skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The metallicity of the intracluster medium over cosmic time: further evidence for early enrichment

Abstract

Here, we use Chandra X-ray data to measure the metallicity of the intracluster medium (ICM) in 245 massive galaxy clusters selected from X-ray and Sunyaev–Zel'dovich (SZ) effect surveys, spanning redshifts 0 < z < 1.2. Metallicities were measured in three different radial ranges, spanning cluster cores through their outskirts. We explore trends in these measurements as a function of cluster redshift, temperature and surface brightness ‘peakiness’ (a proxy for gas cooling efficiency in cluster centres). The data at large radii (0.5–1 r500) are consistent with a constant metallicity, while at intermediate radii (0.1–0.5 r500) we see a late-time increase in enrichment, consistent with the expected production and mixing of metals in cluster cores. In cluster centres, there are strong trends of metallicity with temperature and peakiness, reflecting enhanced metal production in the lowest entropy gas. Within the cool-core/sharply peaked cluster population, there is a large intrinsic scatter in central metallicity and no overall evolution, indicating significant astrophysical variations in the efficiency of enrichment. The central metallicity in clusters with flat surface brightness profiles is lower, with a smaller intrinsic scatter, but increases towards lower redshifts. Our results are consistent with other recent measurements of ICM metallicity as a function ofmore » redshift. They reinforce the picture implied by observations of uniform metal distributions in the outskirts of nearby clusters, in which most of the enrichment of the ICM takes place before cluster formation, with significant later enrichment taking place only in cluster centres, as the stellar populations of the central galaxies evolve.« less

Authors:
ORCiD logo [1];  [2];  [2];  [3];  [1];  [4];  [1]
  1. Stanford Univ., Stanford, CA (United States)
  2. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. Institute of Space and Astronautical Science (ISAS), Kanagawa (Japan)
  4. MTA-Eotvos Univ. Lendulet Hot Universe Research Group, Budapest (Hungary); Masaryk Univ., Brno (Czech Republic); Hiroshima Univ., Higashi-Hiroshima (Japan)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1410451
Grant/Contract Number:
AC02-76SF00515; NNX15AE12G
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 472; Journal Issue: 3; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: clusters: intracluster medium; X-rays: galaxies: clusters

Citation Formats

Mantz, Adam B., Allen, Steven W., Morris, R. Glenn, Simionescu, Aurora, Urban, Ondrej, Werner, Norbert, and Zhuravleva, Irina. The metallicity of the intracluster medium over cosmic time: further evidence for early enrichment. United States: N. p., 2017. Web. doi:10.1093/mnras/stx2200.
Mantz, Adam B., Allen, Steven W., Morris, R. Glenn, Simionescu, Aurora, Urban, Ondrej, Werner, Norbert, & Zhuravleva, Irina. The metallicity of the intracluster medium over cosmic time: further evidence for early enrichment. United States. doi:10.1093/mnras/stx2200.
Mantz, Adam B., Allen, Steven W., Morris, R. Glenn, Simionescu, Aurora, Urban, Ondrej, Werner, Norbert, and Zhuravleva, Irina. 2017. "The metallicity of the intracluster medium over cosmic time: further evidence for early enrichment". United States. doi:10.1093/mnras/stx2200.
@article{osti_1410451,
title = {The metallicity of the intracluster medium over cosmic time: further evidence for early enrichment},
author = {Mantz, Adam B. and Allen, Steven W. and Morris, R. Glenn and Simionescu, Aurora and Urban, Ondrej and Werner, Norbert and Zhuravleva, Irina},
abstractNote = {Here, we use Chandra X-ray data to measure the metallicity of the intracluster medium (ICM) in 245 massive galaxy clusters selected from X-ray and Sunyaev–Zel'dovich (SZ) effect surveys, spanning redshifts 0 < z < 1.2. Metallicities were measured in three different radial ranges, spanning cluster cores through their outskirts. We explore trends in these measurements as a function of cluster redshift, temperature and surface brightness ‘peakiness’ (a proxy for gas cooling efficiency in cluster centres). The data at large radii (0.5–1 r500) are consistent with a constant metallicity, while at intermediate radii (0.1–0.5 r500) we see a late-time increase in enrichment, consistent with the expected production and mixing of metals in cluster cores. In cluster centres, there are strong trends of metallicity with temperature and peakiness, reflecting enhanced metal production in the lowest entropy gas. Within the cool-core/sharply peaked cluster population, there is a large intrinsic scatter in central metallicity and no overall evolution, indicating significant astrophysical variations in the efficiency of enrichment. The central metallicity in clusters with flat surface brightness profiles is lower, with a smaller intrinsic scatter, but increases towards lower redshifts. Our results are consistent with other recent measurements of ICM metallicity as a function of redshift. They reinforce the picture implied by observations of uniform metal distributions in the outskirts of nearby clusters, in which most of the enrichment of the ICM takes place before cluster formation, with significant later enrichment taking place only in cluster centres, as the stellar populations of the central galaxies evolve.},
doi = {10.1093/mnras/stx2200},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 3,
volume = 472,
place = {United States},
year = 2017,
month = 8
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on August 26, 2018
Publisher's Version of Record

Save / Share:
  • Here, we present the results of an X-ray spectral analysis of 153 galaxy clusters observed with the Chandra, XMM-Newton, and Suzaku space telescopes. These clusters, which span 0 < z < 1.5, were drawn from a larger, mass-selected sample of galaxy clusters discovered in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich (SPT-SZ) survey. With a total combined exposure time of 9.1 Ms, these data yield the strongest constraints to date on the evolution of the metal content of the intracluster medium (ICM). We find no evidence for strong evolution in the global (r < R 500) ICM metallicity (dZ/dz = –0.06 ± 0.04 Z ⊙), with a mean value at z = 0.6 ofmore » $$\langle Z\rangle =0.23\pm 0.01$$ Z ⊙ and a scatter of σ Z = 0.08 ± 0.01 Z ⊙. These results imply that the emission-weighted metallicity has not changed by more than 40% since z = 1 (at 95% confidence), consistent with the picture of an early (z > 1) enrichment. We find, in agreement with previous works, a significantly higher mean value for the metallicity in the centers of cool core clusters versus non-cool core clusters. We find weak evidence for evolution in the central metallicity of cool core clusters (dZ/dz = –0.21 ± 0.11 Z ⊙), which is sufficient to account for this enhanced central metallicity over the past ~10 Gyr. We find no evidence for metallicity evolution outside of the core (dZ/dz = –0.03 ± 0.06 Z ⊙), and no significant difference in the core-excised metallicity between cool core and non-cool core clusters. This suggests that strong radio-mode active galactic nucleus feedback does not significantly alter the distribution of metals at $$r\gt 0.15{R}_{500}$$. Given the limitations of current-generation X-ray telescopes in constraining the ICM metallicity at z > 1, significant improvements on this work will likely require next-generation X-ray missions.« less
  • Here, we present the results of an X-ray spectral analysis of 153 galaxy clusters observed with the Chandra, XMM-Newton, and Suzaku space telescopes. These clusters, which span 0 < z < 1.5, were drawn from a larger, mass-selected sample of galaxy clusters discovered in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich (SPT-SZ) survey. With a total combined exposure time of 9.1 Ms, these data yield the strongest constraints to date on the evolution of the metal content of the intracluster medium (ICM). We find no evidence for strong evolution in the global ( r < R 500) ICMmore » metallicity ( dZ/dz = -0.06 ± 0.04 Z ), with a mean value at z = 0.6 of < Z > = 0.23 ± 0.01 Z and a scatter of σ Z = 0.08 ± 0.01 Z . These results imply that the emission-weighted metallicity has not changed by more than 40% since z = 1 (at 95% confidence), consistent with the picture of an early ( z > 1) enrichment. We find, in agreement with previous works, a significantly higher mean value for the metallicity in the centers of cool core clusters versus non-cool core clusters. We find weak evidence for evolution in the central metallicity of cool core clusters ( dZ/dz = -0.21 ± 0.11 Z ), which is sufficient to account for this enhanced central metallicity over the past similar to 10 Gyr. We find no evidence for metallicity evolution outside of the core ( dZ/dz = -0.03 ± 0.06 Z ), and no significant difference in the core-excised metallicity between cool core and non-cool core clusters. This suggests that strong radio-mode active galactic nucleus feedback does not significantly alter the distribution of metals at r > 0.15R 500. Lastly, given the limitations of current-generation X-ray telescopes in constraining the ICM metallicity at z > 1, significant improvements on this work will likely require next-generation X-ray missions.« less
  • Observations have been made of 18 distance class 5 and 6 Abell clusters of galaxies using the VLA in its C configuration at a frequency of 1460 MHz. Half of the clusters in the sample are confirmed or probable sources of X-ray emission. All the detected radio sources with flux densities above 10 mJy are reported, and information is provided concerning the angular extent of the sources, as well as the most likely optical identification. The existence of an extensive intracluster medium is inferred by identifying extended/distorted radio sources with galaxies whose apparent magnitudes are consistent with their being clustermore » members and that are at projected distances of 3-4 Abell radii (6-8 Mpc) from the nearest cluster center. By requiring that the radio sources are confined by the ambient medium, the ambient density is calculated and the total cluster mass is estimated. As a sample calculation, a wide-angle-tail radio source some 5 Mpc from the center of Abell 348 is used to estimate these quantities. 37 references.« less
  • Active galactic nuclei (AGNs) play a central role in solving the decades-old cooling-flow problem. Although there is consensus that AGNs provide the energy to prevent catastrophically large star formation, one major problem remains: How is the AGN energy thermalized in the intracluster medium (ICM)? We perform a suite of three-dimensional magnetohydrodynamical adaptive mesh refinement simulations of AGN feedback in a cool core cluster including cosmic rays (CRs). CRs are supplied to the ICM via collimated AGN jets and subsequently disperse in the magnetized ICM via streaming, and interact with the ICM via hadronic, Coulomb, and streaming instability heating. We findmore » that CR transport is an essential model ingredient at least within the context of the physical model considered here. When streaming is included, (i) CRs come into contact with the ambient ICM and efficiently heat it, (ii) streaming instability heating dominates over Coulomb and hadronic heating, (iii) the AGN is variable and the atmosphere goes through low-/high-velocity dispersion cycles, and, importantly, (iv) CR pressure support in the cool core is very low and does not demonstrably violate observational constraints. However, when streaming is ignored, CR energy is not efficiently spent on the ICM heating and CR pressure builds up to a significant level, creating tension with the observations. Overall, we demonstrate that CR heating is a viable channel for the AGN energy thermalization in clusters and likely also in ellipticals, and that CRs play an important role in determining AGN intermittency and the dynamical state of cool cores.« less