|
Description
We present the first spectroscopic survey of intrinsically low X-ray luminosity clusters at z>>0, with Hubble Space Telescope (HST) WFPC2 imaging and spectroscopy from Calar Alto and WHT-LDSS2. We study 172 confirmed cluster members in a sample of ten clusters at 0.23<z<0.3, with LX<~4x10^43^h^-2^erg/s[0.1-2.4keV]. The core of each cluster is imaged with WFPC2 in the F702W filter, and the spectroscopic sample is statistically complete to Mr~-19.0+5logh, within an 11' (~1.8h^-1^Mpc) field. The clusters are dynamically well-separated from the surrounding field and most have velocity distributions consistent with Gaussians. The velocity dispersions range from 350-850km/s, consistent with the local L_X_-{sigma} correlation. All 10 clusters host a bright, giant elliptical galaxy without emission lines, near the centre of the X-ray emission. We measure the equivalent width of two nebular emission lines, [O II] and H{alpha}, and the H{delta} absorption line to classify the cluster members spectrally. Galaxy morphologies are measured from the HST images, using the two-dimensional surface-brightness fitting software GIM2D.
|
