X-ray spectral observations of clusters of galaxies undergoing merger events

Abstract

view Abstract Citations (12) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS X-Ray Spectral Observations of Clusters of Galaxies Undergoing Merger Events Henriksen, Mark J. Abstract We have analyzed the HEAO 1 A2 observations of two clusters whose optical and X-ray isophotes are suggestive of merging subclusters, A 119 and A754, and find evidence of nonisothermal X-ray emission from both clusters. The X-ray spectrum of both clusters, when fitted with a single isothermal model, shows residual soft X-ray emission. There is a statistically significant reduction in χ^2^ (98% probability based on the F-test) when a second temperature component is added. If the asymmetric isophotes seen in the soft X-ray image are indicative of merging subclusters, then our analysis of the Einstein Imaging Proportional Counter (IPC) spectra and Solid State Spectrometer (SSS) observations of A754, which provide some spatial and spectral resolution, suggests that the two temperature components seen in the HEAO 1 A2 spectra are associated with gas trapped in the subcluster potential wells. The implied subcluster isothermal masses suggest that a more massive cluster is accreting a less massive companion in A754. The present observations cannot rule out the alternative possibility that the cooler gas is associated with the outer cluster atmosphere rather than individual subclusters, as appears to be the case for A 119. Astro D observations will be necessary to distinguish between these two possibilities for both clusters. Publication: The Astrophysical Journal Pub Date: September 1993 DOI: 10.1086/186982 Bibcode: 1993ApJ...414L...5H Keywords: Galactic Clusters; Galactic Evolution; Galactic Structure; X Ray Spectra; Isophotes; Spectrum Analysis; Stellar Temperature; X Ray Astronomy; Astrophysics; GALAXIES: CLUSTERING full text sources ADS | data products SIMBAD (2) NED (2)