X-ray Absorption by Cold Gas in Cluster Cooling Flows

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Scientific paper

Recent analyses of X-ray spectra from the Einstein Observatory have revealed evidence for significant levels of excess absorption over that expected from the Galaxy associated with some cluster cooling flows (White {et al. } 1991; Wang & Stocke 1992). These observations imply the presence of large quantities of cold absorbing material (Mcold ~ 10(11) --10(12) Msun) and could represent direct evidence for the large amounts of cool material which current cooling flow models predict. In addition, such large quantities of absorbing material could have a significant impact on the observed X-ray properties of cluster cooling flows. To assess this impact, we have calculated the emergent X-ray properties for a set of cooling flow models including the effects of accumulated cold gas on the transfer of radiation through the cluster. These models are steady--state, spherically symmetric, and exhibit inhomogeneous gas distributions with material cooling out of the flow over all radii. Our results indicate that the accumulated cold material can have a dramatic effect on the observed X-ray properties of the cluster, reducing the total X-ray luminosity, L_X, in the range 0.1--10 keV by as much as 25% compared to the optically thin case. In the central regions of the flow (r < 1 kpc), the effects are even more extreme with absorption levels reaching values of 70%. Spatially, the opacity due to the cold gas results in X-ray surface brightness profiles which are much less centrally peaked than their optically thin counterparts with decreases between 40%--80% for radii less than 10 kpc. The surface brightness profiles for X-ray lines show similar effects. In addition, the continuum opacity produces spectral line profiles which are asymmetric and have reduced intensity on the ``blue'' side of the line. These photons correspond to emission from the far side of the cluster and must, consequently, traverse a greater pathlength than those on the near side. Finally, we find that the emergent optically thick X-ray spectra cannot be explained by a simple foreground absorption model.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

X-ray Absorption by Cold Gas in 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 X-ray Absorption by Cold Gas in Cluster Cooling Flows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray Absorption by Cold Gas in Cluster Cooling Flows will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1112078

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.