Astronomy and Astrophysics – Astrophysics
Scientific paper
1994-05-26
Astrophys.J.449:18,1995
Astronomy and Astrophysics
Astrophysics
20 pages, uuencoded compressed postscript, CITA/93/37
Scientific paper
10.1086/176027
Long arcs in clusters of galaxies, produced by gravitational lensing, can be used to estimate the mass interior to the arcs and therefore, constrain the cluster mass distribution. The radial density distribution of the intracluster gas (ICM) can be extracted from the X-ray surface brightness observations. If the gas temperature is also known, it is then possible to probe the dynamical state of the gas and test whether the ICM is in hydro- static equilibrium within the gravitational potential of the cluster as a result of thermal pressure support. We analyze three clusters that exhibit large arcs, whose X-ray surface brightness profiles have been observed, and whose gas temperatures have been determined. In two of the clusters, A2218 and A1689, the central mass implied by lensing is a factor of $2$--$2.5$ too large for the gas at the observed temperature to be in hydrostatic equilibrium solely due to thermal pressure support. In other words, if we accept the mass estimate derived from the lensing analysis and demand that the X-ray surface brightness profile be consistent with the observations, the required gas temperature is a factor of $2$--$2.5$ higher than observed. The results for the third cluster, A2163 (the most luminous and the hottest cluster known), are more ambiguous. The discrepancy between the X-ray and the lensing mass estimates arise because the presence of arcs imply a highly concentrated cluster mass distribution whereas the observed X-ray profiles imply a more extended mass distribution. The large X-ray core radii are not the result of the limited resolution of the X-ray detectors. We consider various possibilities that could account for the discrepancy.
Babul Arif
Miralda-Escude' Jordi
No associations
LandOfFree
Gravitational Lensing in Clusters of Galaxies: New Clues Regarding the Dynamics of Intracluster Gas 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 Gravitational Lensing in Clusters of Galaxies: New Clues Regarding the Dynamics of Intracluster Gas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gravitational Lensing in Clusters of Galaxies: New Clues Regarding the Dynamics of Intracluster Gas will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-144421