Large scale view of the NGC 1333 ridge in Perseus. The image represents the total column density map derived from our Herschel-Planck maps (in colour scale), including two contours of equivalent column densities of A_V = 2^mag and 10^mag, respectively. Offsets are referred to the map centre with coordinates in radio projection. The four subregions around NGC 1333 and their boundaries are labelled in the plot. The different symbols correspond to the Class 0/I (stars) and Flat/ClassII/III objects (squares) identified by different Spitzer surveys (Gutermuth et al. 2008; Evans et al. 2009). The dotted line encloses the NGC 1333 clump studied in this work.