Observed Non-Steady State Cooling and the Moderate Cluster Cooling Flow Model

Abstract

We examine recent developments in the cluster cooling flow scenario following recent observations by Chandra and XMM-Newton. We show that the distribution of gas emissivity verses temperature determined by XMM-Newton gratings observations demonstrates that the central gas in cooling flow clusters cannot be in simple steady-state. Combining this result with the lack of spectroscopic evidence for gas below one-third of the ambient cluster temperature is strong evidence that the gas is heated intermittently. While the old steady-state isobaric cooling flow model is incompatible with recent observations, a "moderate cooling flow model", in which the gas undergoes intermittent heating that effectively reduces the age of a cooling flow is consistent with observations. Most of the gas within cooling flows resides in the hottest gas, which is prevented from cooling continuously and attaining a steady-state configuration. This results in a mass cooling rate that decreases with decreasing temperature, with a much lower mass cooling rate at the lowest temperatures. The present paper strengthens the moderate cooling flow model, which can accommodate the unique activities observed in cooling flow clusters.

ApJ, in press

References in corpus (4)

• High Resolution X-ray Spectroscopic Constraints on Cooling-Flow Models for Clusters of Galaxies
• Hot Bubbles from Active Galactic Nuclei as a Heat Source in Cooling Flow Clusters
• Heating, conduction and minimum temperatures in cooling flows
• Chandra Observation of the Cooling Flow Cluster Abell 2052

Cited by in corpus (9)

• Thermal Instability & the Feedback Regulation of Hot Halos in Clusters, Groups, and Galaxies
• On the Nature of Feedback Heating in Cooling Flow Clusters
• Solving the angular momentum problem in the cold feedback mechanism of cooling flows
• OVI Observations of Galaxy Clusters: Evidence for Modest Cooling Flows
• Feedback Heating with Slow Jets in Cooling Flow Clusters
• The Source of Mass Accreted by the Central Black Hole in Cooling Flow Clusters
• A Moderate Cooling Flow Phase at Galaxy Formation
• Cooling by Heat Conduction Inside Magnetic Flux Loops and the Moderate Cluster Cooling Flow Model
• Entropy Limit and the Cold Feedback Mechanism in Cooling Flow Clusters