Publications
672 results found
Sufian AT, Abdullah BM, Ateeq M, et al., 2019, A Roadmap Towards the Smart Factory, 12th International Conference on the Developments in eSystems Engineering (DeSE), Publisher: IEEE, Pages: 978-983, ISSN: 2161-1343
- Author Web Link
- Cite
- Citations: 7
Egami E, Gallerani S, Schneider R, et al., 2018, Probing the high-redshift universe with SPICA: Toward the epoch of reionisation and beyond, Publications of the Astronomical Society of Australia, Vol: 35, Pages: 1-19, ISSN: 1323-3580
With the recent discovery of a dozen dusty star-forming galaxies and around 30 quasars at z > 5 that are hyper-luminous in the infrared (μ LIR > 1013 L⊙, where μ is a lensing magnification factor), the possibility has opened up for SPICA, the proposed ESA M5 mid-/far-infrared mission, to extend its spectroscopic studies toward the epoch of reionisation and beyond. In this paper, we examine the feasibility and scientific potential of such observations with SPICA’s far-infrared spectrometer SAFARI, which will probe a spectral range (35–230 μm) that will be unexplored by ALMA and JWST. Our simulations show that SAFARI is capable of delivering good-quality spectra for hyper-luminous infrared galaxies at z = 5 − 10, allowing us to sample spectral features in the rest-frame mid-infrared and to investigate a host of key scientific issues, such as the relative importance of star formation versus AGN, the hardness of the radiation field, the level of chemical enrichment, and the properties of the molecular gas. From a broader perspective, SAFARI offers the potential to open up a new frontier in the study of the early Universe, providing access to uniquely powerful spectral features for probing first-generation objects, such as the key cooling lines of low-metallicity or metal-free forming galaxies (fine-structure and H2 lines) and emission features of solid compounds freshly synthesised by Population III supernovae. Ultimately, SAFARI’s ability to explore the high-redshift Universe will be determined by the availability of sufficiently bright targets (whether intrinsically luminous or gravitationally lensed). With its launch expected around 2030, SPICA is ideally positioned to take full advantage of upcoming wide-field surveys such as LSST, SKA, Euclid, and WFIRST, which are likely to provide extraordinary targets for SAFARI.
Saintonge A, Wilson CD, Xiao T, et al., 2018, JINGLE, a JCMT legacy survey of dust and gas for galaxy evolution studies - I. Survey overview and first results, Monthly Notices of the Royal Astronomical Society, Vol: 481, Pages: 3497-3519, ISSN: 0035-8711
JINGLE is a new JCMT legacy survey designed to systematically study the cold interstellar medium of galaxies in the local Universe. As part of the survey we perform 850 µm continuum measurements with SCUBA-2 for a representative sample of 193 Herschel-selected galaxies with M* > 109 M⊙, as well as integrated CO(2–1) line fluxes with RxA3m for a subset of 90 of these galaxies. The sample is selected from fields covered by the Herschel-ATLAS survey that are also targeted by the MaNGA optical integral-field spectroscopic survey. The new JCMT observations combined with the multiwavelength ancillary data will allow for the robust characterization of the properties of dust in the nearby Universe, and the benchmarking of scaling relations between dust, gas, and global galaxy properties. In this paper we give an overview of the survey objectives and details about the sample selection and JCMT observations, present a consistent 30-band UV-to-FIR photometric catalogue with derived properties, and introduce the JINGLE Main Data Release. Science highlights include the non-linearity of the relation between 850 µm luminosity and CO line luminosity (log LCO(2–1) = 1.372 logL850–1.376), and the serendipitous discovery of candidate z > 6 galaxies.
Rowan-Robinson M, Wang L, Farrah D, et al., 2018, Extreme submillimetre starburst galaxies, Astronomy and Astrophysics, Vol: 619, ISSN: 0004-6361
We have used two catalogues, a Herschel catalogue selected at 500 μm (HerMES) and an IRAS catalogue selected at 60 μm (RIFSCz), to contrast the sky at these two wavelengths. Both surveys demonstrate the existence of “extreme” starbursts, with star-formation rates (SFRs) > 5000 M⊙ yr−1. The maximum intrinsic star-formation rate appears to be ~30 000 M⊙ yr−1. The sources with apparent SFR estimates higher than this are in all cases either lensed systems, blazars, or erroneous photometric redshifts. At redshifts between three and five, the time-scale for the Herschel galaxies to make their current mass of stars at their present rate of star formation is ~108 yr, so these galaxies are making a significant fraction of their stars in the current star-formation episode. Using dust mass as a proxy for gas mass, the Herschel galaxies at redshift three to five have gas masses comparable to their mass in stars. Of the 38 extreme starbursts in our Herschel survey for which we have more complete spectral energy distribution (SED) information, 50% show evidence for QSO-like optical emission, or exhibit AGN dust tori in the mid-infrared SEDs. In all cases however the infrared luminosity is dominated by a starburst component. We derive a mean covering factor for AGN dust as a function of redshift and derive black hole masses and black hole accretion rates. There is a universal ratio of black-hole mass to stellar mass in these high redshift systems of ~10−3, driven by the strong period of star-formation and black-hole growth at z = 1−5.
Eales SA, Baes M, Bourne N, et al., 2018, The causes of the red sequence, the blue cloud, the green valley, and the green mountain, Monthly Notices of the Royal Astronomical Society, Vol: 481, Pages: 1183-1194, ISSN: 0035-8711
The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a ‘green mountain’. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause of the red sequence and the blue cloud is the geometric mapping between stellar mass/specific star formation rate and absolute magnitude/colour, which distorts a continuous Galaxy Sequence in the diagram of intrinsic properties into a bimodal distribution in the diagram of observed properties. The cause of the green mountain is Malmquist bias in the submillimetre waveband, with submillimetre surveys tending to select galaxies on the curve of the Galaxy Sequence, which have the highest ratios of submillimetre-to-optical luminosity. This effect, working in reverse, causes galaxies on the curve of the Galaxy Sequence to be underrepresented in optical samples, deepening the green valley. The green valley is therefore not evidence (1) for there being two distinct populations of galaxies, (2) for galaxies in this region evolving more quickly than galaxies in the blue cloud and the red sequence, and (3) for rapid-quenching processes in the galaxy population.
Mattila S, Pérez-Torres M, Efstathiou A, et al., 2018, A dust-enshrouded tidal disruption event with a resolved radio jet in a galaxy merger, Science, Vol: 361, Pages: 482-485, ISSN: 0036-8075
Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 1052 erg in the infrared and radio but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.
Lewis AJR, Ivison RJ, Best PN, et al., 2018, Ultra-red Galaxies Signpost Candidate Protoclusters at High Redshift, Astrophysical Journal, Vol: 862, ISSN: 0004-637X
We present images obtained with LABOCA of a sample of 22 galaxies selected via their red Herschel SPIRE colors. We aim to see if these luminous, rare, and distant galaxies are signposting dense regions in the early universe. Our 870 μm survey covers an area of ≈1 deg2 down to an average rms of $3.9\,\mathrm{mJy}\,{\mathrm{beam}}^{-1}$, with our five deepest maps going ≈2× deeper still. We catalog 86 dusty star-forming galaxies (DSFGs) around our "signposts," detected above a significance of 3.5σ. This implies a ${100}_{-30}^{+30} \% $ overdensity of ${S}_{870}\gt 8.5\,\mathrm{mJy}$ (or ${L}_{\mathrm{FIR}}=6.7\times {10}^{12}\mbox{--}2.9\times {10}^{13}\,{L}_{\odot }$) DSFGs, excluding our signposts, when comparing our number counts to those in "blank fields." Thus, we are 99.93% confident that our signposts are pinpointing overdense regions in the universe, and ≈95% [50%] confident that these regions are overdense by a factor of at least ≥1.5 × [2×]. Using template spectral energy distributions (SEDs) and SPIRE/LABOCA photometry, we derive a median photometric redshift of z = 3.2 ± 0.2 for our signposts, with an inter-quartile range of z = 2.8–3.6, somewhat higher than expected for ~850 μm selected galaxies. We constrain the DSFGs that are likely responsible for this overdensity to within $| {\rm{\Delta }}z| \leqslant 0.65$ of their respective signposts. These "associated" DSFGs are radially distributed within (physical) distances of 1.6 ± 0.5 Mpc from their signposts, have median star formation rates (SFRs) of $\approx (1.0\pm 0.2)\times {10}^{3}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ (for a Salpeter stellar inital mass function) and median gas reservoirs of $\sim 1.7\times {10}^{11}\,{M}_{\odot }$. These candidate protoclusters have average total SFRs of at least $\approx (2.3\pm 0.5)\times {10}^{3}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ and space densities of ~9 × 1
Duivenvoorden S, Oliver S, Scudder JM, et al., 2018, Red, redder, reddest: SCUBA-2 imaging of colour-selected Herschel sources, Monthly Notices of the Royal Astronomical Society, Vol: 477, Pages: 1099-1119, ISSN: 0035-8711
High-redshift, luminous, dusty star-forming galaxies (DSFGs) constrain the extremity of galaxy formation theories. The most extreme are discovered through follow-up on candidates in large area surveys. Here, we present extensive 850μm SCUBA-2 follow-up observations of 188 red DSFG candidates from the Herschel Multitiered Extragalactic Survey (HerMES) Large Mode Survey, covering 274 deg2. We detected 87 per cent with a signal-to-noise ratio >3 at 850μm. We introduce a new method for incorporating the confusion noise in our spectral energy distribution fitting by sampling correlated flux density fluctuations from a confusion limited map. The new 850μm data provide a better constraint on the photometric redshifts of the candidates, with photometric redshift errors decreasing from σz/(1 + z) ≈ 0.21 to 0.15. Comparison spectroscopic redshifts also found little bias (〈(z − zspec)/(1 + zspec)〉 = 0.08). The mean photometric redshift is found to be 3.6 with a dispersion of 0.4 and we identify 21 DSFGs with a high probability of lying at z > 4. After simulating our selection effects we find number counts are consistent with phenomenological galaxy evolution models. There is a statistically significant excess of WISE-1 and SDSS sources near our red galaxies, giving a strong indication that lensing may explain some of the apparently extreme objects. Nevertheless, our sample includes examples of galaxies with the highest star formation rates in the Universe (≫103 M⊙ yr−1)
Clements DL, 2018, Life before Fermi - Back to the solar system, ISSN: 0007-084X
The existence of intelligent, interstellar traveling and colonising life is a key assumption behind the Fermi Paradox. Until recently, Detecting signs of life elsewhere has been so technically challenging as to seem almost impossible. However, new observational insights and otherDevelopments mean that signs of life elsewhere might realistically be uncovered in the nextDecade or two. We here review what are believed to be the basic requirements for life, the history of life on Earth, and then apply this knowledge to potential sites for life in our own Solar System. We conclude that the necessities of life - liquid water and sources of energy - are in fact quite common in the Solar System, but most potential sites are beneath the icy surfaces of gas giant moons. If this is the case elsewhere in the Galaxy, life may be quite common but, even if intelligence develops, is essentially sealed in a finite environment, unable to communicate with the outside world.
Greenslade J, Clements DL, Cheng T, et al., 2018, Candidate high-z protoclusters among the Planck compact sources, as revealed by Herschel-SPIRE, Monthly Notices of the Royal Astronomical Society, Vol: 476, Pages: 3336-3359, ISSN: 0035-8711
By determining the nature of all the Planck compact sources within 808.4 deg2 of large Herschel surveys, we have identified 27 candidate protoclusters of dusty star-forming galaxies (DSFGs) that are at least 3σ overdense in either 250, 350, or 500μm sources. We find roughly half of all the Planck compact sources are resolved by Herschel into multiple discrete objects, with the other half remaining unresolved by Herschel. We find a significant difference between versions of the Planck catalogues, with earlier releases hosting a larger fraction of candidate protoclusters and Galactic cirrus than later releases, which we ascribe to a difference in the filters used in the creation of the three catalogues. We find a surface density of DSFG candidate protoclusters of (3.3 ± 0.7) × 10−2 sources deg−2, in good agreement with previous similar studies. We find that a Planck colour selection of S857/S545 < 2 works well to select candidate protoclusters, but can miss protoclusters at z < 2. The Herschel colours of individual candidate protocluster members indicate our candidate protoclusters all likely all lie at z > 1. Our candidate protoclusters are a factor of 5 times brighter at 353 GHz than expected from simulations, even in the most conservative estimates. Further observations are needed to confirm whether these candidate protoclusters are physical clusters, multiple protoclusters along the line of sight, or chance alignments of unassociated sources.
De Zotti G, Gonzalez-Nuevo J, Lopez-Caniego M, et al., 2018, Exploring cosmic origins with CORE: Extragalactic sources in cosmic microwave background maps, JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, Vol: 2018, ISSN: 1475-7516
We discuss the potential of a next generation space-borne Cosmic Microwave Background (CMB) experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of the future space project, CORE, that has been submitted in response to ESA's call for a Medium-size mission opportunity as the successor of the Planck satellite. Even though the effective telescope size will be somewhat smaller than that of Planck, CORE will have a considerably better angular resolution at its highest frequencies, since, in contrast with Planck, it will be diffraction limited at all frequencies. The improved resolution implies a considerable decrease of the source confusion, i.e. substantially fainter detection limits. In particular, CORE will detect thousands of strongly lensed high-z galaxies distributed over the full sky. The extreme brightness of these galaxies will make it possible to study them, via follow-up observations, in extraordinary detail. Also, the CORE resolution matches the typical sizes of high-z galaxy proto-clusters much better than the Planck resolution, resulting in a much higher detection efficiency; these objects will be caught in an evolutionary phase beyond the reach of surveys in other wavebands. Furthermore, CORE will provide unique information on the evolution of the star formation in virialized groups and clusters of galaxies up to the highest possible redshifts. Finally, thanks to its very high sensitivity, CORE will detect the polarized emission of thousands of radio sources and, for the first time, of dusty galaxies, at mm and sub-mm wavelengths, respectively.
Amvrosiadis A, Eales SA, Negrello M, et al., 2018, ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm, Monthly Notices of the Royal Astronomical Society, Vol: 475, Pages: 4939-4952, ISSN: 0035-8711
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 submillimetre-selected 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 ∼1013 M⊙ 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.
Delabrouille J, de Bernardis P, Bouchet FR, et al., 2018, Exploring cosmic origins with CORE: Survey requirements and mission design, Journal of Cosmology and Astroparticle Physics, Vol: 2018, ISSN: 1475-7516
Future observations of cosmic microwave background (CMB) polarisation have the potential to answer some of the most fundamental questions of modern physics and cosmology, including: what physical process gave birth to the Universe we see today? What are the dark matter and dark energy that seem to constitute 95% of the energy density of the Universe? Do we need extensions to the standard model of particle physics and fundamental interactions? Is the ΛCDM cosmological scenario correct, or are we missing an essential piece of the puzzle? In this paper, we list the requirements for a future CMB polarisation survey addressing these scientific objectives, and discuss the design drivers of the COREmfive space mission proposed to ESA in answer to the "M5" call for a medium-sized mission. The rationale and options, and the methodologies used to assess the mission's performance, are of interest to other future CMB mission design studies. COREmfive has 19 frequency channels, distributed over a broad frequency range, spanning the 60–600 GHz interval, to control astrophysical foreground emission. The angular resolution ranges from 2' to 18', and the aggregate CMB sensitivity is about 2 μK⋅arcmin. The observations are made with a single integrated focal-plane instrument, consisting of an array of 2100 cryogenically-cooled, linearly-polarised detectors at the focus of a 1.2-m aperture cross-Dragone telescope. The mission is designed to minimise all sources of systematic effects, which must be controlled so that no more than 10−4 of the intensity leaks into polarisation maps, and no more than about 1% of E-type polarisation leaks into B-type modes. COREmfive observes the sky from a large Lissajous orbit around the Sun-Earth L2 point on an orbit that offers stable observing conditions and avoids contamination from sidelobe pick-up of stray radiation originating from the Sun, Earth, and Moon. The entire sky is observed repeatedly during four year
Oteo I, Ivison RJ, Dunne L, et al., 2018, An extreme protocluster of luminous dusty starbursts in the early universe, Astrophysical Journal, Vol: 856, ISSN: 0004-637X
We report the identification of an extreme protocluster of galaxies in the early universe whose core (nicknamed Distant Red Core, DRC, because of its very red color in Herschel SPIRE bands) is formed by at least 10 dusty star-forming galaxies (DSFGs), spectroscopically confirmed to lie at ${z}_{\mathrm{spec}}=4.002$ via detection of [C i](1–0), 12CO(6–5), 12CO(4–3), 12CO(2–1), and ${{\rm{H}}}_{2}{\rm{O}}({2}_{11}\mbox{--}{2}_{02})$ emission lines with ALMA and ATCA. These DSFGs are distributed over a $260\,\mathrm{kpc}\times 310\,\mathrm{kpc}$ region and have a collective obscured star formation rate (SFR) of $\sim 6500\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$, considerably higher than those seen before in any protocluster at $z\gtrsim 4$. Most of the star formation is taking place in luminous DSFGs since no Lyα emitters are detected in the protocluster core, apart from a Lyα blob located next to one of the DRC components, extending over $60\,\mathrm{kpc}$. The total obscured SFR of the protocluster could rise to $\mathrm{SFR}\sim {\rm{14,400}}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ if all the members of an overdensity of bright DSFGs discovered around DRC in a wide-field Large APEX BOlometer CAmera 870 μm image are part of the same structure. [C i](1–0) emission reveals that DRC has a total molecular gas mass of at least ${M}_{{{\rm{H}}}_{2}}\sim 6.6\times {10}^{11}\,{M}_{\odot }$, and its total halo mass could be as high as $\sim 4.4\times {10}^{13}\,{M}_{\odot }$, indicating that it is the likely progenitor of a cluster at least as massive as Coma at z = 0.
Miyanji F, Nasto LA, Bastrom T, et al., 2018, A Detailed Comparative Analysis of Anterior <i>Versus</i> Posterior Approach to Lenke 5C Curves, SPINE, Vol: 43, Pages: E285-E291, ISSN: 0362-2436
- Author Web Link
- Cite
- Citations: 16
Marques-Chaves R, Perez-Fournon I, Gavazzi R, et al., 2018, The strong gravitationally lensed Herschel galaxy HLock01: optical spectroscopy reveals a close galaxy merger with evidence of inflowing gas, Astrophysical Journal, Vol: 854, ISSN: 0004-637X
The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m UV sime 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M * sime 5 × 1011 M ⊙), with a highly extinguished stellar component (A V sime 4.3 ), the LBG is a young, lower-mass (M * sime 1 × 1010 M ⊙), but still luminous ($10\times {L}_{\mathrm{UV}}^{* }$) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C ii λλ1334 absorption in the red wing of a bright Lyα emitter at z sime 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.
Nayyeri H, Ghotbi N, Cooray A, et al., 2018, Spitzer observations of the North Ecliptic Pole, ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, Vol: 234, ISSN: 0067-0049
We present a photometric catalog for Spitzer Space Telescope warm mission observations of the North Ecliptic Pole (NEP; centered at R.A. = 18h00m00s, decl. = 66d33m38fs552). The observations are conducted with IRAC in the 3.6 and 4.5 μm bands over an area of 7.04 deg2, reaching 1σ depths of 1.29 μJy and 0.79 μJy in the 3.6 μm and 4.5 μm bands, respectively. The photometric catalog contains 380,858 sources with 3.6 and 4.5 μm band photometry over the full-depth NEP mosaic. Point-source completeness simulations show that the catalog is 80% complete down to 19.7 AB. The accompanying catalog can be used for constraining the physical properties of extragalactic objects, studying the AGN population, measuring the infrared colors of stellar objects, and studying the extragalactic infrared background light.
Ade PAR, Aghanim N, Alves MIR, et al., 2018, Planck intermediate results XV. A study of anomalous microwave emission in Galactic clouds (vol 565, A103, 2014), Astronomy and Astrophysics: a European journal, Vol: 610, ISSN: 0004-6361
This article is an erratum for: https://doi.org/10.1051/0004-6361/201322612
Clements D, Mancarella P, 2018, Systemic modelling and integrated assessment of asset management strategies and staff constraints on distribution network reliability, ELECTRIC POWER SYSTEMS RESEARCH, Vol: 155, Pages: 164-171, ISSN: 0378-7796
- Author Web Link
- Cite
- Citations: 11
van der Tak FFS, Madden SC, Roelfsema P, et al., 2018, Probing the Baryon cycle of galaxies with SPICA mid- and far-infrared observations, Publications of the Astronomical Society of Australia, Vol: 35, ISSN: 1323-3580
The SPICA mid- and far-infrared telescope will address fundamental issues in our understanding of star formation and ISM physics in galaxies. A particular hallmark of SPICA is the outstanding sensitivity enabled by the cold telescope, optimised detectors, and wide instantaneous bandwidth throughout the mid- and far-infrared. The spectroscopic, imaging, and polarimetric observations that SPICA will be able to collect will help in clarifying the complex physical mechanisms which underlie the baryon cycle of galaxies. In particular, (i) the access to a large suite of atomic and ionic fine-structure lines for large samples of galaxies will shed light on the origin of the observed spread in star-formation rates within and between galaxies, (ii) observations of HD rotational lines (out to ~10 Mpc) and fine structure lines such as [C ii] 158 μm (out to ~100 Mpc) will clarify the main reservoirs of interstellar matter in galaxies, including phases where CO does not emit, (iii) far-infrared spectroscopy of dust and ice features will address uncertainties in the mass and composition of dust in galaxies, and the contributions of supernovae to the interstellar dust budget will be quantified by photometry and monitoring of supernova remnants in nearby galaxies, (iv) observations of far-infrared cooling lines such as [O i] 63 μm from star-forming molecular clouds in our Galaxy will evaluate the importance of shocks to dissipate turbulent energy. The paper concludes with requirements for the telescope and instruments, and recommendations for the observing strategy.
Bakx TJLC, Eales SA, Negrello M, et al., 2018, The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations, Monthly Notices of the Royal Astronomical Society, Vol: 473, Pages: 1751-1773, ISSN: 0035-8711
We present the Herschel Bright Sources (HerBS) sample, a sample of bright, high-redshift Herschel sources detected in the 616.4 deg2Herschel Astrophysical Terahertz Large Area Survey. The HerBS sample contains 209 galaxies, selected with a 500 μm flux density greater than 80 mJy and an estimated redshift greater than 2. The sample consists of a combination of hyperluminous infrared galaxies and lensed ultraluminous infrared galaxies during the epoch of peak cosmic star formation. In this paper, we present Submillimetre Common-User Bolometer Array 2 (SCUBA-2) observations at 850 μm of 189 galaxies of the HerBS sample, 152 of these sources were detected. We fit a spectral template to the Herschel-Spectral and Photometric Imaging Receiver (SPIRE) and 850 μm SCUBA-2 flux densities of 22 sources with spectroscopically determined redshifts, using a two-component modified blackbody spectrum as a template. We find a cold- and hot-dust temperature of21.29+1.35−1.66and45.80+2.88−3.48 K, a cold-to-hot dust mass ratio of26.62+5.61−6.74and a β of1.83+0.14−0.28. The poor quality of the fit suggests that the sample of galaxies is too diverse to be explained by our simple model. Comparison of our sample to a galaxy evolution model indicates that the fraction of lenses are high. Out of the 152 SCUBA-2 detected galaxies, the model predicts 128.4 ± 2.1 of those galaxies to be lensed (84.5 per cent). The SPIRE 500 μm flux suggests that out of all 209 HerBS sources, we expect 158.1 ± 1.7 lensed sources, giving a total lensing fraction of 76 per cent.
Clements DL, Pearson C, Farrah D, et al., 2017, HERUS: The Far-IR/Submm Spectral Energy Distributions of Local ULIRGs & Photometric Atlas, Monthly Notices of the Royal Astronomical Society, Vol: 475, Pages: 2097-2121, ISSN: 0035-8711
We present the Herschel-SPIRE photometric atlas for a complete flux limitedsample of 43 local Ultraluminous Infrared Galaxies (ULIRGs), selected at60${\mu}$m by IRAS, as part of the HERschel ULIRG Survey (HERUS). Photometryobservations were obtained using the SPIRE instrument at 250, 350 and500${\mu}$m. We describe these observations, present the results, and combinethe new observations with data from IRAS to examine the far-IR spectral energydistributions (SEDs) of these sources. We fit the observed SEDs of HERUSobjects with a simple parameterised modified black body model where temperatureand emissivity $\beta$ are free parameters. We compare the fitted values tothose of non-ULIRG local galaxies, and find, in agreement with earlier results,that HERUS ULIRGs have warmer dust (median temperature T = 37.9+/-4.7 Kcompared to 21.3+/-3.4 K) but a similar $\beta$ distribution (median $\beta$ =1.7 compared to 1.8) to the Herschel reference sample (HRS, Cortese et al.,2014) galaxies. Dust masses are found to be in the range of 10^7.5 to 10^9 Msunsignificantly higher than that of Herschel Reference Sample (HRS) sources. Wecompare our results for local ULIRGs with higher redshift samples selected at250 and 850${\mu}$m. These latter sources generally have cooler dust and/orredder 100-to-250 ${\mu}$m colours than our 60${\mu}$m-selected ULIRGs. We showthat this difference may in part be the result of the sources being selected atdifferent wavelengths rather than being a simple indication of rapid evolutionin the properties of the population.
Fudamoto Y, Ivison RJ, Oteo I, et al., 2017, The most distant, luminous, dusty star-forming galaxies: redshifts from NOEMA and ALMA spectral scans, Monthly Notices of the Royal Astronomical Society, Vol: 472, Pages: 2028-2041, ISSN: 0035-8711
We present 1.3- and/or 3-mm continuum images and 3-mm spectral scans, obtained using Northern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter Array (ALMA), of 21 distant, dusty, star-forming galaxies. Our sample is a subset of the galaxies selected by Ivison et al. on the basis of their extremely red far-infrared (far-IR) colours and low Herschel flux densities; most are thus expected to be unlensed, extraordinarily luminous starbursts at z ≳ 4, modulo the considerable cross-section to gravitational lensing implied by their redshift. We observed 17 of these galaxies with NOEMA and four with ALMA, scanning through the 3-mm atmospheric window. We have obtained secure redshifts for seven galaxies via detection of multiple CO lines, one of them a lensed system at z = 6.027 (two others are also found to be lensed); a single emission line was detected in another four galaxies, one of which has been shown elsewhere to lie at z = 4.002. Where we find no spectroscopic redshifts, the galaxies are generally less luminous by 0.3–0.4 dex, which goes some way to explaining our failure to detect line emission. We show that this sample contains the most luminous known star-forming galaxies. Due to their extreme star-formation activity, these galaxies will consume their molecular gas in ≲ 100 Myr, despite their high molecular gas masses, and are therefore plausible progenitors of the massive, ‘red-and-dead’ elliptical galaxies at z ≈ 3.
Wang W-H, Lin W-C, Lim C-F, et al., 2017, SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES): faint-end counts at 450 μm, Astrophysical Journal, Vol: 850, ISSN: 0004-637X
The SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES) is a three-year JCMT Large Program aiming to reach the 450 μm confusion limit in the COSMOS-CANDELS region to study a representative sample of the high-redshift far-infrared galaxy population that gives rise to the bulk of the far-infrared background. We present the first-year data from STUDIES. We reached a 450 μm noise level of 0.91 mJy for point sources at the map center, covered an area of 151 arcmin2, and detected 98 and 141 sources at 4.0σ and 3.5σ, respectively. Our derived counts are best constrained in the 3.5–25 mJy regime using directly detected sources. Below the detection limits, our fluctuation analysis further constrains the slope of the counts down to 1 mJy. The resulting counts at 1–25 mJy are consistent with a power law having a slope of −2.59 (±0.10 for 3.5–25 mJy, and ${}_{-0.7}^{+0.4}$ for 1–3.5 mJy). There is no evidence of a faint-end termination or turnover of the counts in this flux density range. Our counts are also consistent with previous SCUBA-2 blank-field and lensing-cluster surveys. The integrated surface brightness from our counts down to 1 mJy is 90.0 ± 17.2 Jy deg−2, which can account for up to ${83}_{-16}^{+15} \% $ of the COBE 450 μm background. We show that Herschel counts at 350 and 500 μm are significantly higher than our 450 μm counts, likely caused by its large beam and source clustering. High angular resolution instruments like SCUBA-2 at 450 μm are therefore highly beneficial for measuring the luminosity and spatial density of high-redshift dusty galaxies.
Riechers DA, Leung TKD, Ivison RJ, et al., 2017, Rise of the titans: a dusty, hyper-luminous "870 mu m Riser" galaxy at z~6, Astrophysical Journal, Vol: 850, ISSN: 0004-637X
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/Spectral and Photometric Imaging Receiver (SPIRE) and APEX/LABOCA data as an extremely red "870 μm riser" (i.e., ${S}_{250\mu {\rm{m}}}\lt {S}_{350\mu {\rm{m}}}\lt {S}_{500\mu {\rm{m}}}\lt {S}_{870\mu {\rm{m}}}$), demonstrating the utility of this technique to identify some of the highest-redshift dusty galaxies. A scan of the 3 mm atmospheric window with ALMA yields detections of CO(J = 5 → 4) and CO(J = 6 → 5) emission, and a tentative detection of H2O(211 → 202) emission, which provides an unambiguous redshift measurement. The strength of the CO lines implies a large molecular gas reservoir with a mass of M gas = 2.5 × 1011 $({\alpha }_{\mathrm{CO}}/0.8)(0.39/{r}_{51})$ M ⊙, sufficient to maintain its ~2400 M ⊙ yr−1 starburst for at least ~100 Myr. The 870 μm 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 L IR sime 2.4 × 1013 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 ${{\rm{\Sigma }}}_{\mathrm{SFR}}=730$ and 750 M ⊙ yr−1 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 z ~ 6 quasars and massive quiescent galaxies at z gsim 3.
Spinoglio L, Alonso-Herrero A, Armus L, et al., 2017, Galaxy Evolution Studies with the SPace IR Telescope for Cosmology and Astrophysics (SPICA): The Power of IR Spectroscopy, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA, Vol: 34, ISSN: 1323-3580
IR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ~ 6.
Gruppioni C, Ciesla L, Hatziminaoglou E, et al., 2017, Tracing the Evolution of Dust Obscured Star Formation and Accretion Back to the Reionisation Epoch with SPICA, PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA, Vol: 34, ISSN: 1323-3580
Our current knowledge of star formation and accretion luminosity at high redshift (z > 3–4), as well as the possible connections between them, relies mostly on observations in the rest-frame ultraviolet, which are strongly affected by dust obscuration. Due to the lack of sensitivity of past and current infrared instrumentation, so far it has not been possible to get a glimpse into the early phases of the dust-obscured Universe. Among the next generation of infrared observatories, SPICA, observing in the 12–350 µm range, will be the only facility that can enable us to trace the evolution of the obscured star-formation rate and black-hole accretion rate densities over cosmic time, from the peak of their activity back to the reionisation epoch (i.e., 3 < z ≲ 6–7), where its predecessors had severe limitations. Here, we discuss the potential of photometric surveys performed with the SPICA mid-infrared instrument, enabled by the very low level of impact of dust obscuration in a band centred at 34 µm. These unique unbiased photometric surveys that SPICA will perform will fully characterise the evolution of AGNs and star-forming galaxies after reionisation.
Salam N, Haddade A, Clements DL, et al., 2017, A boundary element method for a class of elliptic boundary value problems of functionally graded media, ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS, Vol: 84, Pages: 186-190, ISSN: 0955-7997
- Author Web Link
- Cite
- Citations: 15
Wilson D, Cooray A, Nayyeri H, et al., 2017, Stacked average far-infrared spectrum of dusty star-forming galaxies from the Herschel/SPIRE Fourier Transform Spectrometer, Astrophysical Journal, Vol: 848, ISSN: 0004-637X
We present stacked average far-infrared spectra of a sample of 197 dusty star-forming galaxies (DSFGs) at $0.005\lt z\lt 4$ using about 90% of the Herschel Space Observatory SPIRE Fourier Transform Spectrometer (FTS) extragalactic data archive based on 3.5 years of science operations. These spectra explore an observed-frame 447–1568 GHz frequency range, allowing us to observe the main atomic and molecular lines emitted by gas in the interstellar medium. The sample is subdivided into redshift bins, and a subset of the bins are stacked by infrared luminosity as well. These stacked spectra are used to determine the average gas density and radiation field strength in the photodissociation regions (PDRs) of DSFGs. For the low-redshift sample, we present the average spectral line energy distributions of CO and H2O rotational transitions and consider PDR conditions based on observed [C i] 370 and 609 μm, and CO (7-6) lines. For the high-z ($0.8\lt z\lt 4$) sample, PDR models suggest a molecular gas distribution in the presence of a radiation field that is at least a factor of 103 larger than the Milky Way and with a neutral gas density of roughly ${10}^{4.5}$–${10}^{5.5}$ cm−3. The corresponding PDR models for the low-z sample suggest a UV radiation field and gas density comparable to those at high-z. Given the challenges in obtaining adequate far-infrared observations, the stacked average spectra we present here will remain the measurements with the highest signal-to-noise ratio for at least a decade and a half until the launch of the next far-infrared facility.
Clements DL, 2017, An introduction to the Planck mission, Contemporary Physics, Vol: 58, Pages: 331-348, ISSN: 0010-7514
The Cosmic Microwave Background (CMB) is the oldest light in the universe. It is seen today as black body radiation at a near-uniform temperature of 2.73 K covering the entire sky. This radiation field is not perfectly uniform, but includes within it temperature anisotropies of order ΔT/T∼10−5ΔT/T∼10-5. Physical processes in the early universe have left their fingerprints in these CMB anisotropies, which later grew to become the galaxies and large scale structure we see today. CMB anisotropy observations are thus a key tool for cosmology. The Planck mission was the European Space Agency’s probe of the CMB. Its unique design allowed CMB anisotropies to be measured to greater precision over a wider range of scales than ever before. This article provides an introduction to the Planck mission, including its goals and motivation, its instrumentation and technology, the physics of the CMB, how the contaminating astrophysical foregrounds were overcome, and the key cosmological results that this mission has so far produced.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.