The Lensing Cluster MS 0440+0204 Seen byHST,ROSAT, andASCA. I. Cluster Properties

We present an analysis of the properties of the lensing cluster MS0440+0204at z=0.1965. MS0440+0204 has been observed with a variety of telescopes atdiverse wavelengths: from the ground with CFHT, MMT and KECK and from Earthorbit with HST, ROSAT and ASCA. Mass determinations are separately obtainedfrom galaxy virial motions and X-ray profile fitting. A simple beta-model fitto the X-ray data yields a mass of (1.3+/-0.2) x10^{14} M_sun within 583 kpc ofthe cluster center, but more general models fit all of our data better andallow a wider range of masses that are consistent with the lensing data. Inaddition, the X-ray data yield a mass distribution profile that is welldescribed by a beta model with a core radius of 26.7 kpc. The velocitydispersion of galaxies yields a mass of 4.8^{+1.5}_{-0.94} x 10^{14} M_sunwithin 900 kpc. In the inner 24.5arcsec there are 24 arcs that appear to bestrong gravitationally lensed images of background sources. Models of thecluster mass distribution and its lensing properties reveal 5 backgroundsources at various redshifts each forming 2 or more arcs. At 100 kpc, the lowerlimit mass from lensing is about a factor of 2 greater than the X-raydetermined mass. lens model than the X-ray determination. To reconcile the massestimates from the X-rays and the lensing and to try to understand the steepslope of the gravitational lens mass, we tentatively explore a model with asupercluster surrounding the cluster and with a mass profile that increasesmore rapidly than a beta model at large radii.Comment: 37 pages, LaTe