AKARI and IRAS: From beam corrections to SEDs

There is significant scientific value to be gained from combining AKARI fluxes with data at other far-infrared (IR) wavelengths from the Infrared Astronomical Satellite (IRAS) and Herschel missions. To be able to do this we must ensure that there are no systematic differences between the data sets that need to be corrected before the fluxes are compatible with each other. One such systematic effect identified in the Bright Source Catalog version 1 (BSCv1) data is the issue of beam corrections. We determine these for the BSC version 2 (BSCv2) data by correlating ratios of appropriate IRAS and AKARI bands with the difference in 2 Micron All Sky Survey (2MASS) J-band extended and point source magnitudes for sources cross-matched between the IRAS Faint Source Catalog (FSC), AKARI BSCv2 and 2MASS catalogs. We find significant correlations (p ≪ 10 −13) indicating that beam corrections are necessary in the 65 and 90 μm bands. We then use these corrected fluxes to supplement existing data in spectral energy distribution (SED) fits for ultraluminous infrared galaxies (ULIRGs) in the Herschel ULIRG Survey (HERUS). The addition of AKARI fluxes makes little difference to the results of simple (T, β) fits to the SEDs of these sources, though there is a general decrease in reduced χ2 values. The utility of the extra AKARI data, however, is in allowing physically more realistic SED models with more parameters to be fitted to the data. We also extend our analysis of beam correction issues in the AKARI data by examining the Herschel Reference Sample (HRS) galaxies, which have Herschel photometry from 100 to 500 μm and which are more spatially extended than the HERUS ULIRGs. 34 of the HRS sources have good Herschel SEDs and matching data from AKARI. This investigation finds that our simple 2MASS-based beam correction scheme is inadequate for these larger and more complex sources. There are also indications that additional beam corrections at 140 and 160 μm are needed for these sources, extended on scales >1′

Rise of the titans: a dusty, hyper-luminous “870 µm riser” galaxy at z~6

We report the detection of ADFS-27, a dusty, starbursting major merger at a redshift of z=5.655, using the Atacama Large Millimeter/submillimeter Array (ALMA). ADFS-27 was selected from Herschel/SPIRE and APEX/LABOCA data as an extremely red “870 m riser” (i.e., S250m<S350m<S500m<S870m), demonstrating the utility of this technique to identify some of the highest-redshift dusty galaxies. A scan of the 3mm atmospheric window with ALMA yields detections of CO(J=54) and CO(J=65) emission, and a tentative detection of H2O(211202) emission, which provides an unambiguous redshift measurement. The strength of the CO lines implies a large molecular gas reservoir with a mass of Mgas=2.51011 (CO=0:8) (0:39=r51)M, sufficient to maintain its 2400M yr1 starburst for at least 100 Myr. The 870 m dust continuum emission is resolved into two components, 1.8 and 2.1 kpc in diameter, separated by 9.0 kpc, with comparable dust luminosities, suggesting an ongoing major merger. The infrared luminosity of LIR'2.41013 L implies that this system represents a binary hyper-luminous infrared galaxy, the most distant of its kind presently known. This also implies star formation rate surface densities of SFR=730 and 750M yr1 kpc2, consistent with a binary “maximum starburst”. The discovery of this rare system is consistent with a significantly higher space density than previously thought for the most luminous dusty starbursts within the first billion years of cosmic time, easing tensions regarding the space densities of z6 quasars and massive quiescent galaxies at z&3

Exploring Cosmic Origins with CORE: Cosmological Parameters

We forecast the main cosmological parameter constraints achievable with theCORE space mission which is dedicated to mapping the polarisation of the CosmicMicrowave Background (CMB). CORE was recently submitted in response to ESA'sfifth call for medium-sized mission proposals (M5). Here we report the resultsfrom our pre-submission study of the impact of various instrumental options, inparticular the telescope size and sensitivity level, and review the great,transformative potential of the mission as proposed. Specifically, we assessthe impact on a broad range of fundamental parameters of our Universe as afunction of the expected CMB characteristics, with other papers in the seriesfocusing on controlling astrophysical and instrumental residual systematics. Inthis paper, we assume that only a few central CORE frequency channels areusable for our purpose, all others being devoted to the cleaning ofastrophysical contaminants. On the theoretical side, we assume LCDM as ourgeneral framework and quantify the improvement provided by CORE over thecurrent constraints from the Planck 2015 release. We also study the jointsensitivity of CORE and of future Baryon Acoustic Oscillation and Large ScaleStructure experiments like DESI and Euclid. Specific constraints on the physicsof inflation are presented in another paper of the series. In addition to thesix parameters of the base LCDM, which describe the matter content of aspatially flat universe with adiabatic and scalar primordial fluctuations frominflation, we derive the precision achievable on parameters like thosedescribing curvature, neutrino physics, extra light relics, primordial heliumabundance, dark matter annihilation, recombination physics, variation offundamental constants, dark energy, modified gravity, reionization and cosmicbirefringence. (ABRIDGED

Dusty Galaxies at the Highest Redshifts

The use of red colour as the basis for selecting candidate high redshift dusty galaxies from surveys made with Herschel has proved highly successful. The highest redshift such object, HFLS3, lies at z = 6.34 and numerous other sources have been found. Spectroscopic followup confirms that most of these lie at z > 4. These sources are found in such numbers that they represent a challenge to current models of galaxy evolution. We also examine the prospects for finding dusty galaxies at still higher redshifts. These would not appear in the SPIRE surveys from Herschel but would be detected in longer wavelength, submm, surveys. Several such 'SPIRE-dropouts' have been found and are now subject to followup observations

SCUBA-2 Ultra Deep Imaging EAO Survey (Studies). III. Multiwavelength Properties, Luminosity Functions, and Preliminary Source Catalog of 450 μm Selected Galaxies

We construct a SCUBA-2 450 μm map in the COSMOS field that covers an area of 300 arcmin2 and reaches a 1σ noise level of 0.65 mJy in the deepest region. We extract 256 sources detected at 450 μm with signal-to-noise ratios >4.0 and analyze the physical properties of their multiwavelength counterparts. We find that most of the sources are at z lesssim 3, with a median of $z={1.79}_{-0.15}^{+0.03} \%$. About ${35}_{-25}^{+32} \%$ of our sources are classified as starburst galaxies based on their total star formation rates (SFRs) and stellar masses (M *). By fitting the far-infrared spectral energy distributions, we find that our 450 μm selected sample has a wide range of dust temperatures (20 K lesssim T d lesssim 60 K), with a median of ${T}_{{\rm{d}}}={38.3}_{-0.9}^{+0.4}$ K. We do not find a redshift evolution in dust temperature for sources with ${L}_{\mathrm{IR}}\gt {10}^{12}\,{L}_{\odot }$ at z < 3. However, we find a moderate correlation where the dust temperature increases with the deviation from the SFR–M * relation. The increase in dust temperature also correlates with optical morphology, which is consistent with merger-triggered starbursts in submillimeter galaxies. Our galaxies do not show the tight IRX–β UV correlation that has been observed in the local universe. We construct the infrared luminosity functions of our 450 μm sources and measure their comoving SFR densities (SFRDs). The contribution of the ${L}_{\mathrm{IR}}\gt {10}^{12}\,{L}_{\odot }$ population to the SFRD rises dramatically from z = 0 to 2 (∝(1 + z)3.9±1.1) and dominates the total SFRD at z gsim 2

STUDIES. III. SCUBA-2 450um gal. with MIPS &amp; VLA obs.

VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). III. Multiwavelength properties, luminosity functions, and preliminary source catalog of 450 {mu}m selected galaxies.' (bibcode: 2020ApJ...889...80L