We present the Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS), a spectroscopic catalogue of radio sources designed to include the full range of radio AGN populations out to redshift z~0.8. The catalogue covers ~800deg^2^ of sky, and provides optical identifications for 19179 radio sources from the 1.4GHz Faint Images of the Radio Sky at Twenty-cm (FIRST) survey down to an optical magnitude limit of i_mod_<20.5 in Sloan Digital Sky Survey (SDSS) images. Both galaxies and point-like objects are included, and no colour cuts are applied. In collaboration with the WiggleZ and Galaxy And Mass Assembly (GAMA) spectroscopic survey teams, we have obtained new spectra for over 5000 objects in the LARGESS sample. Combining these new spectra with data from earlier surveys provides spectroscopic data for 12329 radio sources in the survey area, of which 10 856 have reliable redshifts. 85 per cent of the LARGESS spectroscopic sample are radio AGN (median redshift z=0.44), and 15 per cent are nearby star-forming galaxies (median z=0.08). Low-excitation radio galaxies (LERGs) comprise the majority (83 per cent) of LARGESS radio AGN at z<0.8, with 12 per cent being high-excitation radio galaxies (HERGs) and 5 per cent radio-loud QSOs. Unlike the more homogeneous LERG and QSO sub-populations, HERGs are a heterogeneous class of objects with relatively blue optical colours and a wide dispersion in mid-infrared colours. This is consistent with a picture in which most HERGs are hosted by galaxies with recent or ongoing star formation as well as a classical accretion disc.
We tested the validity of the three Larson relations in a sample of 213 massive clumps selected from the Herschel infrared Galactic Plane (Hi-GAL) survey, also using data from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey of 3-mm emission lines. The clumps are divided into five evolutionary stages so that we can also discuss the Larson relations as a function of evolution. We show that this ensemble does not follow the three Larson relations, regardless of the clump's evolutionary phase. A consequence of this breakdown is that the dependence of the virial parameter {alpha}_vir_ on mass (and radius) is only a function of the gravitational energy, independent of the kinetic energy of the system; thus, {alpha}_vir_ is not a good descriptor of clump dynamics. Our results suggest that clumps with clear signatures of infall motions are statistically indistinguishable from clumps with no such signatures. The observed non-thermal motions are not necessarily ascribed to turbulence acting to sustain the gravity, but they might be a result of the gravitational collapse at the clump scales. This seems to be particularly true for the most massive (M>=1000M_{sun}_) clumps in the sample, where exceptionally high magnetic fields might not be enough to stabilize the collapse.
We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z~0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer {alpha} (H{alpha}) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Ly{alpha} radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope H{alpha} and Lyman{alpha} (Ly{alpha}) images. We can conjecture a causal connection between spatially resolved H{alpha} kinematics and Ly{alpha} photometry for individual galaxies. However, no general trend can be established for the whole sample. Furthermore, we compute the intrinsic velocity dispersion {sigma}_0_, the shearing velocity v_shear_, and the v_shear_/{sigma}_0_ ratio from our kinematic maps. In general LARS galaxies are characterised by high intrinsic velocity dispersions (54km/s median) and low shearing velocities (65km/s median). The v_shear_/{sigma}_0_ values range from 0.5 to 3.2 with an average of 1.5. It is noteworthy that five galaxies of the sample are dispersion-dominated systems with v_shear_/{sigma}_0_<1, and are thus kinematically similar to turbulent star-forming galaxies seen at high redshift. When linking our kinematical statistics to the global LARS Ly{alpha} properties, we find that dispersion-dominated systems show higher Ly{alpha} equivalent widths and higher Ly{alpha} escape fractions than systems with v_shear_/{sigma}_0_>1. Our result indicates that turbulence in actively star-forming systems is causally connected to interstellar medium conditions that favour an escape of Ly{alpha} radiation.
We study the global dust and (molecular) gas content in the Lyman Alpha Reference Sample (LARS), i.e. 14 local star-forming galaxies. We characterize their interstellar medium and relate newly derived properties to quantities relevant for Ly{alpha} escape. We observed LARS galaxies with Herschel/PACS, SOFIA/FIFI-LS, the IRAM 30m telescope and APEX, targeting far-infrared (FIR) continuum and emission lines of [CII]158um, [OI]63um, [OIII]88um and low-J CO lines. Using Bayesian methods we derive dust model parameters and estimate total gas masses for all LARS galaxies, taking into account a metallicity-dependent gas-to-dust ratio. Star formation rates were estimated from FIR, [CII]158um and [OI]63um luminosities. LARS covers a wide dynamic range in the derived properties, with FIR-based star formation rates from ~0.5-100M_{sun}/yr, gas fractions between ~15-80% and gas depletion times ranging from a few hundred Myr up to more than 10Gyr. The distribution of LARS galaxies in the {SIGMA}_gas_ vs. {SIGMA}_SFR_ (Kennicutt-Schmidt plane) is thus quite heterogeneous. However, we find that LARS galaxies with the longest gas depletion times, i.e. relatively high gas surface densities ({SIGMA}_gas_) and low star formation rate densities ({SIGMA}_SFR_ have by far the highest Ly{alpha} escape fraction. A strong [Math Processing Error]linear relation is found between Ly{alpha} escape fraction and the total gas (HI+H_2_) depletion time. We argue that the Ly{alpha} escape in those galaxies is driven by turbulence in the star-forming gas that shifts the Ly{alpha} photons out of resonance close to the places where they originate. We further report on an extreme [CII]158um excess in LARS 5, corresponding to ~14+/-3% of the FIR luminosity, i.e. the most extreme [CII]-to-FIR ratio observed in a non-AGN galaxy to date.
The Las Campanas Observatory and Anglo-Australian Telescope Rich Cluster Survey (LARCS) is a panoramic imaging and spectroscopic survey of an X-ray luminosity-selected sample of 21 clusters of galaxies at 0.97<z<0.16. Charge-coupled device (CCD) imaging was obtained in B and R of typically 2{deg} wide regions centred on the 21 clusters, and the galaxy sample selected from the imaging is being used for an on-going spectroscopic survey of the clusters with the 2dF spectrograph on the Anglo-Australian Telescope.
We present an optically selected catalog of 1073 galaxy cluster and group candidates at 0.3<~z<~1. These candidates are drawn from the Las Campanas Distant Clusters Survey (LCDCS), a drift-scan imaging survey of a 130 square degree strip of the southern sky. The survey data were obtained in 1995 March under photometric conditions using the Las Campanas 1 m telescope, the Great Circle Camera, and the Tek No. 5 CCD. To construct this catalog we utilize a novel detection process in which clusters are detected as positive surface brightness fluctuations in the background sky. This approach permits us to find clusters with significantly shallower data than other matched-filter methods that are based upon number counts of resolved galaxies. Selection criteria for the survey are fully automated so that this sample constitutes a well-defined, homogeneous sample that can be used to address issues of cluster evolution and cosmology. Estimated redshifts are derived for the entire sample, and an observed correlation between surface brightness and velocity dispersion, {sigma}, is used to estimate the limiting velocity dispersion of the survey as a function of redshift.
The Las Campanas Infrared Survey, based on broadband optical and near-infrared photometry, is designed to robustly identify a statistically significant and representative sample of evolved galaxies at redshifts z>1. We have completed an H-band imaging survey over 1.1{deg}^2^ of sky in six separate fields. The average 5{sigma} detection limit in a 4" diameter aperture is H~20.8. Here we describe the design of the survey, the observation strategies, data-reduction techniques, and object identification procedures. We present sample near-infrared and optical photometric catalogs for objects identified in two survey fields. The optical images of the Hubble Deep Field-South region obtained from the literature reach 5{sigma} detection thresholds in a 4" diameter aperture of U~24.6, B~26.1, V~25.6, R~25.1, and I~24.2mag. The optical images of the Chandra Deep Field-South region obtained from our own observations reach 5 {sigma} detection thresholds in a 4" diameter aperture of V~26.8, R~26.2, I~25.3, and z'~23.7mag. We perform object detection in all bandpasses and identify>~54000 galaxies over 1408 arcmin^2^ of sky in the two fields. Of these galaxies, ~14000 are detected in the H band and ~2000 have the colors of evolved galaxies, I-H >~3, at z>~1.
We present deep Keck spectroscopy, using the Deep Imaging Multi-Object Spectrograph and the Low-Resolution Imaging Spectrometer spectrographs, of a large and representative sample of 67 extremely red objects (EROs) to H=20.5 in three fields (SSA22, Chandra Deep Field South and NTT Deep Field) drawn from the Las Campanas Infrared Survey (LCIRS). Using the colour cut (I-H)>3.0 (Vega magnitudes) adopted in earlier papers in this series, we verify the efficiency of this selection for locating and studying distant old sources. Spectroscopic redshifts are determined for 44 sources, of which only two are contaminating low-mass stars. When allowance is made for incompleteness, the spectroscopic redshift distribution closely matches that predicted earlier on the basis of photometric data.
The Las Campanas Redshift Survey (LCRS) consists of 26,418 redshifts of galaxies selected from a CCD-based catalog obtained in the R band. The survey covers over 700deg^2 in six strips, each 1.5x80deg, three each in the north and south Galactic caps. The median redshift in the survey is about 30,000km/s. Essential features of the galaxy selection and redshift measurement methods are described and tabulated here. These details are important for subsequent analysis of the LCRS data. Two-dimensional representations of the redshift distributions reveal many repetitions of voids, on the scale of about 5000km/s, sharply bounded by large walls of galaxies as seen in nearby surveys. Statistical investigations of the mean galaxy properties and of clustering on the large scale are reported elsewhere. These include studies of the luminosity function, power spectrum in two and three dimensions, correlation function, pairwise velocity distribution, identification of large-scale structures, and a group catalog.
The Las Campanas Redshift Survey (LCRS) consists of 26,418 redshifts of galaxies selected from a CCD-based catalog obtained in the R band. The survey covers over 700 deg<sup>2</sup> in six strips, each 1.5 x 80 degrees, three each in the north and south Galactic caps. The median redshift in the survey is about 30,000 km s<sup>-1</sup>. Essential features of the galaxy selection and redshift measurement methods are described and tabulated in the reference paper. These details are important for subsequent analysis of the LCRS data. Two-dimensional representations of the redshift distributions reveal many repetitions of voids, on the scale of about 5000 km s<sup>-1</sup>, sharply bounded by large walls of galaxies as seen in nearby surveys. Statistical investigations of the mean galaxy properties and of clustering on the large scale are reported elsewhere. These include studies of the luminosity function, power spectrum in two and three dimensions, correlation function, pairwise velocity distribution, identification of large-scale structures, and a group catalog. This table contains entries for 94959 objects from the LCRS for which photometric data were obtained and which were initially classified as galaxies on the basis of this photometric information, although subsequent spectroscopy indicated that a small fracton of them are actually stars. There are 27021 objects out of this total which have spectroscopic redshift information (either of themselves or of a nearby object). See also the LCRS home pages at: <a href="http://qold.astro.utoronto.ca/~lin/lcrs.html">http://qold.astro.utoronto.ca/~lin/lcrs.html</a>. This table was created by the HEASARC in May 2010 based on the electronic version of Table 3 from the above reference which was obtained from the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/203">CDS Catalog VII/203</a> file catalog.dat. This is a service provided by NASA HEASARC .