Abstract
We present a structural and morphological catalogue for 45 million objects selected from the first year data of the Dark Energy Survey (DES). Single Sérsic fits and non-parametric measurements are produced for g, r, and i filters. The parameters from the best-fitting Sérsic model (total magnitude, half-light radius, Sérsic index, axis ratio, and position angle) are measured with GALFIT; the non-parametric coefficients (concentration, asymmetry, clumpiness, Gini, M20) are provided using the Zurich Estimator of Structural Types (ZEST+). To study the statistical uncertainties, we consider a sample of state-of-the-art image simulations with a realistic distribution in the input parameter space and then process and analyse them as we do with real data: this enables us to quantify the observational biases due to PSF blurring and magnitude effects and correct the measurements as a function of magnitude, galaxy size, Sérsic index (concentration for the analysis of the non-parametric measurements) and ellipticity. We present the largest structural catalogue to date: we find that accurate and complete measurements for all the structural parameters are typically obtained for galaxies with SEXTRACTORMAG_AUTO_I≤21. Indeed, the parameters in the filters i and r can be overall well recovered up to MAG_AUTO≤21.5, corresponding to a fitting completeness of ∼90 per cent below this threshold, for a total of 25 million galaxies. The combination of parametric and non-parametric structural measurements makes this catalogue an important instrument to explore and understand how galaxies form and evolve. Mehr anzeigen
Persistenter Link
https://doi.org/10.3929/ethz-b-000300186Publikationsstatus
publishedExterne Links
Zeitschrift / Serie
Monthly Notices of the Royal Astronomical SocietyBand
Seiten / Artikelnummer
Verlag
Oxford University PressThema
catalogues; surveys; Galaxy evolution; Galaxy structure; galaxies: generalOrganisationseinheit
03928 - Refregier, Alexandre / Refregier, Alexandre
Anmerkungen
It was possible to publish this article open access thanks to a Swiss National Licence with the publisher.