We present the Spitzer MIPS 24 \mu m source counts in the Extragalactic First Look Survey main , verification and ELAIS-N1 fields .
Spitzer ’ s increased sensitivity and efficiency in large areal coverage over previous infrared telescopes , coupled with the enhanced sensitivity of the 24 \mu m band to sources at intermediate redshift , dramatically improve the quality and statistics of number counts in the mid-infrared .
The First Look Survey observations cover areas of , respectively , 4.4 , 0.26 and 0.015 sq.deg .
and reach 3 \sigma depths of 0.11 , 0.08 and 0.03 mJy .
The extragalactic counts derived for each survey agree remarkably well .
The counts can be fitted by a super-Euclidean power law of index \alpha = { -2.9 } from 0.2 to 0.9 mJy , with a flattening of the counts at fluxes fainter than 0.2 mJy .
Comparison with infrared galaxy evolution models reveals a peak ’ s displacement in the 24 \mu m counts .
This is probably due to the detection of a new population of galaxies with redshift between 1 and 2 , previously unseen in the 15 \mu m deep counts .