Herbig-Haro flows in B335

Abstract

Aims. To study the Herbig-Haro flows in the nearby dark globule B335. To find new HH objects and H2 knots, make a proper motion map of the flow activity and investigate physical properties through shock models. Methods. We have observed optical (Hα and [SII]) and near-IR (2.12 μm H 2) deep fields and taken optical spectra using the 2.56 m Nordic Optical Telescope, as well as a near-UV deep field (U band) using the 3.58 m NTT. In addition we present new SPITZER/IRAC (3.5-8.0 μm) and MIPS (24 μm) observations. We use previous Hα and 2.12 μm H2 observations taken 15 and 9 years earlier to make proper motion maps. We then investigate the shock physics by matching our spectra with planar shock models. Results. We discover five new HH objects (HH 119 D-H) in the eastern and one (HH 1191) in the western lobe of the outflow. From proper motions we find an optically bright, roughly E-W oriented group with high space velocities (200-280 km s-1) and a near-IR bright, slower group (15-75 km s-1) moving to the ESE. We also find a system of at least 15 H2 knots in the western lobe. This (WNW) counterflow suggests the possibility of a binary outflow source, giving rise to two outflow axes with slightly different orientations. We find that the E-W flow is symmetrical with evidence for two outbursts. We make the first detection of [OI] λλ 6300/63 in HH 119 B and Hβ in HH 119 A and B and find their extinctions to be A V ≈ 1.4 and 4.4, respectively. HH 119 A is found to expand much faster than expected from linear expansion with distance from the outflow source. Using planar shock models we find shock velocities of ∼60 km s -1 (A) and ∼35 km s-1 (B and C). This agrees with A being of higher excitation than B and C. In our U image we detect three of the HH objects and propose that the emission arise from the [OII] λ3728 line and the blue continuum. New SPITZER/IRAC and MIPS observations show most of the HH objects at 4.5 μm and a E-W elongated hour-glass shaped structure at the outflow source. Even at 24 μm it is not clear whether most of the light is direct or reflected. © ESO 2007.