NED Abstract 
Copyright by American Astronomical Society.
Reproduced by permission

2006AJ....131.2859F

The Spitzer Space Telescope Extragalactic First Look Survey: 24 microns
Data Reduction, Catalog, and Source Identification 

Dario Fadda, Francine R. Marleau, Lisa J. Storrie-Lombardi, David
Makovoz, David T. Frayer, P. N. Appleton, L. Armus, S. C. Chapman, P. I.
Choi, F. Fang, I. Heinrichsen, G. Helou, M. Im, M. Lacy, D. L. Shupe, B.
T. Soifer, G. K. Squires, J. Surace, H. I. Teplitz, G. Wilson, and L.
Yan 

Abstract. We present the reduction of the 24 microns data obtained
during the first cosmological survey performed by the Spitzer Space
Telescope. Images of a region of sky at moderately high Galactic
latitude (l=88.3deg,b=+34.9deg) were obtained on 2003 December 9 --
11. The survey consists of a shallow observation of 2.5degx2deg
centered at 17^h^18^m^, +59deg30' (main survey) and a deeper observation
of 1degx0.5deg centered at 17^h^17^m^, +59deg45' (verification
survey). Issues with the reduction of the 24 microns MIPS data are
discussed and solutions to attenuate instrumental effects are proposed
and applied to the data. Approximately 17,000 sources are extracted with
a signal-to-noise ratio (S/N) greater than 5. The photometry of the
point sources is evaluated through point-spread function (PSF) fitting
using an empirical PSF derived from the data. Aperture corrections and
the absolute calibration have been checked using stars in the field.
Astrometric and photometric errors depend on the S/N of the source
varying between 0.35" -- 1" and 5% -- 15%, respectively, for sources
detected at 20 -- 5 {sigma}. The fluxes of the 123 extended sources have
been estimated through aperture photometry. The extended sources cover
less than 0.3% of the total area of the survey. Based on simulations,
the main and verification surveys are 50% complete at 0.3 and 0.15 mJy,
respectively. Counterparts have been searched for in optical and radio
catalogs. More than 80% of the 24 microns sources have a reliable
optical counterpart down to R=25.5; 16% of the sources have a 20 cm
counterpart down to 0.1 mJy and ~80% of the radio-IR associations have a
reliable optical counterpart. A residual map is obtained by subtracting
point sources detected at the 3 {sigma} level and interpolating the
regions occupied by extended sources. Several Galactic clouds with low
and intermediate velocities are identified by comparison with neutral
hydrogen data from this field. 

Key words: Catalogs, Infrared: Galaxies, Surveys, Techniques: Photometric