YSO jets in the Galactic Plane from UWISH2: IV - Jets and outflows in Cygnus-X

Abstract

We have performed an unbiased search for outflows from young stars in Cygnus-X using 42 deg${}^2$ of data from the UKIRT Widefield Infrared Survey for H${}_2$ (UWISH2 survey), to identify shock-excited near-IR H${}_2$ emission in the 1$-$0 S(1) 2.122 $\mu$m line. We uncovered 572 outflows, of which 465 are new discoveries, increasing the number of known objects by more than 430%. This large and unbiased sample allows us to statistically determine the typical properties of outflows from young stars. We found 261 bipolar outflows and 16% of these are parsec-scale. The typical bipolar outflow is 0.45pc in length and has gaps of 0.025 to 0.1pc between large knots. The median luminosity in the 1$-$0 S(1) line is 10${}^{-3}$ L${}_{\odot }$. The bipolar flows are typically asymmetrical, with the two lobes misaligned by 5${}^{\circ }$, one lobe 30% shorter than the other, and one lobe twice as bright as the other. Of the remaining outflows, 152 are single-sided and 159 are groups of extended, shock-excited H${}_2$ emission without identifiable driving sources. Half of all driving sources have sufficient WISE data to determine their evolutionary status as either protostars (80%) or classical T-Tauri stars (20%). One fifth of the driving sources are variable by more than 0.5mag in the K-band continuum over several years. Several of the newly-identified outflows provide excellent targets for follow up studies. We particularly encourage the study of the outflows and young stars identified in a bright-rimmed cloud near IRAS 20294$+$4255, which seems to represent a textbook example of triggered star formation.

27 pages, 10 figures, accepted for publication in ApJS. Appendix contains examples from the two image sets and machine-readable data table that will be available in the online journal. Full version available at http://astro.kent.ac.uk/~df/papers.html with full appendix

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• DR 21 South Filament: a Parsec-sized Dense Gas Accretion Flow onto the DR 21 Massive Young Cluster
• Searching for Molecular Outflows with Support Vector Machines: Dark Cloud Complex in Cygnus
• Deep diving off the `Cosmic Cliffs': previously hidden outflows in NGC 3324 revealed by JWST
• Studying a precessing jet of a massive young stellar object within a chemically rich region
• Massive Young Stellar Objects and Outflow in the Infrared-Dark Cloud G79.3+0.3