Using the IRAM Plateau de Bure interferometer (PdBI), we report the detection of water vapor in six new lensed ultra-luminous starburst galaxies at high redshift, discovered in the Herschel... Show moreUsing the IRAM Plateau de Bure interferometer (PdBI), we report the detection of water vapor in six new lensed ultra-luminous starburst galaxies at high redshift, discovered in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). The sources are detected either in the 2$_{02}$-1$_{11}$ or 2$_{11}$-2$_{02}$ H$_{2}$O emission lines with integrated line fluxes ranging from 1.8 to 14 Jy km s$^{-1}$. The corresponding apparent luminosities are {$μ$}L$_{H2}$O ~{} 3-12 { imes} 10$^{8}$ L$_{⊙}$, where {$μ$} is the lensing magnification factor (3 {lt} {$μ$} {lt} 12). These results confirm that H$_{2}$O lines are among the strongest molecular lines in high-z ultra-luminous starburst galaxies, with intensities almost comparable to those of the high-J CO lines, and similar profiles and line widths (~{}200-900 km s$^{-1}$). With the current sensitivity of the PdBI, the water lines can therefore easily be detected in high-z lensed galaxies (with F(500 {$μ$}m) {gt} 100 mJy) discovered in the Herschel surveys. Correcting the luminosities for amplification, using existing lensing models, L$_{H2}$O is found to have a strong dependence on the infrared luminosity, varying as ~{}L$_{IR}$$^{1.2}$. This relation, which needs to be confirmed with better statistics, may indicate a role of radiative (infrared) excitation of the H$_{2}$O lines, and implies that high-z galaxies with L$_{IR}$ {gsim} 10$^{13}$ L$_{⊙}$ tend to be very strong emitters in water vapor, that have no equivalent in the local universe. Herschel (Pilbratt et al. 2010) is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. 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
Bussmann, R.; Pérez-Fournon, I.; Amber, S.; Calanog, J.; Gurwell, M.; Dannerbauer, H.; ... ; Wilner, D. 2013
Strong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and... Show moreStrong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and Gemini-South and Multiple Mirror Telescope optical spectroscopy of strong lens candidates discovered in the two widest extragalactic surveys conducted by the Herschel Space Observatory: the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). From a sample of 30 Herschel sources with S $_{500}$ {gt} 100 mJy, 21 are strongly lensed (i.e., multiply imaged), 4 are moderately lensed (i.e., singly imaged), and the remainder require additional data to determine their lensing status. We apply a visibility-plane lens modeling technique to the SMA data to recover information about the masses of the lenses as well as the intrinsic (i.e., unlensed) sizes (r $_{half}$) and far-infrared luminosities (L $_{FIR}$) of the lensed submillimeter galaxies (SMGs). The sample of lenses comprises primarily isolated massive galaxies, but includes some groups and clusters as well. Several of the lenses are located at z $_{lens}$ {gt} 0.7, a redshift regime that is inaccessible to lens searches based on Sloan Digital Sky Survey spectroscopy. The lensed SMGs are amplified by factors that are significantly below statistical model predictions given the 500 {$μ$}m flux densities of our sample. We speculate that this may reflect a deficiency in our understanding of the intrinsic sizes and luminosities of the brightest SMGs. The lensed SMGs span nearly one decade in L $_{FIR}$ (median L $_{FIR}$ = 7.9 { imes} 10$^{12}$ L $_{☉}$) and two decades in FIR luminosity surface density (median {$Sigma$}$_{FIR}$ = 6.0 { imes} 10$^{11}$ L $_{☉}$ kpc$^{–2}$). The strong lenses in this sample and others identified via (sub-)mm surveys will provide a wealth of information regarding the astrophysics of galaxy formation and evolution over a wide range in redshift. IMAGING OF HERSCHEL Show less
