previous page   back to table of contents   next page

VIII. Post-Cryo Data Release

2. Post-Cryo Data Products

a. Post-Cryo Single-Exposure Source Database Format and Column Descriptions

i. 2013 Post-Cryo Release

The NEOWISE Post-Cryo Single-exposure Source Database contains 7,337,642,955 measurements of positions and brightness information, uncertainties, time of observation and assorted quality flags made on the individual WISE 7.7s (W1 and W2) Single-exposure images. Because WISE scanned every point on the sky multiple times, the Single-exposure Database contains multiple, independent measurements of objects on the sky.

Entries in the Single-exposure Source Database include detections of real astrophysical objects, as well as spurious detections of low SNR noise excursions, transient events such as hot pixels, charged particle strikes and satellite streaks, and image artifacts light from bright sources including the moon. Many of the unreliable detections are flagged in the Single-exposure Database, but they have not been filtered out as they were for the All-Sky Release Source Catalog. Therefore, the Database must be used with caution. Users are strongly encouraged to read the Cautionary Notes before using the Database.

The following table contains brief descriptions of the parameters provided for each source in the Post-Cryo Release Single-exposure Source Database. The table is organized according to the broad function and utility of the parameters: positional information, photometric information, and source quality information. For Database flag parameters, the meaning of each possible flag value is given, along with some practical information on their usage.

The columns in the following table are:

Column NameFormatUnitsnullsDescription 
Basic Position and Identification Information
ra %11.7f deg no J2000 right ascension with respect to the 2MASS PSC reference frame. 
dec %11.7f deg no J2000 declination with respect to the 2MASS PSC reference frame.

 
sigra %8.4f arcsec yes One-sigma uncertainty in right ascension coordinate. 
sigdec %8.4f arcsec yesOne-sigma uncertainty in declination coordinate.  
sigradec %9.4f arcsec yes The co-sigma of the equatorial position uncertainties, sig_ra, sig_dec (σα, σδ). 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. 
glon %7.3f deg no Galactic longitude. CAUTION: This coordinate should not be used as an astrometric reference.  
glat %7.3f deg no Galactic latitude. CAUTION: This coordinate should not be used as an astrometric reference.  
elon %7.3f deg no Ecliptic longitude. CAUTION: This coordinate should not be used as an astrometric reference.  
elat %7.3f deg no Ecliptic latitude. CAUTION: This coordinate should not be used as an astrometric reference.  
w1x %8.3f pix yes The x-pixel coordinate of this source on the W1 Single-Exposure Image. 
w1y %8.3f pix yes The y-pixel coordinate of this source on the W1 Single-Exposure Image. 
w2x %8.3f pix yes The x-pixel coordinate of this source on the W2 Single-Exposure Image. 
w2y %8.3f pix yes The y-pixel coordinate of this source on the W2 Single-Exposure Image. 
w3x %8.3f pix yes The x-pixel coordinate of this source on the W3 Single-Exposure Image. 
w3y %8.3f pix yes The y-pixel coordinate of this source on the W3 Single-Exposure Image. 
w4x %8.3f pix yes The x-pixel coordinate of this source on the W4 Single-Exposure Image. 
w4y %8.3f pix yes The y-pixel coordinate of this source on the W4 Single-Exposure Image. 
cntr %15d ---- no Unique identification number for the Database source. This number is formed entirely from the source_id, which is in turn formed from the scan_id, frame_num 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 image boundaries. Cntr ordering thus provides a useful mapping of the WISE release on storage media. The cntr value is formed by making the source_id into an integer, in the format: SSSSSssMMMIIIIII, where
  • SSSSSss = Scan identifier scan_id, with the letter in the last position translated into two zero-filled digits corresponding to the letter's place in the alphabet.

  • MMM = Frame number frame_num, which is three zero-filled digits.

  • IIIIII = six-digit, zero-filled, sequential extracted source number, src, within the frameset.

For example, a source in scan 08745a, frame number 057, with a source_id of 08745a057-000100, would have a cntr value of 0874501057000100.

source_id %16s ---- no Unique source identifier. Source_id has the general form SSSSSxMMM-IIIIII, where
  • SSSSSx is the scan_id,

  • MMM is the frameset number within the scan, frame_num, and

  • IIIIII is the zero-filled, six-digit source number, src, within the frameset.
 
frame_num %3d ---- no Number of the frameset on which this source was extracted. The identifier has the general form MMM, a zero-filled three-digit number.

The frameset number is computed based on time bins which count from the scan start time:

fr_num = int[(((frame_utc - dt_beg) - scan_start_utc)/bin_size] + 1

where

  • int[] means truncate to an integer
  • frame_utc is the nominal frame exposure center UTC (when the boresight crosses the image center) in seconds
  • dt_beg is 4.4s. This is a nominal offset to approximate when the exposure began
  • scan_start_utc is the scan start time in seconds
  • bin_size is 10s.

For example, a frame with a start time 1234 secs after the scan start time would have a frame number of 124.

N.B.

  • Frame_num is not a frameset sequence number
  • As a result of using a 10 sec bin, every 11th frame skips a number, so it is normal to see breaks in the frame numbering and it doesn't indicate missing data.
  • Because frameset numbering is based on the predicted scan start time from the survey plan, and because frameset data may not start being acquired until well after the start of the scan, frameset numbers often do not start at 1 for a scan.
 
scan_id %6s ---- no Scan identifier. This is a six character string that identifies a block of survey exposures that are acquired between two flight system maneuvers, such as reorientation of the instrument boresight near the ecliptic poles, or slews to acquire TDRSS for data downlink contacts. Because maneuvers often take place near the ecliptic poles, the scan number is roughly associated with a half-orbit's worth of images. However, scans can cover less or more than half of the arc between ecliptic poles.

The scan_id has the general form SSSSSx, where

  • SSSSS is a zero-filled, five-digit integer that is twice the WISE orbit number. The orbit number increments each time the flight system passes the north ecliptic pole (NEP). Orbit number 1 was defined to start with the fictitious NEP passage immediately prior to WISE launch.

  • x   is a letter assigned based on sequential count of scans started in a specific half-orbit. The first scan has x="a", the next x="b", up to a maximum of x="d" for scans in the Post-Cryo Release.

The first scan whose data are used in the Post-Cryo Data Release is scan 08745a. This was the first scan after the SEP crossing in the 4372nd WISE orbit. The final scan included in the Release is 12514a, the first scan after the NEP crossing in the 6257th WISE orbit.

 
src %6d ---- no Sequential number of this source in the Single-Exposure frameset from which it was extracted, in approximate descending order of W1 source brightness. 
Primary Photometric Information
w1mpro %7.3fmag yes W1 magnitude measured with profile-fitting photometry, or the magnitude of the 95% confidence brightness upper limit if the W1 flux measurement has SNR<2. This column is null if the source is nominally detected in W1, but no useful brightness estimate could be made.  
w1sigmpro %5.3fmag yes W1 profile-fit photometric measurement uncertainty in mag units. This column is null if the W1 profile-fit magnitude is a 95% confidence upper limit or if the source is not measurable.  
w1snr %7.1f ---- yes W1 profile-fit measurement signal-to-noise ratio. This value is the ratio of the flux (w1flux to flux uncertainty (w1sigflux)in the W1 profile-fit photometry measurement. This column is null if w1flux is negative, or if w1flux or w1sigflux are null.  
w1rchi2 %9.3e ---- yes Reduced χ2 of the W1 profile-fit photometry measurement. This column is null if the W1 magnitude is a 95% confidence upper limit (i.e. the source is not detected).  
w2mpro %7.3fmag yes W2 magnitude measured with profile-fitting photometry, or the magnitude of the 95% confidence brightness upper limit if the W2 flux measurement has SNR<2. This column is null if the source is nominally detected in W1, but no useful brightness estimate could be made.  
w2sigmpro %5.3fmag yes W2 profile-fit photometric measurement uncertainty in mag units. This column is null if the W2 profile-fit magnitude is a 95% confidence upper limit or if the source is not measurable.  
w2snr %7.1f ---- yes W2 profile-fit measurement signal-to-noise ratio. This value is the ratio of the flux (w2flux to flux uncertainty (w2sigflux) in the W2 profile-fit photometry measurement. This column is null if w2flux is negative, or if w2flux or w2sigflux are null.  
w2rchi2 %9.3e ---- yes Reduced χ2 of the W2 profile-fit photometry measurement. This column is null if the W2 magnitude is a 95% confidence upper limit (i.e. the source is not detected).  
rchi2 %9.3e ---- yes Combine reduced χ2 of the profile-fit photometry measurement in all bands.  
nb %4d ---- yes Number of PSF components used simultaneously in the profile-fitting for this source. This number includes the source itself, so the minimum value of nb is "1". Nb is greater than "1" when the source is fit concurrently with other nearby detections (passive deblending), or when a single detection is split into two components during the fitting process (active deblending).  
na %4d ---- yes Active deblending flag. Active deblending was not performed during Scan/frame source extraction. Therefore, this column is always zero for Single-exposure Source Database entries.  
w1sat %5.3f ---- yes Saturated pixel fraction, W1. The fraction of all pixels within the profile-fitting area of this source that are flagged as saturated. A value larger than 0.0 indicates one or more pixels of saturation. Saturation begins to occur for point sources brighter than [W1]~8 mag. Saturation may occur in fainter sources because of a charged particle strike.

CAUTION: Saturated pixel tagging by the on-board electronics was intermittent for W1 during the Post-Cryo survey phase. The value of the w1sat column may be too low or even zero for some saturated sources.

 
w2sat %5.3f ---- yes Saturated pixel fraction, W2. The fraction of all pixels within the profile-fitting area of this source that are flagged as saturated. A value larger than 0.0 indicates one or more pixels of saturation. Saturation begins to occur for point sources brighter than [W2]~7 mag. Saturation may occur in fainter sources because of a charged particle strike.

CAUTION: Saturated pixel tagging by the on-board electronics was intermittent for W2 during the Post-Cryo survey phase. The value of the w2sat column may be too low or even zero for some saturated sources.

 
satnum %4s ---- no Minimum sample at which saturation occurs in each band. Four character string, one character per band, that indicates the minimum SUTR sample in which any pixel in the profile-fitting area was flagged as having reached the saturation level in the on-board WISE payload processing. If no pixels in a given band are flagged as saturated, the value for that band is "0".  
Measurement Quality and Source Reliability Information
cc_flags %4s ---- no Contamination and confusion flag. 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 are denoted by the following codes. Lower-case letters denote 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 or contaminated by a diffraction spike a nearby bright star on the same image.
  • P,p - Persistence. Source may be a spurious detection of or contaminated by a short-term latent (persistence) image left by a bright source.
  • R,r - Anneal-resistant latent image. Source may be a spurious detection of or contaminated by a long-term latent (persistence) image that was not suppressed by the Single frame Dynamic Calibration.
  • H,h - Halo. Source may be a spurious detection of or contaminated by the scattered light halo associated with a bright star.
  • O,o (letter "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.
  • L,l - Long-term latent image. Source may be a spurious detection of or contaminated by a long-term latent (persistence) image left by a bright source (W3 and W4 only).
  • g - Glint. Source may be contaminated by an optical glint caused by a bright source off the FOV of the frame.
  • 0 (number zero) - Source is unaffected by known artifacts.

For the Post-Cryo Single-exposure Source Database, the third and fourth characters of this string are always "0".

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,R,H,O,L,d,p,r,h,o,g,l,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.

CAUTION: Non-zero cc_flags values in any band are an indicator that the Single-exposure Source Database entry may be a spurious detection, or if it is a real source that its measurements may be contaminated and the photometry should be used with caution. Sources that are flagged as spurious detections of artifacts have not been removed from the Single-exposure Source Database.

  
det_bit %3d ---- no Bit encoded integer indicating bands in which a source has a w?snr>2 detection. For example, a source detected in W1 only has det_bit=1 (binary 0001). A source detected in W2 only has det_bit=2 (binary 10). A source detected in both W1 and W2 has det_bit=3 (binary 11).  
ph_qual %4s ---- no

Photometric quality flag. Four character flag, one character per band [W1/W2/W3/W4], that provides a shorthand summary of the quality of the profile-fit photometry measurement in each band, as derived from the measurement signal-to-noise ratio.

  • A - Source is detected in this band with a flux signal-to-noise ratio w?snr>10.
  • B - Source is detected in this band with a flux signal-to-noise ratio 3<w?snr<10.
  • C - Source is detected in this band with a flux signal-to-noise ratio 2<w?snr<3.
  • U - Upper limit on magnitude. Source measurement has w?snr<2. The profile-fit magnitude w?mpro is a 95% confidence upper limit.
  • X - A profile-fit measurement was not possible at this location possible in this band. The value of w?mpro and w?sigmpro will be "null" in this band.

For the Post-Cryo Single-exposure Source Database, the third and fourth characters of this string are always "X."

  
sso_flg %1d ---- yes Solar system object association flag. This is a single digit flag that indicates if the source is positionally associated with the predicted position of a known asteroid, comet, planet or planetary satellite at the time when this frameset was acquired by WISE.
  • "0" - The source is not associated with the predicted position of a known solar system object.
  • "1" - The source is associated with the predicted position of a known solar system object. Information about the associated object can be found in the Known Solar System Object Association table

CAUTION: An sso_flg=1 value does not necessarily mean that this Single-exposure database entry is a WISE detection of a solar system object. Only approximately 30% of all flagged associations are actual solar system object detections, and the detection rate is even lower during the Post-Cryo mission phase. The remaining 70% are chance alignments between the predicted object position and either an inertial background source or a spurious WISE detection. See the NEOWISE Moving Object Tracklets for the vetted list of both previously known and WISE-discovered solar system detections.

 
qual_frame %2d ---- yes Frame quality score. This column contains the numerical net quality score that was assigned to the single-exposure frameset from which this entry was extracted by the QA process. The score is an integer ranging from 0 to 10, with 10 representing the best quality and 0 the lowest. The net quality score takes into account several factors such as image quality and electronic noise.

CAUTION: Single-exposure source database entries having qual_frame=0 should be used with extreme caution. They may be spurious detections of noise, transient events or scattered light, or if real, their position and/or flux measurements may be contaminated.

CAUTION: A small fraction of the Single-exposure source database entries have qual_frame values that were not properly updated when QA scientists overrode the automatically-assigned quality score. The qual_frame values were properly updated in the Single-exposure Frame Metadata Table, but not the Single-exposure source database. Always defer to the qual_frame value in the corresponding Single-exposure Frame Metadata Table entry to make sure that you have the correct source detection quality score.

 
qi_fact %3.1f ---- yes Frame image quality score. This columns contains the numerical image quality score assigned to the single-exposure frameset from which this entry was extracted by the QA process. The score is a floating point number equal to 1.0, 0.5 or 0.0, with 1.0 representing the best quality and 0.0 the lowest. Image quality score values <1.0 are assigned to framesets if the average image size and elongation exceeds threshold values.

CAUTION: Single-exposure source database entries having qual_frame=0.0 should be used with caution. They were extracted from frameset in which the images are smeared because of residual flight system motion. Position, flux and profile-fitting measurements will be degraded.

 
saa_sep %7.3f deg yes SAA separation. This column contains the angular separation on the sky, in degrees, between the apparent position of WISE and the boundary of the South Atlantic Anomaly (SAA) at the time of observation for the frameset on which this entry was extracted. Positive values indicate that WISE was outside of the SAA boundary. Negative values indicate that WISE was within the SAA boundary.

CAUTION: Single-exposure source database entries having negative or small positive (< 5.0) values of saa_sep should be used with caution. The large flux of charged particles within the SAA produces a very high incidence of radiation hits that can lead to many spurious Single-exposure source extractions. Looking at the Single-exposure images taken of the same position when WISE was not within the SAA is a good way to assess source reliability.

  
moon_masked %4s ---- yes Moon masking flag. This is a four character flag, one character per band, that indicates if the single-exposure database frameset from which this entry was extracted falls within the area covered by the prior moon masks. A value of "0" in a band indicates that the frameset is not in the mask area, and a value of "1" indicates that the frameset is in the mask area. These fixed area masks denote regions contaminated by scattered light from the moon, and are different for each band.

For the Post-Cryo Single-exposure Source Database, the third and fourth characters of this string are always "0".

CAUTION: Single-exposure source database entries having moon_masked=1 in any band should be used with caution. Framesets in the moon mask areas may have large scale image artifacts that induce spurious detections or contaminate real source measurements.

  
mjd %12.6f day yes The Modified Julian Date of the mid-point of the frameset observation. The observation mid-point is defined as the time the optical boresight crosses the center of the WISE focal planes. This time is the same for all bands.

N.B. Because the first sample of the W1 and W2 detector readouts was given zero weight (III.2.a), the mid-point of the W1 and W2 exposures occurs 0.55 sec later than the observation mid-point.

  
w1frtr %5.3f ---- yes Fraction of pixels affected by transients. This column gives the fraction of all W1 pixels in the W1 Single-Exposure image used to characterize this source that may be affected by transient events. This number is computed by counting the number of pixels in the Single-Exposure Bit Mask images with value "21" that are present within the profile-fitting area, a circular region with radius of 7.25", centered on the position of this source, and dividing by the total number of pixels in the same area that are available for measurement.  
w2frtr %5.3f ---- yes Fraction of pixels affected by transients. This column gives the fraction of all W2 pixels in the W2 Single-Exposure image used to characterize this source that may be affected by transient events. This number is computed by counting the number of pixels in the Single-Exposure Bit Mask images with value "25" that are present within the profile-fitting area, a circular region with radius of 7.25", centered on the position of this source, and dividing by the total number of pixels in the same area that are available for measurement.  
w1cc_map %9d ---- yes Contamination and confusion map for this source in W1. This column contains the integer equivalent of the 9-bit binary array that specifies if the W1 measurement is believed to be contaminated by or a spurious detection of an image artifact. The elements of the binary array are:

S0LGOHRPD

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.
  • R - Anneal-resistant latent image. Source may be a spurious detection of or contaminated by a long-term latent (persistence) image that was not suppressed by the Single frame Dynamic Calibration.
  • H - Halo. Source may be a spurious detection of or contaminated by the scattered light halo associated with a bright star.
  • O (letter "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.
  • L - Long-term latent image. Source may be a spurious detection of or contaminated by a long-term latent (persistence) image left by a bright source (W3 and W4 only).
  • G - Glint. Source may be contaminated by an optical glint caused by a bright source off the FOV of the frame.

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.

 
w1cc_map_str %9s ---- yes Contamination and confusion string. This column is a character string that denotes all artifacts that may contaminate the W1 measurement of this source, in the priority order D,P,R,H,O,d,p,r,h,o,g. Lower-case letters denote cases where the source detection in this band is believed to be real but the measurement may be contaminated by the artifact. Upper-case letters denote cases where the source detection in this band may be a spurious detection of an artifact.

For example, a real detection that is contaminated by a diffraction spike and a latent (persistent) image has a w1cc_map_str="dp". A spurious detection of a diffraction spike that is also contaminated by a short-term latent image has w1cc_map_str="Dp".

This string is "null" if there are no artifacts that affect the measurement in this band.

The value that appears in first element of the cc_flags string is the left-most character in w1cc_map_str. If w1cc_map_str is "null", then the corresponding cc_flags entry is "0".

 
w2cc_map %3d ---- yes Contamination and confusion map for this source in W2. This column contains the integer equivalent of the 9-bit binary array that specifies if the W2 measurement is believed to be contaminated by or a spurious detection of an image artifact. The elements of the binary array are:

S0LGOHRPD

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.
  • R - Anneal-resistant latent image. Source may be a spurious detection of or contaminated by a long-term latent (persistence) image that was not suppressed by the Single frame Dynamic Calibration.
  • H - Halo. Source may be a spurious detection of or contaminated by the scattered light halo associated with a bright star.
  • O (letter "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.
  • L - Long-term latent image. Source may be a spurious detection of or contaminated by a long-term latent (persistence) image left by a bright source (W3 and W4 only).
  • G - Glint. Source may be contaminated by an optical glint caused by a bright source off the FOV of the frame.

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 w2cc_map=265.

 
w2cc_map_str %9s ---- yes Contamination and confusion string. This column is a character string that denotes all artifacts that may contaminate the W2 measurement of this source, in the priority order D,P,R,H,O,d,p,r,h,o,g. Lower-case letters denote cases where the source detection in this band is believed to be real but the measurement may be contaminated by the artifact. Upper-case letters denote cases where the source detection in this band may be a spurious detection of an artifact.

For example, a real detection that is contaminated by a diffraction spike and a latent (persistent) image has a w2cc_map_str="dp". A spurious detection of a diffraction spike that is also contaminated by a short-term latent image has w2cc_map_str="Dp".

This string is "null" if there are no artifacts that affect the measurement in this band.

The value that appears in second element of the cc_flags string is the left-most character in w2cc_map_str. If w2cc_map_str is "null", then the corresponding cc_flags entry is "0".

 
Additional Photometric Information
w1sky %9.3f ---- yes The trimmed average of the W1 sky background value in digital numbers measured in an annulus with an inner radius of 50" and outer radius of 70". Both profile-fit and aperture photometry source brightness measurements are made relative to this sky background value.  
w1sigsk %7.3f---- yes The uncertainty in the W1 sky background value in units of digital numbers measured in an annulus with an inner radius of 50" and outer radius of 70".  
w1conf %9.3f---- yes Estimated confusion noise in the W1 sky background annulus, in digital numbers. This number is the difference between the measured noise in the sky background w1sigsk and the noise measured in the same region on the Single-Exposure Uncertainty Maps.  
w2sky %9.3f ---- yes The trimmed average of the W2 sky background value in digital numbers measured in an annulus with an inner radius of 50" and outer radius of 70". Both profile-fit and aperture photometry source brightness measurements are made relative to this sky background value.  
w2sigsk %7.3f---- yes The uncertainty in the W2 sky background value in units of digital numbers measured in an annulus with an inner radius of 50" and outer radius of 70".  
w2conf %9.3f---- yes Estimated confusion noise in the W2 sky background annulus, in digital numbers. This number is the difference between the measured noise in the sky background w2sigsk and the noise measured in the same region on the Single Exposure Uncertainty Maps.  
w1flux %11.4e ---- yes The "raw" W1 source flux measured in profile-fit photometry in units of digital numbers. This value may be negative. This column is null if no useful profile-fit measurement of the source is possible because of masked or otherwise unusable pixels. 
w1sigflux %11.4e ---- yes Uncertainty in the "raw" W1 source flux measurement in profile-fit photometry in units of digital numbers. This column is null if no useful profile-fit measurement of the source is possible. 
w2flux %11.4e ---- yes The "raw" W2 source flux measured in profile-fit photometry in units of digital numbers. This value may be negative. This column is null if no useful profile-fit measurement of the source is possible because of masked or otherwise unusable pixels. 
w2sigflux %11.4e ---- yes Uncertainty in the "raw" W2 source flux measurement in profile-fit photometry in units of digital numbers. This column is null if no useful profile-fit measurement of the source is possible. 
w1mag %7.3f mag yes W1 "standard" aperture magnitude. This is the curve-of-growth corrected source brightness measured in an 8.25" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". The curve-of-growth correction is given in w1mcor.

This column is null if an aperture measurement was not possible in W1.

 
w1sigm %5.3f mag yes Uncertainty in the W1 "standard" aperture magnitude.

This column is null if the W1 "standard" aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg %1d ---- yes W1 "standard" aperture measurement quality flag. This flag indicates 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
  
w1mcor %6.3f mag yes W1 aperture curve-of-growth correction, in magnitudes. This correction is subtracted from the nominal 8.25" aperture photometry brightness, w1mag, to give the "standard-aperture" magnitude.  
w2mag %7.3f mag yes W2 "standard" aperture magnitude. This is the curve-of-growth corrected source brightness measured in an 8.25" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". The curve-of-growth correction is given in w2mcor.

This column is null if an aperture measurement was not possible in W2.

 
w2sigm %5.3f mag yes Uncertainty in the W2 "standard" aperture magnitude.

This column is null if the W2 "standard" aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg %1d ---- yes W2 "standard" aperture measurement quality flag. This flag indicates 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
  
w2mcor %6.3f mag yes W2 aperture curve-of-growth correction, in magnitudes. This correction is subtracted from the nominal 8.25" aperture photometry brightness, w2mag, to give the "standard-aperture" magnitude.  
w1mag_1 %7.3f mag yes W1 5.5" radius aperture magnitude. This is the calibrated source brightness measured in a 5.5" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_1 %5.3f mag yes Uncertainty in the W1 5.5" radius aperture magnitude.

This column is null if the the 5.5" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_1 %1d ---- yes W1 5.5" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_1 %7.3f mag yes W2 5.5" radius aperture magnitude. This is the calibrated source brightness measured in a 5.5" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_1 %5.3f mag yes Uncertainty in the W2 5.5" radius aperture magnitude.

This column is null if the the 5.5" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_1 %1d ---- yes W2 5.5" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_2 %7.3f mag yes W1 8.25" radius aperture magnitude. This is the calibrated source brightness measured in a 8.25" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_2 %5.3f mag yes Uncertainty in the W1 8.25" radius aperture magnitude.

This column is null if the the 8.25" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_2 %1d ---- yes W1 8.25" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_2 %7.3f mag yes W2 8.25" radius aperture magnitude. This is the calibrated source brightness measured in a 8.25" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_2 %5.3f mag yes Uncertainty in the W2 8.25" radius aperture magnitude.

This column is null if the the 8.25" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_2 %1d ---- yes W2 8.25" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_3 %7.3f mag yes W1 11.0" radius aperture magnitude. This is the calibrated source brightness measured in a 11.0" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_3 %5.3f mag yes Uncertainty in the W1 11.0" radius aperture magnitude.

This column is null if the the 11.0" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_3 %1d ---- yes W1 11.0" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_3 %7.3f mag yes W2 11.0" radius aperture magnitude. This is the calibrated source brightness measured in a 11.0" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_3 %5.3f mag yes Uncertainty in the W2 11.0" radius aperture magnitude.

This column is null if the the 11.0" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_3 %1d ---- yes W2 11.0" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_4 %7.3f mag yes W1 13.75" radius aperture magnitude. This is the calibrated source brightness measured in a 13.75" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_4 %5.3f mag yes Uncertainty in the W1 13.75" radius aperture magnitude.

This column is null if the the 13.75" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_4 %1d ---- yes W1 13.75" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_4 %7.3f mag yes W2 13.75" radius aperture magnitude. This is the calibrated source brightness measured in a 13.75" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_4 %5.3f mag yes Uncertainty in the W2 13.75" radius aperture magnitude.

This column is null if the the 13.75" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_4 %1d ---- yes W2 13.75" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_5 %7.3f mag yes W1 16.5" radius aperture magnitude. This is the calibrated source brightness measured in a 16.5" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_5 %5.3f mag yes Uncertainty in the W1 16.5" radius aperture magnitude.

This column is null if the the 16.5" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_5 %1d ---- yes W1 16.5" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_5 %7.3f mag yes W2 16.5" radius aperture magnitude. This is the calibrated source brightness measured in a 16.5" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_5 %5.3f mag yes Uncertainty in the W2 16.5" radius aperture magnitude.

This column is null if the the 16.5" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_5 %1d ---- yes W2 16.5" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_6 %7.3f mag yes W1 19.25" radius aperture magnitude. This is the calibrated source brightness measured in a 19.25" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_6 %5.3f mag yes Uncertainty in the W1 19.25" radius aperture magnitude.

This column is null if the the 19.25" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_6 %1d ---- yes W1 19.25" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_6 %7.3f mag yes W2 19.25" radius aperture magnitude. This is the calibrated source brightness measured in a 19.25" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_6 %5.3f mag yes Uncertainty in the W2 19.25" radius aperture magnitude.

This column is null if the the 19.25" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_6 %1d ---- yes W2 19.25" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_7 %7.3f mag yes W1 22.0" radius aperture magnitude. This is the calibrated source brightness measured in a 22.0" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_7 %5.3f mag yes Uncertainty in the W1 22.0" radius aperture magnitude.

This column is null if the the 22.0" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_7 %1d ---- yes W1 22.0" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_7 %7.3f mag yes W2 22.0" radius aperture magnitude. This is the calibrated source brightness measured in a 22.0" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_7 %5.3f mag yes Uncertainty in the W2 22.0" radius aperture magnitude.

This column is null if the the 22.0" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_7 %1d ---- yes W2 22.0" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
w1mag_8 %7.3f mag yes W1 24.75" radius aperture magnitude. This is the calibrated source brightness measured in a 24.75" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W1.

  
w1sigm_8 %5.3f mag yes Uncertainty in the W1 24.75" radius aperture magnitude.

This column is null if the the 24.75" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w1flg_8 %1d ---- yes W1 24.75" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w1flg.  
w2mag_8 %7.3f mag yes W2 24.75" radius aperture magnitude. This is the calibrated source brightness measured in a 24.75" radius circular aperture centered on the source position on the Single-Exposure Image. If the source is not detected in the aperture measurement, this is the 95% confidence upper limit to the brightness. The background sky reference level is measured in an annular region with inner radius of 50" and outer radius of 70". No curve-of-growth correction has been applied.

This column is null if an aperture measurement was not possible in W2.

  
w2sigm_8 %5.3f mag yes Uncertainty in the W2 24.75" radius aperture magnitude.

This column is null if the the 24.75" radius aperture magnitude is an upper limit, or if an aperture measurement was not possible.

  
w2flg_8 %1d ---- yes W2 24.75" radius aperture magnitude quality flag. This flag indicates 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 values are as described for the standard aperture photometry quality flag, w2flg.  
2MASS PSC Association Information
tmass_key %10d ---- yes 2MASS PSC association. Unique identifier of the closest source in the 2MASS Point Source Catalog (PSC) that falls within 3" of the position of this WISE source. This is equivalent to the pts_key in the 2MASS PSC entry. This column is "null" if there is no 2MASS PSC source within 3" of the WISE source position. The number of 2MASS PSC sources within 3" of the WISE position is given in n_2mass

CAUTION - 2MASS source information included in the WISE source record is an association not an identification. Although the position accuracies of the two Catalogs are good, there is a non-zero probability of chance associations between physically unrelated objects, as well as missed associations between the Catalogs. You should always confirm associations by reviewing the entries from both Catalogs.

 
r_2mass %7.3f arcsec yes Distance separating the positions of the WISE source and associated 2MASS PSC source within 3". This column is "null" if there is no associated 2MASS PSC source.  
pa_2mass %5.1f deg yes Position angle (degrees E of N) of the vector from the WISE source to the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source.  
n_2mass %3d ---- yes The number of 2MASS PSC entries found within a 3" radius of the WISE source position. This column is zero if there is no associated 2MASS PSC source.  
j_m_2mass %7.3f mag yes 2MASS J-band magnitude or magnitude upper limit of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC J-band magnitude entry is "null".  
j_msig_2mass %5.3f mag yes 2MASS J-band corrected photometric uncertainty of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC J-band uncertainty entry is "null".  
h_m_2mass %7.3f mag yes 2MASS H-band magnitude or magnitude upper limit of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC H-band magnitude entry is "null".  
h_msig_2mass %5.3f mag yes 2MASS H-band corrected photometric uncertainty of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC H-band uncertainty entry is "null".  
k_m_2mass %7.3f mag yes 2MASS Ks-band magnitude of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC Ks-band magnitude entry is "null".  
k_msig_2mass %5.3f mag yes 2MASS Ks-band corrected photometric uncertainty of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC Ks-band uncertainty entry is "null".  
Spatial Indexing Information
x %19.16f ---- no Unit sphere position x value  
y %19.16f ---- no Unit sphere position y value  
z %19.16f ---- no Unit sphere position z value  
spt_ind %9d ---- no HTM spatial index key  

Last Update: 2017 October 2

previous page   back to table of contents   next page