VLA imaging of 12CO J = 1-0 and free-free emission in lensed submillimetre galaxies

A. P. Thomson; R. J. Ivison; Ian Smail; A. M. Swinbank; A. Weiss; J. P. Kneib; P. P. Papadopoulos; A. J. Baker; C. E. Sharon; G. A. van Moorsel

doi:10.1111/j.1365-2966.2012.21584.x

VLA imaging of ¹²CO J = 1-0 and free-free emission in lensed submillimetre galaxies

A. P. Thomson, R. J. Ivison, Ian Smail, A. M. Swinbank, A. Weiss, J. P. Kneib, P. P. Papadopoulos, A. J. Baker, C. E. Sharon, G. A. van Moorsel

School of Arts and Sciences, Physics & Astronomy

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

43 Scopus citations

Abstract

We present a study using the Karl G. Jansky Very Large Array (VLA) of ¹²CO J = 1-0 emission in three strongly lensed submillimetre-selected galaxies (SMMJ16359, SMMJ14009 and SMMJ02399) at z = 2.5-2.9. These galaxies span L_IR = 10¹¹-10¹³L_⊙, offering an opportunity to compare the interstellar medium of luminous infrared galaxies and ultraluminous infrared galaxies at high redshift. We estimate molecular gas masses in the range of 2-40 × 10⁹M_⊙ using a method that assumes canonical underlying brightness temperature (T_b) ratios for star-forming and non-star-forming gas phases and a maximal star formation efficiency. A more simplistic method - using X_CO = 0.8 and the measured T_b ratios - yields gas masses twice as high. In SMMJ14009 we find L CO 3-2′/L CO 1-0′=0.95±0.12, indicative of warm, star-forming gas, possibly influenced by the central active galactic nucleus (AGN). We set a gas mass limit of 3σ < 6 × 10⁸M_⊙ for the Lyman break galaxy, A2218 #384, located in the same field as SMMJ16359 at z = 2.515. Finally, we use the rest-frame ∼115GHz free-free flux densities for SMMJ14009 and SMMJ02399 - measurements tied directly to the photoionization rate of massive stars, and made possible by VLA's bandwidth - to estimate star formation rates (SFRs) of 400-600M_⊙yr^-1 and to estimate the fraction of L_IR due to AGN.

Original language	English (US)
Pages (from-to)	2203-2211
Number of pages	9
Journal	Monthly Notices of the Royal Astronomical Society
Volume	425
Issue number	3
DOIs	https://doi.org/10.1111/j.1365-2966.2012.21584.x
State	Published - Sep 21 2012

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Active
Galaxies
General
High-redshift
ISM
Molecules
Starburst
Submillimetre

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10.1111/j.1365-2966.2012.21584.x

Cite this

@article{82db33bb522c4b888c9d1336cddbd8d8,

title = "VLA imaging of 12CO J = 1-0 and free-free emission in lensed submillimetre galaxies",

abstract = "We present a study using the Karl G. Jansky Very Large Array (VLA) of 12CO J = 1-0 emission in three strongly lensed submillimetre-selected galaxies (SMMJ16359, SMMJ14009 and SMMJ02399) at z = 2.5-2.9. These galaxies span LIR = 1011-1013L⊙, offering an opportunity to compare the interstellar medium of luminous infrared galaxies and ultraluminous infrared galaxies at high redshift. We estimate molecular gas masses in the range of 2-40 × 109M⊙ using a method that assumes canonical underlying brightness temperature (Tb) ratios for star-forming and non-star-forming gas phases and a maximal star formation efficiency. A more simplistic method - using XCO = 0.8 and the measured Tb ratios - yields gas masses twice as high. In SMMJ14009 we find L CO 3-2′/L CO 1-0′=0.95±0.12, indicative of warm, star-forming gas, possibly influenced by the central active galactic nucleus (AGN). We set a gas mass limit of 3σ < 6 × 108M⊙ for the Lyman break galaxy, A2218 #384, located in the same field as SMMJ16359 at z = 2.515. Finally, we use the rest-frame ∼115GHz free-free flux densities for SMMJ14009 and SMMJ02399 - measurements tied directly to the photoionization rate of massive stars, and made possible by VLA's bandwidth - to estimate star formation rates (SFRs) of 400-600M⊙yr-1 and to estimate the fraction of LIR due to AGN.",

keywords = "Active, Galaxies, General, High-redshift, ISM, Molecules, Starburst, Submillimetre",

author = "Thomson, {A. P.} and Ivison, {R. J.} and Ian Smail and Swinbank, {A. M.} and A. Weiss and Kneib, {J. P.} and Papadopoulos, {P. P.} and Baker, {A. J.} and Sharon, {C. E.} and {van Moorsel}, {G. A.}",

note = "Funding Information: This work was supported by Medical Research Funds from the Department of Veteran Affairs (CG-S), NIH grants HL27255 and 27737 (CG-S), National Science Foundation grants IBN-9896030 and IBN 0049087 (AS), and Internal Research Funds from the Department of Pathology, University of Tennessee (AS). We are grateful to Ms. Esther Roitmar for undertaking the GC-MS investigations. We also thank Drs J. Ian Mason and Michael Holick for their valuable comments.",

year = "2012",

month = sep,

day = "21",

doi = "10.1111/j.1365-2966.2012.21584.x",

language = "English (US)",

volume = "425",

pages = "2203--2211",

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

issn = "0035-8711",

publisher = "Oxford University Press",

number = "3",

}

TY - JOUR

T1 - VLA imaging of 12CO J = 1-0 and free-free emission in lensed submillimetre galaxies

AU - Thomson, A. P.

AU - Ivison, R. J.

AU - Smail, Ian

AU - Swinbank, A. M.

AU - Weiss, A.

AU - Kneib, J. P.

AU - Papadopoulos, P. P.

AU - Baker, A. J.

AU - Sharon, C. E.

AU - van Moorsel, G. A.

N1 - Funding Information: This work was supported by Medical Research Funds from the Department of Veteran Affairs (CG-S), NIH grants HL27255 and 27737 (CG-S), National Science Foundation grants IBN-9896030 and IBN 0049087 (AS), and Internal Research Funds from the Department of Pathology, University of Tennessee (AS). We are grateful to Ms. Esther Roitmar for undertaking the GC-MS investigations. We also thank Drs J. Ian Mason and Michael Holick for their valuable comments.

PY - 2012/9/21

Y1 - 2012/9/21

N2 - We present a study using the Karl G. Jansky Very Large Array (VLA) of 12CO J = 1-0 emission in three strongly lensed submillimetre-selected galaxies (SMMJ16359, SMMJ14009 and SMMJ02399) at z = 2.5-2.9. These galaxies span LIR = 1011-1013L⊙, offering an opportunity to compare the interstellar medium of luminous infrared galaxies and ultraluminous infrared galaxies at high redshift. We estimate molecular gas masses in the range of 2-40 × 109M⊙ using a method that assumes canonical underlying brightness temperature (Tb) ratios for star-forming and non-star-forming gas phases and a maximal star formation efficiency. A more simplistic method - using XCO = 0.8 and the measured Tb ratios - yields gas masses twice as high. In SMMJ14009 we find L CO 3-2′/L CO 1-0′=0.95±0.12, indicative of warm, star-forming gas, possibly influenced by the central active galactic nucleus (AGN). We set a gas mass limit of 3σ < 6 × 108M⊙ for the Lyman break galaxy, A2218 #384, located in the same field as SMMJ16359 at z = 2.515. Finally, we use the rest-frame ∼115GHz free-free flux densities for SMMJ14009 and SMMJ02399 - measurements tied directly to the photoionization rate of massive stars, and made possible by VLA's bandwidth - to estimate star formation rates (SFRs) of 400-600M⊙yr-1 and to estimate the fraction of LIR due to AGN.

AB - We present a study using the Karl G. Jansky Very Large Array (VLA) of 12CO J = 1-0 emission in three strongly lensed submillimetre-selected galaxies (SMMJ16359, SMMJ14009 and SMMJ02399) at z = 2.5-2.9. These galaxies span LIR = 1011-1013L⊙, offering an opportunity to compare the interstellar medium of luminous infrared galaxies and ultraluminous infrared galaxies at high redshift. We estimate molecular gas masses in the range of 2-40 × 109M⊙ using a method that assumes canonical underlying brightness temperature (Tb) ratios for star-forming and non-star-forming gas phases and a maximal star formation efficiency. A more simplistic method - using XCO = 0.8 and the measured Tb ratios - yields gas masses twice as high. In SMMJ14009 we find L CO 3-2′/L CO 1-0′=0.95±0.12, indicative of warm, star-forming gas, possibly influenced by the central active galactic nucleus (AGN). We set a gas mass limit of 3σ < 6 × 108M⊙ for the Lyman break galaxy, A2218 #384, located in the same field as SMMJ16359 at z = 2.515. Finally, we use the rest-frame ∼115GHz free-free flux densities for SMMJ14009 and SMMJ02399 - measurements tied directly to the photoionization rate of massive stars, and made possible by VLA's bandwidth - to estimate star formation rates (SFRs) of 400-600M⊙yr-1 and to estimate the fraction of LIR due to AGN.

KW - Active

KW - Galaxies

KW - General

KW - High-redshift

KW - ISM

KW - Molecules

KW - Starburst

KW - Submillimetre

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U2 - 10.1111/j.1365-2966.2012.21584.x

DO - 10.1111/j.1365-2966.2012.21584.x

M3 - Article

AN - SCOPUS:84865600967

SN - 0035-8711

VL - 425

SP - 2203

EP - 2211

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 3

ER -