Integral field spectroscopy of SN 1987A

SN 1987A in the Large Magellanic Cloud is close enough for a study of the very late time evolution of a supernova and its transition to a supernova remnant. Nearly two decades after explosion we are witnessing the supernova shock wave engaging the inner circumstellar ring, which had been fluorescing since being ionised by the soft X-ray flash from shock breakout. We present in the following observations of the SN-ring interaction obtained in November 2004 with SINFONI on the VLT. SINFONI's adaptive optics supported integral field spectrograph spatially resolves the equatorial ring and we obtain a better spatial understanding of the spectrum in different emission regions. With a dynamical map of the shock interaction around the ring we determine parameters for its geometry. Since most of the IR emission lines originate behind the shock front we obtain an indication of the expansion velocity of the shocked material. The ring geometry is consistent with a circle and we also derive a new, independent measurement of the systemic ring, and presumably also supernova, velocity.