2001MNRAS.321L..33F

We report the discovery of a 40arcsec long X-ray filament in the core of the cluster of galaxies Abell 1795. The feature coincides with an Hα+Nii filament found by Cowie et al. in the early 1980s and resolved into at least two U-band filaments by McNamara et al. in the mid-1990s. The (emission-weighted) temperature of the X-ray emitting gas along the filament is 2.5-3keV, as revealed by X-ray colour ratios. The deprojected temperature will be less. A detailed temperature map of the core of the cluster presented. The cD galaxy at the head of the filament is probably moving through or oscillating in the cluster core. The radiative cooling time of the X-ray emitting gas in the filament is about {formmu1} which is similar to the age of the filament obtained from its length and velocity. This suggests that the filament is produced by cooling of the gas from the intracluster medium. The filament, much of which is well separated from the body of the cD galaxy and its radio source, is potentially of great importance in helping to understand the energy and ionization source of the optical nebulosity common in cooling flows.