3-D Kinematics of the near-IR HH 223 outflow in L723

In this work we derive the full 3-D kinematics of the near-infrared outflow HH 223, located in the dark cloud Lynds 723 (L723), where a well-defined quadrupolar CO outflow is found. HH 223 appears projected onto the two lobes of the east-west CO outflow. The radio continuum source VLA 2, towards the centre of the CO outflow, harbours a multiple system of low-mass young stellar objects. One of the components has been proposed to be the exciting source of the east-west CO outflow. From the analisys of the kinematics, we get further evidence on the relationship between the near-infrared and CO outflows and on the location of their exciting source. The proper motions were derived using multi-epoch, narrow-band H$_2$ (2.122 $mu$m line) images. Radial velocities were derived from the 2.122 $mu$m line of the spectra. Because of the extended (~5 arcmin), S-shaped morphology of the target, the spectra were obtained with the Multi-Object-Spectroscopy (MOS) observing mode using the instrument LIRIS at the 4.2m William Herschel Telescope. To our knowledge, this work is the first time that MOS observing mode has been successfully used in the near infrared range for an extended target.

The complex structure of HH 110 as revealed from Integral Field Spectroscopy

HH 110 is a rather peculiar Herbig-Haro object in Orion that originates due to the deflection of another jet (HH 270) by a dense molecular clump, instead of being directly ejected from a young stellar object. Here we present new results on the kinematics and physical conditions of HH 110 based on Integral Field Spectroscopy. The 3D spectral data cover the whole outflow extent (~4.5 arcmin, ~0.6 pc at a distance of 460 pc) in the spectral range 6500-7000 AA. We built emission-line intensity maps of H$alpha$, [NII] and [SII] and of their radial velocity channels. Furthermore, we analysed the spatial distribution of the excitation and electron density from [NII]/H$alpha$, [SII]/H$alpha$, and [SII] 6716/6731 integrated line-ratio maps, as well as their behaviour as a function of velocity, from line-ratio channel maps. Our results fully reproduce the morphology and kinematics obtained from previous imaging and long-slit data. In addition, the IFS data revealed, for the first time, the complex spatial distribution of the physical conditions (excitation and density) in the whole jet, and their behaviour as a function of the kinematics. The results here derived give further support to the more recent model simulations that involve deflection of a pulsed jet propagating in an inhomogeneous ambient medium. The IFS data give richer information than that provided by current model simulations or laboratory jet experiments. Hence, they could provide valuable clues to constrain the space parameters in future theoretical works.

The nature of HH 223 from long-slit spectroscopy

HH 223 is a knotty, wiggling nebular emission of ~30 length found in the L723 star-forming region. It lies projected onto the largest blueshifted lobe of the cuadrupolar CO outflow powered by a low-mass YSO system embedded in the core of L723. We analysed the physical conditions and kinematics along HH 223 with the aim of disentangling whether the emission arises from shock-excited, supersonic gas characteristic of a stellar jet, or is only tracing the wall cavity excavated by the CO outflow. We performed long-slit optical spectroscopy along HH 223, crossing all the bright knots (A to E) and part of the low-brightness emission nebula (F filament). One spectrum of each knot, suitable to characterize the nature of its emission, was obtained. The physical conditions and the radial velocity of the HH 223 emission along the slits were also sampled at smaller scale (0.6) than the knot sizes. {The spectra of all the HH 223 knots appear as those of the intermediate/high excitation Herbig-Haro objects. The emission is supersonic, with blueshifted peak velocities ranging from -60 to -130 km/s. Reliable variations in the kinematics and physical conditions at smaller scale that the knot sizes are also found. The properties of the HH 223 emission derived from the spectroscopy confirm the HH nature of the object, the supersonic optical outflow most probably also being powered by the YSOs embedded in the L723 core.