|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'501'711
Articles rated: 2609
19 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Physical Origins of Gas Motions in Galaxy Cluster Cores: Interpreting Hitomi Observations of the Perseus Cluster | | Erwin T. Lau
; Massimo Gaspari
; Daisuke Nagai
; Paolo Coppi
; | | Date: |
17 May 2017 | | Abstract: | The Hitomi X-ray satellite has provided the first direct measurements of the
plasma velocity dispersion inside a galaxy cluster. Looking at the inner core
of the Perseus cluster, Hitomi finds a relatively "quiescent" gas with fairly
uniform properties, in particular a line-of-sight velocity dispersion of ~160
km/s at distances 30-60 kpc from the cluster center. This is potentially
surprising given evidence such as the presence of jets and X-ray cavities that
indicates on-going activity and feedback from the active galactic nucleus (AGN)
at the cluster center. Using a set of mock Hitomi observations generated from a
suite of state-of-the-art cosmological cluster simulations, and an isolated but
higher resolution cluster simulation with cooling and AGN feedback physics, we
examine the likelihood of Hitomi detecting a cluster with the observed
velocities characteristic of Perseus. As long as the Perseus core has not
experienced a major merger in the last few gigayears, and AGN feedback is
effective and operating in a "gentle" mode, we reproduce the level of gas
motions observed by Hitomi. Turbulence, initially driven by cosmic accretion,
provides a background velocity field, which helps to efficiently trigger AGN
outflows via chaotic cold accretion. The frequent mechanical AGN feedback
generates net line-of-sight velocity dispersions ~ 100-200 km/s, bracketing the
values measured in the Perseus core. The large-scale velocity shear observed
across the core, on the other hand, is generated mainly by cosmic accretion
such as mergers. We discuss the implications of these results for AGN feedback
physics and cluster cosmology and how to make progress via improved simulations
and observations, including a Hitomi re-flight and calorimeter-based
instruments with higher spatial resolution. | | Source: | arXiv, 1705.6280 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER