In this tutorial, we will discuss how to extract lightcurves from LAXPC data using the LAXPC software with syntax command:
laxpc_make_lightcurve -p pcu -t timebin - u user_gti_file -e energy_define_file -l Layer_no level2.event.fits
Here,
-p flag is used for pcu. The default value is consider as all LAXPC units.
-t flag is for timebin of lightcurve in seconds. The default value is 1.0 seconds
-u flag is for usergti file. This flag is Optional.
-o flag is for output filename. Default output filename is lightcurve.
-e flag is for energy define file: File containing energy ranges. An example file is given. Default file name is ‘eneinput’. If file does not exist, default energy range chosen is a single lighcurve of 3-80 keV.
-l flag is used for Layer no. Which of the five Layers to be considered. Default is all. At this version only a single layer or all can be considered.
If the output root file is the default value of ‘lightcurve’ the following files will be produced:
lightcurve.txt: Ascii text File containing counts/sec with time for the desired energy bands.
lightcurve_Emin_EmaxkeV.lc: Here Emin and Emax are the input energy range.
Here we demonstrate how to extract lightcurve for a black hole X-ray binary source GRS 1915+105 using observation id G06_033T01_9000001116 for orbit 08120. If the flags mentioned above are not specified the values used for the parameters are default values.
$ laxpc_make_lightcurve -u usergti.fits level2.event.fits
Event file being used: level2.event.fits
User Time bin in seconds: 1.0000000000000000
PCUs being used: all
Output file name: lightcurve
User GTI file name: usergti.fits
Energy input filename: eneinput
extracting from all layers
start time integer stop time
No. of energy bins 1
total no of points in lC= 7833
0.0000000000000000 7832.0000000000000
User start and stop time
2315.0000000000000 4836.0000000000000
No. of segments: 7833 1
percentage read 100.000000
total no of points in lC= 7833
7832.0000000000000 7832.0000000000000
User start and stop time
No. of segments: 7833 7833
An output file lightcurve_3.0_80.0keV.lc will be created.
$ lcurve
lcurve 1.0 (xronos6.0)
Number of time series for this task[1]
Ser. 1 filename +options (or @file of filenames +options)[Bkg_Sub_3.0_50.0keV.lc] lightcurve_3.0_80.0keV.lc
Series 1 file 1:lightcurve_3.0_80.0keV.lc
WARNING: Defaulting to first FITS extension
Selected FITS extensions: 1 - RATE TABLE;
Source ............ GRS 1915+105 Start Time (d) .... 17841 15:56:33.482
FITS Extension .... 1 - `lightcurve` Stop Time (d) ..... 17841 17:17:08.482
No. of Rows ....... 2519 Bin Time (s) ...... 1.000
Right Ascension ... Internal time sys.. Converted to TJD
Declination ....... Experiment ........ ASTROSAT LAXPC3
Corrections applied: Vignetting - No ; Deadtime - No ; Bkgd - No ; Clock - No
Selected Columns: 1- Time; 2- Y-axis; 3- Y-error;
File contains binned data.
Name of the window file ('-' for default window)[-]
Expected Start ... 17841.66427641757 (days) 15:56:33:482 (h:m:s:ms)
Expected Stop .... 17841.72023706572 (days) 17:17: 8:482 (h:m:s:ms)
Minimum Newbin Time 1.0000000 (s)
for Maximum Newbin No.. 4835
Default Newbin Time is: 9.4544388 (s) (to have 1 Intv. of 512 Newbins)
Type INDEF to accept the default value
Newbin Time or negative rebinning[1]
Newbin Time ...... 1.0000000 (s)
Maximum Newbin No. 4835
Default Newbins per Interval are: 512
(giving 10 Intervals of 512 Newbins each)
Type INDEF to accept the default value
Number of Newbins/Interval[7207] 4835
Maximum of 1 Intvs. with 4835 Newbins of 1.00000 (s)
Name of output file[-]
Do you want to plot your results?[yes]
Enter PGPLOT device[/xw]
4835 analysis results per interval
WARNING: Defaulting to first FITS extension
100% completed
Intv 1 Start 17841 16:35:10
Ser.1 Avg 3360. Chisq 0.1143E+06 Var 0.1525E+06 Newbs. 2519
Min 2449. Max 4933. expVar 3360. Bins 2519
PLT> h lightcurve.ps/ps
PLT> exit