532 research outputs found

    Galaxy And Mass Assembly (GAMA): curation and reanalysis of 16.6k redshifts in the G10/COSMOS region

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    We discuss the construction of the Galaxy And Mass Assembly (GAMA) 10h region (G10) using publicly available data in the Cosmic Evolution Survey region (COSMOS) in order to extend the GAMA survey to z ∼ 1 in a single deg2 field. In order to obtain the maximum number of high precision spectroscopic redshifts we re-reduce all archival zCOSMOS-bright data and use the GAMA automatic cross-correlation redshift fitting code autoz. We use all available redshift information (autoz, zCOSMOS-bright 10k, PRIMUS, VVDS, SDSS and photometric redshifts) to calculate robust best-fitting redshifts for all galaxies and visually inspect all 1D and 2D spectra to obtain 16 583 robust redshifts in the full COSMOS region. We then define the G10 region to be the central ∼1 deg2 of COSMOS, which has relatively high spectroscopic completeness, and encompasses the CHILES VLA region. We define a combined r < 23.0 mag and i < 22.0 mag G10 sample (selected to have the highest bijective overlap) with which to perform future analysis, containing 9861 sources with reliable high-precision VLT-VIMOS spectra. All tables, spectra and imaging are available at http://ict.icrar.org/cutout/G10

    Non-Parametric Cell-Based Photometric Proxies for Galaxy Morphology: Methodology and Application to the Morphologically-Defined Star Formation -- Stellar Mass Relation of Spiral Galaxies in the Local Universe

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    (Abridged) We present a non-parametric cell-based method of selecting highly pure and largely complete samples of spiral galaxies using photometric and structural parameters as provided by standard photometric pipelines and simple shape fitting algorithms, demonstrably superior to commonly used proxies. Furthermore, we find structural parameters derived using passbands longwards of the gg band and linked to older stellar populations, especially the stellar mass surface density μ\mu_* and the rr band effective radius rer_e, to perform at least equally well as parameters more traditionally linked to the identification of spirals by means of their young stellar populations. In particular the distinct bimodality in the parameter μ\mu_*, consistent with expectations of different evolutionary paths for spirals and ellipticals, represents an often overlooked yet powerful parameter in differentiating between spiral and non-spiral/elliptical galaxies. We investigate the intrinsic specific star-formation rate - stellar mass relation (ψM\psi_* - M_*) for a morphologically defined volume limited sample of local universe spiral galaxies, defined using the cell-based method with an appropriate parameter combination. The relation is found to be well described by ψM0.5\psi_* \propto M_*^{-0.5} over the range of 109.5MM1011M10^{9.5} M_{\odot} \le M_* \le 10^{11} M_{\odot} with a mean interquartile range of 0.40.4\,dex. This is somewhat steeper than previous determinations based on colour-selected samples of star-forming galaxies, primarily due to the inclusion in the sample of red quiescent disks

    The Hyper Suprime-Cam extended Point Spread Functions and applications to measuring the intra-halo light

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    We present extended point spread function (PSF) models for the Hyper Suprime-Cam Subaru Strategic Program Public Data Release 3 (HSC-SSP PDR3) in all g,r,i,Z\textit{g,r,i,Z} and Y\textit{Y}-bands. Due to its 8.2m primary mirror and long exposure periods, HSC combines deep images with wide-field coverage, making it one of the most suitable observing facilities for low surface brightness (LSB) studies. By applying a median stacking technique of point sources with different brightnesses, we show how to construct the HSC-SSP PDR3 PSF models to an extent of R \sim 5.6 arcmin. These new PSFs provide the community with a crucial tool to characterise LSB properties at large angles. We apply our HSC PSFs and demonstrate that they behave reasonably in two cases: first, to generate a 2-D model of a bright star, and second, to remove the PSF-scattered light from an Ultra Deep image of the 400020 Galaxy And Mass Assembly (GAMA) group in the SXDS field. Our main focus in this second application is characterising the r\textit{r}-band intra-halo light (IHL) component of 400020. Building on advanced source extraction techniques with careful consideration of PSF flux, we measure the IHL surface brightness (SB) group profile up to \sim 31 mag arcsec2^{-2} and R = 300 kpc. We estimate the IHL fraction (fIHL\mathrm{f_{IHL}}) profile, with a mean of fIHL\mathrm{f_{IHL}} \sim 0.13. Our results show that not removing the PSF light can overestimate the IHL SB by \sim 1.7 mag arcsec2^{-2} and the fIHL\mathrm{f_{IHL}} by \sim 30%.Comment: 21 pages, 19 figures, submitted to MNRA

    Preferences for Medical Consultations from Online Providers: Evidence from a Discrete Choice Experiment in the United Kingdom

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    Background: In the UK, consultations for prescription medicines are available via private providers such as online pharmacies. However, these providers may have lower thresholds for prescribing certain drugs. This is a particular concern for antibiotics, given the increasing burden of antimicrobial resistance. Public preferences for consultations with online providers are unknown, hence the impact of increased availability of online consultations on antibiotic use and population health is unclear. Objective: To conduct a discrete choice experiment survey to understand UK public preferences for seeking online consultations, and the factors that influence these preferences, in the context of having symptoms for which antibiotics may be appropriate. Methods: In a survey conducted between July and August 2018, general population respondents completed 16 questions in which they chose a primary care consultation via either their local medical centre or an online provider. Consultations were described in terms of five attributes, including cost and similarity to traditional ‘face-to-face’ appointments. Choices were modelled using regression analysis. Results: Respondents (n = 734) placed a high value on having a consultation via their local medical centre rather than an online provider, and a low value on consultations by phone or video. However, respondents characterised as ‘busy young professionals’ showed a lower strength of preference for traditional consultations, with a higher concern for convenience. Conclusion: Before COVID-19, the UK public had limited appetite for consultations with online providers, or for consultations that were not face-to-face. Nevertheless, prescriptions from online providers should be monitored going forward, particularly for antibiotics, and in key patient groups
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