Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7

M. Aravena, E. J. Murphy, J. E. Aguirre, M. L N Ashby, B. A. Benson, M. Bothwell, M. Brodwin, J. E. Carlstrom, S. C. Chapman, T. M. Crawford, C. de Breuck, C. D. Fassnacht, A. H. Gonzalez, T. R. Greve, B. Gullberg, Y. Hezaveh, G. P. Holder, W. L. Holzapfel, R. Keisler, M. MalkanDaniel P Marrone, V. McIntyre, C. L. Reichardt, K. Sharon, J. S. Spilker, B. Stalder, A. A. Stark, J. D. Vieira, A. Weiß

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We report the detection of CO(1-0) line emission in the bright, lensed star-forming galaxies SPT-S 233227-5358.5 (z = 2.73) and SPT-S 053816-5030.8 (z = 2.78), using the Australia Telescope Compact Array. Both galaxies were discovered in a large-area millimetre survey with the South Pole Telescope (SPT) and found to be gravitationally lensed by intervening structures. The measured CO intensities imply galaxies with molecular gas masses of (3.2 ± 0.5) × 1010(μ/15)-1(XCO/0.8) and (1.7 ± 0.3) × 1010(μ/20)-1(XCO/0.8)M·, and gas depletion time-scales of 4.9 × 107(XCO/0.8) and 2.6 × 107(XCO/0.8) yr, respectively, where μ corresponds to the lens magnification and XCO is the CO luminosity to gas mass conversion factor. In the case of SPT-S 053816-5030.8, we also obtained significant detections of the rest-frame 115.7 and 132.4 GHz radio continuum. Based on the radio-to-infrared spectral energy distribution and an assumed synchrotron spectral index, we find that 42 ± 10 and 55 ±13 per cent of the flux at rest-frame 115.7 and 132.4 GHz arises from free-free emission. We find a radio-derived intrinsic star formation rate of 470 ± 170M· yr-1, consistent within the uncertainties with the infrared estimate. Based on the morphology of this object in the source plane, the derived gas mass and the possible flattening of the radio spectral index towards low frequencies, we argue that SPT-S 053816-5030.8 exhibits properties compatible with a scaled-up local ultraluminous infrared galaxy.

Original languageEnglish (US)
Pages (from-to)498-505
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume433
Issue number1
DOIs
StatePublished - Jul 2013

Fingerprint

telescopes
radio
galaxies
poles
stars
gases
gas
flattening
molecular gases
star formation rate
spectral energy distribution
magnification
timescale
gas reservoir
synchrotrons
depletion
luminosity
lenses
continuums
low frequencies

Keywords

  • Cosmology: observations
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: high-redshift
  • Galaxies: starburst

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Aravena, M., Murphy, E. J., Aguirre, J. E., Ashby, M. L. N., Benson, B. A., Bothwell, M., ... Weiß, A. (2013). Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7. Monthly Notices of the Royal Astronomical Society, 433(1), 498-505. https://doi.org/10.1093/mnras/stt741

Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7. / Aravena, M.; Murphy, E. J.; Aguirre, J. E.; Ashby, M. L N; Benson, B. A.; Bothwell, M.; Brodwin, M.; Carlstrom, J. E.; Chapman, S. C.; Crawford, T. M.; de Breuck, C.; Fassnacht, C. D.; Gonzalez, A. H.; Greve, T. R.; Gullberg, B.; Hezaveh, Y.; Holder, G. P.; Holzapfel, W. L.; Keisler, R.; Malkan, M.; Marrone, Daniel P; McIntyre, V.; Reichardt, C. L.; Sharon, K.; Spilker, J. S.; Stalder, B.; Stark, A. A.; Vieira, J. D.; Weiß, A.

In: Monthly Notices of the Royal Astronomical Society, Vol. 433, No. 1, 07.2013, p. 498-505.

Research output: Contribution to journalArticle

Aravena, M, Murphy, EJ, Aguirre, JE, Ashby, MLN, Benson, BA, Bothwell, M, Brodwin, M, Carlstrom, JE, Chapman, SC, Crawford, TM, de Breuck, C, Fassnacht, CD, Gonzalez, AH, Greve, TR, Gullberg, B, Hezaveh, Y, Holder, GP, Holzapfel, WL, Keisler, R, Malkan, M, Marrone, DP, McIntyre, V, Reichardt, CL, Sharon, K, Spilker, JS, Stalder, B, Stark, AA, Vieira, JD & Weiß, A 2013, 'Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7', Monthly Notices of the Royal Astronomical Society, vol. 433, no. 1, pp. 498-505. https://doi.org/10.1093/mnras/stt741
Aravena, M. ; Murphy, E. J. ; Aguirre, J. E. ; Ashby, M. L N ; Benson, B. A. ; Bothwell, M. ; Brodwin, M. ; Carlstrom, J. E. ; Chapman, S. C. ; Crawford, T. M. ; de Breuck, C. ; Fassnacht, C. D. ; Gonzalez, A. H. ; Greve, T. R. ; Gullberg, B. ; Hezaveh, Y. ; Holder, G. P. ; Holzapfel, W. L. ; Keisler, R. ; Malkan, M. ; Marrone, Daniel P ; McIntyre, V. ; Reichardt, C. L. ; Sharon, K. ; Spilker, J. S. ; Stalder, B. ; Stark, A. A. ; Vieira, J. D. ; Weiß, A. / Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7. In: Monthly Notices of the Royal Astronomical Society. 2013 ; Vol. 433, No. 1. pp. 498-505.
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title = "Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7",
abstract = "We report the detection of CO(1-0) line emission in the bright, lensed star-forming galaxies SPT-S 233227-5358.5 (z = 2.73) and SPT-S 053816-5030.8 (z = 2.78), using the Australia Telescope Compact Array. Both galaxies were discovered in a large-area millimetre survey with the South Pole Telescope (SPT) and found to be gravitationally lensed by intervening structures. The measured CO intensities imply galaxies with molecular gas masses of (3.2 ± 0.5) × 1010(μ/15)-1(XCO/0.8) and (1.7 ± 0.3) × 1010(μ/20)-1(XCO/0.8)M·, and gas depletion time-scales of 4.9 × 107(XCO/0.8) and 2.6 × 107(XCO/0.8) yr, respectively, where μ corresponds to the lens magnification and XCO is the CO luminosity to gas mass conversion factor. In the case of SPT-S 053816-5030.8, we also obtained significant detections of the rest-frame 115.7 and 132.4 GHz radio continuum. Based on the radio-to-infrared spectral energy distribution and an assumed synchrotron spectral index, we find that 42 ± 10 and 55 ±13 per cent of the flux at rest-frame 115.7 and 132.4 GHz arises from free-free emission. We find a radio-derived intrinsic star formation rate of 470 ± 170M· yr-1, consistent within the uncertainties with the infrared estimate. Based on the morphology of this object in the source plane, the derived gas mass and the possible flattening of the radio spectral index towards low frequencies, we argue that SPT-S 053816-5030.8 exhibits properties compatible with a scaled-up local ultraluminous infrared galaxy.",
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T1 - Large gas reservoirs and free-free emission in two lensed star-forming galaxies at z = 2.7

AU - Aravena, M.

AU - Murphy, E. J.

AU - Aguirre, J. E.

AU - Ashby, M. L N

AU - Benson, B. A.

AU - Bothwell, M.

AU - Brodwin, M.

AU - Carlstrom, J. E.

AU - Chapman, S. C.

AU - Crawford, T. M.

AU - de Breuck, C.

AU - Fassnacht, C. D.

AU - Gonzalez, A. H.

AU - Greve, T. R.

AU - Gullberg, B.

AU - Hezaveh, Y.

AU - Holder, G. P.

AU - Holzapfel, W. L.

AU - Keisler, R.

AU - Malkan, M.

AU - Marrone, Daniel P

AU - McIntyre, V.

AU - Reichardt, C. L.

AU - Sharon, K.

AU - Spilker, J. S.

AU - Stalder, B.

AU - Stark, A. A.

AU - Vieira, J. D.

AU - Weiß, A.

PY - 2013/7

Y1 - 2013/7

N2 - We report the detection of CO(1-0) line emission in the bright, lensed star-forming galaxies SPT-S 233227-5358.5 (z = 2.73) and SPT-S 053816-5030.8 (z = 2.78), using the Australia Telescope Compact Array. Both galaxies were discovered in a large-area millimetre survey with the South Pole Telescope (SPT) and found to be gravitationally lensed by intervening structures. The measured CO intensities imply galaxies with molecular gas masses of (3.2 ± 0.5) × 1010(μ/15)-1(XCO/0.8) and (1.7 ± 0.3) × 1010(μ/20)-1(XCO/0.8)M·, and gas depletion time-scales of 4.9 × 107(XCO/0.8) and 2.6 × 107(XCO/0.8) yr, respectively, where μ corresponds to the lens magnification and XCO is the CO luminosity to gas mass conversion factor. In the case of SPT-S 053816-5030.8, we also obtained significant detections of the rest-frame 115.7 and 132.4 GHz radio continuum. Based on the radio-to-infrared spectral energy distribution and an assumed synchrotron spectral index, we find that 42 ± 10 and 55 ±13 per cent of the flux at rest-frame 115.7 and 132.4 GHz arises from free-free emission. We find a radio-derived intrinsic star formation rate of 470 ± 170M· yr-1, consistent within the uncertainties with the infrared estimate. Based on the morphology of this object in the source plane, the derived gas mass and the possible flattening of the radio spectral index towards low frequencies, we argue that SPT-S 053816-5030.8 exhibits properties compatible with a scaled-up local ultraluminous infrared galaxy.

AB - We report the detection of CO(1-0) line emission in the bright, lensed star-forming galaxies SPT-S 233227-5358.5 (z = 2.73) and SPT-S 053816-5030.8 (z = 2.78), using the Australia Telescope Compact Array. Both galaxies were discovered in a large-area millimetre survey with the South Pole Telescope (SPT) and found to be gravitationally lensed by intervening structures. The measured CO intensities imply galaxies with molecular gas masses of (3.2 ± 0.5) × 1010(μ/15)-1(XCO/0.8) and (1.7 ± 0.3) × 1010(μ/20)-1(XCO/0.8)M·, and gas depletion time-scales of 4.9 × 107(XCO/0.8) and 2.6 × 107(XCO/0.8) yr, respectively, where μ corresponds to the lens magnification and XCO is the CO luminosity to gas mass conversion factor. In the case of SPT-S 053816-5030.8, we also obtained significant detections of the rest-frame 115.7 and 132.4 GHz radio continuum. Based on the radio-to-infrared spectral energy distribution and an assumed synchrotron spectral index, we find that 42 ± 10 and 55 ±13 per cent of the flux at rest-frame 115.7 and 132.4 GHz arises from free-free emission. We find a radio-derived intrinsic star formation rate of 470 ± 170M· yr-1, consistent within the uncertainties with the infrared estimate. Based on the morphology of this object in the source plane, the derived gas mass and the possible flattening of the radio spectral index towards low frequencies, we argue that SPT-S 053816-5030.8 exhibits properties compatible with a scaled-up local ultraluminous infrared galaxy.

KW - Cosmology: observations

KW - Galaxies: evolution

KW - Galaxies: formation

KW - Galaxies: high-redshift

KW - Galaxies: starburst

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