Why are some galaxy clusters underluminous? The very low concentration of the CL2015 mass profile

Abstract

Our knowledge of the variety of galaxy clusters has been increasing in the last few years thanks to our progress in understanding the severity of selection effects on samples. To understand the reason for the observed variety, we study CL2015, a cluster easily missed in X-ray selected observational samples. Its core-excised X-ray luminosity is low for its mass M500, well below the mean relation for an X-ray selected sample, but only ~1.5 sigma below that derived for an X-ray unbiased sample. We derived thermodynamic profiles and hydrostatic masses with the acquired deep Swift X-ray data, and we used archival Einstein, Planck, and SDSS data to derive additional measurements, such as integrated Compton parameter, total mass, and stellar mass. The pressure and the electron density profiles of CL2015 are systematically outside the +/- 2 sigma range of the universal profiles; in particular the electron density profile is even lower than the one derived from Planck-selected clusters. CL2015 also turns out to be fairly different in the X-ray luminosity versus integrated pressure scaling compared to an X-ray selected sample, but it is a normal object in terms of stellar mass fraction. CL2015's hydrostatic mass profile, by itself or when is considered together with dynamical masses, shows that the cluster has an unusual low concentration and an unusual sparsity compared to clusters in X-ray selected samples. The different behavior of CL2015 is caused by its low concentration. When concentration differences are accounted for, the properties of CL2015 become consistent with comparison samples. CL2015 is perhaps the first known cluster with a remarkably low mass concentration for which high quality X-ray data exist. Objects similar to CL2015 fail to enter observational X-ray selected samples because of their low X-ray luminosity relative to their mass.

arXiv commentA&A, appeared

References in corpus (68)

• A Universal Density Profile from Hierarchical Clustering
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• Collisional Plasma Models with APEC/APED: Emission Line Diagnostics of Hydrogen-like and Helium-like Ions
• Overview of the DESI Legacy Imaging Surveys
• Chandra sample of nearby relaxed galaxy clusters: mass, gas fraction, and mass-temperature relation
• The SAURON project - IV. The mass-to-light ratio, the virial mass estimator and the fundamental plane of elliptical and lenticular galaxies
• Chandra Cluster Cosmology Project III: Cosmological Parameter Constraints
• The universal galaxy cluster pressure profile from a representative sample of nearby systems (REXCESS) and the Y_SZ-M_500 relation
• The GMRT 150 MHz All-sky Radio Survey: First Alternative Data Release TGSS ADR1
• Galaxy cluster X-ray luminosity scaling relations from a representative local sample (REXCESS)
• The ROSAT-ESO Flux Limited X-ray (REFLEX) Galaxy Cluster Survey. V. The cluster catalogue
• Intracluster Medium Entropy Profiles for a Chandra Archival Sample of Galaxy Clusters
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• Chandra temperature profiles for a sample of nearby relaxed galaxy clusters
• Planck 2013 results. XXIX. Planck catalogue of Sunyaev-Zeldovich sources
• The VLA Low-frequency Sky Survey
• The structural and scaling properties of nearby galaxy clusters - II. The M-T relation
• Virial Scaling of Massive Dark Matter Halos: Why Clusters Prefer a High Normalization Cosmology
• Gas entropy in a representative sample of nearby X-ray galaxy clusters (REXCESS): relationship to gas mass fraction
• The nature and space density of fossil groups of galaxies
• Numerical study of halo concentrations in dark-energy cosmologies
• Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources
• The baseline intracluster entropy profile from gravitational structure formation
• Mass estimation in the outer regions of galaxy clusters
• Evidence for X-ray emission from a large-scale filament of galaxies ?
• Infall Regions of Galaxy Clusters
• A dynamical model for the distribution of dark matter and gas in galaxy clusters
• A Wide Field Hubble Space Telescope Study of the Cluster Cl0024+1654 at z=0.4 II: The Cluster Mass Distribution
• The structural and scaling properties of nearby galaxy clusters: I - The universal mass profile
• Universal thermodynamic properties of the intracluster medium over two decades in radius in the X-COP sample
• Self-similar scaling and evolution in the galaxy cluster X-ray Luminosity-Temperature relation
• The XMM-LSS survey: the Class 1 cluster sample over the initial 5 square degrees and its cosmological modelling
• Planck early results. IX. XMM-Newton follow-up for validation of Planck cluster candidates
• The X-Ray Luminosity--Mass Relation for Local Clusters of Galaxies
• Hydrostatic mass profiles in X-COP galaxy clusters
• Weighing the Giants V: Galaxy Cluster Scaling Relations
• High-energy particle acceleration at the radio-lobe shock of Centaurus A
• The stellar mass fraction and baryon content of galaxy clusters and groups
• Brightest Cluster Galaxies at the Present Epoch
• The Redshift Evolution of the Mean Temperature, Pressure, and Entropy Profiles in 80 SPT-Selected Galaxy Clusters
• The cool core state of Planck SZ-selected clusters versus X-ray selected samples: evidence for cool core bias
• Measuring the escape velocity and mass profiles of galaxy clusters beyond their virial radius
• The XXL Survey III. Luminosity-temperature relation of the Bright Cluster Sample
• JKCS041: a colour-detected galaxy cluster at z_phot=1.9 with deep potential well as confirmed by X-ray data
• XMM-Newton observations of three poor clusters: Similarity in dark matter and entropy profiles down to low mass
• Planck intermediate results. III. The relation between galaxy cluster mass and Sunyaev-Zeldovich signal
• LOFAR discovery of a 700-kpc remnant radio galaxy at low redshift
• Spectral Energy Distribution of Radio Sources in Nearby Clusters of Galaxies: Implications for Sunyaev-Zel'dovich Effect Surveys
• Hydrostatic Chandra X-ray analysis of SPT-selected galaxy clusters - I. Evolution of profiles and core properties
• Chemical Evolution on the Scale of Clusters of Galaxies: A Conundrum?
• Rigorous luminosity function determination in presence of a background: theory and application to two intermediate redshift clusters
• A large sample of shear selected clusters from the Hyper Suprime-Cam Subaru Strategic Program S16A wide field mass maps
• The pressure profiles of hot gas in local galaxy groups
• Planck Intermediate Results. I. Further validation of new Planck clusters with XMM-Newton
• Mass Estimation of Merging Galaxy Clusters
• Do X-ray dark or underluminous galaxy clusters exist?
• A low-scatter survey-based mass proxy for clusters of galaxies
• Cluster X-ray luminosity-temperature relation at z>~1.5
• Chandra Measurements of a Complete Sample of X-ray Luminous Galaxy Clusters: The Luminosity-Mass Relation
• The amazing diversity in the hot gas content of an X-ray unbiased massive galaxy clusters sample
• Galaxy And Mass Assembly: search for a population of high-entropy galaxy groups
• A New X-ray Selected Sample of Very Extended Galaxy Groups from the ROSAT All-Sky Survey
• Variegate galaxy cluster gas content: Mean fraction, scatter, selection effects and covariance with X-ray luminosity
• Probing Cosmology with Dark Matter Halo Sparsity Using X-ray Cluster Mass Measurements
• X-ray scaling relations from a complete sample of the richest maxBCG clusters
• GalWeight: A New and Effective Weighting Technique for Determining Galaxy Cluster and Group Membership
• The X-ray Properties of Weak Lensing Selected Galaxy Clusters
• Relative distribution of dark matter and stellar mass in three massive galaxy clusters

Cited by in corpus (6)

• Cosmology dependency of halo masses and concentrations in hydrodynamic simulations
• SPIDERS: overview of the X-ray galaxy cluster follow-up and the final spectroscopic data release
• Thermodynamic evolution of the $z=1.75$ galaxy cluster IDCS J1426.5+3508
• The eROSITA Final Equatorial-Depth Survey (eFEDS): A complete census of X-ray properties of Subaru Hyper Suprime-Cam weak lensing shear-selected clusters in the eFEDS footprint
• The XXL Survey XLV. Linking the ages of optically selected groups to their X-ray emission
• The flat entropy profile at the outskirts of the Abell 2244 galaxy cluster