English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Feedback from AGN, galactic mergers, and sloshing are thought to give rise toturbulence, which may prevent cooling in clusters. We aim to measure theturbulence in clusters of galaxies and compare the measurements to some oftheir structural and evolutionary properties. It is possible to measure theturbulence of the hot gas in clusters by estimating the velocity widths oftheir X-ray emission lines. The RGS Spectrometers aboard XMM-Newton arecurrently the only instruments provided with sufficient effective area andspectral resolution in this energy domain. We benefited from excellent 1.6Msnew data provided by the CHEERS project. The new observations improve thequality of the archival data and allow us to place constraints for someclusters, which were not accessible in previous work. One-half of the sampleshows upper limits on turbulence less than 500km/s. For several sources, ourdata are consistent with relatively strong turbulence with upper limits on thevelocity widths that are larger than 1000km/s. The NGC507 group of galaxiesshows transonic velocities, which are most likely associated with the mergingphenomena and bulk motions occurring in this object. Where both low- andhigh-ionization emission lines have good enough statistics, we find largerupper limits for the hot gas, which is partly due to the different spatialextents of the hot and cool gas phases. Our upper limits are larger than theMach numbers required to balance cooling, suggesting that dissipation ofturbulence may prevent cooling, although other heating processes could bedominant. The systematics associated with the spatial profile of the sourcecontinuum make this technique very challenging, though still powerful, forcurrent instruments. The ASTRO-H and Athena missions will revolutionize thevelocity estimates and discriminate between different spatial regions andtemperature phases.

Chemical Enrichment RGS cluster sample (CHEERS): Constraints on turbulence