The Nature of 500 micron Risers I: SMA Observations

Abstract

We present SMA observations at resolutions from 0.35 to 3 arcseconds of a sample of 34 candidate high redshift dusty star forming galaxies (DSFGs). These sources were selected from the HerMES Herschel survey catalogues to have SEDs rising from 250 to 350 to 500$\mu$m, a population termed 500-risers. We detect counterparts to 24 of these sources, with four having two counterparts. We conclude that the remaining ten sources that lack detected counterparts are likely to have three or more associated sources which blend together to produce the observed Herschel source. We examine the role of lensing, which is predicted to dominate the brightest (F500 $>$ 60mJy) half of our sample. We find that while lensing plays a role, at least 35% of the bright sources are likely to be multiple sources rather than the result of lensing. At fainter fluxes we find a blending rate comparable to, or greater than, the predicted 40%. We determine far-IR luminosities and star formation rates for the non-multiple sources in our sample and conclude that, in the absence of strong lensing, our 500-risers are very luminous systems with L${}_{FIR}>10^{13}$L${}_{\odot }$ and star formation rates $>1000$M${}_{\odot }$/yr.

Accepted for publication in MNRAS

References in corpus (17)

• Astrophysics Source Code Library
• A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34
• An ALMA survey of Sub-millimeter Galaxies in the Extended Chandra Deep Field South: Physical properties derived from ultraviolet-to-radio modelling
• A massive proto-cluster of galaxies at a redshift of z {\approx} 5.3
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: High resolution 870um source counts
• Galaxy growth in a massive halo in the first billion years of cosmic history
• The SCUBA-2 Cosmology Legacy Survey: ALMA resolves the bright-end of the sub-millimeter number counts
• A Massive Molecular Gas Reservoir in the z=5.3 Submillimeter Galaxy AzTEC-3
• ISM properties of a Massive Dusty Star-Forming Galaxy discovered at z ~ 7
• Spectroscopic Confirmation Of An Extreme Starburst At Redshift 4.547
• A submillimetre galaxy at z=4.76 in the LABOCA survey of the Extended Chandra Deep Field South
• The space density of luminous dusty star-forming galaxies at $z>4$: SCUBA-2 and LABOCA imaging of ultrared galaxies from $Herschel$-ATLAS
• Simulated observations of sub-millimetre galaxies: the impact of single-dish resolution and field variance
• HerMES: The Rest-Frame UV Emission and A Lensing Model for the z=6.34 Luminous Dusty Starburst Galaxy HFLS3
• The most distant, luminous, dusty star-forming galaxies: redshifts from NOEMA and ALMA spectral scans
• ALMACAL II: Extreme star-formation-rate densities in a pair of dusty starbursts at $z=3.442$ revealed by ALMA 20-milliarcsec resolution imaging
• A SCUBA-2 Selected Herschel-SPIRE Dropout and the Nature of this Population

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• The SCUBA-2 Large eXtragalactic Survey: 850um map, catalogue and the bright-end number counts of the XMM-LSS field
• Early Science with the Large Millimeter Telescope: a 1.1 mm AzTEC Survey of Red-$Herschel$ dusty star-forming galaxies
• A High-resolution Far-infrared Survey to Probe Black Hole-Galaxy Co-evolution
• Hiding behind a curtain of dust: Gas and dust properties of an ultra-luminous strongly-lensed z = 3.75 galaxy behind the Milky Way disk