The XMM cluster outskirts project (X‐COP)

Abstract

Galaxy clusters are thought to grow hierarchically through the continuous merging and accretion of smaller structures across cosmic time. In the Local Universe, these phenomena are still active in the outer regions of massive clusters (R > R500), where the matter distribution is expected to become clumpy and asymmetric because of the presence of accreting structures. We present the XMM-Newton Cluster Outskirts Project (X-COP), which targets the outer regions of a sample of 13 massive clusters (M500 > 3 × 10 14 M ) in the redshift range 0.04-0.1 at uniform depth. The sample was selected based on the signal-to-noise ratio in the Planck Sunyaev-Zeldovich (SZ) survey with the aim of combining high-quality X-ray and SZ constraints throughout the entire cluster volume. Our observing strategy allows us to reach a sensitivity of 3 × 10 −16 ergs cm −2 s −1 arcmin −2 in the [0.5-2.0] keV range thanks to a good control of systematic uncertainties. The combination of depth and field of view achieved in X-COP will allow us to pursue the following main goals: i) measure the distribution of entropy and thermal energy to an unprecedented level of precision; ii) assess the presence of non-thermal pressure support in cluster outskirts; iii) study the occurrence and mass distribution of infalling gas clumps. We illustrate the capabilities of the program with a pilot study on the cluster Abell 2142.

Dark matter distribution in X-ray luminous galaxy clusters with Emergent Gravity

“…2 reproduces the mass distribution recovered by using the hydrostatic equilibrium equation applied to two massive, X-ray luminous galaxy clusters that are part of the X-COP sample. The XMMNewton Cluster Outskirts Project (X-COP; Eckert et al 2016) has been built to target the outer regions of a sample of 13 massive clusters (M500 > 3 × 10 14 M ) in the redshift range 0.04 − 0.1 at uniform depth. The sample was selected based on the signal- to-noise ratio in the Planck SZ survey (Planck Collaboration et al 2011) with the aim of combining high-quality X-ray and SZ constraints throughout the entire cluster volume.…”

CLUMP-3D: three-dimensional lensing and multi-probe analysis of MACS J1206.2−0847, a remarkably regular cluster

“…Joint X-ray and SZ analyses can probe the gas physics in detail, e.g. the occurrence and mass distribution of infalling gas clumps (Eckert et al 2016;Tchernin et al 2016).…”

Helium abundance (and H0) in X‐COP galaxy clusters

“…The XMM‐Newton Cluster Outskirts Project (X‐COP, Eckert et al ) is an XMM very large program dedicated to the study of the X‐ray emission in cluster outskirts. It has targeted 12 local, massive galaxy clusters selected for their high signal‐to‐noise ratios in the Planck all‐sky SZ survey (S/N>12 in the PSZ1 sample, Planck Collaboration et al ) as resolved sources ( R 500 > 10 arcmin) in the redshift range 0.04 < z < 0.1 and along the directions with a galactic absorption lower than 10 21 cm – 2 to avoid any significant suppression of the X‐ray emission in the soft band where most of the spatial analysis is performed.…”