Multiwavelength observations of the soft gamma repeater SGR 1900+14 duringits 2001 April activation

The soft gamma repeater SGR 1900+14 became active on 2001 April 18 after ab out 2 years of quiescence; it had remained at a very low state of activity since the fall of 1998, when it exhibited extraordinary flaring. We have ob served the source in the gamma-rays and X-rays with Ulysses and Chandra and in the radio with MERLIN. We report here the confirmation of a two-compone nt X-ray spectrum (power law + blackbody), indicating emission from the neu tron star surface. We have determined that there is a dust halo, due to sca ttering in the interstellar medium, surrounding the source that extends up to greater than or similar to 100 " from the center of SGR 1900+14.