A WHIM origin for the soft excess emission in the Coma cluster

Abstract

This paper provides a new analysis of ROSAT observations of the Coma cluster, to determine the amount of soft X--ray radiation in excess of the contribution from the hot intra--cluster medium. The re--analysis is made possible by a high--resolution study of the hot intra--cluster medium with the XMM-Newton and Planck telescopes out to the cluster's virial radius. The analysis confirms the original findings of a strong excess of soft X--ray radiation, which is likely to be of thermal origin. We find quantitative agreement between the detected soft excess and the physical characteristics of warm--hot intergalactic medium (WHIM) filaments seen in hydrodynamical simulations. We conclude that the most plausible explanation for the soft excess is the presence of $\sim 10$~Mpc--long filaments at $\log T(K)\simeq 6$, with a baryon overdensity $\sim 300$, converging towards the Coma cluster. This interpretation therefore provides support for the identification of the missing low--redshift baryons with WHIM filaments, as predicted by numerical simulations.

arXiv commentMNRAS accepted

References in corpus (46)

• Planck 2015 results. XIII. Cosmological parameters
• Planck 2013 results. XVI. Cosmological parameters
• On the Absorption of X-rays in the Interstellar Medium
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Collisional Plasma Models with APEC/APED: Emission Line Diagnostics of Hydrogen-like and Helium-like Ions
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Where are the Baryons?
• Ionization balance for optically thin plasmas: rate coefficients for all atoms and ions of the elements H to Ni
• Baryons in the Warm-Hot Intergalactic Medium
• Observations of the MIssing Baryons in the warm-hot intergalactic medium
• Baryons in the CosmicWeb of IllustrisTNG - I: Gas in Knots, Filaments, Sheets and Voids
• X-Ray surface brightness and gas density fluctuations in the Coma cluster
• Warm-hot baryons comprise 5-10 per cent of filaments in the cosmic web
• An HST/COS Survey of the Low-Redshift IGM. I. Survey, Methodology, & Overall Results
• Detection of hot gas in the filament connecting the clusters of galaxies Abell 222 and Abell 223
• Probing the missing baryons with the Sunyaev-Zel'dovich effect from filaments
• A Search for Warm/Hot Gas Filaments Between Pairs of SDSS Luminous Red Galaxies
• The dynamical state of the Coma cluster with XMM-Newton
• XMM-Newton confirmation of Soft X-ray excess emission in clusters of galaxies - the discovery of O VII emission from an extended warm baryonic component
• The NGC4839 group falling into the Coma cluster observed by XMM-Newton
• Thermodynamics of the Coma Cluster Outskirts
• Properties of gas phases around cosmic filaments at z=0 in the Illustris-TNG simulation
• The Abell 3391/95 galaxy cluster system: A 15 Mpc intergalactic medium emission filament, a warm gas bridge, infalling matter clumps, and (re-) accelerated plasma discovered by combining SRG/eROSITA data with ASKAP/EMU and DECam data
• Non-thermal Origin of the EUV and Soft X-rays from the Coma Cluster - Cosmic Rays in Equipartition with the Thermal Medium
• An EAGLE view of the missing baryons
• EUV Emission in Abell 1795, Abell 2199, and the Coma Cluster
• The low-redshift intergalactic medium as seen in archival legacy Hubble/STIS and FUSE data
• The soft X-ray emission in a large sample of galaxy clusters with ROSAT PSPC
• Soft X-ray excess emission in clusters of galaxies observed with XMM-Newton
• Tempestuous life beyond R_500: X-ray view on the Coma cluster with SRG/eROSITA. I. X-ray morphology, recent merger, and radio halo connection
• The Role of Penetrating Gas Streams in Setting the Dynamical State of Galaxy Clusters
• A massive warm baryonic halo in the Coma cluster
• The EUV excess emission of the Virgo and A1795 clusters - re-observation with in-situ background measurements
• The abundance and physical properties of O VII and O VIII X-ray absorption systems in the EAGLE simulations
• Establishing HZ43 A, Sirius B, and RX J185635-3754 as soft X-ray standards: a cross-calibration between the Chandra LETG+HRC-S, the EUVE spectrometer, and the ROSAT PSPC
• A possible Chandra and Hubble Space Telescope detection of extragalactic WHIM towards PG 1116+215
• A complete view of the outskirts of the Coma cluster
• Warm-Hot Intergalactic Medium in the Sculptor Supercluster
• Sersic 159-03: discovery of the brightest soft X-ray excess emitting cluster of galaxies
• Simulating the Soft X-ray excess in clusters of galaxies
• ROSAT and BeppoSAX evidence of soft X-ray excess emission in the Shapley supercluster: A3571, A3558, A3560 and A3562
• Revisiting the soft X-ray excess emission in clusters of galaxies observed with XMM-Newton
• Thermal and non-thermal nature of the soft excess emission from Sersic 159-03 observed with XMM-Newton
• The diffuse soft excess emission in the Coma cluster from the ROSAT All-Sky Survey
• X-ray spectroscopy of Abell S1101 with Chandra, XMM-Newton and ROSAT: band-pass dependence of he temperature profile and soft excess emission

Cited by in corpus (6)

• The eROSITA view of the Abell 3391/95 field: Cluster Outskirts and Filaments
• Prospects of detecting soft X-ray emission from typical WHIM filaments around massive clusters and the Coma cluster soft excess
• Soft X-ray emission from warm gas in IllustrisTNG circum-cluster environments
• Studying the Warm Hot Intergalactic Medium in emission: a reprise
• The Three Hundred: Gas Properties Outside of Galaxy Cluster with the WHIM Contribution and Detection
• X-ray emission in IllustrisTNG circum-cluster environments. II -- Possible origins of the soft X-ray excess emission