Browsing by Author "Smith, M. W. L."
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- ItemFar-infrared spectroscopy of a lensed starburst: a blind redshift from Herschel(2013) George, R. D.; Ivison, R. J.; Hopwood, R.; Riechers, D. A.; Bussmann, R. S.; Cox, P.; Dye, S.; Krips, M.; Negrello, M.; Neri, R.; Serjeant, S.; Valtchanov, I.; Baes, M.; Bourne, N.; Clements, D. L.; De Zotti, G.; Dunne, L.; Eales, S. A.; Ibar, E.; Maddox, S.; Smith, M. W. L.; Valiante, E.; van der Werf, P.We report the redshift of HATLAS J132427.0+284452 (hereafter HATLAS J132427), a gravitationally lensed starburst galaxy, the first determined 'blind' by the Herschel Space Observatory. This is achieved via the detection of [C II] consistent with z = 1.68 in a far-infrared spectrum taken with the SPIRE Fourier Transform Spectrometer (FTS). We demonstrate that the [C II] redshift is secure via detections of CO J = 2 -> 1 and 3 -> 2 using the Combined Array for Research in Millimeter-wave Astronomy and the Institut de Radioastronomie Millimetrique's Plateau de Bure Interferometer. The intrinsic properties appear typical of high-redshift starbursts despite the high lensing-amplified fluxes, proving the ability of the FTS to probe this population with the aid of lensing. The blind detection of [C II] demonstrates the potential of the SPICA Far-infrared Instrument imaging spectrometer, proposed for the much more sensitive Space Infrared Telescope for Cosmology and Astrophysics mission, to determine redshifts of multiple dusty galaxies simultaneously without the benefit of lensing.
- ItemH-ATLAS: THE COSMIC ABUNDANCE OF DUST FROM THE FAR-INFRARED BACKGROUND POWER SPECTRUM(2013) Thacker, Cameron; Cooray, Asantha; Smidt, Joseph; De Bernardis, Francesco; Mitchell-Wynne, K.; Amblard, A.; Auld, R.; Baes, M.; Clements, D. L.; Dariush, A.; De Zotti, G.; Dunne, L.; Eales, S.; Hopwood, R.; Hoyos, C.; Ibar, E.; Jarvis, M.; Maddox, S.; Michalowski, M. J.; Pascale, E.; Scott, D.; Serjeant, S.; Smith, M. W. L.; Valiante, E.; van der Werf, P.We present a measurement of the angular power spectrum of the cosmic far-infrared background (CFIRB) anisotropies in one of the extragalactic fields of the Herschel Astrophysical Terahertz Large Area Survey at 250, 350, and 500 mu m bands. Consistent with recent measurements of the CFIRB power spectrum in Herschel-SPIRE maps, we confirm the existence of a clear one-halo term of galaxy clustering on arcminute angular scales with large-scale two-halo term of clustering at 30 arcmin to angular scales of a few degrees. The power spectrum at the largest angular scales, especially at 250 mu m, is contaminated by the Galactic cirrus. The angular power spectrum is modeled using a conditional luminosity function approach to describe the spatial distribution of unresolved galaxies that make up the bulk of the CFIRB. Integrating over the dusty galaxy population responsible for the background anisotropies, we find that the cosmic abundance of dust, relative to the critical density, to be between Omega(dust) = 10-6 and 8 x 10(-6) in the redshift range z similar to 0-3. This dust abundance is consistent with estimates of the dust content in the universe using quasar reddening and magnification measurements in the Sloan Digital Sky Survey.
- ItemH2O emission in high-z ultra-luminous infrared galaxies(2013) Omont, A.; Yang, C.; Cox, P.; Neri, R.; Beelen, A.; Bussmann, R. S.; Gavazzi, R.; van der Werf, P.; Riechers, D.; Downes, D.; Krips, M.; Dye, S.; Ivison, R.; Vieira, J. D.; Weiss, A.; Aguirre, J. E.; Baes, M.; Baker, A. J.; Bertoldi, F.; Cooray, A.; Dannerbauer, H.; De Zotti, G.; Eales, S. A.; Fu, H.; Gao, Y.; Guelin, M.; Harris, A. I.; Jarvis, M.; Lehnert, M.; Leeuw, L.; Lupu, R.; Menten, K.; Michalowski, M. J.; Negrello, M.; Serjeant, S.; Temi, P.; Auld, R.; Dariush, A.; Dunne, L.; Fritz, J.; Hopwood, R.; Hoyos, C.; Ibar, E.; Maddox, S.; Smith, M. W. L.; Valiante, E.; Bock, J.; Bradford, C. M.; Glenn, J.; Scott, K. S.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 Astrophysical Terahertz Large Area Survey (H-ATLAS). The sources are detected either in the 2(02)-1(11) or 2(11)-2(02) H2O emission lines with integrated line fluxes ranging from 1.8 to 14 Jy km s(-1). The corresponding apparent luminosities are mu L-H2O similar to 3-12 x 10(8) L-circle dot, where mu is the lensing magnification factor (3 < mu < 12). These results confirm that H2O 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 (similar to 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 mu m) > 100 mJy) discovered in the Herschel surveys. Correcting the luminosities for amplification, using existing lensing models, L-H2O is found to have a strong dependence on the infrared luminosity, varying as similar to L-IR(1.2). This relation, which needs to be confirmed with better statistics, may indicate a role of radiative (infrared) excitation of the H2O lines, and implies that high-z galaxies with L-IR greater than or similar to 10(13) L-circle dot tend to be very strong emitters in water vapor, that have no equivalent in the local universe.
- ItemHerschel-ATLAS/GAMA: What determines the far-infrared properties of radio galaxies?(2013) Virdee, J. S.; Hardcastle, M. J.; Rawlings, S.; Rigopoulou, D.; Mauch, T.; Jarvis, M. J.; Verma, A.; Smith, D. J. B.; Heywood, I.; White, S. V.; Baes, M.; Cooray, A.; de Zotti, G.; Eales, S.; Michalowski, M. J.; Bourne, N.; Dariush, A.; Dunne, L.; Hopwood, R.; Ibar, E.; Maddox, S.; Smith, M. W. L.; Valiante, E.We perform a stacking analysis of Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) data in order to obtain isothermal dust temperatures and rest-frame luminosities at 250 mu m (L-250), for a well-defined sample of 1599 radio sources over the H-ATLAS Phase 1/Galaxy and Mass Assembly (GAMA) area. The radio sample is generated using a combination of NRAO VLA Sky Survey data and K-band United Kingdom Infrared Telescope Deep Sky Survey-Large Area Survey data, over the redshift range 0.01 < z < 0.8. The far-infrared (FIR) properties of the sample are investigated as a function of 1.4-GHz luminosity, redshift, projected radio-source size and radio spectral index. In order to search for stellar-mass-dependent relations, we split the parent sample into those sources which are below and above 1.5 L-K*.
- ItemHERSCHEL-ATLAS: A BINARY HyLIRG PINPOINTING A CLUSTER OF STARBURSTING PROTOELLIPTICALS(2013) Ivison, R. J.; Swinbank, A. M.; Smail, Ian; Harris, A. I.; Bussmann, R. S.; Cooray, A.; Cox, P.; Fu, H.; Kovacs, A.; Krips, M.; Narayanan, D.; Negrello, M.; Neri, R.; Penarrubia, J.; Richard, J.; Riechers, D. A.; Rowlands, K.; Staguhn, J. G.; Targett, T. A.; Amber, S.; Baker, A. J.; Bourne, N.; Bertoldi, F.; Bremer, M.; Calanog, J. A.; Clements, D. L.; Dannerbauer, H.; Dariush, A.; De Zotti, G.; Dunne, L.; Eales, S. A.; Farrah, D.; Fleuren, S.; Franceschini, A.; Geach, J. E.; George, R. D.; Helly, J. C.; Hopwood, R.; Ibar, E.; Jarvis, M. J.; Kneib, J. -P.; Maddox, S.; Omont, A.; Scott, D.; Serjeant, S.; Smith, M. W. L.; Thompson, M. A.; Valiante, E.; Valtchanov, I.; Vieira, J.; van der Werf, P.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 luminous z = 2.41 galaxies across an approximate to 100 kpc region-a cluster of starbursting protoellipticals. Via subarcsecond interferometric imaging we have measured accurate gas and star formation surface densities. The two brightest galaxies span similar to 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-a scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M-dyn of several x 10(11) M-circle dot, and gas fractions of similar to 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 greater than or similar to 5x 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 approximate to 10(14.6)-M-circle dot cluster.
- ItemHerschel-ATLAS: correlations between dust and gas in local submm-selected galaxies(2013) Bourne, N.; Dunne, L.; Bendo, G. J.; Smith, M. W. L.; Clark, C. J. R.; Smith, D. J. B.; Rigby, E. E.; Baes, M.; Leeuw, L. L.; Maddox, S. J.; Thompson, M. A.; Bremer, M. N.; Cooray, A.; Dariush, A.; de Zotti, G.; Dye, S.; Eales, S.; Hopwood, R.; Ibar, E.; Ivison, R. J.; Jarvis, M. J.; Michalowski, M. J.; Rowlands, K.; Valiante, E.We present an analysis of CO molecular gas tracers in a sample of 500 mu m-selected Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) galaxies at z < 0.05 (cz < 14990 km s(-1)). Using 22-500 mu m photometry from Wide-Field Infrared Survey Explorer, Infrared Astronomical Satellite and Herschel, with HI data from the literature, we investigate correlations between warm and cold dust, and tracers of the gas in different phases. The correlation between global CO(3-2) line fluxes and far-infrared (FIR)-submillimetre (submm) fluxes weakens with increasing infrared wavelength (lambda greater than or similar to 60 mu m), as a result of colder dust being less strongly associated with dense gas. Conversely, CO(2-1) and HI line fluxes both appear to be better correlated with longer wavelengths, suggesting that cold dust is more strongly associated with diffuse atomic and molecular gas phases, consistent with it being at least partially heated by radiation from old stellar populations. The increased scatter at long wavelengths implies that submm fluxes are a poorer tracer of star formation rate (SFR). Fluxes at 22 and 60 mu m are also better correlated with diffuse gas tracers than dense CO(3-2), probably due to very small grain emission in the diffuse interstellar medium, which is not correlated with SFR. The FIR/CO luminosity ratio and the dust mass/CO luminosity ratio both decrease with increasing luminosity, as a result of either correlations between mass and metallicity (changing CO/H-2) or between CO luminosity and excitation [changing CO(3-2)/CO(1-0)].