NAME

growthcurve -- Correct magnitudes using the growth curve for them

USAGE

growthcurve files naps small large

PARAMETERS

files

Input files. These files are the output from APPHOT.

naps

Number of apertures, from the APPHOT output, to use in the growth curve. This number does not have to be the same as the total number of apertures used by APPHOT. The actual number of apertures used will be the minimum between the value specified by naps and the number of apertures used by APPHOT.

small

Small aperture number. This is the number of the aperture having a small diameter. The magnitudes for this aperture will be corrected using the growth curve information.

large

Large aperture number. This is the number of the aperture having a large (or the largest) diameter. The correction to the magnitudes in the small aperture will be such that the average of the latter will match the average of the magnitudes in the large aperture.

function = "legendre"

The type of function with which to fit the data. Choices are legendre , chebyshev , spline1 (linear spline) or spline3 (cubic spline).

order = 8

The order of the fit or number of spline pieces.

interactive = yes

If interactive is set to yes , a plot of the growth curve fit is drawn, the cursor will be available for interactively examining or adjusting the fit, and the user will be prompted for the small and large aperture numbers for each file in the input list.

flist = ""

Used internally by the task.

DESCRIPTION

This is a CL script task that takes output files coming from the APPHOT package, computes a growth curve for the magnitudes determined by APPHOT, and finally corrects the magnitudes for a given aperture using the growth curve information.
The first step done by the script is to extract the magnitudes, for all the objects, from the first aperture to the last aperture specified by naps . Then, for each object, the task computes the difference in magnitude between one aperture and the next one. The differences are then piped to curfit in order to fit a curve to the data (growth curve). Once the fit is finished, the task takes the output from curfit , and sums all the differences, from the aperture specified by small to the aperture specified by large parameter. This sum is used to correct the magnitudes of all objects for the aperture specified by small .
There is one output file for each file in the input list. The output file name will be generated automatically from the input file name. If the input file name contains a ".mag." in its name, then the output file name will be the same as the input file name, but with the ".mag." replaced by a ".grw.". Otherwise the output file name will be the input file name with a".grw" suffix.
Each output file will contain the object id, the magnitude without correction (from APPHOT), the corrected magnitude value, and the magnitude error (from APPHOT).

EXAMPLES

BUGS

The task expects the apertures to be sorted, with the one having the smallest diameter first and the largest diameter at the end.
It is not possible to use any commands that generate output to the standard output when fitting interactively with CURFIT, since the output of CURFIT is internally redirected to a file.

SEE ALSO

apphot.apselect, utilities.curfit