Herschel*-ATLAS: correlations between dust and gas in local submm-selected galaxies

We present an analysis of CO molecular gas tracers in a sample of 500 μ m-selected Herschel -ATLAS galaxies at z < 0 . 05 ( cz < 14990 km s − 1 ). Using 22 − 500 μ m photom- etry from WISE , IRAS and Herschel , with H i 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 FIR–submm fl uxes weakens with increasing IR wavelength ( λ & 60 μ m), as a result of colder dust being less strongly associated with dense gas. Conversely, CO(2–1) and H i line fluxes both ap- pear to be better correlated with longer wavelengths, suggesting that cold dust is more strongly associated with diffuse atomic and molecular gas phases, co nsistent with it being at least partially heated by radiation from old stellar populations . The increased scatter at long wavelengths implies that sub-millimetre fluxes are a po orer tracer of SFR. Fluxes at 22 and 60 μ m are also better correlated with diffuse gas tracers than dense CO(3–2), probably due to very-small-grain emission in the diffu se interstellar medium, which is not correlated with SFR. The FIR/CO luminosity ratio a nd the dust mass/CO luminosity ratio both decrease with increasing luminosit y, 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)].Web of Scienc

Home as a Site of State-Corporate Violence: Grenfell Tower, Aetiologies and Aftermaths

Focusing on the aftermaths and consequences of the Grenfell Tower fire, this article reveals the factors which combined to produce a fire that could have such devastating effects. Further, it delineates the discrete ways in which distinct types of harms – physical, emotional and psychological, cultural and relational, and financial and economic – continue to be produced by a combination of State and corporate acts and omissions. Some of these harms are readily apparent, others are opaque and obscured. It concludes by showing how failures to mitigate these factors constitute one manifestation of the more general phenomenon of ‘social murder’

The SCUBA-2 Cosmology Legacy Survey: galaxies in the deep 850 μm survey, and the star-forming `main sequence'

Galaxie

AzTEC half square degree survey of the SHADES fields - II. Identifications, redshifts, and evidence for large-scale structure

The AzTEC 1.1mm survey of the two SCUBA HAlf Degree Extragalactic Survey (SHADES) fields is the largest (0.7 deg2) blank-field millimetre-wavelength survey un- dertaken to date at a resolution of ≃ 18 arcsec and a depth of ≃ 1mJy. We have used the deep optical-to-radio multi-wavelength data in the SHADES Lockman Hole East and SXDF/UDS fields to obtain galaxy identifications for ≃ 64% (≃ 80% includ- ing tentative identifications) of the 148 AzTEC-SHADES 1.1mm sources reported by Austermann et al. (2010), exploiting deep radio and 24 μm data complemented by methods based on 8 μm flux-density and red optical-infrared (i − K) colour. This unusually high identification rate can be attributed to the relatively bright millimetre- wavelength flux-density threshold, combined with the relatively deep supporting multi- frequency data now available in these two well-studied fields.We have further exploited the optical–mid-infrared–radio data to derive a ≃ 60% (≃ 75% including tentative identifications) complete redshift distribution for the AzTEC-SHADES sources, yield- ing a median redshift of z ≃ 2.2, with a high-redshift tail extending to at least z ≃ 4. Despite the larger area probed by the AzTEC survey relative to the original SCUBA SHADES imaging, the redshift distribution of the AzTEC sources is consistent with that displayed by the SCUBA sources, and reinforces tentative evidence that the red- shift distribution of mm/sub-mm sources in the Lockman Hole field is significantly different from that found in the SXDF/UDS field. Comparison with simulated sur- veys of similar scale extracted from semi-analytic models based on the Millennium simulation indicates that this is as expected if the mm/sub-mm sources are massive (M > 1011M⊙) star-forming galaxies tracing large-scale structures over scales of 10– 20Mpc. This confirms the importance of surveys covering several square degrees (as now underway with SCUBA2) to obtain representative samples of bright (sub)mm- selected galaxies. This work provides a foundation for the further exploitation of the Spitzer and Herschel data in the SHADES fields in the study of the stellar masses and specific star-formation rates of the most active star-forming galaxies in cosmic history.

The SCUBA-2 Cosmology Legacy Survey: ALMA Resolves the Rest-frame Far-infrared Emission of Sub-millimeter Galaxies

We present high-resolution (0.''3) Atacama Large Millimeter Array 870 μm imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey field to investigate the size and morphology of the sub-millimeter (sub-mm) emission on 2-10 kpc scales. We derive a median intrinsic angular size of FWHM = 0.''30 ± 0.''04 for the 23 SMGs in the sample detected at a signal-to-noise ratio (S/N) >10. Using the photometric redshifts of the SMGs we show that this corresponds to a median physical half-light diameter of 2.4 ± 0.2 kpc. A stacking analysis of the SMGs detected at S/N <10 shows they have sizes consistent with the 870 μm bright SMGs in the sample. We compare our results to the sizes of SMGs derived from other multi-wavelength studies, and show that the rest-frame ~250 μm sizes of SMGs are consistent with studies of resolved 12CO (J = 3-2 to 7-6) emission lines, but that sizes derived from 1.4 GHz imaging appear to be approximately two times larger on average, which we attribute to cosmic ray diffusion. The rest-frame optical sizes of SMGs are around four times larger than the sub-millimeter sizes, indicating that the star formation in these galaxies is compact relative to the pre-existing stellar distribution. The size of the starburst region in SMGs is consistent with the majority of the star formation occurring in a central region, a few kiloparsecs in extent, with a median star formation rate surface density of 90 ± 30 M ☉ yr–1 kpc–2, which may suggest that we are witnessing an intense period of bulge growth in these galaxies