U2 - 10.1093/MNRAS/STY1960

DO - 10.1093/MNRAS/STY1960

M3 - Article

VL - 480

SP - 2743

EP - 2756

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -