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We present new Atacama Large Millimeter/Submillimeter Array (ALMA) 850 μm continuum observations of the original Lyα Blob (LAB) in the SSA22 field at z = 3.1 (SSA22-LAB01). The ALMA map resolves the previously identified submillimeter source into three components with a total flux density of S 850 = 1.68 ± 0.06 mJy, corresponding to a star-formation rate of ~150 M ⊙ yr−1. The submillimeter sources are associated with several faint (m ≈ 27 mag) rest-frame ultraviolet sources identified in Hubble Space Telescope Imaging Spectrograph (STIS) clear filter imaging (λ ≈ 5850 Å). One of these companions is spectroscopically confirmed with the Keck Multi-Object Spectrometer For Infra-Red Exploration to lie within 20 projected kpc and 250 km s−1 of one of the ALMA components. We postulate that some of these STIS sources represent a population of low-mass star-forming satellites surrounding the central submillimeter sources, potentially contributing to their growth and activity through accretion. Using a high-resolution cosmological zoom simulation of a 1013 M ⊙ halo at z = 3, including stellar, dust, and Lyα radiative transfer, we can model the ALMA+STIS observations and demonstrate that Lyα photons escaping from the central submillimeter sources are expected to resonantly scatter in neutral hydrogen, the majority of which is predicted to be associated with halo substructure. We show how this process gives rise to extended Lyα emission with similar surface brightness and morphology to observed giant LABs.

We present new results on the cosmic star formation history in the Subaru/XMM–Newton Deep Survey (SXDS)–Ultra Deep Survey (UDS) field out to z = 1.6. We compile narrowband\ud data from the Subaru Telescope and the Visible and Infrared Survey Telescope for Astronomy (VISTA) in conjunction with broad-band data from the SXDS and UDS, to make a selection of 5725 emission-line galaxies in 12 redshift slices, spanning 10 Gyr of cosmic time. We determine photometric redshifts for the sample using 11-band photometry, and use\ud a spectroscopically confirmed subset to fine tune the resultant redshift distribution. We use the maximum-likelihood technique to determine luminosity functions in each redshift slice and model the selection effects inherent in any narrow-band selection statistically, to obviate the retrospective corrections ordinarily required. The deep narrow-band data are sensitive to very low star formation rates (SFRs), and allow an accurate evaluation of the faint end slope of the Schechter function, α. We find that α is particularly sensitive to the assumed faintest\ud broad-band magnitude of a galaxy capable of hosting an emission line, and propose that this limit should be empirically motivated. For this analysis, we base our threshold on the limiting observed equivalent widths of emission lines in the local Universe. We compute the\ud characteristic SFR of galaxies in each redshift slice, and the integrated SFR density, ρSFR. We find our results to be in good agreement with the literature and parametrize the evolution of the SFR density as ρSFR ∝ (1 + z)4.58 confirming a steep decline in star formation activity since z ∼ 1.6.\ud \ud Keywords: surveys – galaxies: evolution – galaxies: formation – galaxies: high-redshift –\ud galaxies: star formation – cosmology: observations.

We present a pan-chromatic analysis of an unprecedented sample of 1402 250 μm selected galaxies at z < 0.5 (z-=0.24) from the Herschel-ATLAS survey. We complement our Herschel 100-500μm data with UV-K-band photometry from the Galaxy And Mass Assembly (GAMA) survey and apply the magphys energy-balance technique to produce pan-chromatic spectral energy distributions (SEDs) for a representative sample of 250μm selected galaxies spanning the most recent 5 Gyr of cosmic history. We derive estimates of physical parameters, including star formation rates, stellar masses, dust masses and infrared (IR) luminosities. The typical H-ATLAS galaxy at z < 0.5 has a far-infrared luminosity in the range 10 10-10 12L ⊙ (SFR: 1-50 M ⊙yr -1) and thus is broadly representative of normal star-forming galaxies over this redshift range. We show that 250μm selected galaxies contain a larger mass of dust at a given IR luminosity or star formation rate than previous samples selected at 60μm from the IRAS. We derive typical SEDs for H-ATLAS galaxies, and show that the emergent SED shape is most sensitive to specific star formation rate. The optical-UV SEDs also become more reddened due to dust at higher redshifts. Our template SEDs are significantly cooler than existing IR templates. They may therefore be most appropriate for inferring total IR luminosities from moderate redshift sub-millimetre selected samples and for inclusion in models of the lower redshift sub-millimetre galaxy populations. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

We have used data from the Herschel-ATLAS at 250, 350 and 500 ��m to determine the far-infrared (FIR) properties of 50 Broad Absorption Line Quasars (BAL QSOs). Our sample contains 49 high-ionization BAL QSOs (HiBALs) and 1 low-ionization BAL QSO (LoBAL) which are compared against a sample of 329 non-BAL QSOs. These samples are matched over the redshift range 1.5 \leq z < 2.3 and in absolute i-band magnitude over the range -28 \leq M_{i} \leq -24. Of these, 3 BAL QSOs (HiBALs) and 27 non-BAL QSOs are detected at the > 5 sigma level. We calculate star-formation rates (SFR) for our individually detected HiBAL QSOs and the non-detected LoBAL QSO as well as average SFRs for the BAL and non-BAL QSO samples based on stacking the Herschel data. We find no difference between the HiBAL and non-BAL QSO samples in the FIR, even when separated based on differing BAL QSO classifications. Using Mrk 231 as a template, the weighted mean SFR is estimated to be \approx240\pm21 M_{\odot} yr^{-1} for the full sample, although this figure should be treated as an upper limit if AGN-heated dust makes a contribution to the FIR emission. Despite tentative claims in the literature, we do not find a dependence of {\sc C\,iv} equivalent width on FIR emission, suggesting that the strength of any outflow in these objects is not linked to their FIR output. These results strongly suggest that BAL QSOs (more specifically HiBALs) can be accommodated within a simple AGN unified scheme in which our line-of-sight to the nucleus intersects outflowing material. Models in which HiBALs are caught towards the end of a period of enhanced spheroid and black-hole growth, during which a wind terminates the star-formation activity, are not supported by the observed FIR properties., 11 pages, 4 figures, 4 tables. Accepted for publication in MNRAS

We present a pan-chromatic analysis of an unprecedented sample of 1402 250 mu m selected galaxies at z < 0.5 ( = 0.24) from the Herschel-ATLAS survey. We complement our Herschel 100-500 mu m data with UV-K-band photometry from the Galaxy And Mass Assembly (GAMA) survey and apply the magphys energy-balance technique to produce pan-chromatic spectral energy distributions (SEDs) for a representative sample of 250 mu m selected galaxies spanning the most recent 5 Gyr of cosmic history. We derive estimates of physical parameters, including star formation rates, stellar masses, dust masses and infrared (IR) luminosities. The typical H-ATLAS galaxy at z < 0.5 has a far-infrared luminosity in the range 10(10)-10(12) L-circle dot (SFR: 1-50 M-circle dot yr(-1)) and thus is broadly representative of normal star-forming galaxies over this redshift range. We show that 250 mu m selected galaxies contain a larger mass of dust at a given IR luminosity or star formation rate than previous samples selected at 60 mu m from the IRAS. We derive typical SEDs for H-ATLAS galaxies, and show that the emergent SED shape is most sensitive to specific star formation rate. The optical-UV SEDs also become more reddened due to dust at higher redshifts. Our template SEDs are significantly cooler than existing IR templates. They may therefore be most appropriate for inferring total IR luminosities from moderate redshift sub-millimetre selected samples and for inclusion in models of the lower redshift sub-millimetre galaxy populations.

We have measured the clustering properties of low-redshift (z < 0.3) submm galaxies detected at 250 mu m in the Herschel-ATLAS science demonstration phase field. We selected a sample for which we have high-quality spectroscopic redshifts, obtained from reliably matching the 250-mu m sources to a complete (for r < 19.4) sample of galaxies from the GAMA data base. Both the angular and spatial clustering strength are measured for all z < 0.3 sources as well as for five redshift slices with thickness Delta z = 0.05 in the range 0.05 < z < 0.3. Our measured spatial clustering length r(0) is comparable to that of optically selected, moderately star-forming (blue) galaxies: we find values around 5 Mpc. One of the redshift bins contains an interesting structure, at z = 0.164.

We measure the projected cross-correlation between low-redshift (z < 0.5) far-infrared selected galaxies in the science demonstration phase (SDP) field of the Herschel-ATLAS (H-ATLAS) survey and optically selected galaxies from the Galaxy and Mass Assembly (GAMA) redshift survey. In order to obtain robust correlation functions, we restrict the analysis to a subset of 969 out of 6900 H-ATLAS galaxies, which have reliable optical counterparts with r < 19.4 mag and well-determined spectroscopic redshifts. The overlap region between the two surveys is 12.6 deg2; the matched sample has a median redshift of z≈ 0.2. The cross-correlation of GAMA and H-ATLAS galaxies within this region can be fitted by a power law, with correlation length r0≈ 4.63 ± 0.51 Mpc. Comparing with the corresponding autocorrelation function of GAMA galaxies within the SDP field yields a relative bias (averaged over 2–8 Mpc) of H-ATLAS and GAMA galaxies of bH/bG≈ 0.6. Combined with clustering measurements from previous optical studies, this indicates that most of the low-redshift H-ATLAS sources are hosted by haloes with masses comparable to that of the Milky Way. The correlation function appears to depend on the 250-μm luminosity, L250, with bright (median luminosity νL250∼ 1.6 × 1010 L⊙) objects being somewhat more strongly clustered than faint (νL250∼ 4.0 × 109 L⊙) objects. This implies that galaxies with higher dust-obscured star formation rates are hosted by more massive haloes.

We present Herschel-SPIRE Fourier Transform Spectrometer (FTS) and radio follow-up observations of two Herschel-ATLAS (H-ATLAS) detected strongly lensed distant galaxies. In one of the targeted galaxies H-ATLAS J090311.6+003906 (SDP.81) we detect [OIII] 88\mum and [CII] 158\mum lines at a signal-to-noise ratio of ~5. We do not have any positive line identification in the other fainter target H-ATLAS J091305.0-005343 (SDP.130). Currently SDP.81 is the faintest sub-mm galaxy with positive line detections with the FTS, with continuum flux just below 200 mJy in the 200-600 \mum wavelength range. The derived redshift of SDP.81 from the two detections is z=3.043 +/-0.012, in agreement with ground-based CO measurements. This is the first detection by Herschel of the [OIII] 88\mum line in a galaxy at redshift higher than 0.05. Comparing the observed lines and line ratios with a grid of photo-dissociation region (PDR) models with different physical conditions, we derive the PDR cloud density n ~ 2000 cm^{-3} and the far-UV ionizing radiation field G_0 ~ 200 (in units of the Habing field -- the local Galactic interstellar radiation field of 1.6x10^{-6} W/m^2). Using the CO derived molecular mass and the PDR properties we estimate the effective radius of the emitting region to be 500-700 pc. These characteristics are typical for star-forming, high redshift galaxies. The radio observations indicate that SDP.81 deviates significantly from the local FIR/radio correlation, which hints that some fraction of the radio emission is coming from an AGN. The constraints on the source size from millimiter-wave observations put a very conservative upper limit of the possible AGN contribution to less than 33%. These indications, together with the high [OIII]/FIR ratio and the upper limit of [OI] 63\mum/[CII] 158\mum suggest that some fraction of the ionizing radiation is likely to originate from an AGN., Comment: 13 pages, 6 figures, published in MNRAS

We use the Herschel-ATLAS science demonstration data to investigate the star-formation properties of radio-selected galaxies in the GAMA-9h field as a function of radio luminosity and redshift. Radio selection at the lowest radio luminosities, as expected, selects mostly starburst galaxies. At higher radio luminosities, where the population is dominated by AGN, we find that some individual objects are associated with high far-infrared luminosities. However, the far-infrared properties of the radio-loud population are statistically indistinguishable from those of a comparison population of radio-quiet galaxies matched in redshift and K-band absolute magnitude. There is thus no evidence that the host galaxies of these largely low-luminosity (Fanaroff-Riley class I), and presumably low-excitation, AGN, as a population, have particularly unusual star-formation histories. Models in which the AGN activity in higher-luminosity, high-excitation radio galaxies is triggered by major mergers would predict a luminosity-dependent effect that is not seen in our data (which only span a limited range in radio luminosity) but which may well be detectable with the full Herschel-ATLAS dataset., 10 pages, 4 colour figures. Accepted for publication in MNRAS (Herschel special issue)

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. © ESO, 2010.

To investigate the poorly constrained sub-mm counts and spectral properties of blazars we searched for these in the Herschel-ATLAS (H-ATLAS) science demostration phase (SDP) survey catalog. We cross-matched 500$\mu$m sources brighter than 50 mJy with the FIRST radio catalogue. We found two blazars, both previously known. Our study is among the first blind blazar searches at sub-mm wavelengths, i.e., in the spectral regime where little is still known about the blazar SEDs, but where the synchrotron peak of the most luminous blazars is expected to occur. Our early results are consistent with educated extrapolations of lower frequency counts and question indications of substantial spectral curvature downwards and of spectral upturns at mm wavelengths. One of the two blazars is identified with a Fermi/LAT $\gamma$-ray source and a WMAP source. The physical parameters of the two blazars are briefly discussed.These observations demonstrate that the H-ATLAS survey will provide key information about the physics of blazars and their contribution to sub-mm counts., Comment: 5 pages, 2 figures, accepted for publication in A&A (Herschel special issue)

We report here on the discovery of a red quasar, J004929.4+351025.7 at a redshift of z = 2.48, situated within a large Lya emission-line halo. The radio spectral energy distribution implies that the radio jets were triggered < 10^4 years prior to the time at which the object is observed, suggesting that the jet triggering of the active galactic nucleus is recent. The loosely biconical structure of the emission-line halo suggests that it is ionised by photons emitted by the central quasar nucleus and that the central nucleus is obscured by a dusty torus with Av ~ 3.0. The large spatial extent of the Lya halo relative to the radio emission means this could only have occurred if the radio jets emerged from an already established highly-accreting black hole. This suggests that the radio-jet triggering is delayed with respect to the onset of accretion activity on to the central supermassive black hole., 9 pages, 5 figures; accepted for publication in MNRAS