Fabry–Perot imaging of molecular hydrogen in NGC 2071

We present Fabry–Perot images of the $$\upsilon = 1-0\enspace S(1)\enspace (\lambda=2.122\enspace \mu \text m)$$ line of molecular hydrogen (H₂) in the core region of the energetic bipolar outflow source associated with NGC 2071. Using a Fabry–Perot with a FWHM of 100 km s⁻¹, we have fully sampled the velocity range – 167 to + 167 km s⁻¹ from the wavelength of peak flux, obtaining a velocity cube of 11 images; each image covers an area of ∼ 36 × 36 arcsec² at a spatial resolution of 0.62 arcsec per pixel. From these data, we have studied the small (spatial) scale intensity structure of the line emission, the gross velocity characteristics of the region and the ratio of line-to-continuum emission over the source. We find that the S(1) emission is highly structured on spatial scales of a few arcsec, and peaks in intensity directly on IRS1. Two additional S(1) emission peaks are placed symmetrically about IRS1 and form a compact bipolar-type nebula. Our relatively crude velocity mapping indicates that the north-east condensation is predominantly blueshifted with respect to IRS1 while the south-west condensation is mostly redshifted. This is in the same sense as earlier CO, CS and H₂ low-resolution maps which show clumpiness on much larger scales. In addition, we observe symmetric emission structure centred on IRS2. In this case, the emission peak south-east of IRS2 is redshifted relative to the emission peak to the north-west, suggesting that IRS2 may drive a relatively compact bipolar outflow almost orthogonal to that of IRS1. The data presented here, together with evidence from previous observations, suggest that IRS1, IRS2 and possibly IRS3 are all self-luminous PMS stars at similar evolutionary stages.