UNITSIM-Galaxies: data release and clustering of emission-line galaxies

New surveys such as European Space Agencys (ESA's) Euclid mission are planned to map with unprecedented precision the large-scale structure of the Universe by measuring the 3D positions of tens of millions of galaxies. It is necessary to develop theoretically modelled galaxy catalogues to estimate the expected performance and to optimize the analysis strategy of these surveys. We populate two pairs of (1 h(-1) Gpc)(3) volume dark matter-only simulations from the UNIT project with galaxies using the Semi-Analytic Galaxy Evolution semi-analytic model of galaxy formation, coupled to the photoionization model GET.EMLINES to estimate their H alpha emission. These catalogues represent a unique suite that includes galaxy formation physics and - thanks to the fixed-pair technique used - an effective volume of similar to (5 h(-1) Gpc)(3), which is several times larger than the Euclid survey. We present the performance of these data and create five additional emission-line galaxy (ELG) catalogues by applying a dust-attenuation model as well as adjusting the flux threshold as a function of redshift in order to reproduce Euclid-forecast dN/dz values. As a first application, we study the abundance and clustering of those model H alpha ELGs: for scales greater than similar to 5 h(-1) Mpc, we find a scale-independent bias with a value of b similar to 1 at redshift z similar to 0.5, that can increase nearly linearly to b similar to 4 at z similar to 2, depending on the ELG catalogue. Model galaxy properties, including their emission-line fluxes (with and without dust extinction) are publicly available.

STAGES: the Space Telescope A901/2 Galaxy Evolution Survey

Yifei Guo

We present an overview of the Space Telescope A901/2 Galaxy Evolution Survey (STAGES). STAGES is a multiwavelength project designed to probe physical drivers of galaxy evolution across a wide range of environments and luminosity. A complex multicluster system at z similar to 0.165 has been the subject of an 80-orbit F606W Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) mosaic covering the full 0 degrees.5 x 0 degrees.5 (similar to 5 x 5 Mpc(2)) span of the supercluster. Extensive multiwavelength observations with XMM-Newton, GALEX, Spitzer, 2dF, Giant Metrewave Radio Telescope and the 17-band COMBO-17 photometric redshift survey complement the HST imaging. Our survey goals include simultaneously linking galaxy morphology with other observables such as age, star formation rate, nuclear activity and stellar mass. In addition, with the multiwavelength data set and new high-resolution mass maps from gravitational lensing, we are able to disentangle the large-scale structure of the system. By examining all aspects of an environment we will be able to evaluate the relative importance of the dark matter haloes, the local galaxy density and the hot X-ray gas in driving galaxy transformation. This paper describes the HST imaging, data reduction and creation of a master catalogue. We perform the Sersic fitting on the HST images and conduct associated simulations to quantify completeness. In addition, we present the COMBO-17 photometric redshift catalogue and estimates of stellar masses and star formation rates for this field. We define galaxy and cluster sample selection criteria, which will be the basis for forthcoming science analyses, and present a compilation of notable objects in the field. Finally, we describe the further multiwavelength observations and announce public access to the data and catalogues.

Blackwell Publishing Ltd, Oxford2009

Clustering properties of g-selected galaxies at z similar to 0.8

Johan Comparat, Timothée Guy Olivier Delubac, Ginevra Favole, Jean-Paul Richard Kneib, David Schlegel

Current and future large redshift surveys, as the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) or the Dark Energy Spectroscopic Instrument (DESI), will use emission-line galaxies (ELGs) to probe cosmological models by mapping the large-scale structure of the Universe in the redshift range 0.6 < z < 1.7. With current data, we explore the halo-galaxy connection by measuring three clustering properties of g-selected ELGs as matter tracers in the redshift range 0.6 < z < 1: (i) the redshift-space two-point correlation function using spectroscopic redshifts from the BOSS ELG sample and VIPERS; (ii) the angular two-point correlation function on the footprint of the CFHT-LS; (iii) the galaxy-galaxy lensing signal around the ELGs using the CFHTLenS. We interpret these observations by mapping them on to the latest high-resolution MultiDark Planck N-body simulation, using a novel (Sub) Halo-Abundance Matching technique that accounts for the ELG incompleteness. ELGs at z similar to 0.8 live in haloes of (1 +/- 0.5) x 10(12) h(-1)M(circle dot) and 22.5 +/- 2.5 per cent of them are satellites belonging to a larger halo. The halo occupation distribution of ELGs indicates that we are sampling the galaxies in which stars form in the most efficient way, according to their stellar-to-halo mass ratio.

Wiley-Blackwell2016

The evolution of the [O II], H beta and [O III] emission line luminosity functions over the last nine billions years

Johan Comparat, Timothée Guy Olivier Delubac, Jean-Paul Richard Kneib, Jeffrey Newman, Anand Stéphane Raichoor, Johan Richard

Emission line galaxies are one of the main tracers of the large-scale structure to be targeted by the next-generation dark energy surveys. To provide a better understanding of the properties and statistics of these galaxies, we have collected spectroscopic data from the VVDS and DEEP2 deep surveys and estimated the galaxy luminosity functions (LFs) of three distinct emission lines, [O II] (lambda lambda 3726, 3729) (0.5 < z < 1.3), H beta (lambda 4861) (0.3 < z < 0.8) and [O III] (lambda 5007) (0.3 < z < 0.8). Our measurements are based on 35 639 emission line galaxies and cover a volume of similar to 10(7) Mpc(3). We present the first measurement of the H beta LF at these redshifts. We have also compiled LFs from the literature that were based on independent data or covered different redshift ranges, and we fit the entire set over the whole redshift range with analytic Schechter and Saunders models, assuming a natural redshift dependence of the parameters. We find that the characteristic luminosity (L-) and density (phi()) of all LFs increase with redshift. Using the Schechter model over the redshift ranges considered, we find that, for [O II] emitters, the characteristic luminosity L-(z = 0.5) = 3.2 x 10(41) erg s(-1) increases by a factor of 2.7 +/- 0.2 from z = 0.5 to 1.3; for H beta emitters L-(z = 0.3) = 1.3 x 10(41) erg s(-1) increases by a factor of 2.0 +/- 0.2 from z = 0.3 to 0.8; and for [O III] emitters L-*(z = 0.3) = 7.3 x 10(41) erg s(-1) increases by a factor of 3.5 +/- 0.4 from z = 0.3 to 0.8.

Oxford Univ Press2016