The SCUBA Local Universe Galaxy Survey Optically-Selected Sample

We discuss the progress of the SCUBA Local Universe Galaxy Survey (SLUGS), the first large, statistical sub-mm survey of the local universe. Since our original survey of a sample of 104 IRAS-selected galaxies we have recently completed a sample of 78 Optically-Selected galaxies. Since SCUBA is sensitive to the large proportion of dust too cold to be detected by IRAS the addition of this optically-selected sample allows us for the first time to determine the amount of cold dust in galaxies of different Hubble types. We detect 6 ellipticals in the sample and find them to have dust masses in excess of 10^7 solar masses. We derive local sub-mm luminosity functions, both directly for the two samples, and by extrapolation from the IRAS PSCz, and find excellent agreement.Comment: 2 pages, 2 figures. In the proceedings of the conference: "Penetrating Bars through Masks of Cosmic Dust: The Hubble Tuning Fork Strikes a New Note", South Africa, June 2004 (Kluwer

The FIR-Radio Relationship at High and Low Redshift

We use the results of the SCUBA Local Universe Galaxy Survey, a submillimetre survey of galaxies in the nearby Universe, to investigate the relationship between the far-infrared--submillimetre and radio emission of galaxies at both low and high redshift. At low redshift we show that the correlation between radio and far-infrared emission is much stronger than the correlation between radio and submillimetre emission, which is evidence that massive stars are the source of both the far-infrared and radio emission. At high redshift we show that the submillimetre sources detected by SCUBA are brighter sources of radio emission than are predicted from the properties of galaxies in the local Universe. We discuss possible reasons for the cosmic evolution of the relationship between radio and far-infrared emission.Comment: 8 pages including 4 figures. Version accepted for publication in MNRA

The new galaxy evolution paradigm revealed by the Herschel surveys

The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys which presents a challenge for galaxy-evolution models. The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a single Galaxy Sequence (GS) rather than a star-forming ‘main sequence’ and a separate region of ‘passive’ or ‘red-and-dead’ galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically red starforming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 < z < 0.4, we show that the galaxies responsible for the rapid low-redshift evolution have high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations – they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population

Scuba local universe galaxy survey : dust along the Hubble sequence

This thesis presents new results from the SCUBA Local Universe Galaxy Survey (SLUGS) the optically-selected sample. SLUGS is the first large systematic submillimetre survey of the local Universe, and was carried out with the SCUBA camera on the James Clerk Maxwell Telescope. Since SCUBA is sensitive to the 90% of dust too cold to radiate significantly in the IRAS bands this new sample, taken from the Center for Astrophysics (CfA) optical redshift survey (Huchra et al. 1983) and hence selected on the basis of optical emission alone, represents the first unbiased survey of dust in galaxies along the whole length of the Hubble sequence. There is little change found in the properties of dust in galaxies along the Hubble sequence, except a marginally significant trend for early-type galaxies to be less luminous submillimetre sources than late-types. Nevertheless, 6 out of 11 elliptical galaxies were detected, although some of the emission may possibly be synchrotron rather than dust emission. The IRAS and submillimetre fluxes are found to be well-fitted by a two-component dust model with dust emissivity index fi=2. The ratio of the mass of cold dust to the mass of warm dust is found to be much higher for the optically-selected galaxies than found for the previous IRAS-selected SLUGS sample (Dunne et al. 2000 Dunne & Eales 2001), and can reach values of 1000. Comparison of the results for the IRAS- and optically-selected samples shows that there is a population of galaxies containing a large proportion of cold dust that is unrepresented in the IRAS sample. Local submillimetre luminosity and dust mass functions are derived, both directly from the optically-selected SLUGS sample, and by extrapolation from the IRAS PSCz survey using the method of Serjeant & Harrison (2005) (by extrapolating the spectral energy distributions of the IRAS PSCz survey galaxies out to 850 /zm we probe a wider range of luminosities than probed directly by the SLUGS samples), and excellent agreement is found between the two. They are found to be well-fitted by Schechter functions except at the highest luminosities. As a consequence of the omission of cold galaxies from the IRAS sample the previous //i45-selected luminosity function is found to be too low by a factor of 2, reducing the amount of cosmic evolution required between the low-z and high-z universe. Finally, the results of the OS SLUGS are used to assess the reliability of the Carilli & Yun (1999, 2000a) radio-submillimetre redshift estimator technique, for the first time using a sample of 'normal' local galaxies

High-resolution VLA Imaging of Obscured Quasars : Young Radio Jets Caught in a Dense ISM

© 2020 IOP Publishing Ltd. This is an author-created, un-copyedited version of an article accepted for publication in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher authenticated version is available online at https://doi.org/10.3847/1538-4357/ab9011.We present new subarcsecond-resolution Karl G. Jansky Very Large Array (VLA) imaging at 10 GHz of 155 ultraluminous (L bol ∼ 1011.7-1014.2 L o˙) and heavily obscured quasars with redshifts z ∼ 0.4-3. The sample was selected to have extremely red mid-infrared-optical color ratios based on data from the Wide-Field Infrared Survey Explorer (WISE) along with a detection of bright, unresolved radio emission from the NRAO VLA Sky Survey (NVSS) or Faint Images of the Radio Sky at Twenty cm Survey. Our high-resolution VLA observations have revealed that the majority of the sources in our sample (93 out of 155) are compact on angular scales <0.″2 (≤1.7 kpc at z ∼ 2). The radio luminosities, linear extents, and lobe pressures of our sources are similar to young radio active galactic nuclei (e.g., gigahertz-peaked spectrum [GPS] and compact steep-spectrum [CSS] sources), but their space density is considerably lower. Application of a simple adiabatic lobe expansion model suggests relatively young dynamical ages (∼104-7 yr), relatively high ambient ISM densities (∼1-104 cm-3), and modest lobe expansion speeds (∼30-10,000 km s-1). Thus, we find our sources to be consistent with a population of newly triggered, young jets caught in a unique evolutionary stage in which they still reside within the dense gas reservoirs of their hosts. Based on their radio luminosity function and dynamical ages, we estimate that only ∼20% of classical large-scale FR I/II radio galaxies could have evolved directly from these objects. We speculate that the WISE-NVSS sources might first become GPS or CSS sources, of which some might ultimately evolve into larger radio galaxies.Peer reviewe

Herschel -ATLAS: The dust energy balance in the edge-on spiral galaxy UGC 4754

We use Herschel PACS and SPIRE observations of the edge-on spiral galaxy UGC 4754, taken as part of the H-ATLAS SDP observations, to investigate the dust energy balance in this galaxy. We build detailed SKIRT radiative models based on SDSS and UKIDSS maps and use these models to predict the far-infrared emission. We find that our radiative transfer model underestimates the observed FIR emission by a factor of two to three. Similar discrepancies have been found for other edge-on spiral galaxies based on IRAS, ISO, and SCUBA data. Thanks to the good sampling of the SED at FIR wavelengths, we can rule out an underestimation of the FIR emissivity as the cause for this discrepancy. Instead we support highly obscured star formation that contributes little to the optical extinction as a more probable explanation.This work used data from the UKIDSS DR5 and SDSS DR7. The UKIDSS project is defined in Lawrence et al. (2007) and uses the UKIRT Wide Field Camera (WFCAM; Casali et al. 2007). Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England

Herschel-ATLAS: Dust temperature and redshift distribution of SPIRE and PACS detected sources using submillimetre colours

We present colour-colour diagrams of detected sources in the Herschel-ATLAS science demonstration field from 100 to 500μm using both PACS and SPIRE. We fit isothermal modified black bodies to the spectral energy distribution (SED) to extract the dust temperature of sources with counterparts in Galaxy And Mass Assembly (GAMA) or SDSS surveys with either a spectroscopic or a photometric redshift. For a subsample of 330 sources detected in at least three FIR bands with a significance greater than 3σ, we find an average dust temperature of (28±8) K. For sources with no known redshift, we populate the colour-colour diagram with a large number of SEDs generated with a broad range of dust temperatures and emissivity parameters, and compare to colours of observed sources to establish the redshift distribution of this sample. For another subsample of 1686 sources with fluxes above 35 mJy at 350μm and detected at 250 and 500μm with a significance greater than 3σ we find an average redshift of 2.2 ±0.6Amblard, Barton, Cooray, Leeuw, Serra and Temi acknowledge support from NASA funds for US participants in Herschel through JPL. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The UKIDSS project is defined in Lawrence et al. (2007)

The new galaxy evolution paradigm revealed by the Herschel surveys

The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys, which presents a challenge for galaxy-evolution models. The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a a single Galaxy Sequence (GS) rather than a star-forming ‘main sequence’ and a separate region of ‘passive’ or ‘red-and-dead’ galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically-red star-forming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 < z < 0.4, we show that the galaxies responsible for the rapid low-redshift evolution have high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations— they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population