Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-03-30
Mon.Not.Roy.Astron.Soc.354:169,2004
Astronomy and Astrophysics
Astrophysics
Six pages, 4 figs, Monthly Notices style
Scientific paper
10.1111/j.1365-2966.2004.08175.x
We revisit the notion that galaxy motions can efficiently heat intergalactic gas in the central regions of clusters through dynamical friction. For plausible values of the galaxy mass-to-light ratio, the heating rate is comparable to the cooling rate due to X-ray emission. Heating occurs only for supersonic galaxy motions, so the mechanism is self-regulating: it becomes efficient only when the gas sound speed is smaller than the galaxy velocity dispersion. We illustrate with the Perseus cluster, assuming a stellar mass-to-light ratio for galaxies in the very central region with the dark-matter contribution becoming comparable to this at some radius $r_s$. For $r_s \la 400 {\rm kpc} \sim 3 r_{\rm cool}$--corresponding to an average mass-to-light ratio of $\sim10$ inside that radius--the dynamical-friction coupling is strong enough to provide the required rate of gas heating. The measured sound speed is smaller than the galaxy velocity dispersion, as required by this mechanism. With this smaller gas temperature and the observed distribution of galaxies and gas, the energy reservoir in galactic motions is sufficient to sustain the required heating rate for the lifetime of the cluster. The galaxies also lose a smaller amount of energy through dynamical friction to the dark matter implying that non--cooling-flow clusters should have flat-cored dark-matter density distributions.
El-Zant Amr A.
Kamionkowski Marc
Kim Woong-Tae
No associations
LandOfFree
Dynamical-Friction Galaxy-Gas Coupling and Cluster Cooling Flows does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Dynamical-Friction Galaxy-Gas Coupling and Cluster Cooling Flows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamical-Friction Galaxy-Gas Coupling and Cluster Cooling Flows will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-616642