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We present wide-field near-IR images of Orion A. K and H2 1-0S(1) images of acontiguous 8 sqr degree region are compared to photometry from Spitzer anddust-continuum maps obtained with MAMBO and SCUBA. We also measure propermotions for H2 features in 33 outflows. We increase the number of known H2outflows in Orion A to 116. A total of 111 H2 flows were observed with Spitzer;outflow sources are identified for at least 72 of them. The MAMBO 1200 micronmaps cover 97 H2 flows; 57 of them are associated with Spitzer sources and dustcores or extended emission. The H2 jets are widely distributed and randomlyorientated; the jets do not appear to be orthogonal to large-scale filaments oreven to the small-scale cores. Moreover, H2 jet lengths and opening angles arenot obviously correlated with indicators of outflow source age - sourcespectral index or (sub)millimetre core flux. We demonstrate that H2 jet sourcesare predominantly protostellar with flat or positive spectral indices, ratherthan disk-excess (or T Tauri) stars. Most protostars in molecular cores driveH2 outflows. However, not all molecular cores are associated with protostars orH2 jets. On statistical grounds, the H2 jet phase may be marginally shorterthan the protostellar phase, though must be considerably shorter than theprestellar phase. In terms of their spectral index, H2 jet sources areindistinguishable from protostars. The few true protostars without H2 jets arealmost certainly more evolved than their H2-jet-driving counterparts. We alsofind that protostars that power molecular outflows are no more (nor no less)clustered than protostars that do not. The H2 emission regions in outflows fromyoung stars clearly weaken and fade very quickly, before the source evolvesfrom protostar to pre-main-sequence star.

A census of molecular hydrogen outflows and their sources along the Orion A molecular ridge: characteristics and overall distribution