Galaxy And Mass Assembly: search for a population of high-entropy galaxy groups

Abstract

Observations with the Chandra X-ray Observatory are used to examine the hot gas properties within a sample of 10 galaxy groups selected from the Galaxy And Mass Assembly survey's optical Friends-of-Friends group catalogue. Our groups have been screened to eliminate spurious and unrelaxed systems, and the effectiveness of this procedure is demonstrated by the detection of intergalactic hot gas in 80 per cent of our sample. However, we find that 9 of the 10 are X-ray underluminous by a mean factor of $\sim$4 compared to typical X-ray-selected samples. Consistent with this, the majority of our groups have gas fractions that are lower and gas entropies somewhat higher than those seen in typical X-ray-selected samples. Two groups, which have high 2σ lower limits on their gas entropy, are candidates for the population of high-entropy groups predicted by some active galactic nucleus feedback models.

18 pages, 7 Figures with 10 subfigures, 5 Tables, Accepted by MNRAS

References in corpus (15)

• Intracluster Medium Entropy Profiles for a Chandra Archival Sample of Galaxy Clusters
• Chandra temperature profiles for a sample of nearby relaxed galaxy clusters
• An Entropy Threshold for Strong H-alpha and Radio Emission in the Cores of Galaxy Clusters
• Dark matter halo properties of GAMA galaxy groups from 100 square degrees of KiDS weak lensing data
• Unifying X-ray Scaling Relations from Galaxies to Clusters
• X-ray thermal coronae of galaxies in hot clusters -- ubiquity of embedded mini cooling cores
• Temperature and abundance profiles of hot gas in galaxy groups - I. Results and statistical analysis
• Chi-square and Poissonian Data: Biases Even in the High-Count Regime and How to Avoid them
• Towards a Holistic View of the Heating and Cooling of the Intracluster Medium
• A statistically-selected Chandra sample of 20 galaxy clusters -- II. Gas properties and cool-core/non-cool core bimodality
• Galaxy and Mass Assembly (GAMA): The halo mass of galaxy groups from maximum-likelihood weak lensing
• Enrichment and Pre-Heating in Intragroup Gas from Galactic Outflows
• First results of the XI Groups Project: Studying an unbiased sample of galaxy groups
• The Solar Wind Charge-eXchange contribution to the Local Soft X-ray Background. Model to data comparison in the 0.1-1.0 keV band
• The Chandra Deep Group Survey -- cool core evolution in groups and clusters of galaxies

Cited by in corpus (12)

• Simulating Groups and the IntraGroup Medium: The Surprisingly Complex and Rich Middle Ground Between Clusters and Galaxies
• Scaling Properties of Galaxy Groups
• The Complete Local Volume Groups Sample - I. Sample Selection and X-ray Properties of the High-Richness Subsample
• SP(k) -- A hydrodynamical simulation-based model for the impact of baryon physics on the non-linear matter power spectrum
• Massive central galaxies of galaxy groups in the Romulus simulations: an overview of galaxy properties at z=0
• Low X-ray surface brightness clusters: Implications on the scatter of the $M-T$ and $L-T$ relations
• The hot gas mass fraction in halos. From Milky Way-like groups to massive clusters
• Measuring the X-ray luminosities of DESI groups from eROSITA Final Equatorial-Depth Survey: I. X-ray luminosity -- halo mass scaling relation
• The perils of stacking optically selected groups in eROSITA data. The Magneticum perspective
• The XXL Survey XLV. Linking the ages of optically selected groups to their X-ray emission
• Why are some galaxy clusters underluminous? The very low concentration of the CL2015 mass profile
• Core to Cosmic Edge: SIMBA-C's New Take on Abundance Profiles in the Intragroup Medium at z = 0