2013-03-23T15:47:00
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WISE All-Sky Release Catalog
The Wide-field Infrared Survey Explorer (WISE) is a space-based imaging
survey of the entire sky in the 3.4 (W1), 4.6 (W2), 12 (W3), and 22 (W4) μm
mid-infrared. This is the project's reliable Source Catalog containing
accurate photometry and astrometry for over 500 million objects.
More details are available in the `Explanatory Supplement`_, which also
has a list of `Cautionary Notes`_.
.. _Explanatory Supplement: http://wise2.ipac.caltech.edu/docs/release/allsky/expsup/sec1_1.html
.. _Cautionary Notes: http://wise2.ipac.caltech.edu/docs/release/allsky/expsup/sec1_4b.html
Wright, E.L.; Cutri, R.C.; et al
surveys
infrared-photometry
Infrared
0/0-11
55203 55414
8.637e-21 6.621e-20
Survey
Catalog
This is the All-Sky source catalog, with several columns
left out since we considered them to be only relevant for re-reduction,
too arcane, or just because of a whim on our side. If you need them,
let us know. The columns left out include: elon, elat, source_id, w?nm
w?m, w?cov, w?cc_map_str, w?flux, w?sigflux, w?sky, w?sigsk, w?conf,
w?mag_?, w?sigm_?, w?flg_?, w?magp, w?sigp1, w?sigp2, rho??,
r_2mass, pa_2mass, n_2mass, [jhk]_m_2mass, [jhk]_msig_2mass,
best_use_cntr, ngrp, x, y, z, spt_ind
Position Galactic "glon" "glat"
Position ICRS "raj2000" "dej2000" Error "sigra" "sigdec"
"bandid","ucdfrag","wl","maxmag"
w1,em.IR.3-4um,3.4µm,8
w2,em.IR.4-8um,4.6µm,7
w3,em.IR.8-15um,12µm,4
w4,em.IR.15-30um,22µm,0
The co-sigma is related to the covariance between the position errors Vαδ
by the formula Vαδ = σαδ×|σαδ|. This maintains the sign information for
the correlation, since σαδ may be negative. It is more natural to carry
the co-sigma along with the other uncertainties instead of the covariance
because the former is in the same units as the other uncertainties.
This number is formed entirely from the source_id, which is in turn
formed from the coadd_id and source number src. On average, sources with
cntr values close to each other are also close to each other on the sky,
except at Tile boundaries.
The cntr value is formed by making the source_id into an integer, in the
format: RRRRsDDDtrevIIIIII, where
:RRRR:
Tile center RA in deci-degrees, truncated not rounded (e.g.
RRRR=int[10*ra]), as in the coadd_id.
:s:
Tile center Declination sign translated from "p" or "m" into "1" or
"0", respectively.
:DDD:
Tile center Declination in deci-degrees, as in the coadd_id. For
positive declinations, the tenths of a degree is truncated not rounded
(e.g. DDD=int[10*dec]). For negative declinations, the tenths of a
degree is always truncated leftward on the number line (e.g.
DDD=ceil[10*abs(dec)].
:[trev]:
Disambiguation string, translated where necessary into digits
corresponding to the letters' places in the alphabet.
* t - Tile type translated into two digits, zero-filled ("a" = "01").
* r - Data Release identifier translated into a single digit, since the
possible values are limited to "a" through "i" ("b" = "2").
* e - Cryogenic Survey Phase ("4" = All-Sky [full cryogenic]).
* v - Processing version.
The translated disambiguation string is always 01241 for Tiles in the
WISE All-Sky Data Release Catalog .
:IIIIII:
six-digit, zero-filled, sequential extracted source number, src, within
the Tile.
For example, a source in the Tile 3041m137_ab41, with a source_id of
'3041m137_ab41-012345', has a cntr value of 3041013701241012345.
The tile identifier has the general form: RRRRsDDD_[trev], where
:RRRR:
Tile center RA in deci-degrees, truncated not rounded (e.g.
RRRR=int[10*ra]).
:s:
Tile center Declination sign ("p"="+", "m"="-")
:DDD:
Tile center Declination in deci-degrees. For positive declinations, the
tenths of a degree is truncated not rounded (e.g. DDD=int[10*dec]). For
negative declinations, the tenths of a degree is always truncated
leftward on the number line (e.g. DDD=ceil[10*abs(dec)].
:[trev]:
Disambiguation string.
* t - Tile type ("a" = Atlas)
* r - Data Release ("b" = All-Sky)
* e - Cryogenic Survey Phase ("4" = All-Sky [full cryogenic])
* v - Processing version.
The disambiguation string is always ab41 for Tiles in the WISE All-Sky
Release products.
For example, the identifier of the 4-band Cryo Atlas Tile with center at
(α,δ = 304.13896,-13.63000) is 3041m137_ab41.
Four character string, one character per band [W1/W2/W3/W4], that
indicates that the photometry and/or position measurements of a source
may be contaminated or biased due to proximity to an image artifact. The
type of artifact that may contaminate the measurements is denoted by the
following codes. Lower-case letters correspond to instances in which the
source detection in a band is believed to be real but the measurement may
be contaminated by the artifact. Upper-case letters are instances in
which the source detection in a band may be a spurious detection of an
artifact.
:D,d:
Diffraction spike. Source may be a spurious detection of (D) or
contaminated by (d) a diffraction spike from a nearby bright star on
the same image, or
:P,p:
Persistence. Source may be a spurious detection of (P) or contaminated
by (p) a short-term latent image left by a bright source, or
:H,h:
Halo. Source may be a spurious detection of (H) or contaminated by (h)
the scattered light halo surrounding a nearby bright source, or
:O,o:
(letter "o") - Optical ghost. Source may be a spurious detection of (O)
or contaminated by (o) an optical ghost image caused by a nearby bright
source, or
:0:
(number zero) - Source is unaffected by known artifacts.
A source extraction may be affected by more than one type of artifact or
condition. In this event, the cc_flags value in each band is set in the
following priority order: D,P,H,O,d,p,h,o,0. The full tally of artifacts
affecting a source in each band is given in the w?cc_map and w?cc_map_str
columns.
A source can appear in the All-Sky Release Source Catalog even if it is
flagged as a spurious artifact detection in a band if there is a reliable
detection in another band that is not flagged as a spurious artifact
detection (see V.3.b). Entries in the All-Sky Release Reject Table may be
flagged as spurious detections of artifacts in all bands.
CAUTION: Non-zero cc_flags values in any band indicate the the
measurement in that band may be contaminated and the photometry should be
used with caution.
The extended source flag is an integer flag, the value of which indicates
whether or not the morphology of a source is consistent with the WISE
point spread function in any band, or whether the source is associated
with or superimposed on a previously known extended object from the 2MASS
Extended Source Catalog (XSC). The values of the ext_flg indicate the
following conditions:
:0:
The source shape is consistent with a point-source and the source is
not associated with or superimposed on a 2MASS XSC source
:1:
The profile-fit photometry goodness-of-fit, w?rchi2, is >3.0 in one or
more bands.
:2:
The source falls within the extrapolated isophotal footprint of a 2MASS
XSC source.
:3:
The profile-fit photometry goodness-of-fit, w?rchi2, is >3.0 in one or
more bands, and The source falls within the extrapolated isophotal
footprint of a 2MASS XSC source.
:4:
The source position falls within 5" of a 2MASS XSC source.
:5:
The profile-fit photometry goodness-of-fit, w?rchi2, is >3.0 in one or
more bands, and the source position falls within 5" of a 2MASS XSC
source.
CAUTION: WISE profile-fit (w?mpro) and standard aperture (w?mag)
measurements are optimized for point sources and will systematically
underestimate the true flux of resolved objects. If a source entry has
ext_flg>0, you may wish to examine the large aperture photometry, or the
elliptical aperture photometry which are measured using areas that are
scaled from 2MASS XSC morphologies.
The variability flag is a four-character string, one character per band,
in which the value for each band is related to the probability that the
source flux measured on the individual WISE exposures was not constant
with time. The probability calculation uses the standard deviation of the
single exposure flux measurements, w?sigp1, as well as the band-to-band
flux correlation significance, q12,q23,q34.
The probability is computed for a band only when there are at least six
single-exposure measurements available that satisfy minimum quality
criteria. A value of "n" in a band indicates insufficient or inadequate
data to make a determination of possible variability. Values of "0"
through "9" indicate increasing probabilities of variation. Values of "0"
through "5" are most likely not variables. Sources with values of "6" and
"7" are likely flux variables, but are the most susceptible to
false-positive variability. Var_flg values greater than "7" have the
highest probability of being true flux variables in a band.
CAUTION: Estimation of flux variability is unreliable for sources that
are extended (ext_flg>0), and sources whose measurements are contaminated
by image artifacts in a band (cc_flags[b] != '0').
10.
:B:
Source is detected in this band with a flux signal-to-noise ratio
3
The contamination and confusion columns contain the integer equivalent of
the 9-bit binary number that specifies if the respective measurement
is believed to be contaminated by or a spurious detection of an image
artifact. The elements of the binary array are::
S 0 0 0 O H 0 P D
The leftmost bit, S, differentiates whether the band-detection is
believed to be a real detection contaminated by an artifact ("0") or a
spurious detection of an artifact ("1"). The remaining bits are set to
"1" to denote contamination by different types of artifacts according to
the letters:
:D:
Diffraction spike. Source may be a spurious detection of or
contaminated by a diffraction spike a nearby bright star on the same
image.
:P:
Persistence. Source may be a spurious detection of or contaminated by a
short-term latent (persistence) image left by a bright source.
:H:
Halo. Source may be a spurious detection of or contaminated by the
scattered light halo associated with a bright star.
:O:
Optical ghost. Source may be a spurious detection of or contaminated by
an optical ghost image caused by a nearby bright source on the same
image.
For example, a measurement that is believed to be a spurious detection of
a diffraction spike and scattered light halo has a binary bit map value
of "100001001" and w1cc_map=265.
The aperture measurement quality flags indicate if one or more image
pixels in the measurement aperture for this band is confused with nearby
objects, is contaminated by saturated or otherwise unusable pixels, or is
an upper limit. The flag value is an integer that is the combination of
one or more of the following values that signify different conditions:
:0:
No contamination
:1:
Source confusion - another source falls within the measurement aperture
:2:
Presence of bad pixels in the measurement aperture
:4:
Non-zero bit flag tripped (other than 2 or 18)
:8:
All pixels are flagged as unusable, or the aperture flux is negative.
In the former case, the aperture magnitude is "null". In the latter
case, the aperture magnitude is a 95% confidence upper limit.
:16:
Saturation - there are one or more saturated pixels in the measurement
aperture
:32:
The magnitude is a 95% confidence upper limit
The probability measure is -log10(Q), where Q = 1 - P(χ^2). P is the
cumulative chi-square distribution probability for the flux sample
measured on the individual single-exposure images. The value is clipped
at 9.
The Q value is the fraction of all cases to be at least as large as that
observed if the null hypothesis is true. The null hypothesis is that the
flux is emitted by a non-variable astrophysical object. It may be false
because the object is a true variable. It may also be false because the
flux measurement is corrupted by artifacts such as cosmic rays, scattered
light, etc. The smaller the Q value, the more implausible the null
hypothesis, i.e., the more likely it is that the flux is either variable
or corrupted or both.
The value is -log10(Q2(rho)), where Q2 is the two-tailed fraction of
all cases expected to show at least this much apparent positive or
negative correlation when in fact there is no correlation. The value is
clipped at 9.
rho is the correlation coefficient between the single-exposure
flux measurements in the two bands.
When the number of measurements is large, the significance of correlation
also tends to be large even though the correlations themselves may have a
small magnitude. This is a typical manifestation of statistical
significance increasing as the sample size increases; eventually the
significant effect can be due to small correlated errors in background
estimation or even roundoff errors. These effects tend to be small but
become significant when there are enough observations of them. High flux
correlation significance should be taken seriously only when the
magnitude of the correlation is also fairly high.
WISE scs
WISE All-Sky Release Catalog SCS
314
35
0.1
For serious querying of this data, use ADQL_ possibly via TAP_ .
.. _ADQL: /adql
.. _TAP: /tap