On entering XRONOS the default user interface is Question/Answer; you can check that by typing cui (change user interface) and replying q to the question:
[2]Xronos> cui Current user interface is : question/answer Enter user interface (? to see list)=> q Current user interface is : question/answer
Now plot the light curve of file a2030.rbf (from the 42 s pulsar EXO2030+375) with application lc1 (this example is useful to learn how to use BINS, NEWBINS and INTERVALS). User's replies follow the => prompt; defaults are indicated in square brackets and allowed replies (where relevant) in curly brackets:
[3]Xronos> lc1
>>>> Program lc1 5-JUL-1992 19:15:07 Xronos vers. 3.00 Jul 92
Enter up to 50 input filenames and options for series 1 (or rtn)
lc1> Ser. 1 filename 1 +options[.rbf]=> a2030
Source ............EXO 2030+40 + Start Time ........1985 302 15:59: 4
Bin Time (s) ...... 1.000 Stop Time ........1985 302 16:11:20
No. of Points ..... 743 Experiment ........ EXOSAT ME
Instrum., OBC rec.. AR , E5 Detectors on Source 5- 8
PHA Bin range ..... 2- 16 Detectors on Bkgd.. 1- 4
lc1> Ser. 1 filename 2 +options[.rbf]=>
lc1 displays a summary of the header information of the file, including the
BIN duration, and prompts for another filename; a carriage return implies that
no other file is specified. Carry on entering carriage returns in response to
the other questions, in order to use default values:
lc1> Window Options ? {y/n}[n]=>
0 Time, 0 Phase, 0 Intensity, 2 Exposure Windows
Expected Start ... 302.66604129903 (days) 15:59: 5:968 (h:m:s:ms)
Expected Stop .... 302.67464446032 (days) 16:11:29:281 (h:m:s:ms)
Minimum Newbin Time 1.0000000 (s)
Maximum Newbin No.. 744
Default Newbin Time 1.4534868 (s) (to have 1 Intv. of 512 Newbins)
lc1 displays the expected start and stop times of the series to be analysed
and the minimum newbin time which can be used in the analysis. In the example
above, since only one input file is used, this corresponds to the duration of
the BINS in the input file (i.e. 1 s). (If there were more than one input
files, the minimum newbin time would be the longest BIN duration of all input
files). The maximum number of expected newbins corresponds to the minimum
newbin time. The default NEWBIN time is chosen so as to produce a single light
curve (i.e.the light curve from a single interval) of 512 points.
Note that in the case of lc1 the NEWBIN time need not be a multiple of the
minimum newbin time. lc1 then prompts the user for the duration of the
NEWBINS to be used in the light curve:
lc1> Enter Newbin Time(s) or neg. rebinning
of Min. Newbin Time [ 1.453 ]=>
Newbin Time ...... 1.4534868 (s)
Maximum Newbin No. 512 (or 1 Intvs. of 512 Newbins)
A single INTERVAL containing a maximum of 512 newbin is thus expected. lc1
then prompts for the number of NEWBINS which define an INTERVAL (the default
is to have intervals of 512 newbins at most):
lc1> No. of Newbins/Intv. (max: 65536)
{value or neg.pow.of 2}[ 512]=>
Maximum of 1 Intvs. with 512 Newbins of 1.45349 (s)
lc1> Order of polynomial trend removal
{0=none,1=1st,....,4=4th}[0]=>
lc1> Time axis units
{0=s from start,1=s,2=h,3=d} [1]=>
lc1> Enter output filename
[xronos.qlc1 ]=>
lc1> Plot options ? {n/y}[n]=>
Intv 1 Start 302 15:59: 6
Ser.1 Avg 42.83 Chisq 3685. Var 329.1 Newbs. 511
Min -7.916 Max 117.1 expVar 49.47 Bins 743
Light curve ready !
Frme 1 Written to output file : xronos.qlc1
lc1 produces a summary of statistical quantities relevant to the interval,
writes the light curve to file xronos.qlc1 and automatically plots it by
using QDP/PLT:
Plot done ! >>>> Program lc1 5-JUL-1992 19:16:29 Normal termination [4]Xronos>lc1 terminates and the XRONOS prompt is issued again.
Repeat the procedure above, this time by using a NEWBIN time of 2 s and INTERVALS of 100 newbins (i.e. 200 s):
lc1> Enter Newbin Time(s) or neg. rebinning
of Minimum Bin Time [ 1.453 ]=> 2.
Newbin Time ...... 2.0000000 (s)
Maximum Newbin No. 372 (or 1 Intvs. of 372 Newbins)
lc1> No. of Newbins/Intv. (max: 65536)
{value or neg.pow.of 2}[ 372]=> 100
Maximum of 4 Intvs. with 100 Newbins of 2.00000 (s)
lc1 now produces 4 subsequent intervals containing 100 newbins at maximum:
for each of them a summary of the statistical quantities is output and a light
curve file written and plotted automatically by QDP/PLT:
Intv 1 Start 302 15:59: 6
Ser.1 Avg 43.54 Chisq 931.5 Var 310.3 Newbs. 100
Min -2.285 Max 100.2 expVar 33.31 Bins 200
Light curve ready !
Frme 1 Written to output file : xronos.qlc1
Plot done !
Intv 2 Start 302 16: 2:26
Ser.1 Avg 42.78 Chisq 1171. Var 369.0 Newbs. 100
Min 12.92 Max 116.0 expVar 31.51 Bins 200
Light curve ready !
Frme 2 Written to output file : xronos.qlc1
Plot done !
Intv 3 Start 302 16: 5:46
Ser.1 Avg 48.18 Chisq 810.5 Var 280.2 Newbs. 100
Min 19.68 Max 96.27 expVar 34.58 Bins 200
Light curve ready !
Frme 3 Written to output file : xronos.qlc1
Plot done !
Intv 4 Start 302 16: 9: 6
Ser.1 Avg 34.69 Chisq 375.6 Var 142.1 Newbs. 72
Min 9.541 Max 66.42 expVar 27.51 Bins 143
Light curve ready !
Frme 4 Written to output file : xronos.qlc1
Plot done !
>>>> Program lc1 6-JUL-1992 16:40:15 Normal termination
In order to leave QDP/PLT in the interactive plotting mode (PLT> prompt)
after each plot and allow customisation, reply as follows to the relevant
questions:
lc1> Plot options ? {n/y}[n]=> y
lc1> Plot results ? {y/n}[y]=>
lc1> Interactive or automatic? {i/a}[i]=> i
lc1> Pgplot device [/vt125 ]=>
lc1> Specify QDP command file? {y/n}[n]=>
To get on line help about QDP/PLT, enter help from the PLT> prompt. QDP/PLT
is terminated by exit or quit.
Now calculate the power spectrum of file c2030.rbf with application psd (this example is useful to learn how to use also FRAMES). Defaults are used after the input filename:
[5]Xronos> psd
>>>> Program psd 6-JUL-1992 18:32:27 Xronos vers. 3.00 Jul 92
Enter up to 50 input filenames and options for series 1 (or rtn)
psd> Ser. 1 filename 1 +options[.rbf]=> c2030
Source ............EXO 2030+40 + Start Time ........1985 302 15:59: 4
Bin Time (s) ...... 1.000 Stop Time ........1985 302 16:11:20
No. of Points ..... 743 Experiment ........ EXOSAT ME
Instrum., OBC rec.. AR , E5 Detectors on Source 5- 8
PHA Bin range ..... 2- 36 Detectors on Bkgd.. 1- 4
psd> Ser. 1 filename 2 +options[.rbf]=>
psd> Window Options ? {y/n}[n]=>
0 Time, 0 Phase, 0 Intensity, 3 Exposure Windows
Expected Start ... 302.66604129903 (days) 15:59: 5:968 (h:m:s:ms)
Expected Stop .... 302.67464446032 (days) 16:11:29:281 (h:m:s:ms)
Minimum Newbin Time 1.0000000 (s)
Maximum Newbin No.. 744
Default Newbin Time 1.0000000 (s) (to have 1 Intv. of 1024 Newbins)
++++ Warning: Newbin Time must be an integer multiple of Minimum Newbin Time
Note the difference with respect to the case of lc1: the NEWBIN time must be
an integer multiple of the minimum newbin time (this is in order to avoid
beats between the bin and newbin times). Moreover the default NEWBIN time in
psd is such as to produce a single interval of 4096 newbins at most. psd
uses an FFT algorithm and the number of newbins in an interval must be a power
of 2.
psd> Enter Newbin Time (s) or neg.rebinning
of Min. Newbin Time [ 1.000 ]=>
Newbin Time ...... 1.0000000 (s)
Maximum Newbin No. 744 (or 1 Intvs. of 1024 Newbins)
psd> No. of Newbins/Intv. (max: 65536)
(it must be a power of 2)
{value or neg.pow.of 2}[ 1024]=>
Maximum of 1 Intvs. with 1024 Newbins of 1.00000 (s)
Only one INTERVAL of 1024 NEWBINS is expected, the power spectrum of which
will be calculated. This will consist of 512 independent Fourier frequencies,
i.e. 512 analysis results. Since there is only one INTERVAL, there will be
only one FRAME containing the results from that interval:
psd> No. of Intvs per Frame [ 1]=>
psd> Rebin results ? {>1= const. rebin,
<-1= geom. reb, 0= no reb}[ 0.00]=>
Results from up to 1 Intvs. will be averaged in a Frame
psd> Order of polynomial trend removal
{0=none,1=1st,....,4=4th}[0]=>
psd> Enter output filename
[xronos.qpsd ]=>
psd> Plot options ? {n/y}[n]=>
512 analysis results per interval
Intv 1 Start 302 15:59: 5
Ser.1 Avg 78.43 Chisq 7342. Var 1243. Newbs. 743
Min -2.481 Max 298.2 expVar 125.7 Bins 743
Power spectrum ready !
Frme 1 Written to output file : xronos.qpsd
Plot done !
The power spectrum is calculated, written to file xronos.qpsd and plotted
automatically with QDP/PLT. Then psd terminates
>>>> Program psd 6-JUL-1992 18:33:08 Normal termination [6]Xronos>Repeat the example above by using a NEWBIN time of 3 s and INTERVALS of 64 newbins (i.e. 192 s):
psd> Enter Newbin Time (s) or neg.rebinning
of Min. Newbin Time [ 1.000 ]=> 3.
Newbin Time ...... 3.0000000 (s)
Maximum Newbin No. 248 (or 1 Intvs. of 256 Newbins)
psd> No. of Newbins/Intv. (max: 65536)
(it must be a power of 2)
{value or neg.pow.of 2}[ 256]=> 64
Maximum of 4 Intvs. with 64 Newbins of 3.00000 (s)
In this case up to 4 INTERVALS of 64 NEWBINS are expected. The default is to
calculate the power spectrum for each interval (32 independent Fourier
frequencies) and average the 4 power spectra to produce the power spectrum of a
FRAME (i.e. the default is again to produce a single frame):
psd> No. of Intvs per Frame [ 4]=>
psd> Rebin results ? {>1= const. rebin,
<-1= geom. reb, 0= no reb}[ 0.00]=>
Results from up to 4 Intvs. will be averaged in a Frame
The average spectrum from the 4 intervals is written to file xronos.qpsd and
plotted automatically with QDP/PLT.
Repeat the same example, but produce a power spectrum for each interval (i.e. each FRAME will consist of 1 INTERVAL only):
psd> No. of Intvs per Frame [ 4]=> 1
psd> Rebin results ? {>1= const. rebin,
<-1= geom. reb, 0= no reb}[ 0.00]=>
Results from up to 1 Intvs. will be averaged in a Frame
4 power spectra will be produced and plotted.
Repeat the same example, but produce this time an average power spectrum for each group of two INTERVALS (i.e. each FRAME will consist of two INTERVALS):
psd> No. of Intvs per Frame [ 4]=> 2
psd> Rebin results ? {>1= const. rebin,
<-1= geom. reb, 0= no reb}[ 0.00]=>
Results from up to 2 Intvs. will be averaged in a Frame
2 power spectra will be produced and plotted.
psd and many other XRONOS applications include a facility to rebin the results of the analysis. To see the way this is done consider again the first psd example above: a single spectrum of 512 independent Fourier frequencies is produced. In order to artificially decrease the Fourier resolution by a factor of four and obtain a power spectrum with 128 frequencies (i.e. rebin the results by four) reply:
psd> Rebin results ? {>1= const. rebin,
<-1= geom. reb, 0= no reb}[ 0.00]=> 4
Results from up to 1 Intvs. will be averaged in a Frame
Results will be rebinned by a factor of 4.01
There is also a way of rebinning a power spectrum in a ``differential" way in
which frequency bins are nearly equispaced in a log-frequency representation
(useful for studying continuum power spectrum components): this is done by
specifying a negative number (usually from -1.1 to -1.4) whose modulus
represents the step of the geometric series used to work out the rebinning
factor, step by step. To do this reply:
psd> Rebin results ? {>1= const. rebin,
<-1= geom. reb, 0= no reb}[ 0.00]=> -1.2
Results from up to 1 Intvs. will be averaged in a Frame
Results will be rebinned geometrically with a series of step 1.20
In this case the power spectrum is rebinned to 25 frequency bins; note the
spectrum is now plotted automatically in a log-log scale.
Now plot the soft and hard light curves of the 42 s pulsar EXO2030+375 and their ratio: the corresponding files are a2030.rbf and b2030.rbf. This is done with application lc2 (this example is useful to learn how to use different SERIES): user's replies follow the => prompt:
[7]Xronos> lc2
>>>> Program lc2 7-JUL-1992 11:19:27 Xronos vers. 3.00 Jul 92
Enter up to 50 input filenames and options for series 1 (or rtn)
lc2> Ser. 1 filename 1 +options[.rbf]=> a2030
Source ............EXO 2030+40 + Start Time ........1985 302 15:59: 4
Bin Time (s) ...... 1.000 Stop Time ........1985 302 16:11:20
No. of Points ..... 743 Experiment ........ EXOSAT ME
Instrum., OBC rec.. AR , E5 Detectors on Source 5- 8
PHA Bin range ..... 2- 16 Detectors on Bkgd.. 1- 4
SERIES 1 is the soft series: after entering a2030 press carriage return to
indicate that there are no other input files for series 1:
lc2> Ser. 1 filename 2 +options[.rbf]=>lc2 then prompts for the 1st input file of SERIES 2 (the hard series)
Enter up to 50 input filenames and options for series 2 (or rtn) lc2> Ser. 2 filename 1 +options[.rbf]=> b2030 Source ............EXO 2030+40 + Start Time ........1985 302 15:59: 4 Bin Time (s) ...... 1.000 Stop Time ........1985 302 16:11:20 No. of Points ..... 743 Experiment ........ EXOSAT ME Instrum., OBC rec.. AR , E5 Detectors on Source 5- 8 PHA Bin range ..... 17- 36 Detectors on Bkgd.. 1- 4 lc2> Ser. 2 filename 2 +options[.rbf]=>After entering b2030 press carriage return to indicate that there are no other input files for series 2. From this point onwards the example closely parallels the first example given for lc1 except for the additional plot options (see below) and the summary of statistical information of each interval which, in the case of lc2, is given separately for the two series:
Intv 1 Start 302 15:59: 6
Ser.1 Avg 42.83 Chisq 3685. Var 329.1 Newbs. 511
Min -7.916 Max 117.1 expVar 49.47 Bins 743
Ser.2 Avg 35.58 Chisq 3182. Var 283.1 Newbs. 511
Min-0.1958 Max 106.8 expVar 48.55 Bins 743
Light curves ready !
Frme 1 Written to output file : xronos.qlc2
Plot done !
>>>> Program lc2 7-JUL-1992 11:22:11 Normal termination
The two light curves and their ratio are written to file xronos.qlc2, and
plotted automatically vs. time with QDP/PLT. Then lc2 terminates and the
XRONOS prompt is issued again.
In order to leave QDP/PLT in the interactive plotting mode (PLT> prompt) and plot the hardness ratio of the two light curves vs. the sum of the two light curves reply as follows to the relevant questions:
lc2> Plot options ? {n/y}[n]=> y
lc2> Plot results ? {y/n}[y]=>
lc2> Interactive or automatic? {i/a}[i]=> i
lc2> Pgplot device [/vt125 ]=>
lc2> Specify QDP command file? {y/n}[n]=>
lc2> Hardness vs. intensity ? {n/y}[n]=> y
lc2> Series 1, 2 or sum on X-axis ?
{0,1,2} [sum=0]=>
In order to plot the sum of the light curves and their ratio vs. time in an
automatic fashion, reply as follows:
lc2> Plot options ? {n/y}[n]=> y
lc2> Plot results ? {y/n}[y]=>
lc2> Interactive or automatic? {i/a}[i]=> a
lc2> Pgplot device [/vt125 ]=>
lc2> Specify QDP command file? {y/n}[n]=>
lc2> Hardness vs. intensity ? {n/y}[n]=>
lc2> Plot only light curves ? {n/y}[n]=>
lc2> Plot hdns and summed l.c.?{n/y}[n]=> y