A POSSIBLE EXCESS ROTATION MEASURE AND LARGE-SCALE MAGNETIC-FIELD IN THE VIRGO SUPERCLUSTER OF GALAXIES

A new large-scale magnetic field has been possibly detected in a cluster of galaxies, covering several Mpc within the ambient gas in the space between the galaxies in a cluster. Evidence is presented for a possible cluster-wide magnetic field in the Virgo Supercluster, with a magnetic field intensity near 1.5 μG consistent with a RM excess of - 10 rad m-2. Previously detected cluster-wide magnetic fields had an observed field intensity near 0.2 μG in the cluster of galaxies Abell 2319 (Vallée et al. 1986, 1987) and an observed field intensity near 0.5 μG in the Coma Cluster of galaxies (e.g., Kronberg 1987). Previous theoretical works predicted such large-scale magnetic fields in clusters of galaxies at widely differing intensity levels between 0.03 and 30 μG. Arp's claim of a local theory of quasars, based on the RM of QSO at different redshifts z (an excess RM seen only for QSO with z near 1 ), is inconsistent with the larger set of RM data (an excess RM is seen at all z for QSO, and at all z for galaxies) toward the Virgo Supercluster of galaxies.