We discuss wide-field near-IR imaging of the NGC1333 , L1448 , L1455 and B1 star forming regions in Perseus .
The observations have been extracted from a much larger narrow-band imaging survey of the Taurus-Auriga-Perseus complex .
These H _ { 2 } 2.122 \mu m observations are complemented by broad-band K imaging , mid-IR imaging and photometry from the Spitzer Space Telescope , and published submillimetre CO J=3-2 maps of high-velocity molecular outflows .
We detect and label 85 H _ { 2 } features and associate these with 26 molecular outflows .
Three are parsec-scale flows , with a mean flow lobe length exceeding 11.5′ .
37 ( 44 % ) of the detected H _ { 2 } features are associated with a known Herbig-Haro object , while 72 ( 46 % ) of catalogued HH objects are detected in H _ { 2 } emission .
Embedded Spitzer sources are identified for all but two of the 26 molecular outflows .
These candidate outflow sources all have high near-to-mid-IR spectral indices ( mean value of \alpha \sim 1.4 ) as well as red IRAC 3.6 \mu m-4.5 \mu m and IRAC/MIPS 4.5 \mu m- 24.0 \mu m colours : 80 % have [ 3.6 ] - [ 4.5 ] > 1.0 and [ 4.5 ] - [ 24 ] > 1.5 .
These criteria – high \alpha and red [ 4.5 ] - [ 24 ] and [ 3.6 ] - [ 4.5 ] colours – are powerful discriminants when searching for molecular outflow sources .
However , we find no correlation between \alpha and flow length or opening angle , and the outflows appear randomly orientated in each region .
The more massive clouds are associated with a greater number of outflows , which suggests that the star formation efficiency is roughly the same in each region .