Source counts from the 15 mu m ISOCAM Deep Surveys
Aussel, H.; Elbaz, D.; Clements, D. L.; Danese, L.; Franceschini, A.; Koo, D. C.; Flores, H.; Cesarsky, C. J.; Starck, J. L.; Harwit, M.; Fadda, D.; Puget, J. L.; Désert, F. X.; Mandolesi, R.
France, Germany, Italy, United States
Abstract
We present the results of the five mid-IR 15 mu m (12-18 mu m LW3 band) ISOCAM Guaranteed Time Extragalactic Surveys performed in the regions of the Lockman Hole and Marano Field. The roughly 1000 sources detected, 600 of which have a flux above the 80% completeness limit, guarantee a very high statistical significance for the integral and differential source counts from 0.1 mJy up to ~ 5 mJy. By adding the ISOCAM surveys of the HDF-North and South (plus flanking fields) and the lensing cluster A2390 at low fluxes and IRAS at high fluxes, we cover four decades in flux from 50 mu Jy to ~ 0.3 Jy. The slope of the differential counts is very steep (alpha =-3.0) in the flux range 0.4-4 mJy, hence much above the Euclidean expectation of alpha =-2.5. When compared with no-evolution models based on IRAS, our counts show a factor ~ 10 excess at 400 mu Jy, and a fast convergence, with alpha =-1.6 at lower fluxes. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA