First Insights into the Spitzer Wide‐Area Infrared Extragalactic Legacy Survey (SWIRE) Galaxy Populations

Abstract

We characterize the Spitzer Wide-area Infrared Extragalactic Legacy Survey (SWIRE) galaxy populations in the SWIRE validation field within the Lockman Hole, based on the 3.6-24 m Spitzer data and deep U, g 0 , r 0 , i 0 optical imaging within an area $1/3 deg 2 for $16,000 Spitzer SWIRE sources. The entire SWIRE survey will discover over 2.3 million galaxies at 3.6 m and almost 350,000 at 24 m; $70,000 of these will be five-band 3.6-24 m detections. The colors cover a broad range, generally well represented by redshifted spectral energy distributions of known galaxy populations; however, significant samples of unusually blue objects in the [3.6]À[4.5] color are found, as well as many objects very red in the 3.6À24 m mid-IR. Nine of these are investigated and are interpreted as star-forming systems, starbursts, and active galactic nuclei (AGNs) from z ¼ 0:37 to 2.8, with luminosities from L IR ¼ 10 10:3 to 10 13.7 L .

EVIDENCE FOR INFRARED-FAINT RADIO SOURCES ASz> 1 RADIO-LOUD ACTIVE GALACTIC NUCLEI

“…The SWIRE survey reaches 5σ depths of 3.5, 7.0, 41, and 49 μJy, respectively, in the four IRAC bands (Lonsdale et al 2004). In the MIPS bands at 24 and 70 μm, the SWIRE 5σ depths are 189 μJy and 16 mJy.…”

“…It overlaps the Great Observatories Origins Deep Survey (GOODS) South field, which is one of the best studied regions of the sky. ATLAS (Norris et al 2006) consists of deep radio observations of a 3.7 deg 2 field surrounding the eCDFS which is coincident with SWIRE (Lonsdale et al 2004). The ATLAS 1.4 GHz observations reach 20-60 μJy rms, with the deepest region covering the 30 × 30 arcmin 2 eCDFS.…”

“…These are radio sources brighter than a few hundred μJy at 1.4 GHz which have no observable infrared counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE; Lonsdale et al 2004). They may be related to the optically invisible radio sources found by Higdon et al (2005Higdon et al ( , 2008, which are compact radio sources with no optical counterpart to R ∼ 25.7.…”

The ASTRO-F mission: Large area infrared survey

“…The uniqueness of the ASTRO-F all-sky survey lies in its' wider wavelength coverage(up to 160µm) and much finer spatial resolution compared to that of IRAS. Moreover, thanks to the high visibility in the regions near the ecliptic poles, we will also be able to obtain a faint source catalog with fluxes down to 80mJy at 90µm (5σ) over a substantially large area(∼4000 deg 2 ), which will complement the on-going SWIRE (Lonsdale et al 2004) survey with SST (see Figure 6(right)). ASTRO-F in all-sky survey mode will detect approximately half million galaxies tracing the large-scale structure of the Universe out to redshifts of unity, detecting rare, exotic extraordinarily luminous objects at high redshift, numerous brown dwarfs, Vega-like stars, protostars, and will reveal the large-scale structure of the star-forming regions in both the solar neighbourhood, the distribution of the interplanetary dust in our solar system, and towards the Galactic plane where SST cannot observe because of the saturation of its' detectors (30-50 MJy/sr at 160µm).…”

ASPITZER SPACE TELESCOPEATLAS OF ω CENTAURI: THE STELLAR POPULATION, MASS LOSS, AND THE INTRACLUSTER MEDIUM

“…When including all sources with very red colors and faint magnitudes at all wavelengths, we find a total background galaxy density of ≈1 × 10 4 galaxies deg −2 (Figure 7). To determine the expected background galaxy density, we queried the Spitzer Space Telescope Wide-Area Infrared Extragalactic (SWIRE) database (Lonsdale et al 2004) for sources located in the same region of the CMD as our galaxy candidates. In the six SWIRE fields, there are ≈900-2200 sources deg CMD.…”