ORCID Profile
0000-0002-9871-6490
Current Organisation
Swinburne University of Technology
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Astronomical sciences | Astronomical and Space Sciences | Astronomical instrumentation | Cosmology and Extragalactic Astronomy
Publisher: Elsevier BV
Date: 03-2011
Publisher: American Geophysical Union (AGU)
Date: 08-2016
DOI: 10.1002/2016JC011687
Publisher: Oxford University Press (OUP)
Date: 17-06-2020
Abstract: We use high-resolution H i data from the Westerbork H i Survey of Spiral and Irregular Galaxies (WHISP) to study the H i and angular momentum properties of a s le of 114 late-type galaxies. We explore the specific baryonic angular momentum–baryonic mass (jb–Mb) relation, and find that an unbroken power law of the form $j_\\mathrm{ b} \\propto M_\\mathrm{ b}^{0.55 \\pm 0.02}$ fits the data well, with an intrinsic scatter of ∼0.13 ± 0.01 dex. We revisit the relation between the atomic gas fraction, fatm, and the integrated atomic stability parameter q (the fatm–q relation), originally introduced by Obreschkow et al., and probe this parameter space by populating it with galaxies from different environments, in order to study the influence of the environment on their jb, fatm, and q values. We find evidence that galaxies with close neighbours show a larger intrinsic scatter about the fatm–q relation compared to galaxies without close neighbours. We also find enhanced star formation rate among the deviating galaxies with close neighbours. In addition, we use the bulge-to-total (B/T) ratio as a morphology proxy, and find a general trend of decreasing B/T values with increasing disc stability and H i fraction in the fatm–q plane, indicating a fundamental link between mass, specific angular momentum, gas fraction, and morphology of galaxies.
Publisher: Oxford University Press (OUP)
Date: 22-02-2017
DOI: 10.1093/MNRAS/STX441
Publisher: American Astronomical Society
Date: 30-11-2010
Publisher: Wiley
Date: 06-2022
Publisher: Oxford University Press (OUP)
Date: 06-04-2022
Abstract: We construct the halo mass function (HMF) from the GAMA (Galaxy And Mass Assembly) galaxy group catalogue over the mass range of 1012.7–1015.5 M⊙, and find good agreement with the expectation from Lambda cold dark matter. In comparison to previous studies, this result extends the mass range over which the HMF has now been measured over by an order of magnitude. We combine the GAMA data release (DR) 4 HMF with similar data from the Sloan Digital Sky Survey (SDSS) DR12 and REFLEX II (ROSAT-ESO Flux Limited X-ray Galaxy Cluster Survey) surveys, and fit a four-parameter Murray–Robotham–Power function, valid at $\\tilde{z} \\approx 0.1$, yielding a density normalization of log10 (ϕ* Mpc$^{3})= -3.96^{+0.55}_{-0.82}$, a high mass turnover of log10 (M* M$_{\\odot }^{-1})=14.13^{+0.43}_{-0.40}$, a low-mass power-law slope of $\\alpha =-1.68^{+0.21}_{-0.24}$, and a high-mass softening parameter of $\\beta =0.63^{+0.25}_{-0.11}$. If we fold in the constraint on ΩM from the Planck 2018 cosmology, we are able to reduce these uncertainties further, but this relies on the assumption that the power-law trend can be extrapolated from 1012.7 M⊙ to zero mass. Throughout, we highlight the effort needed to improve on our HMF measurement: improved halo mass estimates that do not rely on calibration to simulations reduced halo mass uncertainties needed to mitigate the strong Eddington bias that arises from the steepness of the HMF low-mass slope and deeper wider area spectroscopic surveys. To our halo mass limit of 1012.7 M⊙, we are directly resolving (‘seeing’) 41 ± 5 per cent of the total mass density, i.e. ΩM,& .7 = 0.128 ± 0.016, opening the door for the direct construction of three-dimensional dark matter mass maps at Mpc resolution.
Publisher: Copernicus GmbH
Date: 21-02-2020
Abstract: Abstract. Dissolved Fe (DFe) s les from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analyzed using a seaFAST-pico™ coupled to an Element XR sector field inductively coupled plasma mass spectrometer (SF-ICP-MS) and provided interesting insights into the Fe sources in this area. Overall, DFe concentrations ranged from 0.09±0.01 to 7.8±0.5 nmol L−1. Elevated DFe concentrations were observed above the Iberian, Greenland, and Newfoundland margins likely due to riverine inputs from the Tagus River, meteoric water inputs, and sedimentary inputs. Deep winter convection occurring the previous winter provided iron-to-nitrate ratios sufficient to sustain phytoplankton growth and lead to relatively elevated DFe concentrations within subsurface waters of the Irminger Sea. Increasing DFe concentrations along the flow path of the Labrador Sea Water were attributed to sedimentary inputs from the Newfoundland Margin. Bottom waters from the Irminger Sea displayed high DFe concentrations likely due to the dissolution of Fe-rich particles in the Denmark Strait Overflow Water and the Polar Intermediate Water. Finally, the nepheloid layers located in the different basins and at the Iberian Margin were found to act as either a source or a sink of DFe depending on the nature of particles, with organic particles likely releasing DFe and Mn particle scavenging DFe.
Publisher: Oxford University Press (OUP)
Date: 19-12-2019
Abstract: We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to in idual galaxies with no measurable influence from the galaxies’ larger environment. We first define a clean s le of passive galaxies without a significant contribution to their UV flux from low-level star formation. We confirm that galaxies with the optical colours of red sequence galaxies often have signs of residual star formation, which, without other information, would prevent a convincing demonstration of the presence of UV upturns. However, by including (NUV−u) and WISE (W2–W3) colours, and FUV data where it exists, we can convincingly constrain s les to be composed of non-star-forming objects. Using such a s le, we examine GALEX photometry of low-redshift GAMA galaxies in a range of low-density environments, from groups to the general field, searching for UV upturns. We find a wide range of (NUV−r) colours, entirely consistent with the range seen – and attributed to the UV upturn – in low-redshift red sequence cluster galaxies. The range of colours is independent of group multiplicity or velocity dispersion, with isolated passive galaxies just as likely to have blue UV-to-optical colours, implying significant upturn components, as those in richer groups and in the previous data on clusters. This is supported by equivalent results for (FUV−r) colours which are clear indicators of upturn components.
Publisher: American Astronomical Society
Date: 04-04-2012
Publisher: Cambridge University Press (CUP)
Date: 2018
DOI: 10.1017/PASA.2018.9
Abstract: We present a multi-frequency study of the intermediate spiral SAB(r)bc type galaxy NGC 6744, using available data from the Chandra X-Ray telescope, radio continuum data from the Australia Telescope Compact Array and Murchison Widefield Array , and Wide-field Infrared Survey Explorer infrared observations. We identify 117 X-ray sources and 280 radio sources. Of these, we find nine sources in common between the X-ray and radio catalogues, one of which is a faint central black hole with a bolometric radio luminosity similar to the Milky Way’s central black hole. We classify 5 objects as supernova remnant (SNR) candidates, 2 objects as likely SNRs, 17 as H ii regions, 1 source as an AGN the remaining 255 radio sources are categorised as background objects and one X-ray source is classified as a foreground star. We find the star-formation rate (SFR) of NGC 6744 to be in the range 2.8–4.7 M ⊙ ~yr − 1 signifying the galaxy is still actively forming stars. The specific SFR of NGC 6744 is greater than that of late-type spirals such as the Milky Way, but considerably less that that of a typical starburst galaxy.
Publisher: Oxford University Press (OUP)
Date: 14-04-2018
DOI: 10.1093/MNRAS/STY933
Publisher: Oxford University Press (OUP)
Date: 04-03-2014
Publisher: American Astronomical Society
Date: 18-01-2010
Publisher: Copernicus GmbH
Date: 04-04-2018
Publisher: Oxford University Press (OUP)
Date: 20-06-2016
Publisher: American Astronomical Society
Date: 16-07-2012
Publisher: Oxford University Press (OUP)
Date: 02-03-2019
DOI: 10.1093/MNRAS/STZ593
Abstract: We present a s le of 91 H i galaxies with little or no star formation, and discuss the analysis of the integral field unit (IFU) spectra of 28 of these galaxies. We identified H i galaxies from the H i Parkes All-Sky Survey Catalog (HICAT) with Wide-field Infrared Survey Explorer (WISE) colours consistent with low specific star formation (& −10.4 yr−1), and obtained optical IFU spectra with the Wide-Field Spectrograph (WiFeS). Visual inspection of the PanSTARRS, Dark Energy Survey, and Carnegie-Irvine imaging of 62 galaxies reveals that at least 32 galaxies in the s le have low levels of star formation, primarily in arms/rings. New IFU spectra of 28 of these galaxies reveals 3 galaxies with central star formation, 1 galaxy with low-ionization nuclear emission-line regions (LINERs), 20 with extended low-ionization emission-line regions (LIERs), and 4 with high excitation Seyfert (Sy) emission. From the spectroscopic analysis of H i selected galaxies with little star formation, we conclude that 75 per cent of this population are LINERs/LIERs.
Publisher: Oxford University Press (OUP)
Date: 29-06-2013
DOI: 10.1093/MNRAS/STT890
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/MF13137
Abstract: The Tasman Sea and the adjacent subantarctic zone (SAZ) are economically important regions, where the parameters controlling the phytoplankton community composition and carbon fixation are not yet fully resolved. Contrasting nutrient distributions, as well as phytoplankton biomass, bio ersity and productivity were observed between the North Tasman Sea and the SAZ. In situ photosynthetic efficiency (FV/FM), dissolved and particulate nutrients, iron biological uptake, and nitrogen and carbon fixation were used to determine the factor-limiting phytoplankton growth and productivity in the North Tasman Sea and the SAZ. Highly productive cyanobacteria dominated the North Tasman Sea. High atmospheric nitrogen fixation and low nitrate dissolved concentrations indicated that non-diazotroph phytoplankton are nitrogen limited. Deck-board incubations also suggested that, at depth, iron could limit eukaryotes, but not cyanobacteria in that region. In the SAZ, the phytoplankton community was dominated by a bloom of haptophytes. The low productivity in the SAZ was mainly explained by light limitation, but nitrogen, silicic acid as well as iron were all depleted to the extent that they could become co-limiting. This study illustrates the challenge associated with identification of the limiting nutrient, as it varied between phytoplankton groups, depths and sites.
Publisher: Oxford University Press (OUP)
Date: 19-12-2014
Publisher: American Astronomical Society
Date: 04-2023
Abstract: We derive new empirical scaling relations between Wide-field Infrared Survey Explorer (WISE) mid-IR (MIR) galaxy photometry and well-determined stellar masses from spectral energy distribution modeling of a suite of optical–infrared photometry provided by the Data Release 4 (DR4) Catalog of the GAMA-KiDS-VIKING survey of the southern G23 field. The MIR source extraction and characterization are drawn from the WISE Extended Source Catalogue and the archival ALLWISE catalog, combining both resolved and compact galaxies in the G23 s le to a redshift of 0.15. Three scaling relations are derived: W1 3.4 μ m luminosity versus stellar mass, and WISE W1–W2, W1–W3 colors versus mass-to-light ratio ( M / L , sensitive to a variety of galaxy types from passive to star-forming). For each galaxy in the s le, we then derive the combined stellar mass from these scaling relations, producing M ⋆ estimates with better than ∼25%–30% accuracy for galaxies with 9 M ⊙ and %–50% for lower-luminosity dwarf galaxies. We also provide simple prescriptions for rest-frame corrections and estimating stellar masses using only the W1 flux and the W1–W2 color, making stellar masses more accessible to users of the WISE data. Given a redshift or distance, these new scaling relations will enable stellar mass estimates for any galaxy in the sky detected by WISE with high fidelity across a range of M / L ratios.
Publisher: Oxford University Press (OUP)
Date: 02-03-2022
Abstract: In Galaxy And Mass Assembly Data Release 4 (GAMA DR4), we make available our full spectroscopic redshift s le. This includes 248 682 galaxy spectra, and, in combination with earlier surveys, results in 330 542 redshifts across five sky regions covering ∼250 deg2. The redshift density, is the highest available over such a sustained area, has exceptionally high completeness (95 per cent to rKiDS = 19.65 mag), and is well-suited for the study of galaxy mergers, galaxy groups, and the low redshift (z & 0.25) galaxy population. DR4 includes 32 value-added tables or Data Management Units (DMUs) that provide a number of measured and derived data products including GALEX, ESO KiDS, ESO VIKING, WISE, and HerschelSpace Observatory imaging. Within this release, we provide visual morphologies for 15 330 galaxies to z & 0.08, photometric redshift estimates for all 18 million objects to rKiDS ∼ 25 mag, and stellar velocity dispersions for 111 830 galaxies. We conclude by deriving the total galaxy stellar mass function (GSMF) and its sub- ision by morphological class (elliptical, compact-bulge and disc, diffuse-bulge and disc, and disc only). This extends our previous measurement of the total GSMF down to 106.75 M$_{\\odot } \\, h_{70}^{-2}$ and we find a total stellar mass density of ρ* = (2.97 ± 0.04) × 108 M$_{\\odot } \\, h_{70}$ Mpc−3 or $\\Omega _*=(2.17 \\pm 0.03) \\times 10^{-3} \\, h_{70}^{-1}$. We conclude that at z & 0.1, the Universe has converted 4.9 ± 0.1 per cent of the baryonic mass implied by big bang Nucleosynthesis into stars that are gravitationally bound within the galaxy population.
Publisher: American Geophysical Union (AGU)
Date: 08-2018
DOI: 10.1029/2018JC013932
Publisher: Oxford University Press (OUP)
Date: 24-11-2017
Publisher: American Astronomical Society
Date: 28-10-2022
Abstract: The identification of active galactic nuclei (AGNs) in large surveys has been h ered by seemingly discordant classifications arising from differing diagnostic methods, usually tracing distinct processes specific to a particular wavelength regime. However, as shown in Yao et al., the combination of optical emission-line measurements and mid-infrared photometry can be used to optimize the discrimination capability between AGN and star formation activity. In this paper we test our new classification scheme by combining the existing GAMA-WISE data with high-quality MeerKAT radio continuum data covering 8 deg 2 of the GAMA G23 region. Using this s le of 1841 galaxies ( z 0.25), we investigate the total infrared (derived from 12 μ m) to radio luminosity ratio, q (TIR) , and its relationship to optical–infrared AGN and star-forming (SF) classifications. We find that while q (TIR) is efficient at detecting AGN activity in massive galaxies generally appearing quiescent in the infrared, it becomes less reliable for cases where the emission from star formation in the host galaxy is dominant. However, we find that the q (TIR) can identify up to 70% more AGNs not discernible at optical and/or infrared wavelengths. The median q (TIR) of our SF s le is 2.57 ± 0.23, consistent with previous local universe estimates.
Publisher: AIP
Date: 2010
DOI: 10.1063/1.3458568
Publisher: American Astronomical Society
Date: 13-07-2016
Publisher: Oxford University Press (OUP)
Date: 30-11-2016
Publisher: Frontiers Media SA
Date: 14-06-2019
Publisher: American Astronomical Society
Date: 29-10-2014
Publisher: American Astronomical Society
Date: 17-04-2019
Publisher: Elsevier BV
Date: 08-2013
Publisher: Copernicus GmbH
Date: 06-02-2015
Abstract: Abstract. The KEOPS2 project aims to elucidate the role of natural Fe fertilisation on biogeochemical cycles and ecosystem functioning, including quantifying the sources and processes by which iron is delivered in the vicinity of the Kerguelen Archipelago, Southern Ocean. The KEOPS2 process study used an upstream high-nutrient, low-chlorophyll (HNLC), deep water (2500 m), reference station to compare with a shallow (500 m), strongly fertilised plateau station and continued the observations to a downstream, bathymetrically trapped recirculation of the Polar Front where eddies commonly form and persist for hundreds of kilometres into the Southern Ocean. Over the Kerguelen Plateau, mean particulate (1–53 μm) Fe and Al concentrations (pFe = 13.4 nM, pAl = 25.2 nM) were more than 20-fold higher than at an offshore (lower-productivity) reference station (pFe = 0.53 nM, pAl = 0.83 nM). In comparison, over the plateau dissolved Fe levels were only elevated by a factor of ~ 2. Over the Kerguelen Plateau, ratios of pMn / pAl and pFe / pAl resemble basalt, likely originating from glacial/fluvial inputs into shallow coastal waters. In downstream, offshore deep-waters, higher pFe / pAl, and pMn / pAl ratios were observed, suggesting loss of lithogenic material accompanied by retention of pFe and pMn. Biological uptake of dissolved Fe and Mn and conversion into the biogenic particulate fraction or aggregation of particulate metals onto bioaggregates also increased these ratios further in surface waters as the bloom developed within the recirculation structure. While resuspension of shelf sediments is likely to be one of the important mechanisms of Fe fertilisation over the plateau, fluvial and glacial sources appear to be important to areas downstream of the island. Vertical profiles within an offshore recirculation feature associated with the Polar Front show pFe and pMn levels that were 6-fold and 3.5-fold lower, respectively, than over the plateau in surface waters, though still 3.6-fold and 1.7-fold higher respectively than the reference station. Within the recirculation feature, strong depletions of pFe and pMn were observed in the remnant winter water (temperature-minimum) layer near 175 m, with higher values above and below this depth. The correspondence between the pFe minima and the winter water temperature minima implies a seasonal cycle is involved in the supply of pFe into the fertilised region. This observed association is indicative of reduced supply in winter, which is counterintuitive if sediment resuspension and entrainment within the mixed layer is the primary fertilising mechanism to the downstream recirculation structure. Therefore, we hypothesise that lateral transport of pFe from shallow coastal waters is strong in spring, associated with snow melt and increased runoff due to rainfall, drawdown through summer and reduced supply in winter when snowfall and freezing conditions predominate in the Kerguelen region.
Publisher: American Astronomical Society
Date: 2022
Abstract: We present Hubble Space Telescope Cosmic Origin Spectrograph (COS) UV line spectroscopy and integral-field unit (IFU) observations of the intragroup medium in Stephan’s Quintet (SQ). SQ hosts a 30 kpc long shocked ridge triggered by a galaxy collision at a relative velocity of 1000 km s −1 , where large amounts of molecular gas coexist with a hot, X-ray-emitting, plasma. COS spectroscopy at five positions s ling the erse environments of the SQ intragroup medium reveals very broad (≈2000 km s −1 ) Ly α line emission with complex line shapes. The Ly α line profiles are similar to or much broader than those of H β , [C ii ]157.7 μ m, and CO (1–0) emission. The extreme breadth of the Ly α emission, compared with H β , implies resonance scattering within the observed structure. Scattering indicates that the neutral gas of the intragroup medium is clumpy, with a significant surface covering factor. We observe significant variations in the Ly α /H β flux ratio between positions and velocity components. From the mean line ratio averaged over positions and velocities, we estimate the effective escape fraction of Ly α photons to be ≈10%–30%. Remarkably, over more than four orders of magnitude in temperature, the powers radiated by X-rays, Ly α , H 2 , and [C ii ] are comparable within a factor of a few, assuming that the ratio of the Ly α to H 2 fluxes over the whole shocked intragroup medium stay in line with those observed at those five positions. Both shocks and mixing layers could contribute to the energy dissipation associated with a turbulent energy cascade. Our results may be relevant for the cooling of gas at high redshifts, where the metal content is lower than in this local system, and a high litude of turbulence is more common.
Publisher: American Astronomical Society
Date: 20-07-2020
Publisher: American Astronomical Society
Date: 27-11-2018
Publisher: Copernicus GmbH
Date: 04-04-2018
DOI: 10.5194/BG-2018-147
Abstract: Abstract. Dissolved Fe (DFe) s les from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analysed using a SeaFAST-picoTM coupled to an Element XR HR-ICP-MS and provided interesting insights on the Fe sources in this area. Overall, DFe concentrations ranged from 0.09 ± 0.01 nmol L−1 to 7.8 ± 0.5 nmol L−1. Elevated DFe concentrations were observed above the Iberian, Greenland and Newfoundland Margins likely due to riverine inputs from the Tagus River, meteoric water inputs and sedimentary inputs. Air-sea interactions were suspected to be responsible for the increase in DFe concentrations within subsurface waters of the Irminger Sea due to deep convection occurring the previous winter, that provided iron-to-nitrate ratios sufficient to sustain phytoplankton growth. Increasing DFe concentrations along the flow path of the Labrador Sea Water were attributed to sedimentary inputs from the Newfoundland Margin. Bottom waters from the Irminger Sea displayed high DFe concentrations likely due to the dissolution of Fe-rich particles from the Denmark Strait Overflow Water and the Polar Intermediate Water. Finally, the nepheloid layers were found to act as either a source or a sink of DFe depending on the nature of particles.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.TALANTA.2019.01.047
Abstract: A seawater preconcentration system (seaFAST) with offline sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS) detection was critically evaluated for ultra-low trace elemental analysis of Southern Ocean s les over a four-year period (2015-2018). The commercially available system employs two Nobias PA1 resin columns for buffer cleaning and s le preconcentration, allowing salt matrix removal with simultaneous extraction of a range of trace elements. With a primary focus on method simplicity and practicality, a range of experimental parameters relevant to oceanographic analysis were considered, including reduction of blank levels (over weeks and years), instrument conditioning, extraction efficiencies over different pH ranges (5.8-6.4), and preconcentration factors (~10-70 times). Conditions were optimised for the analysis of ten important trace elements (Cd, Co, Cu, Fe, Ga, Mn, Ni, Pb, Ti and Zn) in open ocean seawater s les, and included initial pre-cleaning and conditioning of the seaFAST unit for one week before each separate analytical sequence a controlled narrow buffer pH of 6.20 ± 0.02 used for extraction and a s le preconcentration factor of 10 for (relatively) concentrated rainwater or sea ice, 40 for typical seawater s les, and up to 67 times for seawater s les collected in the remote open ocean such as the Southern Ocean. Method accuracy (both short - days to weeks - and long term - months to years) were evaluated through extensive analysis of a range of oceanographic standard reference s les including SAFe D1 (n = 20), D2 (n = 3), S (n = 15), GEOTRACES GD (n = 6), GSC (n = 42) and GSP (n = 42), as well as NASS-6 (n = 6). Measured values for oceanographic s les were found to agree with consensus values to within ± 6% for Cd, Cu, Fe, Ni, Pb and Zn. Offsets were noted for Co (labile fraction only no UV oxidation), Mn (difference also noted in other recent studies) and Ti (limited reference values). No consensus values currently exist for Ga. Iron and Mn in Southern Ocean s les were also independently verified via flow injection analysis methods (R
Publisher: American Astronomical Society
Date: 25-06-2018
Publisher: Elsevier BV
Date: 08-2015
Publisher: American Geophysical Union (AGU)
Date: 11-2012
DOI: 10.1029/2012GL053478
Publisher: American Astronomical Society
Date: 17-10-2013
Publisher: Oxford University Press (OUP)
Date: 13-02-2021
Abstract: We have conducted a systematic survey for z & 0.04 active Galactic nuclei (AGNs) that may have changed spectral class over the past decade. We use SkyMapper, Pan-STARRS and the Véron-Cetty & Véron catalogue to search the entire sky for these ‘changing-look’ AGNs (CLAGNs) using a variety of selection methods, where Pan-STARRS has a coverage of 3$\\pi$ steradians (sky north of Declination −30○) and SkyMapper has coverage of ∼21000 $~\\rm {deg^2}$ (sky south of Declination 0○). We use small aperture photometry to measure how colour and flux have changed over time, where a change may indicate a change in spectral type. Optical colour and flux are used as a proxy for changing Hα equivalent width, while WISE 3.4 μm flux is used to look for changes in the hot dust component. We have identified four AGNs with varying spectra selected using our optical colour selection method. Three AGNs were confirmed from recent observations with WiFeS on the 2.3 m telescope at Siding Spring and the other was identified from archival spectra alone. From this, we identify two new CLAGNs NGC 1346 and 2MASX J20075129–1108346. We also recover Mrk 915 and Mrk 609, which are known to have varying spectra in the literature, but they do not meet our specific criteria for CLAGNs.
Publisher: Copernicus GmbH
Date: 29-07-2015
Abstract: Abstract. Iron availability in the Southern Ocean controls phytoplankton growth, community composition and the uptake of atmospheric CO2 by the biological pump. The KEOPS-2 (KErguelen Ocean and Plateau compared Study 2) "process study", took place around the Kerguelen Plateau in the Indian sector of the Southern Ocean. This is a region naturally fertilised with iron on the scale of hundreds to thousands of square kilometres, producing a mosaic of spring blooms which show distinct biological and biogeochemical responses to fertilisation. This paper presents biogeochemical iron budgets (incorporating vertical and lateral supply, internal cycling, and sinks) for three contrasting sites: an upstream high-nutrient low-chlorophyll reference, over the plateau and in the offshore plume east of the Kerguelen Islands. These budgets show that distinct regional environments driven by complex circulation and transport pathways are responsible for differences in the mode and strength of iron supply, with vertical supply dominant on the plateau and lateral supply dominant in the plume. Iron supply from "new" sources (diffusion, upwelling, entrainment, lateral advection, atmospheric dust) to the surface waters of the plume was double that above the plateau and 20 times greater than at the reference site, whilst iron demand (measured by cellular uptake) in the plume was similar to that above the plateau but 40 times greater than at the reference site. "Recycled" iron supply by bacterial regeneration and zooplankton grazing was a relatively minor component at all sites ( 8 % of new supply), in contrast to earlier findings from other biogeochemical iron budgets in the Southern Ocean. Over the plateau, a particulate iron dissolution term of 2.5 % was invoked to balance the budget this approximately doubled the standing stock of dissolved iron in the mixed layer. The exchange of iron between dissolved, biogenic particulate and lithogenic particulate pools was highly dynamic in time and space, resulting in a decoupling of the iron supply and carbon export and, importantly, controlling the efficiency of fertilisation.
Publisher: Oxford University Press (OUP)
Date: 02-07-2013
Publisher: American Astronomical Society
Date: 31-01-2014
Publisher: American Astronomical Society
Date: 17-02-2017
Publisher: American Astronomical Society
Date: 14-02-2017
Publisher: Copernicus GmbH
Date: 23-06-2015
Abstract: Abstract. This study examined upper-ocean particulate organic carbon (POC) export using the 234Th approach as part of the second KErguelen Ocean and Plateau compared Study expedition (KEOPS2). Our aim was to characterize the spatial and the temporal variability of POC export during austral spring (October–November 2011) in the Fe-fertilized area of the Kerguelen Plateau region. POC export fluxes were estimated at high productivity sites over and downstream of the plateau and compared to a high-nutrient low-chlorophyll (HNLC) area upstream of the plateau in order to assess the impact of iron-induced productivity on the vertical export of carbon. Deficits in 234Th activities were observed at all stations in surface waters, indicating early scavenging by particles in austral spring. 234Th export was lowest at the reference station R-2 and highest in the recirculation region (E stations) where a pseudo-Lagrangian survey was conducted. In comparison 234Th export over the central plateau and north of the polar front (PF) was relatively limited throughout the survey. However, the 234Th results support that Fe fertilization increased particle export in all iron-fertilized waters. The impact was greatest in the recirculation feature (3–4 fold at 200 m depth, relative to the reference station), but more moderate over the central Kerguelen Plateau and in the northern plume of the Kerguelen bloom (~2-fold at 200 m depth). The C : Th ratio of large ( μm) potentially sinking particles collected via sequential filtration using in situ pumping (ISP) systems was used to convert the 234Th flux into a POC export flux. The C : Th ratios of sinking particles were highly variable (3.1 ± 0.1 to 10.5 ± 0.2 μmol dpm−1) with no clear site-related trend, despite the variety of ecosystem responses in the fertilized regions. C : Th ratios showed a decreasing trend between 100 and 200 m depth suggesting preferential carbon loss relative to 234Th possibly due to heterotrophic degradation and/or grazing activity. C : Th ratios of sinking particles s led with drifting sediment traps in most cases showed very good agreement with ratios for particles collected via ISP deployments ( μm particles). Carbon export production varied between 3.5 ± 0.9 and 11.8 ± 1.3 mmol m−2 d−1 from the upper 100 m and between 1.8 ± 0.9 and 8.2 ± 0.9 mmol m−2 d−1 from the upper 200 m. The highest export production was found inside the PF meander with a range of 5.3 ± 1.0 to 11.8 ± 1.1 mmol m−2 d−1 over the 19-day survey period. The impact of Fe fertilization is highest inside the PF meander with 2.9–4.5-fold higher carbon flux at 200 m depth in comparison to the HNLC control station. The impact of Fe fertilization was significantly less over the central plateau (stations A3 and E-4W) and in the northern branch of the bloom (station F-L) with 1.6–2.0-fold higher carbon flux compared to the reference station R. Export efficiencies (ratio of export to primary production and ratio of export to new production) were particularly variable with relatively high values in the recirculation feature (6 to 27 %, respectively) and low values (1 to 5 %, respectively) over the central plateau (station A3) and north of the PF (station F-L), indicating spring biomass accumulation. Comparison with KEOPS1 results indicated that carbon export production is much lower during the onset of the bloom in austral spring than during the peak and declining phases in late summer.
Publisher: Oxford University Press (OUP)
Date: 08-12-2022
Abstract: We present new and archival atomic hydrogen (H i) observations of 15 of the most massive spiral galaxies in the local Universe (${M_{\\star }}\\gt 10^{11} \\, {\\rm M}_\\odot$). From 3D kinematic modeling of the datacubes, we derive extended H i rotation curves, and from these, we estimate masses of the dark matter halos and specific angular momenta of the discs. We confirm that massive spiral galaxies lie at the upper ends of the Tully–Fisher relation (mass vs velocity, M ∝ V4) and Fall relation (specific angular momentum vs mass, j ∝ M0.6), in both stellar and baryonic forms, with no significant deviations from single power laws. We study the connections between baryons and dark matter through the stellar (and baryon)-to-halo ratios of mass fM ≡ M⋆/Mh and specific angular momentum fj, ⋆ ≡ j⋆/jh and fj, bar ≡ jbar/jh. Combining our s le with others from the literature for less massive disc-dominated galaxies, we find that fM rises monotonically with M⋆ and Mh (instead of the inverted-U shaped fM for spheroid-dominated galaxies), while fj, ⋆ and fj, bar are essentially constant near unity over four decades in mass. Our results indicate that disc galaxies constitute a self-similar population of objects closely linked to the self-similarity of their dark halos. This picture is reminiscent of early analytical models of galaxy formation wherein discs grow by relatively smooth and gradual inflow, isolated from disruptive events such as major mergers and strong active galactic nuclei feedback, in contrast to the more chaotic growth of spheroids.
Publisher: American Astronomical Society
Date: 20-02-2013
Publisher: Oxford University Press (OUP)
Date: 26-04-2023
Abstract: We develop a framework for using clustering-based redshift inference (cluster-$z$ ) to measure the evolving galaxy luminosity function (GLF) and galaxy stellar mass function (GSMF) using Wide-field Infrared Survey Explorer W1 (3.4 μm) mid-infrared photometry and positions. We use multiple reference sets from the Galaxy And Mass Assembly survey, Sloan Digital Sky Survey and Baryon Oscillation Spectroscopic Survey. Combining the resulting cluster-$z$ s allows us to enlarge the study area, and by accounting for the specific properties of each reference set, making best use of each reference set to produce the best overall result. Thus we are able to measure the GLF and GSMF over ∼7500 deg2 of the Northern Galactic Cap up to $z$ & 0.6. Our method can easily be adapted for new studies with fainter magnitudes, which pose difficulties for the derivation of photo-$z$ s. With better statistics in future surveys this technique is a strong candidate for studies with new emerging data from, e.g. the Vera C Rubin Observatory, the Euclid mission or the Nancy Grace Roman Space Telescope.
Publisher: Wiley
Date: 13-05-2010
Publisher: EDP Sciences
Date: 28-04-2014
Publisher: Oxford University Press (OUP)
Date: 02-10-2021
Abstract: We use the 21-cm emission-line data from the Deep Investigation of Neutral Gas Origin-Very Large Array (DINGO-VLA) project to study the atomic hydrogen gas H i of the Universe at redshifts z & 0.1. Results are obtained using a stacking analysis, combining the H i signals from 3622 galaxies extracted from 267 VLA pointings in the G09 field of the Galaxy and Mass Assembly Survey (GAMA). Rather than using a traditional one-dimensional spectral stacking method, a three-dimensional cubelet stacking method is used to enable deconvolution and the accurate recovery of average galaxy fluxes from this high-resolution interferometric data set. By probing down to galactic scales, this experiment also overcomes confusion corrections that have been necessary to include in previous single-dish studies. After stacking and deconvolution, we obtain a 30σ H i mass measurement from the stacked spectrum, indicating an average H i mass of ${\\rm{M_{\\rm{{H}\\,\\small{I}}}}}=(1.67\\pm 0.18)\\times 10^{9}~{\\rm{{\\rm M}_{\\odot }}}$. The corresponding cosmic density of neutral atomic hydrogen is ${\\rm{\\Omega _{\\rm{{H}\\,\\small{I}}}}}=(0.38\\pm 0.04)\\times 10^{-3}$ at redshift of z = 0.051. These values are in good agreement with earlier results, implying there is no significant evolution of $\\Omega _{\\rm{{H}\\,\\small{I}}}$ at lower redshifts.
Publisher: Cambridge University Press (CUP)
Date: 09-2011
DOI: 10.1017/S1743921312009088
Abstract: HIZOA J0836–43 is one of the most H i -massive galaxies in the local ( z 0.1) Universe. Not only are such galaxies extremely rare, but this “coelacanth” galaxy exhibits characteristics – in particular its active, inside-out stellar disk-building – that appear more typical of past ( z ~ 1) star formation, when large gas fractions were more common. Unlike most local giant H i galaxies, it is actively star forming. Moreover, the strong infrared emission is not induced by a merger event or AGN, as is commonly found in other local LIRGs. The galaxy is suggestive of a scaled-up version of local spiral galaxies its extended star formation activity likely being fueled by its large gas reservoir and, as such, can aid our understanding of star formation in systems expected to dominate at higher redshifts. The multi-wavelength imaging and spectroscopic observations that have led to these deductions will be presented. These include NIR ( JHK ) and MIR (Spitzer 3 – 24μm) imaging and photometry, MIR spectroscopy, ATCA H i -interferometry and Mopra CO line emission observations. But no optical data, as the galaxy is heavily obscured due to its location in Vela behind the Milky Way.
Publisher: Oxford University Press (OUP)
Date: 10-11-2021
Abstract: In this study, we present a new experimental design using clustering-based redshift inference to measure the evolving galaxy luminosity function (GLF) spanning 5.5 decades from L ∼ 1011.5 to 106 L⊙. We use data from the Galaxy And Mass Assembly (GAMA) survey and the Kilo-Degree Survey (KiDS). We derive redshift distributions in bins of apparent magnitude to the limits of the GAMA-KiDS photometric catalogue: mr ≲ 23 more than a decade in luminosity beyond the limits of the GAMA spectroscopic redshift s le via clustering-based redshift inference. This technique uses spatial cross-correlation statistics for a reference set with known redshifts (in our case, the main GAMA s le) to derive the redshift distribution for the target ensemble. For the calibration of the redshift distribution, we use a simple parametrization with an adaptive normalization factor over the interval 0.005 & z & 0.48 to derive the clustering redshift results. We find that the GLF has a relatively constant power-law slope α ≈ −1.2 for −17 ≲ Mr ≲ −13, and then appears to steepen sharply for −13 ≲ Mr ≲ −10. This upturn appears to be where globular clusters (GCs) take over to dominate the source counts as a function of luminosity. Thus, we have mapped the GLF across the full range of the z ∼ 0 field galaxy population from the most luminous galaxies down to the GC scale.
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.BIOPSYCH.2015.11.020
Abstract: The food addiction model proposes that obesity overlaps with addiction in terms of neurobiological alterations in the striatum and related clinical manifestations (i.e., craving and persistence of unhealthy habits). Therefore, we aimed to examine the functional connectivity of the striatum in excess-weight versus normal-weight subjects and to determine the extent of the association between striatum connectivity and in idual differences in food craving and changes in body mass index (BMI). Forty-two excess-weight participants (BMI > 25) and 39 normal-weight participants enrolled in the study. Functional connectivity in the ventral and dorsal striatum was indicated by seed-based analyses on resting-state data. Food craving was indicated with subjective ratings of visual cues of high-calorie food. Changes in BMI between baseline and 12 weeks follow-up were assessed in 28 excess-weight participants. Measures of connectivity in the ventral striatum and dorsal striatum were compared between groups and correlated with craving and BMI change. Participants with excess weight displayed increased functional connectivity between the ventral striatum and the medial prefrontal and parietal cortices and between the dorsal striatum and the somatosensory cortex. Dorsal striatum connectivity correlated with food craving and predicted BMI gains. Obesity is linked to alterations in the functional connectivity of dorsal striatal networks relevant to food craving and weight gain. These neural alterations are associated with habit learning and thus compatible with the food addiction model of obesity.
Publisher: University of California Press
Date: 2016
DOI: 10.12952/JOURNAL.ELEMENTA.000130
Abstract: The discovery that melting sea ice can fertilize iron (Fe)-depleted polar waters has recently fostered trace metal research efforts in sea ice. The aim of this review is to summarize and synthesize the current understanding of Fe biogeochemistry in sea ice. To do so, we compiled available data on particulate, dissolved, and total dissolvable Fe (PFe, DFe and TDFe, respectively) from sea-ice studies from both polar regions and from sub-Arctic and northern Hemisphere temperate areas. Data analysis focused on a circum-Antarctic Fe dataset derived from 61 ice cores collected during 10 field expeditions carried out between 1997 and 2012 in the Southern Ocean. Our key findings are that 1) concentrations of all forms of Fe (PFe, DFe, TDFe) are at least a magnitude larger in fast ice and pack ice than in typical Antarctic surface waters 2) DFe, PFe and TDFe behave differently when plotted against sea-ice salinity, suggesting that their distributions in sea ice are driven by distinct, spatially and temporally decoupled processes 3) DFe is actively extracted from seawater into growing sea ice 4) fast ice generally has more Fe-bearing particles, a finding supported by the significant negative correlation observed between both PFe and TDFe concentrations in sea ice and water depth 5) the Fe pool in sea ice is coupled to biota, as indicated by the positive correlations of PFe and TDFe with chlorophyll a and particulate organic carbon and 6) the vast majority of DFe appears to be adsorbed onto something in sea ice. This review also addresses the role of sea ice as a reservoir of Fe and its role in seeding seasonally ice-covered waters. We discuss the pivotal role of organic ligands in controlling DFe concentrations in sea ice and highlight the uncertainties that remain regarding the mechanisms of Fe incorporation in sea ice.
Publisher: Oxford University Press (OUP)
Date: 03-12-2015
Publisher: Elsevier BV
Date: 08-2010
DOI: 10.1016/J.ACA.2010.07.037
Abstract: Trace elements often limit phytoplankton growth in the ocean, and the quantification of particulate forms is essential to fully understand their biogeochemical cycling. There is presently a lack of reliable measurements on the trace elemental content of marine particles, in part due to the inadequacies of the s ling and analytical methods employed. Here we report on the development of a series of state-of-the-art trace metal clean methods to collect and process oceanic particulate material in open-ocean and sea ice environments, including s ling, size-fractionated filtration, particle digestions and analysis by magnetic sector inductively coupled plasma-mass spectrometry (ICP-MS). Particular attention was paid to the analysis of certified reference materials (CRMs) and field blanks, which are typically the limiting factor for the accurate analysis of low concentrations of trace metals in marine particulate s les. Theoretical detection limits (3 s of the blank) were low for all 17 elements considered, and varied according to filter material and porosity (sub-microg L(-1) for polycarbonate filters and 1-2 microg L(-1) for quartz and polyester filters). Analytical accuracy was verified using fresh water CRMs, with excellent recoveries noted (93-103%). Digestion efficiencies for various acid combinations were assessed using sediment and plankton CRMs. Using nitric acid only, good recoveries (79-90%) were achieved for Mo, Cd, Ba, Pb, Mn, Fe, Co, Ni, Cu, Zn and Ga. The addition of HF was necessary for the quantitative recovery of the more refractory trace elements such as U, Al, V and Cr. Bioactive elements such as P can also be analysed and used as a biomass normaliser. Our developed s ling and analytical methods proved reliable when applied during two major field programs in both the open Southern Ocean and Antarctic sea ice environments during the International Polar Year in 2007. Trace elemental data are presented for particulate s les collected in both suspended and sinking marine material, and also within sea ice cores.
Publisher: American Astronomical Society
Date: 07-2023
Abstract: We combine James Webb Space Telescope (JWST) and Hubble Space Telescope imaging with Atacama Large Millimeter Array CO(2–1) spectroscopy to study the highly turbulent multiphase intergalactic medium (IGM) in Stephan’s Quintet on 25–150 pc scales. Previous Spitzer observations revealed luminous H 2 line cooling across a 45 kpc-long filament, created by a giant shock wave, following the collision with an intruder galaxy, NGC 7318b. We demonstrate that the Mid-Infrared Instrument/F1000W/F770W filters are dominated by 0–0 S(3) H 2 and a combination of polycyclic aromatic hydrocarbon and 0–0 S(5) H 2 emission. These observations reveal the dissipation of kinetic energy as massive clouds experience collisions, interactions, and likely destruction/recycling within different phases of the IGM. In 1 kpc-scaled structure, warm H 2 was seen to form a triangular-shaped head and tail of compressed and stripped gas behind a narrow shell of cold H 2 . In another region, two cold molecular clumps with very different velocities are connected by an arrow-shaped stream of warm, probably shocked, H 2 suggesting a cloud–cloud collision is occurring. In both regions, a high warm-to-cold molecular gas fraction indicates that the cold clouds are being disrupted and converted into warm gas. We also map gas associated with an apparently forming dwarf galaxy. We suggest that the primary mechanism for exciting strong mid-IR H 2 lines throughout Stephan’s Quintet is through a fog of warm gas created by the shattering of denser cold molecular clouds and mixing/recycling in the post-shocked gas. A full picture of the erse kinematics and excitation of the warm H 2 will require future JWST mid-IR spectroscopy. The current observations reveal the rich variety of ways that different gas phases can interact with one another.
Publisher: Oxford University Press (OUP)
Date: 15-01-2018
DOI: 10.1093/MNRAS/STY115
Publisher: Springer Science and Business Media LLC
Date: 16-06-2020
Publisher: Oxford University Press (OUP)
Date: 18-10-2022
Abstract: We use spectral energy distribution (SED) fitting to place constraints on the stellar population properties of 29 quiescent ultra-diffuse galaxies (UDGs) across different environments. We use the fully Bayesian routine PROSPECTOR coupled with archival data in the optical, near, and mid-infrared from Spitzer and Wide-field Infrared Survey Explorer under the assumption of an exponentially declining star formation history. We recover the stellar mass, age, metallicity, dust content, star formation time scales, and photometric redshifts (photo-zs) of the UDGs studied. Using the mid-infrared data, we probe the existence of dust in UDGs. Although its presence cannot be confirmed, we find that the inclusion of small amounts of dust in the models brings the stellar populations closer to those reported with spectroscopy. Additionally, we fit the redshifts of all galaxies. We find a high accuracy in recovering photo-zs compared to spectroscopy, allowing us to provide new photo-z estimates for three field UDGs with unknown distances. We find evidence of a stellar population dependence on the environment, with quiescent field UDGs being systematically younger than their cluster counterparts. Lastly, we find that all UDGs lie below the mass–metallicity relation for normal dwarf galaxies. Particularly, the globular cluster (GC)-poor UDGs are consistently more metal-rich than GC-rich ones, suggesting that GC-poor UDGs may be puffed-up dwarfs, while most GC-rich UDGs are better explained by a failed galaxy scenario. As a byproduct, we show that two galaxies in our s le, NGC 1052-DF2 and NGC 1052-DF4, share equivalent stellar population properties, with ages consistent with 8 Gyr. This finding supports formation scenarios where the galaxies were formed together.
Publisher: Cambridge University Press (CUP)
Date: 2014
DOI: 10.1017/PASA.2014.44
Abstract: We present a revised effective wavelength and photometric calibration for the Wide-field Infrared Survey Explorer W 4 band, including tests of empirically motivated modifications to its pre-launch laboratory-measured relative system response curve. We derived these by comparing measured W 4 photometry with photometry synthesised from spectra of galaxies and planetary nebulae. The difference between measured and synthesised photometry using the pre-launch laboratory-measured W 4 relative system response can be as large as 0.3 mag for galaxies and 1 mag for planetary nebulae. We find the W 4 effective wavelength should be revised upward by 3.3%, from 22.1 to 22.8 μm, and the W 4 AB magnitude of Vega should be revised from m W 4 = 6.59 to m W 4 = 6.66. In an attempt to reproduce the observed W 4 photometry, we tested three modifications to the pre-launch laboratory-measured W 4 relative system response curve, all of which have an effective wavelength of 22.8 μm. Of the three relative system response curve models tested, a model that matches the laboratory-measured relative system response curve, but has the wavelengths increased by 3.3% (or ≃ 0.73 μm) achieves reasonable agreement between the measured and synthesised photometry.
Publisher: EDP Sciences
Date: 28-04-2016
Publisher: Cambridge University Press (CUP)
Date: 03-2016
DOI: 10.1017/S1743921316011637
Abstract: As an extreme kind of environment, Hickson Compact groups (HCGs) have shown to be very complex systems. HI-VLA observations revealed an intrincated network of HI tails and bridges, tracing pre-processing through extreme tidal interactions. We found HCGs to show a large HI deficiency supporting an evolutionary sequence where gas-rich groups transform via tidal interactions and ISM (interstellar medium) stripping into gas-poor systems. We detected as well a diffuse HI component in the groups, increasing with evolutionary phase, although with uncertain distribution. The complex net of detected HI as observed with the VLA seems hence so puzzling as the missing one. In this talk we revisit the existing VLA information on the HI distribution and kinematics of HCGs by means of X3D visualization. X3D constitutes a powerful tool to extract the most from HI data cubes and a mean of simplifying and easing the access to data visualization and publication via three-dimensional (3-D) diagrams.
Publisher: Oxford University Press (OUP)
Date: 11-12-2017
Publisher: American Geophysical Union (AGU)
Date: 06-08-2011
DOI: 10.1029/2010JG001628
Publisher: Oxford University Press (OUP)
Date: 18-09-2014
Publisher: Wiley
Date: 27-10-2022
Publisher: Oxford University Press (OUP)
Date: 29-11-0001
Publisher: Wiley
Date: 08-2019
DOI: 10.1002/LOM3.10327
Publisher: Oxford University Press (OUP)
Date: 20-05-2014
DOI: 10.1093/MNRAS/STU727
Publisher: Copernicus GmbH
Date: 25-06-2015
Abstract: Abstract. Dissolved Fe (dFe) concentrations were measured in the upper 1300 m of the water column in the vicinity of the Kerguelen Islands as part of the second KErguelen Ocean Plateau compared Study (KEOPS2). Concentrations ranged from 0.06 nmol L−1 in offshore, Southern Ocean waters to 3.82 nmol L−1 within Hillsborough Bay, on the north-eastern coast of the Kerguelen Islands. Direct island runoff, glacial melting and resuspended sediments were identified as important inputs of dFe that could potentially fertilise the northern part of the plateau. A significant deep dFe enrichment was observed over the plateau with dFe concentrations increasing up to 1.30 nmol L−1 close to the seafloor, probably due to sediment resuspension and pore water release. Biological uptake was shown to induce a significant decrease in dFe concentrations between two visits (28 days apart) at a station above the plateau. Our work also considered other processes and sources, such as lateral advection of enriched seawater, remineralisation processes, and the influence of the polar front (PF) as a vector for Fe transport. Overall, heterogeneous sources of Fe over and off the Kerguelen Plateau, in addition to strong variability in Fe supply by vertical or horizontal transport, may explain the high variability in dFe concentrations observed during this study.
Publisher: Oxford University Press (OUP)
Date: 08-07-2015
Publisher: Oxford University Press (OUP)
Date: 03-12-2015
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 05-2011
Publisher: Oxford University Press (OUP)
Date: 09-09-2015
Publisher: Elsevier BV
Date: 05-2011
Publisher: Oxford University Press (OUP)
Date: 21-07-2014
Publisher: Elsevier BV
Date: 11-2013
Publisher: American Astronomical Society
Date: 21-05-2010
Publisher: Oxford University Press (OUP)
Date: 05-10-2020
Abstract: Using mid-infrared star formation rate and stellar mass indicators in WISE (Wide-field Infrared Survey Explorer), we construct and contrast the relation between star formation rate and stellar mass for isolated and paired galaxies. Our s les comprise a selection of AMIGA (Analysis of the interstellar Medium in Isolated GAlaxies isolated galaxies) and pairs of ALFALFA (Arecibo Legacy Fast ALFA) galaxies with H i detections such that we can examine the relationship between H i content (gas fraction, H i deficiency) and galaxy location on the main sequence (MS) in these two contrasting environments. We derive for the first time an H i scaling relation for isolated galaxies using WISE stellar masses, and thereby establish a baseline predictor of H i content that can be used to assess the impact of environment on H i content when compared with s les of galaxies in different environments. We use this updated relation to determine the H i deficiency of both our paired and isolated galaxies. Across all the quantities examined as a function of environment in this work (MS location, gas fraction, and H i deficiency), the AMIGA s le of isolated galaxies is found to have the lower dispersion: σAMIGA = 0.37 versus σPAIRS = 0.55 on the MS, σAMIGA = 0.44 versus σPAIRS = 0.54 in gas fraction, and σAMIGA = 0.28 versus σPAIRS = 0.34 in H i deficiency. We also note fewer isolated quiescent galaxies, 3 (0.6${{\\ \\rm per\\ cent}}$), compared to 12 (2.3${{\\ \\rm per\\ cent}}$) quiescent pair members. Our results suggest the differences in scatter measured between our s les are environment driven. Galaxies in isolation behave relatively predictably, and galaxies in more densely populated environments adopt a more stochastic behaviour, across a broad range of quantities.
Publisher: Oxford University Press (OUP)
Date: 09-07-2013
Publisher: Oxford University Press (OUP)
Date: 16-09-2016
Publisher: Oxford University Press (OUP)
Date: 13-09-2017
Publisher: European Southern Observatory (ESO)
Date: 2019
Publisher: EDP Sciences
Date: 07-2010
Publisher: American Astronomical Society
Date: 30-04-2012
Publisher: American Astronomical Society
Date: 06-12-2019
Publisher: American Astronomical Society
Date: 25-02-2014
Publisher: American Astronomical Society
Date: 28-10-2014
Publisher: Oxford University Press (OUP)
Date: 02-2016
Publisher: Oxford University Press (OUP)
Date: 11-08-2021
Abstract: We use high-resolution ASKAP observations of galaxies in the Eridanus supergroup to study their H i, angular momentum, and star formation properties, as part of the WALLABY pre-pilot survey efforts. The Eridanus supergroup is composed of three sub-groups in the process of merging to form a cluster. The main focus of this study is the Eridanus (or NGC 1395) sub-group. The baryonic specific angular momentum – baryonic mass (jb−Mb) relation for the Eridanus galaxies is observed to be an unbroken power law of the form $j_{\\mathrm{b}} \\propto M_{\\mathrm{b}}^{0.57 \\pm 0.05}$, with a scatter of ∼0.10 ± 0.01 dex, consistent with previous works. We examine the relation between the atomic gas fraction, fatm, and the integrated atomic disc stability parameter q (the fatm−q relation), and find that the Eridanus galaxies deviate significantly from the relation owing to environmental processes such as tidal interactions and ram pressure affecting their H i gas. We find that a majority of the Eridanus galaxies are H i deficient compared to normal star-forming galaxies in the field. We also find that the star formation among the Eridanus galaxies may be suppressed owing to their environment, thus hinting at significant levels of pre-processing within the Eridanus sub-group, even before the galaxies have entered a cluster-like environment.
Publisher: American Astronomical Society
Date: 08-2023
Abstract: In this empirical work, we aim to quantify the systematic uncertainties in stellar-mass ( M ⋆ ) estimates made from spectral energy distribution (SED) fitting through stellar population synthesis (SPS) for galaxies in the local Universe by using the dynamical mass ( M dyn ) estimator as an SED-independent check on stellar mass. We first construct a statistical model of the high-dimensional space of galaxy properties including size ( R e ), velocity dispersion ( σ e ), surface brightness ( I e ), mass-to-light ratio ( M ⋆ / L ), rest-frame color, Sérsic index ( n ), and dynamical mass ( M dyn ), and accounting for selection effects and covariant errors. We disentangle the correlations among galaxy properties and find that the variation in M ⋆ / M dyn is driven by σ e , Sérsic index and color. We use these parameters to calibrate an SED-independent M ⋆ estimator, M ˆ ⋆ . We find the random scatter of the relation M ⋆ − M ˆ ⋆ to be 0.108 dex and 0.147 dex for quiescent and star-forming galaxies, respectively. Finally, we inspect the residuals as a function of SPS parameters (dust, age, metallicity, and star formation rate) and spectral indices (H α , H δ , and D n 4000). For quiescent galaxies, ∼65% of the scatter can be explained by the uncertainty in SPS parameters, with dust and age being the largest sources of uncertainty. For star-forming galaxies, while age and metallicity are the leading factors, SPS parameters account for only ∼13% of the scatter. These results leave us with remaining unmodelled scatters of 0.055 dex and 0.122 dex for quiescent and star-forming galaxies, respectively. This can be interpreted as a conservative limit on the precision in M ⋆ that can be achieved via simple SPS modeling.
Publisher: Oxford University Press (OUP)
Date: 12-04-2016
DOI: 10.1093/MNRAS/STW832
Publisher: EDP Sciences
Date: 2023
DOI: 10.1051/0004-6361/202243193
Abstract: Aims. We investigate how different mid-infrared (mid-IR) properties of galaxies are correlated with the environment in which the galaxies are located. For this purpose, we first study the dependence of galaxy clustering on the absolute magnitude at 3.4 μm and redshift. Then, we look into the environmental dependence of mid-IR luminosities and the galaxy properties derived from these luminosities. We also explore how various IR galaxy luminosity selections influence the galaxy clustering measurements. Methods. We used a set of W 1 (3.4 μm) absolute magnitude ( M W 1 ) selected s les from the Galaxy and Mass Assembly (GAMA) survey matched with mid-IR properties from the Wide-field Infrared Survey Explorer (WISE) in the redshift range 0.07 ≤ z 0.43. We computed the galaxy two-point correlation function (2pCF) and compared the clustering lengths between subs les binned in M W 1 and in redshift. We also measured the marked correlation function (MCF), in which the galaxies are weighted by marks when measuring clustering statistics, using the luminosities in the WISE W 1 to W 4 (3.4 to 22 μm) bands as marks. Additionally, we compared the measurements of MCFs with different estimates of stellar mass and star formation rate (SFR) used as marks. Finally, we checked how different selections applied to the s le affect the clustering measurements. Results. We show strong clustering dependence on the W 1 absolute magnitude: galaxies brighter in the W 1 band are more strongly clustered than their fainter counterparts. We also observe a lack of significant redshift dependence of clustering in the redshift range 0.07 ≤ z 0.43. We show that although the W 1 and W 2 bands are direct indicators of stellar mass, a galaxy s le selected based on W 1 or W 2 bands does not perfectly show the clustering behaviour of a stellar mass-selected s le. The proxy relation between W 3 and W 4 bands and SFR is similar. We also demonstrate the influence of estimation techniques of stellar mass and SFR on the clustering measurements.
Publisher: American Astronomical Society
Date: 07-10-2019
Publisher: Oxford University Press (OUP)
Date: 30-12-2015
Publisher: American Astronomical Society
Date: 04-10-2018
Publisher: American Geophysical Union (AGU)
Date: 08-2023
DOI: 10.1029/2022GB007613
Abstract: Manganese (Mn) is an essential element involved in photosynthesis, yet its concentrations in Southern Ocean open waters are very low, arising from biological uptake and limited external inputs. At southern latitudes, waters overlying the Antarctic shelf are expected to have much higher Mn concentrations due to their proximity to external sources. In this study, we investigated the potential export of Mn‐rich Antarctic shelf waters toward depleted open Southern Ocean waters. Our results showed that while high Mn concentrations were observed over the shelf, biological uptake decreased dissolved Mn concentrations in surface waters north of the South Antarctic Circumpolar Current Front ( .1 nmol kg −1 ), limiting its export. Conversely, mixing between Mn‐rich Antarctic Bottom Waters and Mn‐depleted Lower Circumpolar Deep Waters combined with oxidative and scavenging processes led to a decrease in dissolved Mn concentrations within bottom waters, with distance from the coast. Particulate Mn concentrations also showed a decreasing trend with distance from the coast. A comparison with other Antarctic coastal regions suggests this bottom water Mn removal may be widespread and that East Antarctica may be characterized by lower Mn concentrations compared to other regions. Still, subsurface dissolved Mn maxima (0.3–0.6 nmol kg −1 ) represented a potential reservoir for surface waters. We hypothesize that these high subsurface values result from external sources near the shelf. Overall, these results suggest that the moderate lateral export of trace metal‐enriched waters contributes to the extremely low and potentially limiting Mn concentrations previously reported further north in this Southern Ocean region.
Publisher: American Astronomical Society
Date: 14-12-2018
Publisher: Oxford University Press (OUP)
Date: 04-2015
DOI: 10.1093/MNRAS/STV589
Publisher: Elsevier BV
Date: 09-2016
Publisher: Oxford University Press (OUP)
Date: 06-07-2016
Publisher: Oxford University Press (OUP)
Date: 08-08-2016
Publisher: Springer Science and Business Media LLC
Date: 07-2020
Publisher: Cambridge University Press (CUP)
Date: 06-2014
DOI: 10.1017/S1743921316009753
Abstract: Our view of the low-redshift Cosmic Web has been revolutionized by galaxy redshift surveys such as 6dFGS, SDSS and 2MRS. However, the trade-off between depth and angular coverage limits a systematic three-dimensional account of the entire sky beyond the Local Volume ( z 0.05). In order to reliably map the Universe to cosmologically significant depths over the full celestial sphere, one must draw on multiwavelength datasets and state-of-the-art photometric redshift techniques. We have undertaken a dedicated program of cross-matching the largest photometric all-sky surveys – 2MASS, WISE and SuperCOSMOS – to obtain accurate redshift estimates of millions of galaxies. The first outcome of these efforts – the 2MASS Photometric Redshift catalog (2MPZ, Bilicki et al . 2014a) – has been publicly released and includes almost 1 million galaxies with a mean redshift of z =0.08. Here we summarize how this catalog was constructed and how using the WISE mid-infrared s le together with SuperCOSMOS optical data allows us to push to redshift shells of z ∼ 0.2 –0.3 on unprecedented angular scales. Our catalogs, with ∼ 20 million sources in total, provide access to cosmological volumes crucial for studies of local galaxy flows (clustering dipole, bulk flow) and cross-correlations with the cosmic microwave background such as the integrated Sachs-Wolfe effect or lensing studies.
Publisher: Elsevier BV
Date: 08-2018
Publisher: Oxford University Press (OUP)
Date: 11-07-2016
Publisher: American Astronomical Society
Date: 16-03-2018
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.JAAC.2018.06.039
Abstract: Adolescents with excess weight are particularly sensitive to stress, which may contribute to the presence of emotional eating behaviors. It is proposed that this may be due to alterations in the connectivity between hypothalamic networks and regions of the "emotional nervous system," involved in the regulation of energy balance and stress processing. However, this remains to be clarified in adolescents with excess weight. We investigated whole-brain differences in the functional connectivity of the medial and lateral hypothalamus (MH and LH) between adolescents with excess weight (EW, n = 53 mean age = 14.64 years, SD = 1.78) and normal weight (NW, n = 51 mean age = 15.29 years, SD = 1.75) using seed-based resting-state analyses. Then, in a subset of 22 adolescents with EW (mean age = 15.75 years, SD = 1.70) and 32 with NW (mean age = 15.27, SD = 2.03), we explored for group interactions between the MH/LH networks and stress response in the Trier Social Stress Task (TSST) and emotional eating, assessed with the Dutch Eating Behavior Questionnaire (DEB-Q). Compared to NW, EW showed higher functional connectivity in the LH-orbitofrontal cortex, ventral striatum, anterior insula, and in the MH-middle temporal cortex networks. EW also showed lower connectivity in the LH-cerebellum, and in the MH-middle prefrontal, pre-, and postcentral gyri networks. In EW, higher connectivity of the LH-nucleus accumbens and LH-midbrain networks were associated with stress response. Higher connectivity in the LH-midbrain was also associated with a greater presence of emotional eating behaviors in EW. Adolescents with EW showed functional connectivity alterations within both MH/LH networks. Alterations in the LH network were linked with higher levels of stress response and emotional-driven eating patterns.
Publisher: American Astronomical Society
Date: 23-09-2008
DOI: 10.1086/592784
Publisher: European Southern Observatory (ESO)
Date: 2019
Publisher: Oxford University Press (OUP)
Date: 26-11-2014
Publisher: American Geophysical Union (AGU)
Date: 02-2018
DOI: 10.1002/2017GB005736
Publisher: Elsevier BV
Date: 04-2014
Publisher: Elsevier BV
Date: 09-2016
Publisher: American Astronomical Society
Date: 02-2022
Abstract: We report on the detection of a large, extended H i cloud complex in the Galaxy and Mass Survey G23 field, located at a redshift of z ∼ 0.03, observed as part of the MeerKAT Habitat of Galaxies Survey c aign (a pilot survey to explore the mosaicing capabilities of the MeerKAT telescope). The cloud complex, with a total mass of 10 10.0 M ⊙ , lies in proximity to a large galaxy group with M dyn ∼ 10 13.5 M ⊙ . We identify seven H ɪ peak concentrations, interconnected as a tenuous chain structure, extending ∼400 kpc from east to west, with the largest (central) concentration containing 10 9.7 M ⊙ in H ɪ gas distributed across 50 kpc. The main source is not detected in ultraviolet, optical, or infrared imaging. The implied gas mass-to-light ratio ( M H I / L r ) is extreme ( ) even in comparison to other dark clouds . The complex has very little kinematic structure (110 km s −1 ), making it difficult to identify cloud rotation. Assuming pressure support, the total mass of the central concentration is 10 10.2 M ⊙ , while a lower limit to the dynamical mass in the case of full rotational support is 10 10.4 M ⊙ . If the central concentration is a stable structure, it has to contain some amount of unseen matter, but potentially less than is observed for a typical galaxy. It is, however, not clear whether the structure has any gravitationally stable concentrations. We report a faint UV-optical-infrared source in proximity to one of the smaller concentrations in the gas complex, leading to a possible stellar association. The system nature and origins is enigmatic, potentially being the result of an interaction with or within the galaxy group it appears to be associated with.
Publisher: Oxford University Press (OUP)
Date: 08-11-2016
Publisher: American Astronomical Society
Date: 30-11-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3AY41312H
Abstract: A simplified, automated, low cost, portable, off-line extraction method with high throughput for trace metal analysis in seawater by SF-ICP-MS.
Publisher: Oxford University Press (OUP)
Date: 16-03-2019
DOI: 10.1093/MNRAS/STZ799
Publisher: Oxford University Press (OUP)
Date: 13-03-2015
DOI: 10.1093/MNRAS/STV237
Publisher: Oxford University Press (OUP)
Date: 10-01-2015
Publisher: Oxford University Press (OUP)
Date: 21-09-2020
Abstract: How do galaxy properties (such as stellar mass, luminosity, star formation rate, and morphology) and their evolution depend on the mass of their host dark matter halo? Using the Galaxy and Mass Assembly group catalogue, we address this question by exploring the dependence on host halo mass of the luminosity function (LF) and stellar mass function (SMF) for grouped galaxies sub ided by colour, morphology, and central/satellite. We find that spheroidal galaxies in particular dominate the bright and massive ends of the LF and SMF, respectively. More massive haloes host more massive and more luminous central galaxies. The satellites LF and SMF, respectively, show a systematic brightening of characteristic magnitude, and increase in characteristic mass, with increasing halo mass. In contrast to some previous results, the faint-end and low-mass slopes show little systematic dependence on halo mass. Semi-analytic models and simulations show similar or enhanced dependence of central mass and luminosity on halo mass. Faint and low-mass simulated satellite galaxies are remarkably independent of halo mass, but the most massive satellites are more common in more massive groups. In the first investigation of low-redshift LF and SMF evolution in group environments, we find that the red/blue ratio of galaxies in groups has increased since redshift z ≈ 0.3 relative to the field population. This observation strongly suggests that quenching of star formation in galaxies as they are accreted into galaxy groups is a significant and ongoing process.
Publisher: Springer Science and Business Media LLC
Date: 17-08-2018
DOI: 10.1038/S41366-018-0173-3
Abstract: Accumulation of visceral adiposity can disrupt the brain's sensitivity to interoceptive feedback, which is coded in the insula. This study aimed to test the link between visceral fat and the functional connectivity of two insulae regions relevant for eating behavior: the middle-dorsal insula (mIns), which codes homeostatic changes, and the rostral insula (rIns), which codes stable representations of food properties. We also assessed the impact of visceral adiposity-associated insulae networks on food craving. Seventy-five adults ranging in weight status (normal and excess weight) underwent resting-state functional magnetic resonance imaging (fMRI) and subjective food craving measures. We examined the association between visceral fat and seed-based functional connectivity of the mIns and the rIns, controlling for BMI, age, and sex, using multiple regressions in SPM8. We also tested if visceral fat mediated the association between insulae connectivity and food craving. Higher visceral adiposity was associated with decreased connectivity between the mIns and a cluster involving the hypothalamus and the bed nucleus of the stria terminalis. Decreased connectivity in this network was associated with greater food craving, a relation mediated by visceral adiposity. Visceral adiposity was also associated with increased connectivity between the mIns and the middle frontal gyri and the right intraparietal cortex, and between the rIns and the right amygdala. Accumulation of visceral adiposity is linked to disrupted functional connectivity within the mIns and rIns networks. Furthermore, the link between the mIns network and food craving is mediated by visceral fat. Findings suggest that visceral fat disrupts insula coding of bodily homeostatic signals, which may boost externally driven food cravings.
Publisher: Oxford University Press (OUP)
Date: 07-06-2016
Publisher: Oxford University Press (OUP)
Date: 30-07-2016
Publisher: Oxford University Press (OUP)
Date: 09-2020
Abstract: We use KiDS weak lensing data to measure variations in mean halo mass as a function of several key galaxy properties (namely stellar colour, specific star formation rate, Sérsic index, and effective radius) for a volume-limited s le of GAMA galaxies in a narrow stellar mass range [M* ∼ (2–5) × 1010 M⊙]. This mass range is particularly interesting, inasmuch as it is where bimodalities in galaxy properties are most pronounced, and near to the break in both the galaxy stellar mass function and the stellar-to-halo mass relation (SHMR). In this narrow mass range, we find that both size and Sérsic index are better predictors of halo mass than either colour or SSFR, with the data showing a slight preference for Sérsic index. In other words, we find that mean halo mass is more tightly correlated with galaxy structure than either past star formation history or current star formation rate. Our results lead to an approximate lower bound on the dispersion in halo masses among log M* ≈ 10.5 galaxies: We find that the dispersion is ≳0.3 dex. This would imply either that offsets from the mean SHMR are closely coupled to size/structure or that the dispersion in the SHMR is larger than what past results have suggested. Our results thus provide new empirical constraints on the relationship between stellar and halo mass assembly at this particularly interesting mass range.
Publisher: Elsevier BV
Date: 12-2015
Publisher: American Astronomical Society
Date: 13-12-2013
Publisher: EDP Sciences
Date: 10-2014
Publisher: American Geophysical Union (AGU)
Date: 31-08-2010
DOI: 10.1029/2009JG001031
Publisher: American Astronomical Society
Date: 14-10-2015
Publisher: Oxford University Press (OUP)
Date: 19-06-2015
Publisher: Oxford University Press (OUP)
Date: 03-11-2018
Publisher: American Astronomical Society
Date: 06-11-2020
Publisher: Oxford University Press (OUP)
Date: 14-12-2013
Publisher: American Astronomical Society
Date: 14-10-2015
Publisher: Oxford University Press (OUP)
Date: 02-06-2021
Abstract: We report the discovery of large amounts of previously undetected cold neutral atomic hydrogen (H i) around the core triplet galaxies in the nearby NGC 7232 galaxy group with MeerKAT. With a physical resolution of ∼1 kpc, we detect a complex web of low-surface-brightness H i emission down to a 4σ column density level of ∼1 × 1019 cm−2 (over 44 km s−1). The newly discovered H i streams extend over ∼20 arcmin corresponding to 140 kpc in projection. This is approximately three times the H i extent of the galaxy triplet (52 kpc). The H i debris has an H i mass of ∼6.6 × 109 M⊙, more than 50 per cent of the total H i mass of the triplet. Within the galaxy triplet, NGC 7233 and NGC 7232 have lost a significant amount of H i while NGC 7232B appears to have an excess of H i. The H i deficiency in NGC 7232 and NGC 7233 indicates that galaxy–galaxy interaction in the group concentrates on this galaxy pair while the other disc galaxies have visited them over time. In comparison to the AMIGA s le of isolated galaxies, we find that with regards to its total H i mass the NGC 7232/3 galaxy triplet is not H i-deficient. Despite the many interactions associated to the triplet galaxies, no H i seems to have been lost from the group (yet).
Publisher: American Astronomical Society
Date: 17-11-2017
Publisher: American Astronomical Society
Date: 09-02-2017
Publisher: Oxford University Press (OUP)
Date: 07-02-2013
DOI: 10.1093/MNRAS/STT030
Publisher: EDP Sciences
Date: 31-01-2023
DOI: 10.1051/0004-6361/202244622
Abstract: Context. Hickson compact groups (HCGs) are dense configurations of four to ten galaxies, whose H I morphology appears to follow an evolutionary sequence of three phases, with gas initially confined to galaxies, then significant amounts spread throughout the intra-group medium, and finally with almost no gas remaining in the galaxies themselves. It has also been suggested that several groups may harbour a diffuse H I component that is resolved out by interferometric observations. Aims. The H I deficiency of HCGs is expected to increase as the H I morphological phase progresses along the evolutionary sequence. If this is the case, H I deficiency would be a rough proxy for the age and evolutionary state of a HCG. We aim to test this hypothesis for the first time using a large s le of HCGs and to investigate the evidence for diffuse H I in HCGs. Methods. We performed a uniform reduction of all publicly available VLA H I observations (38 HCGs) with a purpose-built pipeline that also maximises the reproducibility of this study. The resulting H I data cubes were then analysed with the latest software tools to perform a manual separation of emission features into those belonging to galaxies and those extending into the intra-group medium. We thereby classified the H I morphological phase of each group as well as quantified their H I deficiency compared to galaxies in isolation. Results. We find little evidence that H I deficiency can be used as a proxy for the evolutionary phase of a compact group in either of the first two phases, with the distribution of H I deficiency being consistent in both. However, for the final phase, the distribution clearly shifts to high H I deficiencies, with more than 90% of the expected H I content typically missing. Across all HCGs studied, we identify a few cases where there is strong evidence for a diffuse gas component in the intra-group medium, which might be detectable with improved observations. We also classify a new sub-phase where groups contain a lone H I -bearing galaxy, but are otherwise devoid of gas. Conclusions. The new morphological phase we have identified is likely the result of an evolved, gas-poor group acquiring a new, gas-rich member. The large spread of H I deficiencies in the first two morphological phases suggests that there is a broad range of initial H I content in HCGs, which is perhaps influenced by large-scale environment, and that the timescale for morphological changes is, in general, considerably shorter than the timescale for the destruction or consumption of neutral gas in these systems.
Publisher: Elsevier BV
Date: 10-2021
Publisher: American Geophysical Union (AGU)
Date: 11-2018
DOI: 10.1029/2018JC014245
Publisher: Oxford University Press (OUP)
Date: 19-04-2022
Abstract: We extend the analysis of Bok et al. (2020) in which the H i content of isolated galaxies from the AMIGA (Analysis of the interstellar Medium in Isolated GAlaxies) s le and selected paired galaxies from ALFALFA (Arecibo Legacy Fast ALFA) were examined as a potential driver of galaxy location on the WISE (Wide-field Infrared Survey Explorer) mid-infrared SFR–M⋆ sequence. By further characterizing the isolated and pair galaxy s les, i.e. in terms of optical galaxy morphology, a more detailed and quantitative description of local galaxy environment by way of the local number density (η) and tidal strength (Q) parameters, star formation efficiency (SFE$_{\\rm {H{\\small {\\rm ~I}}}}$), and H i integrated profile asymmetries, we present plausible pathways for the broadening of the pair s le H i deficiency distribution towards both high and low deficiencies compared to the narrower isolated galaxy s le distribution (i.e. σPAIRS = 0.34 versus σAMIGA = 0.28). We associate the gas-rich tail of the pair deficiency distribution with the highest Q values, large profile asymmetries, and low SFEs. From this, we infer that merger activity is enhancing gas supplies, as well as disrupting the efficiency of star formation, via strong gravitational torques. The gas-poor wing of the deficiency distribution appears to be populated with galaxies in denser environments (with larger η values on average), more akin to groups. Despite our gas-rich selection criterion, there is a small population of early-type galaxies in the pair s le, which primarily fall in the positive deficiency wing of the distribution. These results suggest that a combination of a denser galaxy environment, early-type morphology, and higher stellar mass is contributing to the broadening of the deficiency distribution towards larger deficiencies.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.AAP.2018.12.024
Abstract: There is an outstanding need to identify predictors of driving under the influence of alcohol (DUI) among young adults, particularly women. Impulsivity, or the tendency to act without thinking, is a predictor of DUI, but the specific facets of impulsivity that predict DUI and their interaction with sex differences remain unclear. We aimed to investigate sex differences in the link between impulsivity facets and DUI. Moreover, we sought to replicate previous findings regarding sex differences on impulsivity, and associations between impulsivity facets and DUI. A total of 506 university students participated in the study (males, n = 128 females, n = 378). Participants completed measures of impulsivity (UPPS-P short version), alcohol use (AUDIT-C), frequency of DUI episodes and related perception of risk. The UPPS-P assesses five facets of impulsivity: sensation seeking, (lack of) premeditation and perseverance and positive and negative urgency. Men showed higher sensation seeking and lack of perseverance, alcohol use and DUI frequency and lower risk perception than women. DUI frequency was negatively associated with perception of risk and positively associated with alcohol use and the five impulsivity facets. After controlling for alcohol use and risk perception, only lack of premeditation was associated with DUI frequency in the whole s le. Sensation seeking was positively associated with DUI frequency only in women. The link between lack of premeditation and DUI suggest that pre-drinking planning strategies can contribute to prevent risky driving. In women, specific links between sensation seeking and DUI suggest the need for personality-tailored prevention strategies.
Publisher: Elsevier BV
Date: 08-2009
Publisher: American Astronomical Society
Date: 03-10-2017
Publisher: Elsevier BV
Date: 11-2016
Publisher: American Astronomical Society
Date: 11-07-2013
Location: United States of America
Start Date: 2023
End Date: 12-2025
Amount: $758,689.00
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2018
End Date: 02-2022
Amount: $679,334.00
Funder: Australian Research Council
View Funded Activity