Journal Article

The ATLAS<sup>3D</sup> project – I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria

Michele Cappellari, Eric Emsellem, Davor Krajnović, Richard M. McDermid, Nicholas Scott, G. A. Verdoes Kleijn, Lisa M. Young, Katherine Alatalo, R. Bacon, Leo Blitz, Maxime Bois, Frédéric Bournaud, M. Bureau, Roger L. Davies, Timothy A. Davis, P. T. de Zeeuw, Pierre-Alain Duc, Sadegh Khochfar, Harald Kuntschner, Pierre-Yves Lablanche, Raffaella Morganti, Thorsten Naab, Tom Oosterloo, Marc Sarzi, Paolo Serra and Anne-Marie Weijmans

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 413, issue 2, pages 813-836
Published in print May 2011 | ISSN: 0035-8711
Published online April 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.18174.x
The ATLAS3D project – I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria

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The ATLAS3D project is a multiwavelength survey combined with a theoretical modelling effort. The observations span from the radio to the millimetre and optical, and provide multicolour imaging, two-dimensional kinematics of the atomic (H i), molecular (CO) and ionized gas (Hβ, [O iii] and [N i]), together with the kinematics and population of the stars (Hβ, Fe5015 and Mg b), for a carefully selected, volume-limited (1.16 × 105 Mpc3) sample of 260 early-type (elliptical E and lenticular S0) galaxies (ETGs). The models include semi-analytic, N-body binary mergers and cosmological simulations of galaxy formation. Here we present the science goals for the project and introduce the galaxy sample and the selection criteria. The sample consists of nearby (D < 42 Mpc, |δ− 29°| < 35°, |b| > 15°) morphologically selected ETGs extracted from a parent sample of 871 galaxies (8 per cent E, 22 per cent S0 and 70 per cent spirals) brighter than MK < −21.5 mag (stellar mass M≳ 6 ×109 M). We analyse possible selection biases and we conclude that the parent sample is essentially complete and statistically representative of the nearby galaxy population. We present the size–luminosity relation for the spirals and ETGs and show that the ETGs in the ATLAS3D sample define a tight red sequence in a colour–magnitude diagram, with few objects in the transition from the blue cloud. We describe the strategy of the SAURON integral field observations and the extraction of the stellar kinematics with the ppxf method. We find typical 1σ errors of ΔV≈ 6 km s−1, Δσ≈ 7 km s−1, Δh3≈Δh4≈ 0.03 in the mean velocity, the velocity dispersion and Gauss–Hermite (GH) moments for galaxies with effective dispersion σe≳ 120 km s−1. For galaxies with lower σe (≈40 per cent of the sample) the GH moments are gradually penalized by ppxf towards zero to suppress the noise produced by the spectral undersampling and only V and σ can be measured. We give an overview of the characteristics of the other main data sets already available for our sample and of the ongoing modelling projects.

Keywords: galaxies: distances and redshifts; galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: formation; galaxies: kinematics and dynamics; galaxies: structure

Journal Article.  14008 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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