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B. E. Sugerman, S. S. Lawrence (Columbia University), P. Bouchet (CTIO), A. P. S. Crotts, R. R. Uglesich (Columbia University), S. R. Heathcote (CTIO)
The development of SNR~1987A provides a once-in-many-lifetimes opportunity to observe, at high spatial, spectral, and temporal resolution, the birth of a supernova remnant (SNR). Observations of the SNR might reveal the angular and velocity distribution of the ejecta by highlighting where it impacts a presumably well-known nebular structure. As such, the early discovery of these interaction regions is crucial.
As part of an ongoing ground-based monitoring campaign, data from the CTIO 4-m Tip-Tilt with first order wavefront correction taken on 1998 Oct 6 and 1999 Dec 25 in the \ion{He}{1}~1.083\mum line were processed with the image subtraction technique of Tomaney & Crotts (1996). At early times, new spots appear at greater contrast above the ER in near--IR \ion{He}{1} 1.083\mum than in strong optical transitions. We present in this data the first discovery of interaction (i.e.\ hotspots) between the ejecta and equatorial circumstellar ring (ER) since 1997 (Pun et al.).
Difference imaging of archival {\em HST} WFPC2 data from 1998 and 1999 in the F656N (H\alpha) filter confirms the discovery of this new spot, as well as that from Maran et al.\ (2000), and three from Garnavich et al.\ (2000). We present the probable appearance of 5 additional spots distributed about the northeast and northwest quadrants, and 3 marginal features near the west.
The full-scale collision between the SN ejecta and the inner ring has begun, and necessitates frequent, multi-wavelength monitoring of this rapidly developing event, with emphasis on \ion{He}{1} 1.083\mum, H\alpha and [\ion{N}{2}] imaging and spectroscopy.
(This research was supported by several grants from NASA, NSF and STScI)