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fold xray.xtiming


NAME · USAGE · DESCRIPTION · PARAMETERS · EXAMPLES · TIME_REQUIREMENTS
BUGS · SEE_ALSO

NAME

fold - Fold time data at a given period and compute the count rates.

USAGE

fold source_file background_file out_table fold_period bins

DESCRIPTION

Task FOLD superimposes a time series upon itself with respect to a specified period. It is useful in the analysis of data containing or suspected of containing periodic signals.

The precursor task is TIMSORT which selects and sorts the QPOE file in time order. TIMPRINT will display the output file and FLDPLOT will plot the data. Corrections are not yet being applied for Fractional Spatial Exposure.

PARAMETERS

source_file (auto string) = prompt = Input Source Timing File

Required input in time ordered QPOE format. The file is created by running TIMSORT on a specified source region. The file may be specified by supplying the rootname and a "_sti.qp" extension will be appended by the task before looking for the file. For example input "i6757" is interpreted as "i6757_sti.qp".

background_file = "NONE" prompt = Input Background Timing File

Optional input in time ordered QPOE format. The file is created by running TIMSORT on a specified background region. The file may be specified by supplying the rootname and a "_bti.qp" extension will be appended by the task before looking for the file. For example input "i6757" becomes "i6757_bti.qp". Enter "none" to skip this parameter.

out_table = prompt = root name for output file [root_fld.tab]

Required Output filename. The file is written in table format. The file may be specified by supplying the rootname and a "_ltc.tab" extension will be appended. For example input "i6757" becomes "i6757_ltc.tab". Each row in the table represents 1 bin of folded data. The column titles and definitions are as follows:

	ctrt ----------- count rate
	err ------------ count rate error
        exp ------------ exposure
	src ------------ source counts
        bkgd ----------- background counts
	net ------------ net counts (src - bkgd)
	neterr --------- net error

A table file header is also written. It consists of parameters copied from the input QPOE file and parameters recorded from running this task.
fold_period = prompt = Fold Period in Seconds

Period upon which to fold the data specified in seconds.

bins = prompt = Number of Bins

The number of data bins.

(pdot = 0.0) [double]

The period rate of change. When pdot = 0.0 the period is constant.

(save_two = yes) [boolean]

Write the fold output data to the table twice. This is useful as input into FLDPLOT so that the plot of the folded lightcurve shows the period plotted twice.

(display = 1) [int]

The display level. A few of the parameters and computed time intervals are displayed to the user for those who like to see that things are happening.

(clobber = no) [boolean]

Boolean flag specifying whether or not the table file can be overwritten if it already exists.

(get_gintvs = yes) [boolean]

Boolean flag specifying whether to filter the input events through the good time intervals stored in the QPOE file. It useful to turn this parameter off when analyzing lab data where good intervals are not applicable or in a file without the intervals.

(bk_norm_fact = 1.) [real]

Background Normalization factor. This is an extra fudge factor that can be used to adjust the ratio of source to background area.

EXAMPLES

Type `help timfilter` and `help timsort` for information concerning
input files.
1. Fold data in snr_sti.qp at a period of 3.49 seconds into 20 bins.

	xt> fold
	Input Source Timing File: snr_sti.qp
	Input Background Timing File (NONE):
	root name for output file [root_fld.tab]: .
	Fold Period in Seconds: 3.49
	Number of Bins: 20

	Creating Fold file : ./snr_fld.tab

2. Fold net of snr_sti.qp and snr_bit.qp data at a period of 3.49 seconds into 20 bins.

	xt> fold
	Input Source Timing File: snr_sti.qp	
	Input Background Timing File (NONE): snr_bti.qp
	root name for output file [root_fld.tab]: net
	Fold Period in Seconds: 3.49
	Number of Bins: 20

	Creating Fold file : ./net_fld.tab

3. Fold data in GTI#3 of snr_sti.qp at a period of 3.49 seconds into 16 bins. Set get_gintvs=no because we are using a time filter for the third GTI.
	xt> fold
	Input Source Timing File: snr_sti.qp[time=(79492987.0:79494011.0)]
	Input Background Timing File (NONE):
	root name for output file [root_fld.tab]: snr3
	Fold Period in Seconds: 3.49
	Number of Bins: 16
	
	Creating Fold file : snr3_fld.tab
	

TIME REQUIREMENTS

BUGS

No Corrections are being applied for Fractional Spatial Exposure.

SEE ALSO

Documentation on errors (help explain_errors ) for a description of the error calculations implemented in PROS.

Documentation on region filtering (help regions ) for a description of the spatial filter user interface.

Documentation on QPOE filtering (help qpoe ) for a description of the QPOE filter user interface.

Documentation on file extensions (help extensions ) for a description of PROS file extensions.

Documentation on coordinates (help coords ) for a description of PROS coordinate conventions.


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