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We present measurements of the angular correlation function of sub-millimetre (sub-mm) galaxies (SMGs) identified in four out of the five fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) – GAMA-9h, GAMA-12h, GAMA-15h, and NGP – with flux densities |$S_{250 \, \mu {\rm m}} \gt 30$| mJy at 250 μm. We show that galaxies selected at this wavelength trace the underlying matter distribution differently at low and high redshifts. We study the evolution of the clustering finding that at low redshifts sub-mm galaxies exhibit clustering strengths of r 0 ∼ 2–3 h −1 Mpc, below |$z$| < 0.3. At high redshifts, on the other hand, we find that sub-mm galaxies are more strongly clustered with correlation lengths r 0 = 8.1 ± 0.5, 8.8 ± 0.8, and 13.9 ± 3.9 h −1 Mpc at |$z$|  = 1–2, 2–3. and 3–5, respectively. We show that sub-mm galaxies across the redshift range 1 < |$z$| < 5, typically reside in dark-matter halos of mass of the order of |${\sim } 10^{12.5}\hbox{--}10^{13.0} \, h^{-1}\, \mathrm{M}_{\odot}$| and are consistent with being the progenitors of local massive elliptical galaxies that we see in the local Universe. [ABSTRACT FROM AUTHOR]

With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 µm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetreselected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ~1013M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro-Frenk-White profile. We show that we would need a sample of ~500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys. [ABSTRACT FROM AUTHOR]

We investigate the mean star formation rates (SFRs) in the host galaxies of ~3000 optically selected quasi-stellar objects (QSOs) from the Sloan Digital Sky Survey within the Herschel-ATLAS fields, and a radio-luminous subsample covering the redshift range of z = 0.2-2.5. Using Wide-field Infrared Survey Explorer (WISE) and Herschel photometry (12-500 μm) we construct composite spectral energy distributions (SEDs) in bins of redshift and active galactic nucleus (AGN) luminosity. We perform SED fitting to measure the mean infrared luminosity due to star formation, removing the contamination from AGN emission. We find that the mean SFRs show a weak positive trend with increasing AGN luminosity. However, we demonstrate that the observed trend could be due to an increase in black hole (BH) mass (and a consequent increase of inferred stellar mass) with increasing AGN luminosity. We compare to a sample of X-ray selected AGN and find that the two populations have consistent mean SFRs when matched in AGN luminosity and redshift. On the basis of the available virial BH masses, and the evolving BH mass to stellar mass relationship, we find that the mean SFRs of our QSO sample are consistent with those of main sequence star-forming galaxies. Similarly the radio-luminous QSOs have mean SFRs that are consistent with both the overall QSO sample and with star-forming galaxies on the main sequence. In conclusion, on average QSOs reside on the main sequence of star-forming galaxies, and the observed positive trend between the mean SFRs and AGN luminosity can be attributed to BH mass and redshift dependencies. [ABSTRACT FROM AUTHOR]

We use new Band 3 CO(1-0) observations taken with the Atacama Large Millimeter/submillimeter Array (ALMA) to study the physical conditions in the interstellar gas of a sample of 27 dusty main-sequence star-forming galaxies at 0:03 < z < 0:2 present in the Valparaíso ALMA Line Emission Survey (VALES). The sample is drawn from far-IR bright galaxies over ~160 deg2 in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), which is covered by high-quality ancillary data including Herschel [Cπ] 158 μm spectroscopy and far-infrared (FIR) photometry. The [Cπ] and CO(1-0) lines are both detected at >5σ in 26 sources. We find an average [Cπ] to CO(1-0) luminosity ratio of 3500 ± 1200 for our sample that is consistent with previous studies. Using the [Cπ], CO(1-0) and FIR measurements as diagnostics of the physical conditions of the interstellar medium, we compare these observations to the predictions of a photodissociation region (PDR) model to determine the gas density, surface temperature, pressure, and the strength of the incident far-ultraviolet (FUV) radiation field, G0, normalised to the Habing Field. The majority of our sample exhibit hydrogen densities of 4 < log n=cm³ < 5:5 and experience an incident FUV radiation field with strengths of 2 < logG0 < 3 when adopting standard adjustments. A comparison to galaxy samples at different redshifts indicates that the average strength of the FUV radiation field appears constant up to redshift z ~ 6:4, yet the neutral gas density increases as a function of redshift by a factor of ~100 from z = 0 to z = 0:2 that persists regardless of various adjustments to our observable quantities. Whilst this evolution could provide an explanation for the observed evolution of the star formation rate density with cosmic time, the result most likely arises from a combination of observational biases when using different suites of emission lines as diagnostic tracers of PDR gas. [ABSTRACT FROM AUTHOR]

This paper is the second in a pair of papers presenting data release 1 (DR1) of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), the largest single open-time key project carried out with the Herschel Space Observatory. The H-ATLAS is a wide-area imaging survey carried out in five photometric bands at 100, 160, 250, 350 and 500 µm covering a total area of 600 deg². In this paper, we describe the identification of optical counterparts to submillimetre sources in DR1, comprising an area of 161 deg² over three equatorial fields of roughly 12 × 4.5 deg centred at 9h, 12h and 14. h 5, respectively. Of all the H-ATLAS fields, the equatorial regions benefit from the greatest overlap with current multiwavelength surveys spanning ultraviolet (UV) to mid-infrared regimes, as well as extensive spectroscopic coverage. We use a likelihood ratio technique to identify Sloan Digital Sky Survey counterparts at r < 22.4 for 250-μm-selected sources detected at ≥4σ (28 mJy). We find 'reliable' counterparts (reliability R ≥ 0.8) for 44 835 sources (39 per cent), with an estimated completeness of 73.0 per cent and contamination rate of 4.7 per cent. Using redshifts and multi-wavelength photometry from GAMA and other public catalogues, we show that H-ATLAS-selected galaxies at z < 0.5 span a wide range of optical colours, total infrared (IR) luminosities and IR/UV ratios, with no strong disposition towards mid-IR-classified active galactic nuclei in comparison with optical selection. The data described herein, together with all maps and catalogues described in the companion paper, are available from the H-ATLAS website at www.h-atlas.org. [ABSTRACT FROM AUTHOR]

We describe a far-infrared survey of the Coma cluster and the galaxy filament it resides within. Our survey covers an area of ~150 deg² observed by Herschel H-ATLAS (Herschel Astrophysical Terahertz Large Area Survey) in five bands at 100, 160, 250, 350 and 500 μm. The SDSS spectroscopic survey (mr ≤ 17.8) is used to define an area (within the virial radius) and redshift selected (4268 < v < 9700 km s-1) sample of 744 Coma cluster galaxies - the Coma Cluster Catalogue. For comparison, we also define a sample of 951 galaxies in the connecting filament - the Coma Filament Catalogue. The optical positions and parameters are used to define appropriate apertures to measure each galaxy's far-infrared emission. We have detected 99 of 744 (13 per cent) and 422 of 951 (44 per cent) of the cluster and filament galaxies in the SPIRE 250 μm band. We consider the relative detection rates of galaxies of different morphological types finding that it is only the S0/Sa population that shows clear differences between the cluster and filament. We find no differences between the dust masses and temperatures of cluster and filament galaxies with the exception of early-type galaxy dust temperatures, which are significantly hotter in the cluster than in the filament (X-ray heating?). From a chemical evolution model, we find no evidence for different evolutionary processes (gas loss or infall) between galaxies in the cluster and filament. [ABSTRACT FROM AUTHOR]

We use 10 387 galaxies from the Herschel Astrophysical TeraHertz Large Area Survey (H-ATLAS) to probe the far-infrared radio correlation (FIRC) of star-forming galaxies as a function of redshift, wavelength, and effective dust temperature. All of the sources in our 250 μm-selected sample have spectroscopic redshifts, as well as 1.4 GHz flux density estimates measured from the Faint Images of the Radio Sky at Twenty centimetres (FIRST) survey. This enables us to study not only individual sources, but also the average properties of the 250 μm-selected population using median stacking techniques. We find that individual sources detected at ≥5σ in both the H-ATLAS and FIRST data have logarithmic flux ratios (i.e. FIRC qλ parameters) consistent with previous studies of the FIRC. In contrast, the stacked values show larger qλ, suggesting excess far-IR flux density/luminosity in 250 μm-selected sources above what has been seen in previous analyses. In addition, we find evidence that 250 μm sources with warm dust spectral energy distributions have a larger 1.4 GHz luminosity than the cooler sources in our sample. Though we find no evidence for redshift evolution of the monochromatic FIRC, our analysis reveals significant temperature dependence. Whilst the FIRC is reasonably constant with temperature at 100 μm, we find increasing inverse correlation with temperature as we probe longer PACS and SPIRE wavelengths. These results may have important implications for the use of monochromatic dust luminosity as a star formation rate indicator in star-forming galaxies, and in the future, for using radio data to determine galaxy star formation rates. [ABSTRACT FROM AUTHOR]