High-resolution near-IR Spectral mapping with H${}_2$ and [Fe II] lines of Multiple Outflows around LkH$\alpha$ 234

Abstract

We present a high-resolution, near-IR spectroscopic study of multiple outflows in the LkH$\alpha$ 234 star formation region using the Immersion GRating INfrared Spectrometer (IGRINS). Spectral mapping over the blueshifted emission of HH 167 allowed us to distinguish at least three separate, spatially overlapped, outflows in H${}_2$ and [Fe II] emission. We show that the H${}_2$ emission represents not a single jet, but complex multiple outflows driven by three known embedded sources: MM1, VLA 2, and VLA 3. There is a redshifted H${}_2$ outflow at a low velocity, $\VLSR$ $<$ $+$50 {\kms}, with respect to the systemic velocity of $\VLSR$ $=$ $-$11.5 {\kms}, that coincides with the H${}_2$O masers seen in earlier radio observations two arcseconds southwest of VLA 2. We found that the previously detected [Fe II] jet with $|$$\VLSR$$|$ $>$ 100 {\kms} driven by VLA 3B is also detected in H${}_2$ emission, and confirm that this jet has a position angle about 240$°$. Spectra of the redshifted knots at 14$\arcsec$$-$65$\arcsec$ northeast of LkH$\alpha$ 234 are presented for the first time. These spectra also provide clues to the existence of multiple outflows. We detected high-velocity (50$-$120 {\kms}) H${}_2$ gas in the multiple outflows around LkH$\alpha$ 234. Since these gases move at speeds well over the dissociation velocity ($>$ 40 {\kms}), the emission must originate from the jet itself rather than H${}_2$ gas in the ambient medium. Also, position-velocity diagrams and excitation diagram indicate that emission from knot C in HH 167 come from two different phenomena, shocks and photodissociation.

arXiv comment32 pages, 12 figures, 2 tables, Accepted for publication in the Astrophysical Journal

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