The XXL Survey. LI. Pressure profile and YSZ − M scaling relation in three low-mass galaxy clusters at z ∼ 1 observed with NIKA2
Berta, S.; Altieri, B.; Aussel, H.; Adam, R.; Benoît, A.; Catalano, A.; Désert, F. -X.; Lagache, G.; Macías-Pérez, J. F.; Perotto, L.; Roussel, H.; Pierre, M.; Bremer, M.; Faccioli, L.; Gastaldello, F.; Eckert, D.; Gomez, A.; Madden, S.; Maury, A.; Ladjelate, B.; Birkinshaw, M.; Romero, C.; Benoist, C.; Horellou, C.; Giles, P.; Koulouridis, E.; Pacaud, F.; Maurogordato, S.; Cappi, A.; Kramer, C.; André, P.; Beelen, A.; Ade, P.; Ajeddig, H.; Artis, E.; Bourrion, O.; Calvo, M.; De Petris, M.; Doyle, S.; Driessen, E. F. C.; Goupy, J.; Kéruzoré, F.; Leclercq, S.; Lestrade, J. -F.; Mauskopf, P.; Monfardini, A.; Muñoz-Echeverría, M.; Pisano, G.; Ponthieu, N.; Revéret, V.; Ritacco, A.; Ruppin, F.; Schuster, K.; Sievers, A.; Tucker, C.; Zylka, R.; Maughan, B.; Hahn, O.; Ferrari, C.; Ricci, M.; Sereno, M.; Pompei, E.; Bing, L.; Boutigny, D.; Hanser, C.; Rigby, A.; Tintoré Vidal, G.
France, Switzerland, United Kingdom, Spain, Italy, Sweden, United States, Greece, Germany, Chile
Abstract
Context. The thermodynamical properties of the intracluster medium (ICM) are driven by scale-free gravitational collapse, but they also reflect the rich astrophysical processes at play in galaxy clusters. At low masses (∼1014 M⊙) and high redshift (z ≳ 1), these properties remain poorly constrained, observationally speaking, due to the difficulty in obtaining resolved and sensitive data.
Aims: We aim to investigate the inner structure of the ICM as seen through the Sunyaev-Zel'dovich (SZ) effect in this regime of mass and redshift. We focused on the thermal pressure profile and the scaling relation between SZ flux and mass, namely the YSZ − M scaling relation.
Methods: The three galaxy clusters XLSSC 072 (z = 1.002), XLSSC 100 (z = 0.915), and XLSSC 102 (z = 0.969), with M500 ∼ 2 × 1014 M⊙, were selected from the XXL X-ray survey and observed with the NIKA2 millimeter camera to image their SZ signal. XMM-Newton X-ray data were used as a complement to the NIKA2 data to derive masses based on the YX − M relation and the hydrostatic equilibrium.
Results: The SZ images of the three clusters, along with the X-ray and optical data, indicate dynamical activity related to merging events. The pressure profile is consistent with that expected for morphologically disturbed systems, with a relatively flat core and a shallow outer slope. Despite significant disturbances in the ICM, the three high-redshift low-mass clusters follow the YSZ − M relation expected from standard evolution remarkably well.
Conclusions: These results indicate that the dominant physics that drives cluster evolution is already in place by z ∼ 1, at least for systems with masses above M500 ∼ 1014 M⊙.