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Coordinated Hydrodynamic and Astrophysical Research, Modeling, and Synthesis (CHARMS)
| RW Aur A from the X-Wind Point of View: General Features |
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Image Credit: Chun-Fan Liu and Hsien Shang
Left: position-velocity diagrams of RW Aur A redshifted and blueshifted jets in [S II] emission line are shown in the upper two panels. Observed (black) and synthetic (red and blue for the redshifted and blueshifted jets, respectively) spectra are compared. Velocity centroids fitted from the observed (discrete symbols) and synthetic (thick lines) line spectra are shown in the lower panel.
Right: Cross line-ratio plots obtained from observed (discrete symbols) and synthetic (shaded areas) spectra. The difference in physical conditions of the jets and the match between observations and models can be seen. |
The RW Aur A microjet is studied from the point of view of X-wind models. The archival Hubble Space Telescope/STIS spectra of the optical forbidden lines [O I], [S II], and [N II] from RW Aur A with seven parallel slits along the jet axis, spaced at 0”.07 apart, were analyzed. Images, position-velocity diagrams, and line ratios among the species were constructed, and compared with synthetic observations generated by selected solutions of the X-wind. Prominent features arising in a steady-state X-wind could be identified within the convolved images and position-velocity diagrams, including FWHM and high-velocity peaks on both of the redshifted and blueshifted jets. The well-known asymmetric velocity profiles of the opposite jets were built into the selected models. Despite the apparent asymmetry in the terminal velocities, line intensities and mass-loss rates, the average linear momenta from the opposite sides of the jet are actually balanced. These previously hard-to-explain features of the asymmetric RW Aur A jet system can now be interpreted in a different but self-consistent manner within the X-wind framework. (Liu & Shang 2012, ApJ, 761, 94) |
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