A Deep 12μm Survey with ISO

I present results from a deep 12μm extragalactic survey conducted with the ISOCAM instrument. The survey covers about 0.1 sq. deg. in four fields and reaches a 5σ flux limit of ∼500μJy. 50 sources are identified to this flux limit. Of these, 37 are classified as galaxies on the basis of optical/mid-IR colours using identifications from the USNO-A photographic survey. Number counts for these objects exceed those predicted for no-evolution models in simple models. However, these conclusions are somewhat dependent on the assumed K-corrections. For this reason, and to better determine the nature of the evolution of this population, followup observations are required to determine redshifts, broadband optical-IR colours, and optical morphologies. The first results from these followups are presented. Images and optical/IR photometry for one of the four fields is discussed, and I also present the first results from optical spectroscopy. The highest redshift for the sample so far is z=1.2 for a broad-line object.