Hubble Space TelescopeNICMOS Images of the HH 7/11 Outflow in NGC 1333

We present near infrared images in H2 at 2.12um of the HH 7/11 outflow andits driving source SVS 13 taken with HST NICMOS 2 camera, as well as archivalHa and [SII] optical images obtained with the WFPC2 camera. The NICMOS highangular resolution observations confirm the nature of a small scale jet arisingfrom SVS 13, and resolve a structure in the HH 7 working surface that couldcorrespond to Mach disk H2 emission. The H2 jet has a length of 430 AU (at adistance of 350 pc), an aspect ratio of 2.2 and morphologically resembles thewell known DG Tau optical micro-jet. The kinematical age of the jet (approx. 10yr) coincides with the time since the last outburst from SVS 13. If weinterpret the observed H2 flux density with molecular shock models of 20-30km/s, then the jet has a density as high as 1.e+5 cc. The presence of thissmall jet warns that contamination by H2 emission from an outflow in studiessearching for H2 in circumstellar disks is possible. At the working surface,the smooth H2 morphology of the HH 7 bowshock indicates that the magnetic fieldis strong, playing a major role in stabilizing this structure. The H2 fluxdensity of the Mach disk, when compared with that of the bowshock, suggeststhat its emission is produced by molecular shocks of less than 20 km/s. TheWFPC2 optical images display several of the global features already inferredfrom groundbased observations, like the filamentary structure in HH 8 and HH10, which suggests a strong interaction of the outflow with its cavity. The H2jet is not detected in {SII] or Ha, however, there is a small clump at approx.5'' NE of SVS 13 that could be depicting the presence either of a differentoutburst event or the north edge of the outflow cavity.Comment: 13 pages, 5 figures (JPEGs