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A multi-wavelength analysis of the cluster of galaxies ABCG 194
E. Nikogossyan 1,
F. Durret 2,3,
D. Gerbal 2,3 and
F. Magnard 2
Received 10 May 1999 / Accepted 19 July 1999
We present a morphological and structural analysis of the Richness zero cluster ABCG 194, known as a "linear cluster". This study is based on a catalogue of 97 galaxies with B magnitudes and redshifts belonging to the cluster, a ROSAT PSPC image and radio data.
We show that the overall large scale structure is rather smooth and comparable at optical and X-ray wavelengths. The cluster is elongated along PA ; however it appears as "linear" when taking into account only galaxies in the very central part (the axial ratio varies from 0.2 in the central region to 0.8 for a larger region). We have obtained the galaxy density profile and despite the very low X-ray emission the X-ray emitting gas density profile. We have estimated the X-ray gas and dynamical masses up to the limiting radius of the PSPC image (respectively and 8 1013 ) and the stellar mass up to and to 3 Mpc (3 and 7.5 1012 ).
At smaller scales, the analysis of both positions and velocities reveals the existence of several groups but which are not strongly linked dynamically; however a main structure with a nearly gaussian velocity distribution is exhibited. The velocity dispersion is small ( = 360 km s-1). A wavelet analysis of the X-ray image reveals no large scale substructures. Small scale X-ray sources are detected, mainly corresponding to individual galaxies; we give an estimate of their luminosities. The lack of strong substructuring suggests that ABCG 194 is overall a relaxed cluster.
ABCG 194 is a poor and cold cluster; we compare how its characteristics fit into various correlations found in the literature, but generally for richer/hotter clusters, such as the -, -, - relations or the ratios of various kinds of masses.
Key words: galaxies: clusters: general galaxies: clusters: individual: ABCG 194
Send offprint requests to: F. Durret (firstname.lastname@example.org)
Online publication: August 25, 1999