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Session 46 - Supernova Remnants.
Display session, Tuesday, January 14
Metropolitan Ballroom,

[46.01] Infrared Observations of Cassiopeia A and the Crab Nebula

S. Lawrence, J. Bohigas (Obs. Astronomico Nacional--UNAM)

We have used the Camaleon infrared spectrograph/camera on the 2.1-m telescope of the Observatorio Astronómico Nacional of Mexico to image the Cassiopiea A and Crab Nebula supernova remnants in various bands between 1.0 and 2.5 \mum. Camaleon uses a 256x256 NICMOS array detector. The low resolution imaging mode used for these observations has a field of view of 3.63 arcminutes and an image scale of 0.85 arcseconds per pixel. Mosaics of Cas A were observed in J, K', and deeply in H. As expected, extended emission was detected in the H band, arising from the [Fe II] 1.644 \mum line in the ejecta. Abundance anisotropies have been inferred in the fast moving knots on the basis of the relative strengths of their oxygen and sulfur lines. Due to the heavy extinction towards Cas A, the infrared iron line may be best to investigate the distribution of iron-peak elements. We will present calibrated maps of the [Fe II] emission, and compare the intensity distribution with those of the optical oxygen and sulfur lines. We will also discuss the relative strengths of the [Fe II] emission between the fast moving knots and the quasi-stationary flocculi. Mosaics of the Crab Nebula were taken in J, H, K', and deeply in a narrow filter centered on the H_2 2.122 \mum line. Our goal is to map the H_2 emission from the dense cores of the ejecta filaments (as detected by Graham et al. 1990). We will also present maps of the infrared spectral index variations of the synchrotron nebula.

Program listing for Tuesday