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    Rights statement: This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.3847/1538-4357/ab32e7

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  • 1904 (1).08944

    Rights statement: This is an author-created, un-copyedited version of an article accepted for publication/published in Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.3847/1538-4357/ab32e7

    Accepted author manuscript, 1.17 MB, PDF document

    Available under license: CC BY-NC: Creative Commons Attribution-NonCommercial 4.0 International License

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Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies: Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion?

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Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies: Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion? / Thomson, A. P.; Smail, Ian; Swinbank, A. M. et al.
In: The Astrophysical Journal, Vol. 883, No. 2, 204, 04.10.2019.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Thomson, AP, Smail, I, Swinbank, AM, Simpson, JM, Arumugam, V, Stach, S, Murphy, EJ, Rujopakarn, W, Almaini, O, An, F, Blain, AW, Chen, CC, Cooke, EA, Dudzeviciute, U, Edge, AC, Farrah, D, Gullberg, B, Hartley, W, Ibar, E, Maltby, D, Michalowski, MJ, Simpson, C, van der Werf, P & Wardlow, JL 2019, 'Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies: Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion?', The Astrophysical Journal, vol. 883, no. 2, 204. https://doi.org/10.3847/1538-4357/ab32e7

APA

Thomson, A. P., Smail, I., Swinbank, A. M., Simpson, J. M., Arumugam, V., Stach, S., Murphy, E. J., Rujopakarn, W., Almaini, O., An, F., Blain, A. W., Chen, C. C., Cooke, E. A., Dudzeviciute, U., Edge, A. C., Farrah, D., Gullberg, B., Hartley, W., Ibar, E., ... Wardlow, J. L. (2019). Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies: Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion? The Astrophysical Journal, 883(2), Article 204. https://doi.org/10.3847/1538-4357/ab32e7

Vancouver

Thomson AP, Smail I, Swinbank AM, Simpson JM, Arumugam V, Stach S et al. Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies: Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion? The Astrophysical Journal. 2019 Oct 4;883(2):204. doi: 10.3847/1538-4357/ab32e7

Author

Bibtex

@article{930384f5083c4072960ce9482f1e8bc2,
title = "Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies: Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion?",
abstract = "We analyze the multifrequency radio spectral properties of 41 6GHz-detected Atacama Large Millimeter/submillimeter Array(ALMA)-identified, submillimeter galaxies (SMGs), observed at 610 MHz,1.4 GHz, and 6 GHz with the Giant Metrewave Radio Telescope and the VeryLarge Array. Combining high-resolution (∼0.″5) 6 GHz radio andALMA 870 μm imaging (tracing rest frame ∼20 GHz, and ∼250μm dust continuum), we study the far-infrared/radio correlation viathe logarithmic flux ratio q IR, measuring <{q}IR}> =2.20+/- 0.06 for our sample. We show that thehigh-frequency radio sizes of SMGs are ∼1.9 ± 0.4×(∼2–3 kpc) larger than those of the cool dust emission, andfind evidence for a subset of our sources being extended on ∼10 kpcscales at 1.4 GHz. By combining radio flux densities measured at threefrequencies, we can move beyond simple linear fits to the radio spectraof high-redshift star-forming galaxies, and search for spectralcurvature, which has been observed in local starburst galaxies. At leasta quarter (10/41) of our sample shows evidence of a spectral break, witha median <{α }610 {GHz}1.4 {GHz}>=-0.60+/- 0.06, but <{α }1.4 {GHz}6{GHz}> =-1.06+/- 0.04—a high-frequency flux deficitrelative to simple extrapolations from the low-frequency data. Weexplore this result within this subset of sources in the context ofage-related synchrotron losses, showing that a combination of weakmagnetic fields (B ∼ 35 μG) and young ages (t SB ∼40–80 Myr) for the central starburst can reproduce the observedspectral break. Assuming these represent evolved (but ongoing)starbursts, and we are observing these systems roughly halfway throughtheir current episode of star formation, this implies starburstdurations of ≲100 Myr, in reasonable agreement with estimatesderived via gas depletion timescales.",
keywords = "cosmic rays, galaxies: evolution, galaxies: high-redshift, galaxies: starburst, radio continuum: galaxies, submillimeter: galaxies",
author = "Thomson, {A. P.} and Ian Smail and Swinbank, {A. M.} and Simpson, {J. M.} and V. Arumugam and S. Stach and Murphy, {E. J.} and W. Rujopakarn and O. Almaini and F. An and Blain, {A. W.} and Chen, {C. C.} and Cooke, {E. A.} and U. Dudzeviciute and Edge, {A. C.} and D. Farrah and B. Gullberg and W. Hartley and E. Ibar and D. Maltby and Michalowski, {M. J.} and C. Simpson and {van der Werf}, P. and Wardlow, {J. L.}",
note = "This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.3847/1538-4357/ab32e7",
year = "2019",
month = oct,
day = "4",
doi = "10.3847/1538-4357/ab32e7",
language = "English",
volume = "883",
journal = "The Astrophysical Journal",
issn = "0004-637X",
publisher = "Institute of Physics Publishing",
number = "2",

}

RIS

TY - JOUR

T1 - Radio Spectra and Sizes of Atacama Large Millimeter/submillimeter Array-identified Submillimeter Galaxies

T2 - Evidence of Age-related Spectral Curvature and Cosmic-Ray Diffusion?

AU - Thomson, A. P.

AU - Smail, Ian

AU - Swinbank, A. M.

AU - Simpson, J. M.

AU - Arumugam, V.

AU - Stach, S.

AU - Murphy, E. J.

AU - Rujopakarn, W.

AU - Almaini, O.

AU - An, F.

AU - Blain, A. W.

AU - Chen, C. C.

AU - Cooke, E. A.

AU - Dudzeviciute, U.

AU - Edge, A. C.

AU - Farrah, D.

AU - Gullberg, B.

AU - Hartley, W.

AU - Ibar, E.

AU - Maltby, D.

AU - Michalowski, M. J.

AU - Simpson, C.

AU - van der Werf, P.

AU - Wardlow, J. L.

N1 - This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.3847/1538-4357/ab32e7

PY - 2019/10/4

Y1 - 2019/10/4

N2 - We analyze the multifrequency radio spectral properties of 41 6GHz-detected Atacama Large Millimeter/submillimeter Array(ALMA)-identified, submillimeter galaxies (SMGs), observed at 610 MHz,1.4 GHz, and 6 GHz with the Giant Metrewave Radio Telescope and the VeryLarge Array. Combining high-resolution (∼0.″5) 6 GHz radio andALMA 870 μm imaging (tracing rest frame ∼20 GHz, and ∼250μm dust continuum), we study the far-infrared/radio correlation viathe logarithmic flux ratio q IR, measuring <{q}IR}> =2.20+/- 0.06 for our sample. We show that thehigh-frequency radio sizes of SMGs are ∼1.9 ± 0.4×(∼2–3 kpc) larger than those of the cool dust emission, andfind evidence for a subset of our sources being extended on ∼10 kpcscales at 1.4 GHz. By combining radio flux densities measured at threefrequencies, we can move beyond simple linear fits to the radio spectraof high-redshift star-forming galaxies, and search for spectralcurvature, which has been observed in local starburst galaxies. At leasta quarter (10/41) of our sample shows evidence of a spectral break, witha median <{α }610 {GHz}1.4 {GHz}>=-0.60+/- 0.06, but <{α }1.4 {GHz}6{GHz}> =-1.06+/- 0.04—a high-frequency flux deficitrelative to simple extrapolations from the low-frequency data. Weexplore this result within this subset of sources in the context ofage-related synchrotron losses, showing that a combination of weakmagnetic fields (B ∼ 35 μG) and young ages (t SB ∼40–80 Myr) for the central starburst can reproduce the observedspectral break. Assuming these represent evolved (but ongoing)starbursts, and we are observing these systems roughly halfway throughtheir current episode of star formation, this implies starburstdurations of ≲100 Myr, in reasonable agreement with estimatesderived via gas depletion timescales.

AB - We analyze the multifrequency radio spectral properties of 41 6GHz-detected Atacama Large Millimeter/submillimeter Array(ALMA)-identified, submillimeter galaxies (SMGs), observed at 610 MHz,1.4 GHz, and 6 GHz with the Giant Metrewave Radio Telescope and the VeryLarge Array. Combining high-resolution (∼0.″5) 6 GHz radio andALMA 870 μm imaging (tracing rest frame ∼20 GHz, and ∼250μm dust continuum), we study the far-infrared/radio correlation viathe logarithmic flux ratio q IR, measuring <{q}IR}> =2.20+/- 0.06 for our sample. We show that thehigh-frequency radio sizes of SMGs are ∼1.9 ± 0.4×(∼2–3 kpc) larger than those of the cool dust emission, andfind evidence for a subset of our sources being extended on ∼10 kpcscales at 1.4 GHz. By combining radio flux densities measured at threefrequencies, we can move beyond simple linear fits to the radio spectraof high-redshift star-forming galaxies, and search for spectralcurvature, which has been observed in local starburst galaxies. At leasta quarter (10/41) of our sample shows evidence of a spectral break, witha median <{α }610 {GHz}1.4 {GHz}>=-0.60+/- 0.06, but <{α }1.4 {GHz}6{GHz}> =-1.06+/- 0.04—a high-frequency flux deficitrelative to simple extrapolations from the low-frequency data. Weexplore this result within this subset of sources in the context ofage-related synchrotron losses, showing that a combination of weakmagnetic fields (B ∼ 35 μG) and young ages (t SB ∼40–80 Myr) for the central starburst can reproduce the observedspectral break. Assuming these represent evolved (but ongoing)starbursts, and we are observing these systems roughly halfway throughtheir current episode of star formation, this implies starburstdurations of ≲100 Myr, in reasonable agreement with estimatesderived via gas depletion timescales.

KW - cosmic rays

KW - galaxies: evolution

KW - galaxies: high-redshift

KW - galaxies: starburst

KW - radio continuum: galaxies

KW - submillimeter: galaxies

U2 - 10.3847/1538-4357/ab32e7

DO - 10.3847/1538-4357/ab32e7

M3 - Journal article

VL - 883

JO - The Astrophysical Journal

JF - The Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 204

ER -