ORCID Profile
0000-0002-4872-2294
Current Organisations
The George Institute for Global Health Food Policy
,
UNSW Sydney
,
Technical University of Denmark
,
Københavns Universitet Niels Bohr Instituttet
,
Københavns Universitet
,
Danmarks Tekniske Universitet
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: EDP Sciences
Date: 09-2011
Publisher: American Astronomical Society
Date: 23-05-2023
Abstract: We select and characterize a s le of massive (log( M * / M ⊙ ) 10.6) quiescent galaxies (QGs) at 3 z 5 in the latest Cosmological Evolution Survey catalog (COSMOS2020). QGs are selected using a new rest-frame color-selection method, based on their probability of belonging to the quiescent group defined by a Gaussian mixture model (GMM) trained on rest-frame colors ( NUV − U , U − V , V − J ) of similarly massive galaxies at 2 z 3. We calculate the quiescent probability threshold above which a galaxy is classified as quiescent using simulated galaxies from the shark semi-analytical model. We find that, at z ≥ 3 in shark , the GMM/ NUVU − VJ method outperforms classical rest-frame UVJ selection and is a viable alternative. We select galaxies as quiescent based on their probability in COSMOS2020 at 3 z 5, and compare the selected s le to both UVJ - and NUVrJ -selected s les. We find that, although the new selection matches UVJ and NUVrJ in number, the overlap between color selections is only ∼50%–80%, implying that rest-frame color commonly used at lower-redshift selections cannot be equivalently used at z 3. We compute median rest-frame spectral energy distributions for our s le and find the median QG at 3 z 5 has a strong Balmer/4000 Å break, and residual NUV flux indicating recent quenching. We find the number densities of the entire quiescent population (including post-starbursts) more than doubles from 3.5 ± 2.2 × 10 −6 Mpc −3 at 4 z 5 to 1.4 ± 0.4 × 10 −5 Mpc −3 at 3 z 4, confirming that the onset of massive galaxy quenching occurs as early as 3 z 5.
Publisher: American Astronomical Society
Date: 27-12-2019
Publisher: American Astronomical Society
Date: 04-12-2012
Publisher: EDP Sciences
Date: 07-2010
Publisher: Oxford University Press (OUP)
Date: 21-09-2020
Abstract: We thoroughly explore the properties of (sub)-millimetre (mm) selected galaxies (SMGs) in the shark semi-analytic model of galaxy formation. Compared to observations, the predicted number counts at wavelengths (λ) 0.6–2 mm and redshift distributions at 0.1–2 mm, agree well. At the bright end (≳1 mJy), shark galaxies are a mix of mergers and disc instabilities. These galaxies display a stacked far-ultraviolet (FUV)-to-far-infrared (FIR) spectrum that agrees well with observations. We predict that current optical/NIR surveys are deep enough to detect bright (& mJy) λ = 0.85–2 mm-selected galaxies at z ≲ 5, but too shallow to detect counterparts at higher redshift. A James Webb Space Telescope 10 000s survey should detect all counterparts for galaxies with S0.85mm ≳ 0.01 mJy. We predict SMG’s disks contribute significantly (negligibly) to the rest-frame UV (IR). We investigate the 0 ≤ z ≤ 6 evolution of the intrinsic properties of & mJy λ = 0.85–2 mm-selected galaxies finding their: (i) stellar masses are $\\gt 10^{10.2}\\rm \\, M_{\\odot }$, with the 2 mm ones tracing the most massive galaxies ($\\gt 10^{11}\\rm \\, M_{\\odot }$) (ii) specific star formation rates (SFR) are mildly (≈3–10 times) above the main sequence (MS) (iii) host halo masses are $\\gtrsim 10^{12.3}\\, \\rm M_{\\odot }$, with 2 mm galaxies tracing the most massive haloes (protoclusters) (iv) SMGs have lower dust masses ($\\approx 10^{8}\\, \\rm M_{\\odot }$), higher dust temperatures (≈40–45 K) and higher rest-frame V-band attenuation (& .5) than MS galaxies (v) sizes decrease with redshift, from 4 kpc at z = 1 to ≲1 kpc at z = 4 and (vi) the carbon monoxide line spectra of S0.85mm ≳ 1 mJy sources peak at 4 → 3. Finally, we study the contribution of SMGs to the molecular gas and cosmic SFR density at 0 ≤ z ≤ 10, finding that & mJy sources make a negligible contribution at z ≳ 3 and 5, respectively, suggesting current observations have unveiled the majority of the SF at 0 ≤ z ≤ 10.
Publisher: American Astronomical Society
Date: 29-10-2012
Publisher: Elsevier BV
Date: 09-2023
Publisher: Oxford University Press (OUP)
Date: 25-10-2010
Publisher: Oxford University Press (OUP)
Date: 13-02-2019
DOI: 10.1093/MNRAS/STZ428
Publisher: EDP Sciences
Date: 06-2012
Publisher: American Astronomical Society
Date: 03-04-2020
Publisher: EDP Sciences
Date: 28-07-2011
Publisher: EDP Sciences
Date: 07-2010
Publisher: EDP Sciences
Date: 07-2010
Publisher: American Astronomical Society
Date: 03-2021
Abstract: We present the first results from the Mapping Obscuration to Reionization with ALMA (MORA) survey, the largest Atacama Large Millimeter/submillimeter Array (ALMA) blank-field contiguous survey to date (184 arcmin 2 ) and the only at 2 mm to search for dusty star-forming galaxies (DSFGs). We use the 13 sources detected above 5 σ to estimate the first ALMA galaxy number counts at this wavelength. These number counts are then combined with the state-of-the-art galaxy number counts at 1.2 and 3 mm and with a backward evolution model to place constraints on the evolution of the IR luminosity function and dust-obscured star formation in the past 13 billion years. Our results suggest a steep redshift evolution on the space density of DSFGs and confirm the flattening of the IR luminosity function at faint luminosities, with a slope of . We conclude that the dust-obscured component, which peaks at z ≈ 2–2.5, has dominated the cosmic history of star formation for the past ∼12 billion years, back to z ∼ 4. At z = 5, the dust-obscured star formation is estimated to be ∼35% of the total star formation rate density and decreases to 25%–20% at z = 6–7, implying a minor contribution of dust-enshrouded star formation in the first billion years of the universe. With the dust-obscured star formation history constrained up to the end of the epoch of reionization, our results provide a benchmark to test galaxy formation models, to study the galaxy mass assembly history, and to understand the dust and metal enrichment of the universe at early times.
Publisher: EDP Sciences
Date: 12-2009
Publisher: Oxford University Press (OUP)
Date: 31-10-2020
Abstract: We present an analysis of the chemical abundance properties of ≈650 star-forming galaxies at z ≈ 0.6 – 1.8. Using integral-field observations from the K - band Multi-Object Spectrograph (KMOS), we quantify the [N ii]/Hα emission-line ratio, a proxy for the gas-phase Oxygen abundance within the interstellar medium. We define the stellar mass – metallicity relation at z ≈ 0.6 – 1.0 and z ≈ 1.2 – 1.8 and analyse the correlation between the scatter in the relation and fundamental galaxy properties (e.g. Hα star-formation rate, Hα specific star-formation rate, rotation dominance, stellar continuum half-light radius and Hubble-type morphology). We find that for a given stellar mass, more highly star-forming, larger and irregular galaxies have lower gas-phase metallicities, which may be attributable to their lower surface mass densities and the higher gas fractions of irregular systems. We measure the radial dependence of gas-phase metallicity in the galaxies, establishing a median, beam smearing-corrected, metallicity gradient of ΔZ/ΔR= 0.002 ± 0.004 dex kpc−1, indicating on average there is no significant dependence on radius. The metallicity gradient of a galaxy is independent of its rest-frame optical morphology, whilst correlating with its stellar mass and specific star-formation rate, in agreement with an inside-out model of galaxy evolution, as well as its rotation dominance. We quantify the evolution of metallicity gradients, comparing the distribution of ΔZ/ΔR in our s le with numerical simulations and observations at z ≈ 0 – 3. Galaxies in our s le exhibit flatter metallicity gradients than local star-forming galaxies, in agreement with numerical models in which stellar feedback plays a crucial role redistributing metals.
Publisher: American Astronomical Society
Date: 12-11-2015
Publisher: Oxford University Press (OUP)
Date: 19-08-2010
Publisher: Oxford University Press (OUP)
Date: 07-02-2017
DOI: 10.1093/MNRAS/STX217
Publisher: EDP Sciences
Date: 09-2023
Publisher: Oxford University Press (OUP)
Date: 04-02-2016
DOI: 10.1093/MNRAS/STW129
Publisher: Oxford University Press (OUP)
Date: 04-2013
DOI: 10.1093/MNRAS/STT330
Publisher: American Astronomical Society
Date: 17-08-2010
Publisher: EDP Sciences
Date: 2015
Publisher: Oxford University Press (OUP)
Date: 12-10-2010
Publisher: American Astronomical Society
Date: 19-05-2011
Publisher: American Astronomical Society
Date: 20-08-2010
Publisher: EDP Sciences
Date: 07-2010
Publisher: EDP Sciences
Date: 2012
Publisher: MDPI AG
Date: 30-06-2022
DOI: 10.3390/NU14132741
Abstract: Australian families increasingly rely on eating foods from outside the home, which increases intake of energy-dense nutrient-poor foods. ‘Kids’ Menus’ are designed to appeal to families and typically lack healthy options. However, the nutritional quality of Kids’ Menus from cafes and full-service restaurants (as opposed to fast-food outlets) has not been investigated in Australia. The aim of this study was to evaluate the nutritional quality of Kids’ Menus in restaurants and cafés in metropolitan Perth, Western Australia. All 787 cafes and restaurants located within the East Metropolitan Health Service area were contacted and 33% had a separate Kids’ Menu. The validated Kids’ Menu Healthy Score (KIMEHS) was used to assess the nutritional quality of the Kids’ Menus. Almost all Kids’ Menus (99%) were rated ‘unhealthy’ using KIMEHS. The mean KIMEHS score for all restaurants and cafés was −8.5 (range −14.5 to +3.5) which was lower (i.e., more unhealthy) than the mean KIMEHS score for the top 10 most frequented chain fast-food outlets (mean −3.5, range −6.5 to +3). The findings highlight the need for additional supports to make improvements in the nutritional quality of Kids’ Menus. Local Government Public Health Plans provide an opportunity for policy interventions, using locally relevant tools to guide decision making.
Publisher: EDP Sciences
Date: 07-2010
Publisher: Oxford University Press (OUP)
Date: 09-05-2019
Publisher: EDP Sciences
Date: 08-2011
Publisher: Oxford University Press (OUP)
Date: 06-07-2012
Publisher: Oxford University Press (OUP)
Date: 21-04-2016
DOI: 10.1093/MNRAS/STW936
Publisher: Oxford University Press (OUP)
Date: 17-10-2018
Publisher: MDPI AG
Date: 27-03-2023
DOI: 10.3390/NU15071623
Abstract: University food environments have a strong influence on the dietary choices of students and staff. The aim of this study was to assess the food environment at a large university in Sydney, Australia. Data were collected between March and July 2022 from 27 fixed food outlets and 24 vending machines. The healthiness of the food environment was evaluated using the Healthy Food and Drink in NSW Health Facilities for Staff and Visitors Framework (‘Framework’), which assesses food environment parameters including the availability, placement, and promotion of ‘Everyday’ (healthy) and ‘Occasional’ (less healthy) products. Each parameter was evaluated overall and across each food outlet type. Across all outlets, Everyday foods and drinks made up 43.9% of all products. Only two outlets met the Framework’s product availability benchmark of ≥75% Everyday foods and drinks. A total of 43 outlets (84.3%) sold sugary drinks as part of their product range. Occasional products made up 68.4%, 53.3%, and 59.9% of all items for sale at checkout areas, countertops, and eye-level shelves, respectively. Finally, 79.7% of meal deals included Occasional products. Our findings highlight the need to improve the availability, placement, and promotion of foods and drinks sold at a major university c us in Sydney, Australia.
Publisher: American Astronomical Society
Date: 29-08-2014
Publisher: EDP Sciences
Date: 07-2010
Publisher: EDP Sciences
Date: 09-2014
Publisher: Oxford University Press (OUP)
Date: 14-07-2017
Publisher: Oxford University Press (OUP)
Date: 23-11-2018
Publisher: American Astronomical Society
Date: 23-12-2019
Publisher: EDP Sciences
Date: 07-2010
Publisher: EDP Sciences
Date: 07-2010
Publisher: Oxford University Press (OUP)
Date: 29-10-2010
Publisher: Oxford University Press (OUP)
Date: 08-08-2013
Publisher: American Astronomical Society
Date: 04-12-2012
Publisher: Oxford University Press (OUP)
Date: 22-01-2016
Publisher: EDP Sciences
Date: 07-2010
Publisher: American Astronomical Society
Date: 11-12-2019
Location: Australia
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Georgios Magdis.