SWIRE MIPS 70/160 Data Catalog Definition
SWIRE Overview
The Spitzer Wide-area InfraRed Extragalactic survey
(SWIRE), the largest Spitzer Legacy program, is a
wide-area, imaging survey to trace the evolution of dusty,
star-forming galaxies, evolved stellar populations, and AGN as a
function of environment, from redshifts z~3 to the current epoch.
SWIRE surveys 6 high-latitude fields, totaling ~50 sq. deg. in
all 7 Spitzer bands: 3.6, 4.5, 5.8, and 8 microns with IRAC and
24, 70, and 160 microns with MIPS (Lonsdale et al. 2003). The
SWIRE Legacy Extragalactic Source Catalogs will eventually
contain in excess of 2 million IR-selected galaxies, from those
dominated by the light of stellar populations detected primarily
by IRAC, to starbursts, ultra-luminous infrared galaxies and AGN
detected also by MIPS. The SWIRE project page can be found
here.
The key scientific goals of SWIRE are to determine: (1) the
evolution of actively star-forming and passively evolving
galaxies to determine the history of galaxy formation in the
context of cosmic structure formation; (2) the evolution of the
spatial distribution and clustering of evolved galaxies,
starbursts and AGN in the key redshift range, 0.5<z<1.5,
when the sharp decline in star formation activity has occurred;
(3) the evolutionary relationship between ``normal galaxies'' and
AGN, and the contribution of AGN accretion energy vs. stellar
nucleosynthesis to the cosmic backgrounds. The large area of
SWIRE is important to establish statistically significant
population samples over enough volume cells that we can resolve
the star formation history as a function of epoch and
environment, i.e. in the context of structure formation. The
large volume is also optimised for finding rare objects.
SWIRE Fields
The Spitzer Wide-area InfraRed Extragalactic survey (SWIRE;
Lonsdale et al. 2003) Versions 2.0 & 3.0 data products
releases (Spring 2005 & Fall 2005) include an image atlas
and source catalogs for most of the six SWIRE fields to be
observed by Spitzer:
- ELAIS-N1 (European Large-Area ISO Survey) [images
& catalogs released]
- ELAIS-N2 [images and catalogs released]
- XMM Large-Scale Structure Survey (LSS)
[images and catalogs released]
- Lockman Hole (LH) [images and catalogs
released]
- ELAIS-S1 [catalogs released]
- Chandra Deep Field South (CDFS) [catalogs
released]
The release includes both Spitzer IRAC and MIPS
mid/far-infrared data products for all four fields as well as U,
g', r', i', and Z optical data covering selected subregions of
the data (McMahon et al. 2001, Gonzalez-Solares et al. 2004). The
document "The SWIRE Data Release 2: Image Atlases and Source
Catalogs for ELAIS-N1, ELAIS-N2, XMM-LSS, and the Lockman Hole"
by Surace et al. describes the creation of these data products in
detail [
SWIRE Delivery
Document (PDF)]. For each of the MIPS bands, the SWIRE team
has produced single-band catalogs. Below is a selected subset of
the description of the columns found within the single-band MIPS
70 micron and 160 micron catalogs. the MIPS-24 micron catalog
column descriptions are available
here. The
column descriptions for IRAC/Ancillary/Band-merged catalogs can
be found
here.
SWIRE MIPS-70 and MIPS-160 Catalog Column Descriptions
Gator serves the SWIRE Spring 2005 EN1, EN2,
Lockman, and XMM-LSS catalogs, and the Fall 2005
CDFS and ES1 catalogs. The column descriptions for
the far-infrared catalogs are listed below.
Column Name |
Data Type |
Units |
Description |
cntr
|
int |
|
An internal record number from the master database table
from which the sources were selected. It is included in the
released Catalog for database linkage reasons. It is not
useful as a sequential record number because it does not
increase monotonically with Right Ascension, and because
there are gaps in a sequential listing of CNTR for the
catalog. However it is useful as a purely numerical source
identifier within the Table. |
object
|
character |
|
The name of the source, conforming to IAU standards. All
sources in the 70 and 160 catalogs are labeled "SWIRE",
followed an integer denoting the version of the SWIRE Data
Products. The MIPS band is next indicated by the string
"_70_" or "_160_". The remainder of the name is the J2000
position of the object in hhmmss+ddmmss format. Sufficient
precision is provided to ensure the name is unique. |
ra
dec
|
double |
degrees |
The Right Ascension and Declination of the source in
J2000 decimal degrees. The position is determined by the
point-source-fitting extraction using the MOPEX software
(Makovoz & Marleau 2005, PASP, 117, 1113), and the World
Coordinate System keywords in the header of the mosaicked
image. For the 160um band only, a correction of about 5
arcseconds has been made in the catalog coordinates, which is
uncorrected in the released 160um mosaics. |
unc_ra
unc_dec
unc_rd
|
double |
arcseconds |
The uncertainties in the celestial coordinates, in
arcseconds, as determined from point-source-fitting and the
mosaic uncertainty image. The quantities derive from the
square root of the corresponding elements of the covariance
matrix. The sign of "unc_rd" is the same as the sign of the
covariance between right ascension and declination. |
detid
|
int |
|
A detection identification number, retained only for
internal traceback purposes. |
flux_prf
uncf_prf
|
double |
milliJy |
The point-source-fitted flux density and uncertainty from
the MOPEX package. The flux density is quoted for an assumed
spectrum varying as the reciprocal of frequency. |
flux_ap4
flux_ap3
|
double |
milliJy |
The flux density measured in a large aperture (27
arcsecond radius for 70um; 60 arcsecond radius for 160um).
This column should only be considered for bright, possibly
extended sources. In general, the flux_prf value is more
reliable. |
snr
|
double |
|
The signal-to-noise ratio as determined from point-source
fitting. |
flag
|
int |
|
Flag for the extraction based on manual examination of
the extractions. A value of 1 means the source is brighter
than the nominal 5-sigma flux limit and no problems were
noted. A value of 2 indicates the source brightness is below
the flux limit and may be unreliable. A value of 3 indicates
the source is considered reliable, but the flux may be under-
or over-estimated, due either to proximity to the noisy
border of the mosaic, or because the source was extracted as
two detections by MOPEX. |
redchi2 |
double |
|
The reduced chi-squared value from the point-source
fitting. A value near 1 is expected for sources that are
fitted well by the point-response function used. |