The Scuba-2 Cosmology Legacy Survey: Alma Resolves the Bright-End of the Sub-Millimeter Number Counts

Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Chapman, Scott; Geach, J. E.; Ivison, R. J.; Thomson, A. P.; Aretxaga, I.; Blain, A. W.; Cowley, William I.; Chen, Chian-Chou; Coppin, K. E. K.; Dunlop, James; Edge, A. C.; Farrah, D.; Ibar, E.; Karim, A.; Knudsen, K. K.; Meijerink, R.; Michałowski, M. J.; Scott, D.; Spaans, Marco; Werf, P. P. van der

doi:10.1088/0004-637x/807/2/128

Cited by 179 publications

(313 citation statements)

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“…The maps show the continuum morphologies to be either compact and smooth (ALESS 61.1, ALESS 65.1 and ALESS 73.1) or break up into apparent substructures on ∼200 pc scales (UDS 47.0). These 0 03 resolution observations recover between 44% and 81% of the continuum flux detected at lower resolution in ALMA Cycle 0/1 (Swinbank et al 2012;De Breuck et al 2014;Simpson et al 2015a). Middle row: intermediate-resolution 345 GHz continuum maps uv-tapered to 0 05 (∼300 pc), showing the morphologies of the more extended emission in these sources.…”

Section: Size Estimates From Uv-plane Fits 421 Continuummentioning

confidence: 62%

“…The peaks of the 345 GHz continuum for the four sources are detected at 7.4-8.3σ, with an optimized aperture size determined by using a curve of growth we recover between 44±3 and 81±12% of the integrated flux density measured from the low-resolution ALMA Cycle 0/1 observations (Swinbank et al 2012;De Breuck et al 2014;Simpson et al 2015a). This suggests that our maps are missing a fraction of the emission from the most extended low surface brightness dust on scales 200 kpc.…”

Section: Discussionmentioning

confidence: 74%

“…A pilot study observed the 30 brightest SCUBA-2 sources in the ∼1 deg 2 UKIDSS/UDS field (Simpson et al 2015a(Simpson et al , 2015b(Simpson et al , 2017. These 0 3 resolution ALMA observations revealed a serendipitous detection of [C II] emission at 350.78 GHz, establishing the redshift as z=4.420.…”

Section: Samplementioning

confidence: 95%

“…To estimate the size of the rest frame 160 μm emission in the SMGs, we determine the behavior of the amplitude as a function of uv-distance. We do this by first aligning the phase center of our cubes with the Note.Column 5: percentage of recovered flux from ALMA cycle 0/1 data (Swinbank et al 2012;De Breuck et al 2014;Simpson et al 2015a). Column 9: percentage of recovered flux from ALMA cycle 0/1 data (Swinbank et al 2012;De Breuck et al 2014;Simpson et al 2015a).…”

Section: Size Estimates From Uv-plane Fits 421 Continuummentioning

confidence: 99%

“…However, studies have shown important differences between SMGs and ULIRGs. For example, the spatial extent of the gas and star formation in SMGs appears to be much larger than that typically seen in local ULIRGs (∼few kpc in SMGs compared to just hundreds of pc in local ULIRGs, e.g., Chapman et al 2004;Sakamoto et al 2008;Kennicutt et al 2011;Croxall et al 2012;Ivison et al 2012;Ikarashi et al 2015;Simpson et al 2015a;Hodge et al 2016), and while the intense star formation seen in local ULIRGs appears to be triggered by major mergers (e.g., Clements & Baker 1996;Farrah et al 2001;Surace et al 2001;Veilleux 2002), theoretical predictions have suggested that SMGs at z∼1-5 comprise a heterogeneous mix of star formation occurring in extended disks, pre-coalescence mergers, and late-stage mergers (e.g., Hayward et al 2011;Cowley et al 2017), which may be consistent with Hubble Space Telescope (HST) imaging (Chen et al 2015).…”

Section: Introductionmentioning

confidence: 95%

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The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift

Gullberg

Swinbank

Smail

et al. 2018

ApJ

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Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractWe present deep, high-resolution (0 03, 200 pc) ALMA Band 7 observations covering the dust continuum and [C II] λ157.7 μm emission in four z∼4.4-4.8 sub-millimeter galaxies (SMGs) selected from the ALESS and AS2UDS surveys. The data show that the rest-frame 160 μm (observed 345 GHz) dust emission is consistent with smooth morphologies on kpc scales for three of the sources. One source, UDS 47.0, displays apparent substructure, but this is also consistent with a smooth morphology-as indicated by simulations showing that smooth exponential disks can appear clumpy when observed at the high angular resolution (0 03) and depth of these observations (s~-27 47 345 GHz μJy beam −1 ). The four SMGs are bright [C II] emitters. We extract [C II] spectra from the high-resolution data, and recover ∼20%-100% of the [C II] flux and ∼40%-80% of the dust continuum emission, compared to the previous lower-resolution observations. When tapered to 0 2 resolution, our maps recover ∼80%-100% of the continuum emission, indicating that ∼60% of the emission is resolved out on ∼200 pc scales. We find that the [C II] emission in high-redshift galaxies is more spatially extended than the rest-frame 160 μm dust continuum by a factor of 1.6±0.4. By considering the [ ] L C II /L FIR ratio as a function of the star formation rate surface density (S SFR ), we revisit the [C II] deficit and suggest that the decline in the [ ] L C II /L FIR ratio as a function of S SFR is consistent with local processes. We also explore the physical drivers that may be responsible for these trends and can give rise to the properties found in the densest regions of SMGs.

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Section: Size Estimates From Uv-plane Fits 421 Continuummentioning

confidence: 62%

Section: Discussionmentioning

confidence: 74%

Section: Samplementioning

confidence: 95%

Section: Size Estimates From Uv-plane Fits 421 Continuummentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

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The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift

Gullberg

Swinbank

Smail

et al. 2018

ApJ

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Cosmic Structure Scale: Number Density and Clustering

Fujimoto

2021

Demographics of the Cold Universe With ALMA

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(Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies

Miettinen

Novak

Smolčić

et al. 2015

A&A

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Radio emission at centimetre wavelengths from highly star-forming galaxies, like submillimetre galaxies (SMGs), is dominated by synchrotron radiation arising from supernova activity. Hence, radio continuum imaging has the potential to determine the spatial extent of star formation in these types of galaxies. Using deep, high-resolution (1σ = 2.3 μJy beam −1 ; 0. 75) centimetre radio-continuum observations taken by the Karl G. Jansky Very Large Array (VLA)-COSMOS 3 GHz Large Project, we studied the radio-emitting sizes of a flux-limited sample of SMGs in the COSMOS field. The target SMGs were originally discovered in a 1.1 mm continuum survey carried out with the AzTEC bolometer, and followed up with higher resolution interferometric (sub)millimetre continuum observations. Of the 39 SMGs studied here, 3 GHz emission was detected towards 18 of them (∼46 ± 11%) with signal-to-noise ratios in the range of S /N = 4.2-37.4. Towards four SMGs (AzTEC2, 5, 8, and 11), we detected two separate 3 GHz sources with projected separations of ∼1. 5-6. 6, but they might be physically related in only one or two cases (AzTEC2 and 11). Using two-dimensional elliptical Gaussian fits, we derived a median deconvolved major axis FWHM size of 0. 54 ± 0. 11 for our 18 SMGs detected at 3 GHz. For the 15 SMGs with known redshift we derived a median linear major axis FWHM of 4.2 ± 0.9 kpc. No clear correlation was found between the radio-emitting size and the 3 GHz or submm flux density, or the redshift of the SMG. However, there is a hint of larger radio sizes at z ∼ 2.5-5 compared to lower redshifts. The sizes we derived are consistent with previous SMG sizes measured at 1.4 GHz and in mid-J CO emission, but significantly larger than those seen in the (sub)mm continuum emission (typically probing the rest-frame far-infrared with median FWHM sizes of only ∼1.5-2.5 kpc). One possible scenario is that SMGs have i) an extended gas component with a low dust temperature, which can be traced by low-to mid-J CO line emission and radio continuum emission; and ii) a warmer, compact starburst region giving rise to the high-excitation line emission of CO, which could dominate the dust continuum size measurements. Because of the rapid cooling of cosmic-ray electrons in dense starburst galaxies (∼10 4 -10 5 yr), the more extended synchrotron radio-emitting size being a result of cosmic-ray diffusion seems unlikely. Instead, if SMGs are driven by galaxy mergers -a process where the galactic magnetic fields can be pulled out to larger spatial scales -the radio synchrotron emission might arise from more extended magnetised interstellar medium around the starburst region.

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The Scuba-2 Cosmology Legacy Survey: Alma Resolves the Bright-End of the Sub-Millimeter Number Counts

Cited by 179 publications

References 87 publications

The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift

The Dust and [C ii] Morphologies of Redshift ∼4.5 Sub-millimeter Galaxies at ∼200 pc Resolution: The Absence of Large Clumps in the Interstellar Medium at High-redshift

Cosmic Structure Scale: Number Density and Clustering

(Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies

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