SWIRE: Spitzer Wide-Area Infrared Extragalactic Survey

SWIRE Observing Strategies and Fields

SWIRE has surveyed 49 square degrees distributed over 6 fields in the northern and southern sky, enabling follow-up with many existing ground and space telescope facilities.

Hammer-Aitoff equal area projection in galactic coordinates of the 100µm sky with SWIRE Survey Fields shown in red. The contour levels in blue, green yellow are 1, 2, 4 MJy/sr, respectively. The yellow ellipses mark ecliptic latitudes of 30° and 40°. (Map by S. Oliver, U. Sussex, from the COBE/DIRBE & IRAS/ISSA maps by Schlegel, Finkbeiner & Davis 1998, ApJ, 500, 525.)

Field Selection

The SWIRE Team performed an exhaustive search for high-latitude fields with low-background to maximize the sensitivity of the SWIRE Legacy Survey. The fields selected represent, in many respects, the largest, lowest infrared background regions in the sky. The selection criteria were:

Low galactic cirrus emission (I < 0.5 MJy/SR) in order to minimize confusion and noise.
High galactic latitude in order to ensure Spitzer and Herschel visibility and to minimize zodiacal background.
Large contiguous area, to enable large scale structure studies.
Minimum contamination by bright stars, galaxies, radio sources, and galaxy clusters.
Availability of unique datasets at other wavelengths. Fields selected for SWIRE include areas of:
- The XMM Large-Scale Structure Survey XMM-LSS and the NOAO Deep Wide-Field Survey NOAO DWS (South)
- The European Large-Area ISO Survey (ELAIS) - ELAIS N1, N2, and S1.
- The Chandra Deep South Survey Field.
- The well-studied Lockman Hole.

For more information about field selection see Seb Oliver's SWIRE Field Candidates Web Pages.

You can also check out how some of your favorite fields stack up against SWIRE, e.g.:

Hubble Deep Fields: HDF-N, HDF-S
Marano Hole
NOAO Deep-Wide Survey: North, South
Complete list of candidates.

Survey Areas

The total survey area is 48.3 sq deg in IRAC and 49 sq deg in MIPS. The survey areas and dimensions in each field are given for the final survey, and represent coverage in all bands of either the IRAC or MIPS instrument.

The Astronomical Observing Requests (AORs) are available using the SSC's Spot tool. Use the File->View Program option, and enter either the program name or program ID from the table below. The AORs can be visualized in Spot using the observation dates in the table.

Field	Center (J2000)		Area		Observing Dates				P.A. at Start Date		Program
	RA	DEC	IRAC	MIPS	IRAC Start	IRAC End	MIPS Start	MIPS End	IRAC (°E of N)	MIPS (°E of N)	Name	ID
ELAIS N1	16^h 11^m 00^s	+55° 00'	3.09° x 3.01° = 9.3 sq deg	3.08° x 3.00° = 9.2 sq deg	Jan 14 2004 15:05	Jan 20 2004 07:06	Jan 22 2004 00:28	Jan 28 2004 01:41	226°	219°	SWIRES_ELAIS_N1	185
Lockman Field (image)	10^h 45^m 00^s	+58° 00'	3.69° x 3.01° = 11.1 sq deg	3.66° x 3.00° = 11.0 sq deg	Apr 24 2004 12:11	Apr 30 2004 02:19	May 04 2004 00:53	May 11 2004 02:04	46°	38°	SWIRES_LOCKMAN	142
ELAIS N2	16^h 36^m 48^s	+41° 01' 45"	1.74° x 2.41° = 4.2 sq deg	1.92° x 2.50° = 4.8 sq deg	Jul 05 2004 04:58	Jul 07 2004 03:47	Jul 07 2004 23:27	Jul 11 2004 00:42	60°	57.2°	SWIRES_ELAIS_N2	183
XMM-LSS (image)	02^h 21^m 20^s	-04° 30'	3.01° x 3.01° = 9.1 sq deg	3.08° x 3.00° = 9.2 sq deg	Jul 23 2004 17:53	Jul 28 2004 05:22	Jul 30 2004 02:39	Aug 05 2004 02:48	158°	160°	SWIRES_XMM_LSS	181
Chandra-S	03^h 32^m 00^s	-28° 16'	2.64° x 2.97° = 7.8 sq deg	2.61° x 3.00° = 7.9 sq deg	Sep 09 2004 13:00	Sep 12 2004 23:04	Sep 13 2004 21:04	Sep 18 2004 11:31	184°	188°	SWIRES_CHANDRA_S	184
ELAIS S1	00^h 35^m 00^s	-43° 40'	2.31° x 2.93° = 6.8 sq deg	2.30° x 3.00° = 6.9 sq deg	Dec 18 2004 09:46	Dec 21 2004 04:57	Dec 22 2004 11:49	Dec 24 2004 07:26	328°	331°	SWIRES_ELAIS_S1	182

Ancillary Data

This is a list of data which are being used as part of the SWIRE science project. More data exists (e.g. SCUBA fields in the Lockman Hole, etc.) than has been listed here.

Pre-Existing Data

Optical/Near-IR Imaging

The ELAIS fields have been extensively surveyed at a variety of wavelengths with optical data to typical depths of 22-25 in a variety of Gunn filters.

Radio

The extremely large size of the fields and great depths makes observation of a radio dataset of comparable depth and breadth impossibly time-consuming. The ELAIS fields have radio observations already available.

New Data

In addition to the large amount of data already extant for at least portions of the above survey fields, the SWIRE team has aquired new ground-based data for use in interpreting the Spitzer data. Specifically, we have acquired:

Optical/Near-IR Imaging

Ground-based observations at KPNO, CTIO and Palomar Observatories for optical identification of the entire Lockman, Lonsdale and Chandra-S fields to r' ~ 25. We are executing multi-band imaging of smaller areas (3-4 sq deg) within those fields to g'~26, r'~25, i'~24 using the NOAO/CTIO Mosaic Cameras and the Palomar Large Format Camera and . Lockman/Lonsdale to K'~19.5, using FLAMINGOS at KPNO. Further observations are underway for the ELAIS Fields by UK team members. Extensive XMM-LSS Optical follow-up is planned at ESO and the CFHT with additional Near-IR observations also planned.

Radio

The XMM-LSS field will be completely surveyed at radio wavelengths 90 and 400cm to a depth of 1 mJy.

Watch this space!

A variety of additional observations are being executed including X-Ray and Radio observations. Details will be forthcoming...