This module allows you to select the columns to be written to the final extract table. The module also allows you to select which rows to write out, based on a range of conditions.
INPUT
Columns selection:
srcid: Extracted source number.
detid: Detected source number.
N_PS: Number of point sources needed to fit the data simultaneously. N_PS > 1 indicates passive or active de-blending.
RA: Right Ascension (deg) of source.
delta_RA: RA uncertainty.
Dec: Declination (deg) of source.
delta_Dec: Dec uncertainty.
delta_RAD: RA-Dec cross-term error determined from delta_xy.
x: x-coordinate of source in the mosaic (pixels).
delta_x: x-coordinate uncertainty.
y: y-coordinate of source in the mosaic (pixels).
delta_y: y-coordinate uncertainty.
delta_xy: x-y cross term of the error matrix.
flux: Flux of the point source. Units are specified in the header. Currently set to microJy.
delta_flux: Flux uncertainty from the fit. See also SNR below.
bckgrnd: Background estimate, constant in the fitting area. It is produced if Background_Fit = 1 is set in the Source Estimate GUI panel or namelist file (or -back is given on the command line).
chi2/dof: χ2 / dof (number of degrees of freedom) of the fit.
ps_chi2/dof: Partial χ2 / dof (number of degrees of freedom) of one point source in the fit. Different from the previous column for passive deblending. See below for the explanation of the difference between the two.
status: The fit is considered successful if χ2 / dof is lower than Chi2_Threshold.
Status Value
Meaning
-4
Initialization in Simplex failed.
-3
Number of degrees of freedom <=0. The reasons for "losing" pixels are bad pixels and point sources on the edge or even outside of the image.
-2
Fitting converged, i.e. the changes in χ2/dof were smaller than the limit set by MinumumFtol in the namelist.
-1
The maximum number of iterations Max_N_Iteration has been reached.
0
Fitting has not been performed.
1
Successful fitting; terminated because it converged, i.e. the changes in χ2/dof were smaller than the limit set by MinimumFtolSuccess in the namelist.
2
Successful fitting; terminated because the number of iterations exceeded the maximum Max_N_Success_Iteration.
SNR: The ratio of the estimated point-source flux to the noise in the fitting area. The default is the noise computed by the Gaussnoise module if present.
N_dof: The number of degrees of freedom, i.e. the number of pixels used in the fitting minus the number of the fitting parameters.
PRFPortion: The ratio of the sum of the PRF over the pixels used in the calculation to the total PRF.
depth: The number of input images used in fitting this point source.
deblend: Indicates whether passive or active de-blending has been performed.
Deblend Value
Meaning
N
No de-blending has been performed.
O
The point source is outside of the fitting area.
P
Passive de-blending has been performed.
A
Active de-blending has been performed.
There can be the following combination of the values above: N, NO, P, PO, A, AO, PA, PAO.
aperture#: N_apertures columns giving the aperture photometry.
bad_pix#: N_apertures columns giving unusable pixels of the aperture.
ap_unc#: N_apertures columns giving the uncertainty in the aperture flux. Bad value is "-9.99".
Condition Builder: Some simple selection ranges, such as > and <, can be added.
select_conditions = "SNR > 5" and "deblend ! NO and deblend ! PO and deblend ! AO and deblend ! PAO"
OUTPUT
Output Table (*_extract.tbl): The requested columns are written into the final extract table.
DISCUSSION
Some simple selection ranges, such as > and <, can be added in the namelists in the Condition Builder. For example one might choose to select only those sources with SNR > 5.0.
