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  • Final Report Summary - DEGAS (Deciphering the Evolution of Galaxies and the Assembly of Structure: Probing the Growth of Non-Linear Structure in the Dark Universe with Statistical Analyses of Galaxy Surveys)
ERC

DEGAS Report Summary

Project ID: 259586
Funded under: FP7-IDEAS-ERC
Country: United Kingdom

Final Report Summary - DEGAS (Deciphering the Evolution of Galaxies and the Assembly of Structure: Probing the Growth of Non-Linear Structure in the Dark Universe with Statistical Analyses of Galaxy Surveys)

The DEGAS project is aimed at measuring the growth of non-linear structure in the dark universe, following galaxy groups identified in the Galaxy And Mass Assembly (GAMA) survey as tracers of dark matter haloes in the last 4 Gyrs and using galaxies as tracers of the underlying dark matter density field over the last 7 Gyrs using data from photometric surveys, like Pan-STARRS and PAUS.
Both goals are dependent on an accurate understanding and modeling of the galaxy distribution in cosmological surveys and provide a key stepping stone towards the future surveys, like DESI and WAVES (Driver et al. 2016).

The initial focus was to assemble the necessary ingredients for these key analyses to become possible. In particular, significant effort was devoted to acquire the GAMA survey data and to construct a robust pipeline from which mock lightcones are built. These efforts came to fruition mid-way through the project, with the mock pipeline ready to be fully deployed to produce a range of mock lightcones with different galaxy formation models (Merson et al. 2013), including the creation of the VirgoDB portal in 2015 ( http://virgodb.dur.ac.uk ). VirgoDB hosts several galaxy formation models and associated lightcones for specific surveys, including already mock realisations of the GAMA, DESI and Euclid surveys.

With realistic GAMA mocks and a good understanding of the GAMA survey selection function, numerous results can be reported, ranging from the calibration of group masses using weak-lensing information (Han et al. 2015; Viola et al. 2015) to the clustering of galaxies over several Gyrs (Farrow et al. 2015) via the environmental dependence of the galaxy luminosity function (McNaught-Roberts et al. 2014; Eardley et al. 2015). Many of the GAMA results build on the GAMA group finder (Robotham et al. 2011) for which the mocks were developed and have led to numerous publications, including the determination of mass of satellite galaxies in groups (Sifon et al. 2015), the effect of close interaction on star formation in galaxies (Davies et al. 2015), the dependence of halo masses on the cosmic web (Brouwer et al. 2016) and the dependence of the Far-IR luminosity function of group properties (Guo et al. 2014). All these results together with many others extracted from the GAMA survey provide new stringent constraints on theoretical models of galaxy formation and evolution.

Additional developments undertaken by the DEGAS team include a detailed clustering analysis of a pre-cursor to PAUS, the Alhambra narrow band survey, providing a better understanding of the effect on photometric redshift errors from imaging surveys (Arnalte-Mur et al. 2014), as well as various investigation about the nature of dark energy and tests of modified gravity models (Shi et al. 2015, 2016, 2017; Arnalte-Mur et al. 2017).

Contact

Sally Hewlett, (Director of Research Office)
Tel.: 00 44 191 3344 635
Fax: 00 44 191 3344 634
E-mail
Record Number: 197989 / Last updated on: 2017-05-12
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