Header of QDP Output Files

QDP Output files created by XRONOS applications always start with a series of QDP/PLT commands; these are (see the QDP/PLT specifications):

 LA T ....... Contains some basic infos: source name, year of observ. + summary
              from 1st file of each series (e.g. instrument channel range etc.)
 LA OX ...... Contains start/stop times of analysed data (times refer to the
              center of the 1st and last good newbins)
 READ SERR .. Specifies which vectors in file have errors
 CO 1 ON .... Specifies which vectors will be plotted by default
 CO 0 ON .... Specifies which vectors will not be plotted by default
 VPORT ...... Specifies the QDP/PLT viewport
 CSIZE ...... Specifies the label character size
 LA Y1 ...... Describes the X-axis variable (i.e. vector number 1)
 LA Yn ...... Describes the Y-axis variable n-1 (i.e. vector number n)
              (n is not specified if only 1 Y-variable is plotted)

Then a number of lines starting with ! follow: these are regarded as comments by QDP/PLT but they contain useful infos obtained from XRONOS applications and some of them are read by XRONOS applications. Note that in the description below k is the number of input series used by the applications which creates the file.

 ! file ..... Specifies QDP output filename and XRONOS application used
 ! created .. Specifies file creation date and XRONOS version used
 ! iflags ... the 20 numbers in the following two lines starting with `!!0`
              are the INTEGER FLAGS used in analysis
 ! rflags ... the 10 numbers in the following two lines starting with `!!0`
              are the REAL FLAGS used in analysis
 !H ......... Describes the content of the XRONOS HEADER LINE
 !!H ........ XRONOS HEADER LINE
 !! new/int.. Describes the content of the INTEGER VARIABLES in the following
              k lines (lines containing the relevant variables start with
              `!!1`, `!!2` or `!!3`, respectively, for the 1st, 2nd and 3rd
              series)
 !! avg(c/s). Describes the content of some of the REAL VARIABLES in the
              following 2k lines (lines containing the relevant variables start
              with `!!1`, `!!2` or `!!3` and lines containing the errors of the
              corresponding variables start with `!E1`, `!E2` and `!E3`,
              respectively, for the 1st, 2nd and 3rd series).
 !! min(c/s). Describes the content of the other REAL VARIABLES in the
              following 2k lines (lines containing the relevant variables start
              with `!!1`, `!!2` or `!!3` and lines containing the errors of the
              corresponding variables start with `!E1`, `!E2` and `!E3`,
              respectively, for the 1st, 2nd and 3rd series).
 !! epoch ..  Describes the content of some of the DOUBLE PRECISION VARIABLES
              in the following k lines (lines containing the relevant variables
              start with `!!1`, `!!2` or `!!3`, respectively, for the 1st, 2nd
              and 3rd series)
 !! newb ...  Describes the content of the other DOUBLE PRECISION VARIABLES
              in the following k lines (lines containing the relevant variables
              start with `!!1`, `!!2` or `!!3`, respectively, for the 1st, 2nd
              and 3rd series)
 !! ........  Dummy line

Then all the lines containing vectors (in the QDP/PLT sense) follow. Gaps in the vector(s) are indicated by the (QDP/PLT) value =-1.2e-34. Note that in .qefs files two additional QDP/PLT label lines are written at the end of the file.

The DEV ... command (specifying the plot device), the PLOT VERT ... command (used only when more than one Y-variable is plotted by default), any additional plot options (specified from individual applications such as lc2, or through a .pco file) and the EXIT command (for automatic plotting) are written at the end of the file.

Note that errors on the Y-axis variables are evaluated from the standard deviation of the average (based on measured scatter), as opposed to (theoretical) error propagation, depending on the value of the 9th global parameter.

Integer Flags

Below is the meaning of each flag

1 - File type (currently =0) as in Xronos header line
2 - Units for time axis (0=secs from start, 1=secs from start of the hour 2=hour from start of the day, 3=days) as in Xronos Header Line
3 - Trend removal flag (0=none; 1,2,3,4= degree of polynomial removed)
4 - Mode for trend removal (1=Subtract; 2=Divide; 3=Replace)
5 - Total number of windows used in analysis
6 - Min. number of expected good intvs/frame to calculate scatter errors
7 - Analysis normalisation flag
8 - Number of result columns (Y-axis columns)
9 - Number of indep. variable columns (X-axis columns)
10 - Number of input series
11 - Max number of boxes/plot in QDP (exposure variable is not counted)
12 - Max number of frames expected
13 - Expected number of result bins after rebinning
14 - Requested number of analysis points before rebinning
15 - Max number of analysis points
16 - Simultaneousness flag
17 - Number of newbins used in running mean for filling in gaps
18-20 - Spare (=0)

Real Flags

Below is the meaning of each flag

1 - Rebinning constant (d/f=0, >0 linear reb., <0 geometr. reb. )
2 - Rescaling factor for results (d/f=1.)
3 - Additive constant for results (d/f=0.)
4 - Expected white noise level (only for power spectrum applications)
5-10 - Spare (=0)

Xronos Header Line

The Xronos header line starts with !!H and contains the following information

1 - Binning time (in secs) used in the analysis
2 - Start Time (in days) of the data analysed (this is the center time of the 1st newbin in frame independent of whether it was a good or a rejected newbin). For folding applications this is the epoch
3 - Stop Time (in days) of the data analysed (this is the center time of the last good newbin in frame
4 - Type of file: this is set =0 to indicate counts/s units (or any equivalent of that in input files)
5 - Unit of time axis: used only if the X-axis in the file is time (=0 in all other cases: =0 units are secs from the Start Time; =1 units are secs from the beginning of the hour specified in Start Time =2 units are hours from the beginning of the day specified in Start Time =3 units are days.

The XRONOS header line is used by XRONOS applications to reconstruct the timing information when QDP Output Files are used as input to XRONOS applications.

Integer Variables

 newb/int .... requested number of newbins in interval
 intv/frame .. requested number of intervals in frame (-1 means: frame=intv)
 good bins ... number of good bins analysed in frame
 good newb ... number of good newbins analysed in frame
 good intv ... number of good intervals in frame
 bin anal .... requested number of analysis bins before rebinning
 bin result... expected number of result bins after rebinning

Real Variables

Note that errors on the variables below are evaluated from the standard deviation of the average (based on measured scatter), as opposed to (theoretical) error propagation, depending on the value of the 9th global parameter. For some variables only the former errors are available. Averages are unweighted.

 avg(c/s) .... average count/s in frame (average of averages in intervals)
 frac.expos... fractional exposure in frame (from average of fractional
               exposures in intervals)(fractional exposure in interval =
               = ratio of good newbins to number of newbins/interval)
 variance .... variance in frame (average of variances in intervals)
 expec.var.... expected variance in frame (average of expected variances in
               intervals) (expected variance in interval is calculated from
               the error bars of the newbins)
 3rd moment... 3rd moment in frame (average of 3rd moments in intervals)
 min(c/s)..... minimum count/s in frame (error=0)
 max(c/s)..... maximum count/s in frame (error=0)
 excess var... excess variance in frame (average of excess variances in
               intervals)(excess variance in interval = variance-exp.var.)
 chi-square....chi-square in frame (average of chi-squares in intervals)
 rms variation rms fractional variation in frame (average of rms fractional
               variation in intervals)(rms fractional variation in interval
               = sqrt(excess var)/avg(c/s) )

Double Precision Variables

 epoch or 1st newb .... epoch used in folding or time center of first newbin
                        analysed (days)(=2nd number in Xronos header line)
 frme baryc.time ...... barycenter time of frame (average of barycenter time
                        of intervals)(days). To be used as `center` time of a
                        frame weighted for gaps, rejected data etc.
 period(s) ............ period (secs) in folding
 newb duration ........ newbin duration (secs)(=1st number in Xronos header
                        line)
 first good newb ...... center time of first good newbin in frame
 last good newb ....... center time of last good newbin in frame (=3rd number
                        in Xronos header line)

Next: Format of QDP Up: Output Files Previous: Output Files

Lorella Angelini
Thu 12 Oct 16:35:19 1995