nIFTy cosmology: comparison of galaxy formation models

Alexander Knebe , Frazer Pearce , Peter Thomas , Andrew Benson , Jérémy Blaizot (1) , Richard Bower (2) , Jorge Carretero , Francisco J. Castander (3) , Andrea Cattaneo (4, 5) , Sofia Cora , Darren Croton , Weiguang Cui , Daniel Cunnama , Gabriella de Lucia , Julien Devriendt (1) , Pascal Elahi , Andreea Font , Fabio Fontanot (6) , Juan Garcia-Bellido (7) , Ignacio Gargiulo , Violeta Gonzalez-Perez , John Helly , Bruno Henriques , Michaela Hirschmann (8) , Jaehyun Lee (9) , Gary Mamon (8) , Pierluigi Monaco (10) , Julian Onions , Nelson Padilla , Chris Power (11) , Arnau Pujol (12) , Ramin Skibba , Rachel Somerville (13) , Chaichalit Srisawat , Cristian Vega-Martínez , Sukyoung Yi

1 CRAL - Centre de Recherche Astrophysique de Lyon
2 ICC - Institute for Computational Cosmology
3 ICE-CSIC - Institut de Ciencies de l'Espai [Barcelona]
4 LAM - Laboratoire d'Astrophysique de Marseille
5 GEPI - Galaxies, Etoiles, Physique, Instrumentation
6 H-ITS - Heidelberger Institut für Theoretische Studien
7 Departamento de Fisica Teorica
8 IAP - Institut d'Astrophysique de Paris
9 James Watt School of Engineering [Univ Glasgow]
10 Università degli studi di Trieste = University of Trieste
11 Centre for Paediatric Epidemiology and Biostatistics
12 DAP - Département d'Astrophysique (ex SAP)
13 Rutgers University [Camden]

We present a comparison of 14 galaxy formation models: 12 different semi-analytical models and 2 halo occupation distribution models for galaxy formation based upon the same cosmological simulation and merger tree information derived from it. The participating codes have proven to be very successful in their own right but they have all been calibrated independently using various observational data sets, stellar models, and merger trees. In this paper, we apply them without recalibration and this leads to a wide variety of predictions for the stellar mass function, specific star formation rates, stellar-to-halo mass ratios, and the abundance of orphan galaxies. The scatter is much larger than seen in previous comparison studies primarily because the codes have been used outside of their native environment within which they are well tested and calibrated. The purpose of the `nIFTy comparison of galaxy formation models' is to bring together as many different galaxy formation modellers as possible and to investigate a common approach to model calibration. This paper provides a unified description for all participating models and presents the initial, uncalibrated comparison as a baseline for our future studies where we will develop a common calibration framework and address the extent to which that reduces the scatter in the model predictions seen here.

Domaines: Planète et Univers [physics]; Astrophysique [astro-ph]

Alexander Knebe, Frazer Pearce, Peter Thomas, Andrew Benson, Jérémy Blaizot, et al.. nIFTy cosmology: comparison of galaxy formation models. Monthly Notices of the Royal Astronomical Society, 2015, 451 (4), pp.4029-4059. ⟨10.1093/mnras/stv1149⟩. ⟨hal-02453332⟩