2MASS near-infrared images of RCW 103: A young SNR in a dense medium.

We present near-infrared images of the supernova remnant RCW 103 (G332.4-0.4) from the Two Micron All Sky Survey (2MASS). In all three 2MASS bands—J, H, K[sub s]—emission is detected, revealing a barrel-shaped, shell-like morphology. However, the J and H band shells are displaced with K[sub s] band shell. The J and H band emission are mostly from [Fe II] lines while the K[sub s] band emission is mostly from molecular hydrogen, as inferred from previous near-infrared spectroscopy. The 2MASS images show that the displacement between the [Fe II] and H[sub 2] is not just due to a projection effect; instead, it appears that the layers emitting [Fe II] and H[sub 2] lines are intrinsically double shells. We compared the 2MASS images with radio and X-ray images at comparable resolutions. The X-ray and radio shells coincide with the J and H band shells, while the K[sub s] band shell is located outside of the shock front. We discuss the origin of the molecular hydrogen shell in terms of a magnetic precursor or excitation by a radiative precursor. We also discuss the ISM environment of RCW 103 using physical parameters inferred from near-infrared lines. [ABSTRACT FROM AUTHOR]