We present the spatially resolved H{$α$} dynamics of 16 star-forming galaxies at z ~{} 0.81 using the new KMOS multi-object integral field spectrograph on the ESO Very Large Telescope. These... Show moreWe present the spatially resolved H{$α$} dynamics of 16 star-forming galaxies at z ~{} 0.81 using the new KMOS multi-object integral field spectrograph on the ESO Very Large Telescope. These galaxies, selected using 1.18 {$μ$}m narrowband imaging from the 10 deg$^{2}$ CFHT-HiZELS survey of the SA 22 hr field, are found in a ~{}4 Mpc overdensity of H{$α$} emitters and likely reside in a group/intermediate environment, but not a cluster. We confirm and identify a rich group of star-forming galaxies at z = 0.813 {plusmn} 0.003, with 13 galaxies within 1000 km s$^{–1}$ of each other, and seven within a diameter of 3 Mpc. All of our galaxies are ''typical'' star-forming galaxies at their redshift, 0.8 {plusmn} 0.4 SFR^{}*_${$z = 0.8$}$, spanning a range of specific star formation rates (sSFRs) of 0.2-1.1 Gyr$^{–1}$ and have a median metallicity very close to solar of 12 + log(O/H) = 8.62 {plusmn} 0.06. We measure the spatially resolved H{$α$} dynamics of the galaxies in our sample and show that 13 out of 16 galaxies can be described by rotating disks and use the data to derive inclination corrected rotation speeds of 50-275 km s$^{–1}$. The fraction of disks within our sample is 75% {plusmn} 8%, consistent with previous results based on Hubble Space Telescope morphologies of H{$α$}-selected galaxies at z ~{} 1 and confirming that disks dominate the SFR density at z ~{} 1. Our H{$α$} galaxies are well fitted by the z ~{} 1-2 Tully-Fisher (TF) relation, confirming the evolution seen in the zero point. Apart from having, on average, higher stellar masses and lower sSFRs, our group galaxies at z = 0.81 present the same mass-metallicity and TF relation as z ~{} 1 field galaxies and are all disk galaxies. Show less
We present results from a {ap}100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four... Show moreWe present results from a {ap}100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four optically-selected QSOs at z = 2.23 within a 15 { imes} 15 arcmin$^{2}$ region. Narrow-band imaging in the near-IR (within the K band) revealed that the structure contains an additional overdensity of 22 z = 2.23 H{$α$}-emitting galaxies (HAEs), resulting in 23 unique z = 2.23 HAEs/QSOs (22 within the Chandra field of view). Our Chandra observations reveal that three HAEs in addition to the four QSOs harbor powerfully accreting supermassive black holes (SMBHs), with 2-10 keV luminosities of {ap}(8-60) { imes} 10$^{43}$ erg s$^{-1}$ and X-ray spectral slopes consistent with unobscured active galactic nucleus (AGN). Using a large comparison sample of 210 z = 2.23 HAEs in the Chandra-COSMOS field (C-COSMOS), we find suggestive evidence that the AGN fraction increases with local HAE galaxy density. The 2QZ Clus HAEs reside in a moderately overdense environment (a factor of {ap}2 times over the field), and after excluding optically-selected QSOs, we find that the AGN fraction is a factor of {ap}3.5$^{+3.8}$ $_{-2.2}$ times higher than C-COSMOS HAEs in similar environments. Using stacking analyses of the Chandra data and Herschel SPIRE observations at 250 {$μ$}m, we respectively estimate mean SMBH accretion rates ($ackslash$dot${$M$}$_BH) and star formation rates (SFRs) for the 2QZ Clus and C-COSMOS samples. We find that the mean 2QZ Clus HAE stacked X-ray luminosity is QSO-like (L $_{2-10 keV}$ {ap} [6-10] { imes} 10$^{43}$ erg s$^{-1}$), and the implied $ackslash$dot${$M$}$_BH/SFR {ap} (1.6-3.2) { imes} 10$^{-3}$ is broadly consistent with the local M $_{BH}$/M $_{sstarf}$ relation and z {ap} 2 X-ray selected AGN. In contrast, the C-COSMOS HAEs are on average an order of magnitude less X-ray luminous and have $ackslash$dot${$M$}$_BH/SFR {ap} (0.2-0.4) { imes} 10$^{-3}$, somewhat lower than the local M $_{BH}$/M $_{sstarf}$ relation, but comparable to that found for z {ap} 1-2 star-forming galaxies with similar mean X-ray luminosities. We estimate that a periodic QSO phase with duty cycle {ap}2%-8% would be sufficient to bring star-forming galaxies onto the local M $_{BH}$/M $_{sstarf}$ relation. This duty cycle is broadly consistent with the observed C-COSMOS HAE AGN fraction ({ap}0.4%-2.3%) for powerful AGN with L $_X$ {gt}~{} 10$^{44}$ erg s$^{-1}$. Future observations of 2QZ Clus will be needed to identify key factors responsible for driving the mutual growth of the SMBHs and galaxies. Show less
Ivison, R.; Swinbank, A.; Smail, I.; Harris, A.; Bussmann, R.; Cooray, A.; ... ; Werf, P.P. van der 2013
Panchromatic observations of the best candidate hyperluminous infrared galaxies from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically... Show morePanchromatic observations of the best candidate hyperluminous infrared galaxies from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z = 2.41 galaxies across an {ap}100 kpc region{mdash}a cluster of starbursting protoellipticals. Via subarcsecond interferometric imaging we have measured accurate gas and star formation surface densities. The two brightest galaxies span ~{}3 kpc FWHM in submillimeter/radio continuum and CO J = 4-3, and double that in CO J = 1-0. The broad CO line is due partly to the multitude of constituent galaxies and partly to large rotational velocities in two counter-rotating gas disks{mdash}a scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M $_{dyn}$ of several { imes} 10$^{11}$ M $_{⊙}$, and gas fractions of ~{}40%. Velocity dispersions are modest so the disks are unstable, potentially on scales commensurate with their radii: these galaxies are undergoing extreme bursts of star formation, not confined to their nuclei, at close to the Eddington limit. Their specific star formation rates place them {gt}~{} 5 { imes} above the main sequence, which supposedly comprises large gas disks like these. Their high star formation efficiencies are difficult to reconcile with a simple volumetric star formation law. N-body and dark matter simulations suggest that this system is the progenitor of a B(inary)-type {ap}10$^{14.6}$-M $_{⊙}$ cluster. Show less
In the course of our 870 {$μ$}m APEX/LABOCA follow-up of the Herschel Lensing Survey we have detected a source in AS1063 (RXC J2248.7-4431) that has no counterparts in any of the Herschel PACS... Show moreIn the course of our 870 {$μ$}m APEX/LABOCA follow-up of the Herschel Lensing Survey we have detected a source in AS1063 (RXC J2248.7-4431) that has no counterparts in any of the Herschel PACS/SPIRE bands, it is a Herschel ''drop-out'' with S$_{870}$/S$_{500}$ {ge} 0.5. The 870 {$μ$}m emission is extended and centered on the brightest cluster galaxy, suggesting either a multiply imaged background source or substructure in the Sunyaev-Zel'dovich increment due to inhomogeneities in the hot cluster gas of this merging cluster. We discuss both interpretations with emphasis on the putative lensed source. Based on the observed properties and on our lens model we find that this source may be the first submillimeter galaxy (SMG) with a moderate far-infrared (FIR) luminosity (L$_{FIR}$ {lt} 10$^{12}$ L$_{⊙}$) detected so far at z {gt} 4. In deep HST observations we identified a multiply imaged z ~{} 6 source and measured its spectroscopic redshift to be z = 6.107 with VLT/FORS. This source may be associated with the putative SMG, but it is most likely offset spatially by 10-30 kpc and they may be interacting galaxies. With a FIR luminosity in the range [5-15] { imes} 10$^{11}$ L$_{⊙}$ corresponding to a star formation rate in the range [80-260] M$_{⊙}$ yr$^{-1}$, this SMG would be more representative of the z {gt} 4 dusty galaxies than the extreme starbursts detected so far. With a total magnification of ~{}25 it would open a unique window to the normal dusty galaxies at the end of the epoch of reionization. Show less
Hodge, J.; Karim, A.; Smail, I.; Swinbank, A.; Walter, F.; Biggs, A.; ... ; Werf, P.P. van der 2013
We present an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 0 survey of 126 submillimeter sources from the LABOCA ECDFS Submillimeter Survey (LESS). Our 870 {$μ$}m survey with ALMA ... Show moreWe present an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 0 survey of 126 submillimeter sources from the LABOCA ECDFS Submillimeter Survey (LESS). Our 870 {$μ$}m survey with ALMA (ALESS) has produced maps ~{}3{ imes} deeper and with a beam area ~{}200{ imes} smaller than the original LESS observations, doubling the current number of interferometrically-observed submillimeter sources. The high resolution of these maps allows us to resolve sources that were previously blended and accurately identify the origin of the submillimeter emission. We discuss the creation of the ALESS submillimeter galaxy (SMG) catalog, including the main sample of 99 SMGs and a supplementary sample of 32 SMGs. We find that at least 35% (possibly up to 50%) of the detected LABOCA sources have been resolved into multiple SMGs, and that the average number of SMGs per LESS source increases with LESS flux density. Using the (now precisely known) SMG positions, we empirically test the theoretical expectation for the uncertainty in the single-dish source positions. We also compare our catalog to the previously predicted radio/mid-infrared counterparts, finding that 45% of the ALESS SMGs were missed by this method. Our ~{}1.''6 resolution allows us to measure a size of ~{}9 kpc { imes} 5 kpc for the rest-frame ~{}300 {$μ$}m emission region in one resolved SMG, implying a star formation rate surface density of 80 M $_{⊙}$ yr$^{-1}$ kpc$^{-2}$, and we constrain the emission regions in the remaining SMGs to be {lt}10 kpc. As the first statistically reliable survey of SMGs, this will provide the basis for an unbiased multiwavelength study of SMG properties. Show less
