The Spitzer Space Telescope mapped the Perseus molecular cloud complex with IRAC and MIPS as part of the c2d Spitzer Legacy project .
This paper combines the observations from both instruments giving an overview of low-mass star formation across Perseus from 3.6 to 70 µm .
We provide an updated list of young stellar objects with new classifications and source fluxes from previous works , identifying 369 YSOs in Perseus with the Spitzer dataset .
By synthesizing the IRAC and MIPS maps of Perseus and building on the work of previous papers in this series ( 35 ; 56 ) , we present a current census of star formation across the cloud and within smaller regions .
67 % of the YSOs are associated with the young clusters NGC 1333 and IC 348 .
The majority of the star formation activity in Perseus occurs in the regions around the clusters , to the eastern and western ends of the cloud complex .
The middle of the cloud is nearly empty of YSOs despite containing regions of high visual extinction .
The western half of Perseus contains three-quarters of the total number of embedded YSOs ( Class 0+I and Flat SED sources ) in the cloud and nearly as many embedded YSOs as Class II and III sources .
Class II and III greatly outnumber Class 0+I objects in eastern Perseus and IC 348 .
These results are consistent with previous age estimates for the clusters .
Across the cloud , 56 % of YSOs and 91 % of the Class 0+I and Flat sources are in areas where A _ { \textnormal { v } } \geq 5 mag , indicating a possible extinction threshold for star formation .