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. Malkan; D. P. Marrone; V. McIntyre; C. L. Reichardt; K. Sharon; J. S. Spilker; B. Stalder; A. A. Stark; J. D. Vieira; A. Weiß

doi:10.1093/mnras/stt741

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. MalkanD. P. Marrone, V. McIntyre, C. L. Reichardt, K. Sharon, J. S. Spilker, B. Stalder, A. A. Stark, J. D. Vieira, A. Weiß

Astronomy

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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(X_CO/0.8) and (1.7 ± 0.3) × 10¹⁰(μ/20)^-1(X_CO/0.8)M_·, and gas depletion time-scales of 4.9 × 107(X_CO/0.8) and 2.6 × 10⁷(X_CO/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 language	English (US)
Pages (from-to)	498-505
Number of pages	8
Journal	Monthly Notices of the Royal Astronomical Society
Volume	433
Issue number	1
DOIs	https://doi.org/10.1093/mnras/stt741
State	Published - Jul 2013

Keywords

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

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1093/mnras/stt741

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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., ... 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

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

@article{d558db068ce242eebf512f4bcd821429,

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.",

keywords = "Cosmology: observations, Galaxies: evolution, Galaxies: formation, Galaxies: high-redshift, Galaxies: starburst",

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

year = "2013",

month = jul,

doi = "10.1093/mnras/stt741",

language = "English (US)",

volume = "433",

pages = "498--505",

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

issn = "0035-8711",

publisher = "Oxford University Press",

number = "1",

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TY - JOUR

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, D. 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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UR - http://www.scopus.com/inward/citedby.url?scp=84880404134&partnerID=8YFLogxK

U2 - 10.1093/mnras/stt741

DO - 10.1093/mnras/stt741

M3 - Article

AN - SCOPUS:84880404134

SN - 0035-8711

VL - 433

SP - 498

EP - 505

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -

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

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