Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-04-09
Astrophys.J. 485 (1997) 447
Astronomy and Astrophysics
Astrophysics
35 pages in latex, 17 figures in Postscript, accepted for publication in the Astrophysical Journal
Scientific paper
10.1086/304458
We investigate the dynamical properties of the cluster of galaxies A3558 (Shapley 8). Studying a region of one square degree ($\sim$ 3 Mpc$^2$) centered on the cluster cD galaxy, we have obtained a statistically complete photometric catalog with positions and magnitudes of 1421 galaxies (down to a limiting magnitude of $B \sim 21$). This catalog has been matched to the recent velocity data obtained by Mazure et al. (1997) and from the literature, yielding a radial velocity catalog containing 322 galaxies. Our analysis shows that the position/velocity space distribution of galaxies shows significant substructure. A central bimodal core detected previously in preliminary studies is confirmed by using the Adaptive Kernel Technique and Wavelet Analysis. We show that this central bimodal subtructure is nevertheless composed of a projected feature, kinematically unrelated to the cluster, plus a group of galaxies probably in its initial merging phase into a relaxed core. The cD velocity offset with respect to the average cluster redshift, reported earlier by several authors, is completely eliminated as a result of our dynamical analysis. The untangling of the relaxed core component also allows a better, more reliable determination of the central velocity dispersion, which in turn eliminates the ``$\beta$-problem'' for A3558. The cluster also shows a ``preferential'' distribution of subclumps coinciding with the direction of the major axis position angle of the cD galaxy and of the central X-ray emission ellipsoidal distribution, in agreement with an anisotropic merger scenario.
Capelato Hugo V.
Dantas Christine C.
de Carvalho Reinaldo R.
Mazure Alain
No associations
LandOfFree
Evidence of Substructure in the Cluster of Galaxies A3558 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 Evidence of Substructure in the Cluster of Galaxies A3558, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evidence of Substructure in the Cluster of Galaxies A3558 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-289291