Volume 650, June 2021
|Number of page(s)||17|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 June 2021|
The GOGREEN survey: Internal dynamics of clusters of galaxies at redshift 0.9–1.4
INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34131 Trieste, Italy
2 IFPU-Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy
3 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
4 Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada
5 Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, ON N2L 3G1, Canada
6 Department of Physics & Astronomy, University of California Irvine, 4129 Reines Hall, Irvine, CA 92697, USA
7 Departamento de Astronomía, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Concepción, Chile
8 Physics Institute, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauverny, Switzerland
9 Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, ON MJ3 1P3, Canada
10 Departamento de Ciencias Físicas, Universidad Andres Bello, Fernández Concha 700, Las Condes, 7591538 RM, Chile
11 European Space Agency (ESA), European Space Astronomy Centre, Villanueva de la Cañada, 28691 Madrid, Spain
12 Department of Physics and Astronomy, The University of Kansas, Malott Room 1082, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA
13 INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, 35122 Padova, Italy
14 Department of Physics and Astronomy, University of California Riverside, 900 University Avenue, Riverside, CA 92521, USA
15 Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 2H4, Canada
16 Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ, USA
17 Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2 A, Helsinki, Finland
18 South African Astronomical Observatory, PO Box 9 Observatory 7935, South Africa
19 Centre for Space Research, North-West University, Potchefstroom 2520, South Africa
20 Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2601, Australia
21 Centre for Gravitational Astrophysics, College of Science, The Australian National University, Canberra, ACT 2601, Australia
22 Department of Physics, McGill University, 3600 Rue University, Montréal, Québec H3P 1T3, Canada
23 Departamento de Ingeniería Informática y Ciencias de la Computación, Facultad de Ingeniería, Universidad de Concepción, Concepción, Chile
Accepted: 2 April 2021
Context. The study of galaxy cluster mass profiles (M(r)) provides constraints on the nature of dark matter and on physical processes affecting the mass distribution. The study of galaxy cluster velocity anisotropy profiles (β(r)) informs the orbits of galaxies in clusters, which are related to their evolution. The combination of mass profiles and velocity anisotropy profiles allows us to determine the pseudo phase-space density profiles (Q(r)); numerical simulations predict that these profiles follow a simple power law in cluster-centric distance.
Aims. We determine the mass, velocity anisotropy, and pseudo phase-space density profiles of clusters of galaxies at the highest redshifts investigated in detail to date.
Methods. We exploited the combination of the GOGREEN and GCLASS spectroscopic data-sets for 14 clusters with mass M200 ≥ 1014 M⊙ at redshifts 0.9 ≤ z ≤ 1.4. We constructed an ensemble cluster by stacking 581 spectroscopically identified cluster members with stellar mass M⋆ ≥ 109.5 M⊙. We used the MAMPOSSt method to constrain several M(r) and β(r) models, and we then inverted the Jeans equation to determine the ensemble cluster β(r) in a non-parametric way. Finally, we combined the results of the M(r) and β(r) analysis to determine Q(r) for the ensemble cluster.
Results. The concentration c200 of the ensemble cluster mass profile is in excellent agreement with predictions from Λ cold dark matter (ΛCDM) cosmological numerical simulations, and with previous determinations for clusters of similar mass and at similar redshifts, obtained from gravitational lensing and X-ray data. We see no significant difference between the total mass density and either the galaxy number density distributions or the stellar mass distribution. Star-forming galaxies are spatially significantly less concentrated than quiescent galaxies. The orbits of cluster galaxies are isotropic near the center and more radial outside. Star-forming galaxies and galaxies of low stellar mass tend to move on more radially elongated orbits than quiescent galaxies and galaxies of high stellar mass. The profile Q(r), determined using either the total mass or the number density profile, is very close to the power-law behavior predicted by numerical simulations.
Conclusions. The internal dynamics of clusters at the highest redshift probed in detail to date are very similar to those of lower-redshift clusters, and in excellent agreement with predictions of numerical simulations. The clusters in our sample have already reached a high degree of dynamical relaxation.
Key words: galaxies: clusters: general / cosmology: observations / galaxies: evolution
© ESO 2021
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