2018ApJS..234....8M

We have performed an unbiased search for outflows from young stars in Cygnus-X using 42 deg² of data from the UKIRT Widefield Infrared Survey for H₂ (UWISH2 Survey), to identify shock-excited near-IR H₂ emission in the 1-0 S(1) 2.122 µm 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 0.45 pc in length and has gaps of 0.025-0.1 pc between large knots. The median luminosity in the 1-0 S(1) line is 10^–3 L_☉. The bipolar flows are typically asymmetrical, with the two lobes misaligned by 5°, 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 H₂ 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 0.5 mag 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.