The XXL Survey: XXX. Characterisation of the XLSSsC N01 supercluster and analysis of the galaxy stellar populations
Journal article, 2018
Context. Superclusters form from the largest enhancements in the primordial density perturbation field and extend for tens of Mpc, tracing the large-scale structure of the Universe. X-ray detections and systematic characterisations of superclusters and the properties of their galaxies have only been possible in the last few years. Aims. We characterise XLSSsC N01, a rich supercluster at z ∼ 0.3 detected in the XXL Survey, composed of X-ray clusters of different virial masses and X-ray luminosities. As one of the first studies on this topic, we investigate the stellar populations of galaxies in different environments in the supercluster region. Methods. We study a magnitude-limited (r ≤ 20) and a mass-limited sample (log(M ∗ Mo) ≥ 10.8) of galaxies in the virialised region and in the outskirts of 11 XLSSsC N01 clusters, in high-density field regions, and in the low-density field. We compute the stellar population properties of galaxies using spectral energy distribution (SED) and spectral fitting techniques, and study the dependence of star formation rates (SFR), colours, and stellar ages on environment. Results. For r ≤ 20, the fraction of star-forming/blue galaxies, computed either from the specific-SFR (sSFR) or rest-frame colour, shows depletion within the cluster virial radii, where the number of galaxies with log (sSFR/ yr-1) > -12 and with (g - r) restframe < 0.6 is lower than in the field. For log(M ∗ Mo) ≥ 10.8, no trends with environment emerge, as massive galaxies are mostly already passive in all environments. No differences among low- and high-density field members and cluster members emerge in the sSFR-mass relation in the mass-complete regime. Finally, the luminosity-weighted age-mass relation of the passive populations within cluster virial radii show signatures of recent environmental quenching. Conclusions. The study of luminous and massive galaxies in this supercluster shows that while environment has a prominent role in determining the fractions of star-forming/blue galaxies, its effects on the star formation activity in star-forming galaxies are negligible.
galaxies: star formation
X-rays: galaxies: clusters
galaxies: evolution
galaxies: stellar content
galaxies: groups: general
large-scale structure of Universe
Author
V. Guglielmo
Laboratoire d'Astrophysique de Marseille
Max Planck Society
Istituto nazionale di astrofisica (INAF)
B. M. Poggianti
Istituto nazionale di astrofisica (INAF)
B. Vulcani
University of Melbourne
Istituto nazionale di astrofisica (INAF)
A. Moretti
Istituto nazionale di astrofisica (INAF)
J. Fritz
Universidad Nacional Autónoma de México
F. Gastaldello
Istituto nazionale di astrofisica (INAF)
C. Adami
Laboratoire d'Astrophysique de Marseille
C. Caretta
Universidad de Guanajuato
J. Willis
University of Bristol
E. Koulouridis
University Paris-Saclay
M. E. Ramos-Ceja
University of Bonn
P. Giles
University of Bristol
I. Baldry
Liverpool John Moores University
M. Birkinshaw
University of Bristol
A. Bongiorno
Osservatorio Astronomico di Roma
M. Brown
Monash University
L. Chiappetti
Istituto nazionale di astrofisica (INAF)
S. Driver
University of Western Australia
University of St Andrews
A. Elyiv
Main Astronomical Observatory Nasu
University of Bologna
A. E. Evrard
University of Michigan
M. Grootes
European Space Research and Technology Centre (ESA ESTEC)
L. Guennou
University of KwaZulu-Natal
A. Hopkins
Australian Astronomical Observatory
Cathy Horellou
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
A. Iovino
Istituto nazionale di astrofisica (INAF)
S. Maurogordato
Université Nice Sophia Antipolis (UNS)
M. Owers
Macquarie University
Australian Astronomical Observatory
F. Pacaud
University of Bonn
S. Paltani
University of Geneva
M. Pierre
University Paris-Saclay
M. Plionis
Aristotle University of Thessaloniki
National Observatory of Athens
T. J. Ponman
University of Birmingham
A. Robotham
University of Western Australia
T. Sadibekova
Uzbekistan Academy of Sciences
V. Smolcic
University of Zagreb
R. Tuffs
European Space Research and Technology Centre (ESA ESTEC)
Cristian Vignali
Istituto nazionale di astrofisica (INAF)
University of Bologna
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 620 A15Subject Categories (SSIF 2011)
Evolutionary Biology
Astronomy, Astrophysics and Cosmology
Ecology
DOI
10.1051/0004-6361/201732507