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Title: Radio Bubbles in Clusters of Galaxies

Abstract

We extend our earlier work on cluster cores with distinct radio bubbles, adding more active bubbles, i.e. those with GHz radio emission, to our sample, and also investigating ''ghost bubbles'', i.e. those without GHz radio emission. We have determined k, which is the ratio of the total particle energy to that of the electrons radiating between 10MHz and 10GHz. Constraints on the ages of the active bubbles confirm that the ratio of the energy factor, k, to the volume filling factor, f lies within the range 1 {approx}< k/f {approx}< 1000. In the assumption that there is pressure equilibrium between the radio-emitting plasma and the surrounding thermal X-ray gas, none of the radio lobes has equipartition between the relativistic particles and the magnetic field. A Monte-Carlo simulation of the data led to the conclusion that there are not enough bubbles present in the current sample to be able to determine the shape of the population. An analysis of the ghost bubbles in our sample showed that on the whole they have higher upper limits on k/f than the active bubbles, especially when compared to those in the same cluster. A study of the Brightest 55 cluster sample shows that 17,more » possibly 20, clusters required some form of heating as they have a short central cooling time, t{sub cool} {approx}< 3 Gyr, and a large central temperature drop, T{sub centre}/T{sub outer} < 1/2. Of these between 12 (70 per cent) and 15 (75 per cent), contain bubbles. This indicates that the duty cycle of bubbles is large in such clusters and that they can play a major role in the heating process.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
877504
Report Number(s):
SLAC-PUB-11481
Journal ID: ISSN 0035-8711; MNRAA4; astro-ph/0510191; TRN: US200608%%189
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 364
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BUBBLES; COOLING TIME; ELECTRONS; GALAXIES; HEATING; MAGNETIC FIELDS; PLASMA; SHAPE; SIMULATION; Astrophysics,ASTRO

Citation Formats

Dunn, Robert J.H., Fabian, A.C., /Cambridge U., Inst. of Astron., Taylor, G.B., and /NRAO, Socorro /KIPAC, Menlo Park. Radio Bubbles in Clusters of Galaxies. United States: N. p., 2005. Web. doi:10.1111/j.1365-2966.2005.09673.x.
Dunn, Robert J.H., Fabian, A.C., /Cambridge U., Inst. of Astron., Taylor, G.B., & /NRAO, Socorro /KIPAC, Menlo Park. Radio Bubbles in Clusters of Galaxies. United States. doi:10.1111/j.1365-2966.2005.09673.x.
Dunn, Robert J.H., Fabian, A.C., /Cambridge U., Inst. of Astron., Taylor, G.B., and /NRAO, Socorro /KIPAC, Menlo Park. Wed . "Radio Bubbles in Clusters of Galaxies". United States. doi:10.1111/j.1365-2966.2005.09673.x. https://www.osti.gov/servlets/purl/877504.
@article{osti_877504,
title = {Radio Bubbles in Clusters of Galaxies},
author = {Dunn, Robert J.H. and Fabian, A.C. and /Cambridge U., Inst. of Astron. and Taylor, G.B. and /NRAO, Socorro /KIPAC, Menlo Park},
abstractNote = {We extend our earlier work on cluster cores with distinct radio bubbles, adding more active bubbles, i.e. those with GHz radio emission, to our sample, and also investigating ''ghost bubbles'', i.e. those without GHz radio emission. We have determined k, which is the ratio of the total particle energy to that of the electrons radiating between 10MHz and 10GHz. Constraints on the ages of the active bubbles confirm that the ratio of the energy factor, k, to the volume filling factor, f lies within the range 1 {approx}< k/f {approx}< 1000. In the assumption that there is pressure equilibrium between the radio-emitting plasma and the surrounding thermal X-ray gas, none of the radio lobes has equipartition between the relativistic particles and the magnetic field. A Monte-Carlo simulation of the data led to the conclusion that there are not enough bubbles present in the current sample to be able to determine the shape of the population. An analysis of the ghost bubbles in our sample showed that on the whole they have higher upper limits on k/f than the active bubbles, especially when compared to those in the same cluster. A study of the Brightest 55 cluster sample shows that 17, possibly 20, clusters required some form of heating as they have a short central cooling time, t{sub cool} {approx}< 3 Gyr, and a large central temperature drop, T{sub centre}/T{sub outer} < 1/2. Of these between 12 (70 per cent) and 15 (75 per cent), contain bubbles. This indicates that the duty cycle of bubbles is large in such clusters and that they can play a major role in the heating process.},
doi = {10.1111/j.1365-2966.2005.09673.x},
journal = {Monthly Notices of the Royal Astronomical Society},
number = ,
volume = 364,
place = {United States},
year = {Wed Dec 14 00:00:00 EST 2005},
month = {Wed Dec 14 00:00:00 EST 2005}
}