Tomographic reconstruction of the three-dimensional structure of the HH30 jet

TL;DR

This paper applies tomographic reconstruction to HH30 jet data to produce detailed 3D maps of physical parameters, revealing a more collimated, fragmented, and irregular jet structure than traditional homogeneous models.

Contribution

It introduces a non-parametric tomographic method using HST data to analyze Herbig-Haro jets, providing more accurate physical profiles and insights into jet ejection timescales.

Findings

Reconstructed density, temperature, and ionization fraction profiles are steeper than homogeneous models.

The jet is more collimated (~5 AU width near source) than previously observed (~20 AU).

Jet structure is more fragmented and irregular, indicating complex ejection history.

Abstract

The physical parameters of Herbig-Haro jets are usually determined from emission line ratios, obtained from spectroscopy or narrow band imaging, assuming that the emitting region is homogeneous along the line of sight. Under the more general hypothesis of axisymmetry, we apply tomographic reconstruction techniques to the analysis of Herbig-Haro jets. We use data of the HH30 jet taken by Hartigan & Morse (2007) with the Hubble space telescope using the slitless spectroscopy technique. Using a non-parametric Tikhonov regularization technique, we determine the volumetric emission line intensities of the [SII]6716,6731, [OI]6300 and [NII]6583 forbidden emission lines. From our tomographic analysis of the corresponding line ratios, we produce "three-dimensional" images of the physical parameters. The reconstructed density, temperature and ionization fraction present much steeper profiles than those inferred using the assumption of homogeneity. Our technique reveals that the reconstructed jet is much more collimated than the observed one close to the source (a width ~ 5 AU vs. ~ 20 AU at a distance of 10 AU from the star), while they have similar widths at larger distances. In addition, our results show a much more fragmented and irregular jet structure than the classical analysis, suggesting that the the ejection history of the jet from the star-disk system has a shorter timescale component (~ some months) superimposed on a longer, previously observed timescale (of a few years). Finally, we discuss the possible application of the same technique to other stellar jets and planetary nebulae.