Appendix 6. Merged Working Database Source Information
3. Merged Database Table Formats
b. Merged Extended Source Information Tables
The following table contains brief descriptions of the entries in the Survey, 6x and Calibration Merged Extended Source Information Tables. The merged source tables contain the mean positions magnitudes and uncertainties for extended sources detected multiple times in each of the 2MASS data sets. The merging was carried out using an autocorrelation of the respective databases to identify groups of resolved extractions that are positionally associated with each other, all lying within a 5.0" radius circular region. A number of confirmation statistics are also provided in the tables that can be used to test for source variability, and the general quality of the merge. The merging procedure and the derived quantities are described in Section A6.1.
The order of the entries in this table is the same as that presented in the IRSA/GATOR query page for these tables.
The columns in the following table are:
 Column Name: The parameter name in the Merged Source Information table. Click on this to go to the section of the Explanatory Supplement where the derivation and/or usage of that parameter is described in more detail.
 Format: The asciiequivalent format of the field in the Merged Extended Source Information Table, expressed in "C" readable notation. This is useful when parsing the aligned tabular output from IRSA/GATOR. Although the data values will conform to these formats, the actual width of the field in the GATOR output may be padded with extra blank spaces to accommodate column headers. Note that some fields contain null values that will require special handling when parsing tables drawn from IRSA/GATOR output.
 Units: The units of the parameter. A value of "" in this column means that the parameter is dimensionless.
 nulls: A "yes" in this column means that this parameter can be null in the Merged Source table. A "no" means that there will always be a value in this column in the table. Note that null values are represented differently in the IRSA/GATOR output and the ascii ftp versions of the Merge Source tables.
 Description: A brief description of the parameter and its values.
Column order subject to reorganization
Column Name  Format  Units  nulls  Description 

Group Identifiers, Detection Statistics and Confusion  
gcntr  %10d    no  Unique identifier of the merged group within
a given database. This value is set to be the cntr/pts_key
value of the "seed" extraction for the group (see
A6.2).
The gcntr identifier is given in the individual WDB records for all extractions that are members of merged groups. Links between the cntr/pts_key WDB identifiers of the individual group members and the group identifier, gcntr, are provided in the Survey, 6x and Calibration Merged Extended Source CrossReference tables. Note: gcntr is unique only within a given database. Sources in the Merged Survey, 6x and Calibration Tables with the same gcntr identifiers are not the same object on the sky. 
napp  %5d    no  Total number of extractions associated with this merged group. This number can be larger than the number of scans covering the group position (spos) because it can include multiple extractions within a scan and because of the approximate nature of spos. 
gcnf  %1d    no  Merge confusion flag. This column indicates
if this merged group contains extractions that were positionally associated
with more than one group.

sdet  %5d    no  Number of unique scans in which this merged source is detected in any band. If sdet < napp, then the source is artificially split in at least one scan. 
Position Information  
ra  %10.6f  deg  no  Average right ascension of the merged group.
For the Survey and 6x WDBs, this is the varianceweighted average right ascension, computed using the positional uncertainties of each extraction in the group. For the Calibration WDB, this is the unweighted average right ascension of all extractions in the group. NOTE: All extractions within a group are used in computing the average right ascension. 
dec  %10.6f  deg  no  Average declination of the merged group.
For the Survey and 6x WDBs, this is the varianceweighted average declination, computed using the positional uncertainties of each extraction in the group. For the Calibration WDB, this is the unweighted average declination of all extractions in the group. NOTE: All extractions within a group are used in computing the average declination. 
emj_mrg  %10.4e  arcsec  no  Semimajor axis of the average position error ellipse.
For the Survey and 6x WDBs, the position error ellipse parameters are computed from the covariance of the positions of all extractions in the merged group. For the Calibration WDB, the semimajor axis is the larger of the standard deviation of the mean right ascension or declination. If the right ascension error is larger, then emn_ang=90. If the declination error is larger, then emn_ang=0. 
emn_mrg  %10.4e  arcsec  no  Semiminor axis of the average position error ellipse.
For the Survey and 6x WDBs, the position error ellipse parameters are computed from the covariance of the positions of all extractions in the merged group. For the Calibration WDB, the semiminor axis is the smaller of the standard deviation of the mean right ascension or declination. If the right ascension error is smaller, then emn_ang=0. If the declination error is smaller, then emn_ang=90. 
ean_mrg  %3d  deg  no  Position angle of the
average position error ellipse (degrees E of N).
For the Survey and 6x WDBs, the position error ellipse parameters are computed from the covariance of the positions of all extractions in the merged group. For the Calibration WDB, ean_mrg has values of "0" or "90" only. The value indicates whether the standard deviation of the mean right ascension (ean_mrg=90) or declination (ean_mrg=0) is larger. 
sep_avg  %10.4e  deg  yes  Average radial separation from mean group position for all extractions in the group. 
sep_sig  %10.4e  deg  yes  Standard deviation of the average radial separation from the mean group position for all extractions in group. 
use_cntr  %10d    yes  WDB cntr/pts_key identifier
of the extraction in this group that lies farthest from the edge of
the scan in which it was detected. This is analogous to the
algorithm used to resolve multiplydetected sources during the
generation of the AllSky XSC (V.4).
However, this column does not necessarily identify extractions
in the Merged Survey Extended Source WDB that were selected for
the Survey or 6x XSC because not all scans were considered for
Catalog selection.
This column is null if all extractions in the group lie within 10" of a scan edge. 
smin  %5d    no  Minimum number of scans that cover the 1.5" radius circular region centered on the mean position of the group. 
smax  %5d    no  Maximum number of scans that cover the 1.5" radius circular region centered on the mean position of the group. 
spos  %5d    no  Estimated number of scans that cover the mean group position. This number is computed assuming that the scan boundaries follow greatcircles interpolated between the reconstructed 3band coverage corners of the scan. Because the true telescope scan path sometimes deviated from great circles, and because reconstructed positions of a source from different scans will be distributed over a finite area, the number of detections of a merged source reported (napp and sdet) can sometimes exceed spos. 
Photometric Information  
j_m_7_avg  %7.4f  mag  yes  Average 7 arcsec radius circular aperture J magnitude
of selected
extractions in the merged group. This is computed using the WDB
extractions that meet the following criteria:
The average is computed by first converting the magnitudes of the individual selected extractions to flux units, evaluating the average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Jband detections in this group is zero (j_n_7=0). Note: Because upper limits are not included in the average, the average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
h_m_7_avg  %7.4f  mag  yes  Average 7 arcsec radius circular aperture H magnitude
of selected
extractions in the merged group. This is computed using the WDB
extractions that meet the following criteria:
The average is computed by first converting the magnitudes of the individual selected extractions to flux units, evaluating the average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Hband detections in this group is zero (h_n_7=0). Note: Because upper limits are not included in the average, the average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
k_m_7_avg  %7.4f  mag  yes  Average 7 arcsec radius circular aperture K_{s} magnitude
of selected
extractions in the merged group. This is computed using the WDB
extractions that meet the following criteria:
The average is computed by first converting the magnitudes of the individual selected extractions to flux units, evaluating the average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable K_{s}band detections in this group is zero (k_n_7=0). Note: Because upper limits are not included in the average, the average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
j_mstdev_7  %10.4e  mag  yes  Standard deviation of the mean 7" radius circular J band magnitude
for selected extractions in the group.
If there is only one usable Jband 7" aperture measurement in the group (j_n_7=1), this column is set to 1sigma uncertainty of that measurement (j_msig_7). This column is null if the number of usable Jband 7" aperture measurements in the group is zero (j_n_7=0). 
h_mstdev_7  %10.4e  mag  yes  Standard deviation of the mean 7" radius circular H band magnitude
for selected extractions in the group.
If there is only one usable Hband 7" aperture measurement in the group (h_n_7=1), this column is set to 1sigma uncertainty of that measurement (h_msig_7). This column is null if the number of usable Hband 7" aperture measurements in the group is zero (h_n_7=0). 
k_mstdev_7  %10.4e  mag  yes  Standard deviation of the mean 7" radius circular K_{s} band magnitude for selected extractions in the group.
If there is only one usable K_{s}band 7" aperture measurement in the group (k_n_7=1), this column is set to 1sigma uncertainty of that measurement (k_msig_7). This column is null if the number of usable K_{s}band 7" aperture measurements in the group is zero (k_n_7=0). 
max_7_flg  %1d    yes  Maximum J, H or K_{s} 7" radius circular aperture photometry confusion flag (j_flg_7, h_flg_7, k_flg_7) among all selected extractions in this group. Nonzero values indicate some level of stellar contamination of this extended source. 
j_m_k20fe_avg  %7.4f  mag  yes  Average J isophotal fiducial elliptical aperture magnitude
(j_m_k20fe) of selected
extractions in the merged group. This is computed using the WDB
extractions that meet the following criteria:
The average is computed by first converting the magnitudes of the individual selected extractions to flux units, evaluating the average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Jband detections in this group is zero (j_n_k20fe=0). Note: Because upper limits are not included in the average, the average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
h_m_k20fe_avg  %7.4f  mag  yes  Average H isophotal fiducial elliptical aperture magnitude
(h_m_k20fe) of selected
extractions in the merged group. This is computed using the WDB
extractions that meet the following criteria:
The average is computed by first converting the magnitudes of the individual selected extractions to flux units, evaluating the average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Hband detections in this group is zero (h_n_k20fe=0). Note: Because upper limits are not included in the average, the average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
k_m_k20fe_avg  %7.4f  mag  yes  Average K_{s} isophotal fiducial elliptical aperture magnitude
(k_m_k20fe) of selected
extractions in the merged group. This is computed using the WDB
extractions that meet the following criteria:
The average is computed by first converting the magnitudes of the individual selected extractions to flux units, evaluating the average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable K_{s}band detections in this group is zero (k_n_k20fe=0). Note: Because upper limits are not included in the average, the average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
j_mstdev_k20fe  %10.4e  mag  yes  Standard deviation of the mean "k20fe" isophotal fiducial elliptical
J band magnitude for selected extractions in the group.
If there is only one usable Jband isophotal measurement in the group (j_n_k20fe=1), this column is set to the 1sigma uncertainty of that measurement (j_msig_k20fe). This column is null if the number of usable Jband isophotal measurements in the group is zero (j_n_k20fe=0). 
h_mstdev_k20fe  %10.4e  mag  yes  Standard deviation of the mean "k20fe" isophotal fiducial elliptical
H band magnitude for selected extractions in the group.
If there is only one usable Hband isophotal measurement in the group (h_n_k20fe=1), this column is set to the 1sigma uncertainty of that measurement (h_msig_k20fe). This column is null if the number of usable Hband isophotal measurements in the group is zero (h_n_k20fe=0). 
k_mstdev_k20fe  %10.4e  mag  yes  Standard deviation of the mean "k20fe" isophotal fiducial elliptical
K_{s} band magnitude for selected extractions in the group.
If there is only one usable K_{s}band isophotal measurement in the group (k_n_k20fe=1), this column is set to the 1sigma uncertainty of that measurement (k_msig_k20fe). This column is null if the number of usable K_{s}band isophotal measurements in the group is zero (k_n_k20fe=0). 
max_k20fe_flg  %1d    yes  Maximum J, H or K_{s} "k20fe" isophotal fiducial elliptical photometry confusion flag (j_flg_k20fe, h_flg_k20fe, k_flg_k20fe) among all selected extractions in this group. Nonzero values indicate some level of stellar contamination of this extended source. 
j_m_7_wavg  %7.4f  mag  yes  Inversevarianceweighted average 7" circular aperture J magnitude
of selected extractions in the merged group. This is computed using the
magnitudes and uncertainties of all extractions that meet the
following criteria:
The average is computed by first converting the magnitudes and uncertainties of the individual selected extractions to flux units, evaluating the weighted average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Jband detections in this group is zero (j_n_7=0). Note: Because upper limits are not included in the average, the weighted average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
h_m_7_wavg  %7.4f  mag  yes  Inversevarianceweighted average 7" circular aperture H magnitude
of selected extractions in the merged group. This is computed using the
magnitudes and uncertainties of all extractions that meet the
following criteria:
The average is computed by first converting the magnitudes and uncertainties of the individual selected extractions to flux units, evaluating the weighted average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Hband detections in this group is zero (h_n_7=0). Note: Because upper limits are not included in the average, the weighted average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
k_m_7_wavg  %7.4f  mag  yes  Inversevarianceweighted average 7" circular aperture K_{s} magnitude
of selected extractions in the merged group. This is computed using the
magnitudes and uncertainties of all extractions that meet the
following criteria:
The average is computed by first converting the magnitudes and uncertainties of the individual selected extractions to flux units, evaluating the weighted average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable K_{s}band detections in this group is zero (k_n_7=0). Note: Because upper limits are not included in the average, the weighted average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
j_m_7_wunc  %10.4e  mag  yes  Uncertainty of the inversevarianceweighted average 7" circular
aperture J magnitude.
If there is only one usable Jband aperture measurement in the group (j_n_7=1), this column is set to the 1sigma uncertainty of that measurement (j_msig_7. This column is null if the number of usable Jband detections in the group is zero (j_n_7=0). 
h_m_7_wunc  %10.4e  mag  yes  Uncertainty of the inversevarianceweighted average 7" circular
aperture H magnitude.
If there is only one usable Hband aperture measurement in the group (h_n_7=1), this column is set to the 1sigma uncertainty of that measurement (h_msig_7. This column is null if the number of usable Jband detections in the group is zero (h_n_7=0). 
k_m_7_wunc  %10.4e  mag  yes  Uncertainty of the inversevarianceweighted average 7" circular
aperture K_{s} magnitude.
If there is only one usable K_{s}band aperture measurement in the group (k_n_7=1), this column is set to the 1sigma uncertainty of that measurement (k_msig_7. This column is null if the number of usable K_{s}band detections in the group is zero (k_n_7=0). 
j_m_k20fe_wavg  %7.4f  mag  yes  Inversevarianceweighted average of the "k20fe" isophotal fiducial
elliptical J magnitude
of selected extractions in the merged group. This is computed using the
magnitudes and uncertainties of all extractions that meet the
following criteria:
The average is computed by first converting the magnitudes and uncertainties of the individual selected extractions to flux units, evaluating the weighted average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Jband detections in this group is zero (j_n_k20fe=0). Note: Because upper limits are not included in the average, the weighted average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
h_m_k20fe_wavg  %7.4f  mag  yes  Inversevarianceweighted average of the "k20fe" isophotal fiducial
elliptical H magnitude
of selected extractions in the merged group. This is computed using the
magnitudes and uncertainties of all extractions that meet the
following criteria:
The average is computed by first converting the magnitudes and uncertainties of the individual selected extractions to flux units, evaluating the weighted average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Jband detections in this group is zero (h_n_k20fe=0). Note: Because upper limits are not included in the average, the weighted average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
k_m_k20fe_wavg  %7.4f  mag  yes  Inversevarianceweighted average of the "k20fe" isophotal fiducial
elliptical K_{s} magnitude
of selected extractions in the merged group. This is computed using the
magnitudes and uncertainties of all extractions that meet the
following criteria:
The average is computed by first converting the magnitudes and uncertainties of the individual selected extractions to flux units, evaluating the weighted average of the flux distribution, and then converting back into magnitude units. This column is null if the number of usable Jband detections in this group is zero (k_n_k20fe=0). Note: Because upper limits are not included in the average, the weighted average magnitude will systematically overestimate the brightness of faint sources near the sensitivity limit of the observations that are detected fewer times than are possible (sdet<spos). 
j_m_k20fe_wunc  %10.4e  mag  yes  Uncertainty of the inversevarianceweighted "k20fe" isophotal
fiducial elliptical J magnitude.
If there is only one usable Jband isophotal measurement in the group (j_n_k20fe=1), this column is set to the 1sigma uncertainty of that measurement (j_msig_k20fe. This column is null if the number of usable Jband detections in the group is zero (j_n_k20fe=0). 
h_m_k20fe_wunc  %10.4e  mag  yes  Uncertainty of the inversevarianceweighted "k20fe" isophotal
fiducial elliptical H magnitude.
If there is only one usable Hband isophotal measurement in the group (h_n_k20fe=1), this column is set to the 1sigma uncertainty of that measurement (h_msig_k20fe. This column is null if the number of usable Hband detections in the group is zero (h_n_k20fe=0). 
k_m_k20fe_wunc  %10.4e  mag  yes  Uncertainty of the inversevarianceweighted "k20fe" isophotal
fiducial elliptical K_{s} magnitude.
If there is only one usable K_{s}band isophotal measurement in the group (k_n_k20fe=1), this column is set to the 1sigma uncertainty of that measurement (k_msig_k20fe. This column is null if the number of usable K_{s}band detections in the group is zero (k_n_k20fe=0). 
j_n_7  %5d    no  Number of extractions using in the average and weighted average
7" circular aperture magnitude computations. This is the subset of
extractions in the group that meet the following criteria:

h_n_7  %5d    no  Number of extractions using in the average and weighted average
7" circular aperture magnitude computations. This is the subset of
extractions in the group that meet the following criteria:

k_n_7  %5d    no  Number of extractions using in the average and weighted average
7" circular aperture magnitude computations. This is the subset of
extractions in the group that meet the following criteria:

j_n_k20fe  %5d    no  Number of extractions using in the average and weighted average
"k20fe" isophotal fiducial elliptical magnitude computations. This is the
subset of extractions in the group that meet the following criteria:

h_n_k20fe  %5d    no  Number of extractions using in the average and weighted average
"k20fe" isophotal fiducial elliptical magnitude computations. This is the
subset of extractions in the group that meet the following criteria:

k_n_k20fe  %5d    no  Number of extractions using in the average and weighted average
"k20fe" isophotal fiducial elliptical magnitude computations. This is the
subset of extractions in the group that meet the following criteria:

j_mchisq_7  %6.2f    yes  Chisquared statistic for the distribution of selected Jband
7" circular aperture magnitudes and uncertainties in the merged group.
This column is null if there are fewer than 2 usable Jband aperture measurements in the group. 
h_mchisq_7  %6.2f    yes  Chisquared statistic for the distribution of selected Hband
7" circular aperture magnitudes and uncertainties in the merged group.
This column is null if there are fewer than 2 usable Hband aperture measurements in the group. 
k_mchisq_7  %6.2f    yes  Chisquared statistic for the distribution of selected K_{s}band
7" circular aperture magnitudes and uncertainties in the merged group.
This column is null if there are fewer than 2 usable K_{s}band aperture measurements in the group. 
j_mndev_7  %10.4e  mag  yes  Largest negative deviation from weighted average 7" circular aperture
J magnitude among all extractions in the group, scaled by the
photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Jband aperture measurements in the group. 
h_mndev_7  %10.4e  mag  yes  Largest negative deviation from weighted average 7" circular aperture
H magnitude among all extractions in the group, scaled by the
photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Hband aperture measurements in the group. 
k_mndev_7  %10.4e  mag  yes  Largest negative deviation from weighted average 7" circular aperture
H magnitude among all extractions in the group, scaled by the
photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable K_{s}band aperture measurements in the group. 
j_mxdev_7  %10.4e  mag  yes  Largest positive deviation from weighted average 7" circular aperture
J magnitude among all extractions in the group, scaled by the
photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Jband aperture measurements in the group. 
h_mxdev_7  %10.4e  mag  yes  Largest positive deviation from weighted average 7" circular aperture
H magnitude among all extractions in the group, scaled by the
photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Hband aperture measurements in the group. 
k_mxdev_7  %10.4e  mag  yes  Largest positive deviation from weighted average 7" circular aperture
K_{s} magnitude among all extractions in the group, scaled by the
photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable K_{s}band aperture measurements in the group. 
j_mchisq_k20fe  %6.2f    yes  Chisquared statistic for the distribution of selected Jband "k20fe"
isophotal fiducial elliptical magnitudes and uncertainties in the merged group.
This column is null if there are fewer than 2 usable Jband aperture measurements in the group. 
h_mchisq_k20fe  %6.2f    yes  Chisquared statistic for the distribution of selected Hband "k20fe"
isophotal fiducial elliptical magnitudes and uncertainties in the merged group.
This column is null if there are fewer than 2 usable Hband aperture measurements in the group. 
k_mchisq_k20fe  %6.2f    yes  Chisquared statistic for the distribution of selected K_{s}band "k20fe"
isophotal fiducial elliptical magnitudes and uncertainties in the merged group.
This column is null if there are fewer than 2 usable K_{s}band aperture measurements in the group. 
j_mndev_k20fe  %10.4e  mag  yes  Largest negative deviation from weighted average "k20fe" isophotal
fiducial elliptical J magnitude among all extractions in the group, scaled
by the photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Jband isophotal measurements in the group. 
h_mndev_k20fe  %10.4e  mag  yes  Largest negative deviation from weighted average "k20fe" isophotal
fiducial elliptical H magnitude among all extractions in the group, scaled
by the photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Hband isophotal measurements in the group. 
k_mndev_k20fe  %10.4e  mag  yes  Largest negative deviation from weighted average "k20fe" isophotal
fiducial elliptical K_{s} magnitude among all extractions in the group, scaled
by the photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable K_{s}band isophotal measurements in the group. 
j_mxdev_k20fe  %10.4e  mag  yes  Largest positive deviation from weighted average "k20fe" isophotal
fiducial elliptical J magnitude among all extractions in the group, scaled
by the photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Jband isophotal measurements in the group. 
h_mxdev_k20fe  %10.4e  mag  yes  Largest positive deviation from weighted average "k20fe" isophotal
fiducial elliptical H magnitude among all extractions in the group, scaled
by the photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable Hband isophotal measurements in the group. 
k_mxdev_k20fe  %10.4e  mag  yes  Largest positive deviation from weighted average "k20fe" isophotal
fiducial elliptical K_{s} magnitude among all extractions in the group, scaled
by the photometric uncertainty of the extraction.
This column is null if there are fewer than 2 usable K_{s}band isophotal measurements in the group. 
Shape Information  
r_k20fe_avg  %6.1f  arcsec  yes  Average value of the 20 mag/arcsec^{2} K_{s} elliptical isophote semimajor axis (r_k20fe) for the merged group. Individual extractions were used in the computation of the mean size only if their semimajor axis (r_k20fe), axis ratio (k_ba) and major axis position angle (k_phi) values are not null. 
k_ba_avg  %5.3f    yes  Average value of the 20 mag/arcsec^{2} K_{s} elliptical isophote axial ratio (k_ba) for the merged group. Individual extractions were used in the computation of the mean size only if their semimajor axis (r_k20fe), axis ratio (k_ba) and major axis position angle (k_phi) values are not null. 
k_phi_avg  %3d  deg  yes  Average value of the 20 mag/arcsec^{2} K_{s} elliptical isophote semimajor axis position angle (k_phi) for the merged group. Individual extractions were used in the computation of the mean size only if their semimajor axis (r_k20fe), axis ratio (k_ba) and major axis position angle (k_phi) values are not null. 
k_n_shape  %4d    yes  Number of extractions with valid shape parameters contributing to the average size, axial ratio and position angle computations. 
r_k20fe_rms  %10.4e  arcsec  yes  Standard deviation of the mean 20 mag/arcsec^{2} K_{s} elliptical isophote. 
k_ba_rms  %10.4e    yes  Standard deviation of the mean 20 mag/arcsec^{2} K_{s} elliptical isophote axial ratio. 
k_phi_rms  %10.4e  deg  yes  Standard deviation of the mean 20 mag/arcsec^{2} K_{s} elliptical isophote major axis position angle. 
sup_ba_avg  %5.3f    yes  Average value of the (J+H+K_{s}) "supercoadd" elliptical isophote axial ratio (k_ba) for the merged group. Individual extractions were used in the computation of the mean size only if their semimajor axis (sup_r_3sig), axis ratio (sup_ba) and major axis position angle (sup_phi) values are not null. 
sup_phi_avg  %3d  deg  yes  Average value of the (J+H+K_{s}) "supercoadd" elliptical isophote major axis position angle (k_phi) for the merged group. Individual extractions were used in the computation of the mean size only if their semimajor axis (sup_r_3sig), axis ratio (sup_ba) and major axis position angle (sup_phi) values are not null. 
sup_n_shape  %4d    no  Number of extractions with valid shape parameters contributing to the average "supercoadd" size, axial ratio and position angle computations. 
sup_ba_rms  %10.4e    yes  Standard deviation of the mean "supercoadd" elliptical isophote axial ratio. 
sup_phi_rms  %10.4e  deg  yes  Standard deviation of the mean "supercoadd" elliptical isophote major axis position angle. 
Quality Information  
n_dist  %4d    no  Number of extractions in the group that lie within 15" of a scan edge. 
rel_avg  %c    no  Average reliability score for all extractions in the group. This is computed by converting the reliability score (rel) to an integer between 1 and 5 (rel=F and A, respectively), averaging the integers, and converting back into a letter score. Averages with fractional parts >0.5 were rounded up to the nearest integer, otherwise they were rounded down. 
[Last Updated: 2006 September 28; by S. Wheelock & R. Cutri]
Back to A6.3
Return to Explanatory Supplement TOC Page.