A survey of IRAS young stellar object candidates: Searching for large-scale Herbig-Haro objects

Abstract

Context. Jets and outflows are associated with young stellar objects across the stellar mass spectrum, from brown dwarf protostars to massive Ae/Be stars. Frequently the jet morphology is spatially discontinuous because of the temporal variability of the ejection from the driving source. Images covering a wide field of view around the jet-driving source are useful to map the large-scale jet emission and to explore the mass ejection history. Aims. The aim of our work was to search for large-scale optical Herbig-Haro (HH) objects lying in a wide field around a sample of IRAS sources, which are candidates to trace young stellar objects. Methods. Deep narrowband images through the Hα and [S II ] emission lines, and through an off-line continuum filter, covering a wide (∼15 0 ) field around the IRAS targets were acquired. The images in the three filters were analyzed to identify shock-excited line emission (i.e., HH) in contrast to scattered line emission. Results. New images of a sample of 15 IRAS sources, obtained in a homogeneous way are presented. HH emission was detected in six fields, and the astrometry of the knot features is given. The nature of the extended emission as scattered emission around nine of the IRAS targets is confirmed. For seven IRAS sources with unclear optical counterparts, a more plausible counterpart is proposed. A refined value of the source distance is reported for seven targets. An update of the main data available for each of the sampled fields, including images from public data archives, is also presented.