xselect includes a facility to select times based on the
values of some auxiliary quantities ie those not associated
with each event. Examples could be angle between the pointing
direction and the Earth's limb, some housekeeping parameter, or
the total counting rate. This information must reside in a FITS
file whose first extension is a BINTABLE with time column called
TIME. For ROSAT, the housekeeping information is stored in
the seq_anc.fits (the ancilliary file), the seq_anc.fits file does not,
however, store all the information in the most useful way for xselect
screening and users need to run PCFILT for PSPC data, or HRIFILT for
HRI data.
Using PCFILT as an example (HRIFILT is very similar):
The FTOOL PCFILT can be run prior to starting
an xselect session (or spawned from within xselect).
PCFILT will resample the housekeeping data and
calculate many useful parameters from the raw information contained in
seq_anc.fits, making the ROSAT equivalent of the ASCA makefilter file.
The output (makefilter) file should have a .rmkf extension for
xselect to pick it up automatically when it is required.
Example:
pcfilt
Please enter Ancillary filename[] rp700111_anc.fits
Please enter output filename[] rp700111.rmkf
Main PCFILT Ver 1.0.0
PCFILT ver 1.0.0 completed
The data is actually filtered within xselect as follows
xselect> select mkf
Boolean expression for filter file selection []
at this prompt give a selection expression. This expression can
be in either Fortran or C syntax. For instance, if you wanted all
times when OBI_NUM exceeded 1 then the expression would be ``OBI_NUM .gt.
1''. xselect will then calculate and store all time ranges for which
this is true. These time ranges will be used for any extractions
performed by xselect.
After running "select mkf", a "show status" command will show the filter; any data product extracted while this is in place will be filtered accordingly.
The makefilter file can be used to screen down the "standard events", ie those already screened by SASS, or to rescreen the total set of events. In the latter case, you first need to make a file of the total events, by summing the SASS selected events, and the rejected events, and generating a set of good time intervals which are applicable to this total dataset.
If you wish to bypass the SASS data screening, and do your own screening from the master set of events, you can do this for an RDF dataset by combining the rejected and good events, and calculating the full set of time intervals associated with these data
mk_allevt mk_allevt 0.2.0: Type 'mk_allevt -h' for instructions. *** File: "" is illegal for output You have the following likely looking file groups: 1 rh110267n00 2 rh701446n00 3 rh701447n00 4 rp110590n00 5 rp110231n00 Type corresponding number to select a set of files. Or type a specific file or pathname. Output (abas) Filename: 5
will combine the RDF rejected and good events into a single events
extension in a new file (by default this will be named
rp110231n00_abas.fits in this example). This new
file can be analyzed in xselect as normal.
If you have screened your events file, then you may wish to save the screened events for later analysis, first you must extract the events under all desired filters
xselect> extract events
xselect> save events good.events
After the second command you will be asked whether you want to read
this data back in. If you answer yes then xselect uses the file which
you just created rather than the original data files.
Creates an exposure map for user specified time period and energy range for
any US Rev0 or RDF format ROSAT datasets
EXAMPLE - To exposure correct a PSPC image:
burst.
pcexpmap will pick up the correct GTIs from this file
for use in creating the exposure map.
farith to perform the division of image by exposure map
pcexpmap
To use pcexpmap the detector maps created from the
ROSAT All-Sky Survey data are required.
These may be obtained from the /caldb/data/rosat/pspc/cpf/detmaps/
directory on heasarc.gsfc.nasa.gov. The detector maps are available in a
number of energy bands, and the filenames contain the PI channel ranges
used, where channel 11 is 
keV, channel 200 is 
2 keV
etc. The detector maps currently available have the following rootnames
(one map each for PSPCB and PSPCC):
det_11_19 det_20_41 det_42_131 det_132_201 det_42_201 det_42_51 det_52_69 det_52_90 det_70_90 det_8_19 det_8_41 det_91_131 det_91_201
The output from pcexpmap is a 512x512
FITS image of the whole PSPC field of view (with pixels 14.94733
arcsec per side; representing a blocking factor of 16 over the raw
[0.9341875 arcsec] pixelsize) of the effective exposure time (in
seconds) at that position. The effects of vignetting (for a
spectrum equal to the mean spectrum of the X-ray background in the
PSPC band) and spatial variations in the efficiency of the detector
are included (via the detector maps), along with detector deadtime
effects (applied by pcexpmap).
The program follows the suggestions of Snowden et al. (1992, ApJ, 393 819) and Plucinsky et al. (1993, ApJ, 418, 519) to exclude regions of the PSPC near the edges of the PSPC which are strongly affected by the particle background, the "bright line" regions. These regions are set to have zero exposure time.
In brief, the attitude and GTI files are used to construct a matrix of the time the instrument spent at each pointing position (X,Y relative to the nominal pointing position defined by the optical axis) and roll angle. (The X,Y are in units of 14.94733 arcsec for historical reasons, the ROLL steps are in units of 0.2076 degrees.) The event-rates file is then used to calculate the live-time fraction at each of these positions. Finally the output exposure map is constructed by moving the detector map to each off-axis position, rotated to each roll angle, and adding the detector map with the appropriate weighting factor to the exposure map under construction.
In the following example, the user removes afterpulse events, creates and
image and exposure map, and corrects the image using farith.
Example:
burst
Name of FITS file and [ext][] rp100000n00_bas.fits[2]
Name of output FITS file[burst.out]
Maximum time between events in seconds[0.003]
Whether to keep first event in burst[yes]
Within xselect, extract an image
xselect> set xybinsize 30
to match the resolution of the detector maps
xselect> extract image phalcut=52 phahcut=90
extract our image in the
keV band
xselect> save image image_52_90.fits
pcexpmap
Enter Event rate filename[]rp100000n00_anc.fits
Enter Attitude filename[] rp100000n00_anc.fits
Enter GTI filename[] rp100000n00_bas.fits
Enter Detector map file[] det_52_90_b.fits
Enter output filename[] expmap_52_90.fits
Enter Instrument/Detector name[PSPCB]
MAIN : PCEXPMAP Ver 2.0.1
... Number of unique detector positions 378
... Number of entries when Detector ON 9634
... Number of entries when Detector OFF 0 (A1LL c/rate<10)
... Total ONTIME 9634.00000 s
... Total LIVETIME 9314.57227 s
... Average MV c/rate 111.51972 count/s
PCEXPMAP Ver 2.0.1 completed
farith
Name of Ist FITS file and [ext#][] image_52_90.fits
Name of 2nd FITS file and [ext#][]expmap_52_90.fits
Name of OUTFIL FITS file[] corrected_52_90.fits
Name of operation[Enter Operation ADD,SUB,DIV,MUL(or +,-,/,*)]/
Please see the online help files for pcexpmap and hriexpmap for more details.
Notes & Warnings:
pcexpmap. The exposure corrected image can then be
displayed using saoimage.
pcexpmap will soon be enhanced to generate the image for you
in the same energy band and
at the same spatial resolution as the template detector map.
burst can be run.
hriexpmap will be available soon
First the radil profile should be extracted from the events file using extrpsf
This caltools package task extracts a Radial Point-Spread Function (RPSF) dataset from an event file. An RPSF dataset consists of the number of counts per unit area as a function of radius (using series of concentric annulus). This is calculated using the X & Y (ie RA & dec) columns in the event file centered on a point defined by the user (in either RA & dec or pixel coordinates) for a user-defined number of annuli and outer-radius. If desired, the user can also specify the radius (within the outer radius) beyond which will be used to estimate the number of counts per unit area corresponding to the background. The user can also specify any of several prescriptions to be used to calculate the statistical errors associated with the RPSF data. The output psf file is FITS format, and can be directly compared to the theoretical psf model for the hri or pspc data as described below.
Notes & Warnings:
Then the data should be compared to the model, using the script calcrpsf
This routine is a multi-task wrapper for Radial Point Spread Function (RPSF)
which allows several common steps to be performed by a single script. This
task interfaces with radial profiles produced using either extrpsf or pros
(after conversion of the pros files to FITS format via STWFITS and ST2RPSF).
calcrpsf spawns:
st2rpsf - Reads stsdas.fitsio.stwfits radial profile and
converts to OGIP fits format. This step is ONLY required
if you are comparing PROS data to the model. If using extrpsf
to extract the profile, please answer 'no' when asked if you
want to run st2rpsf
rbnrpsf - Rebins a radial PSF dataset (for example, to get 20
counts per radial bin)
pcrpsf - Calculates a theoretical radial PSF
for the ROSAT PSPC
OR
hrirpsf - Calculates a theoretical radial PSF
for the ROSAT HRI
rpsfqdp - Converts OGIP format radial profile file to
ASCII QDP
The user is prompted as to which of these tasks are desired,
the ftool rpsf2eef is also available, which
converts a radial PSF (RPSF) dataset to a radial
encircled energy function (REEF) dataset. The REEF file can be
converted to qdp using rpsfqdp, in the same way the RPSF file can.
calcrpsf
** CALCRPSF 1.3.0
Input filename[temp] radial_profile.fits
Output filename[calcrpsf.out]
Run st2rspf ?[no]
Run rbnrpsf ?[yes]
Generate a theoretical RPSF dataset ?[no] yes
Run rpsfqdp ?[no] yes
Please enter Telescope name[ROSAT]
Please enter Instrument name[PSPCB]
Please enter Minimum PI channel for image[] 12
Please enter Maximum PI channel for image[] 200
Please enter background count rate (ct/pixel)[] 5e-4
Please enter PHA filename :[] NONE
Please enter Off Axis histogram filename :[%] NONE
Please enter RMF filename :[/caldb/data/rosat/pspc/cpf/matrices/pspcb_gain2_256.
rmf]
Please enter off_axis angle (arcmin) :[0.5]
** pcrpsf 3.0.1
** pcrpsf 3.0.1 completed successfully
*** spawning RPSFQDP to convert RPSF dataset to QDP:
rpsfqdp chatter=5 datafile="rpsfpred.tmp" outfile=xxx.calcrpsf
** rpsfqdp 3.0.1
** rpsfqdp 3.0.1 completed successfully
** CALCRPSF 1.3.1 Finished
The resulting file can now be plotted with QDP (if you skip rpsfqdp then
the resulting file can be plotted using fplot).
Notes & Warnings:
The ftool mathpha can be used to perform mathematical operations
on PHA files. The calculation can optionally be carried out units of
COUNTS or RATE, the user is advised to
carefully read the help which is available
before using this task.
Example:
mathpha
** MATHPHA 3.0.3
Expression to be evaluated[] spectrum1.pha / spectrum2.pha
Units algebraic expression to be performed in (C,R,F or ?)[C] ?
... This parameter indicates the physical units in
which the algebraic expression is to be evaluated,
and the units in which the output file will be written.
The allowed values are C (ie COUNTS), or R (ie RATE),
implying that the algebra will be performed in COUNTS
or COUNTS PER SECOND space respectively. The algebra
will be in this space irrespective of whether the input
files contain data stored in counts or in counts per
second (ie, if units=C, input PHA histograms stored in
counts per sec will be converted to counts prior to any
mathematical operations being performed). Similarly, this
flag gives the implied units of any numerical constants
within the input expression. A third option value is also
allowed, units=F (ie FILE) whereby the algebra is performed
in which ever units most of the files are stored in (COUNTS
in the event of a tie).
Units algebraic expression to be performed in (C,R,F or ?)[?] C
O/p PHA filename[] spectral.ratio
Exposure time flag/value ({value},{file},CALC,NULL or ?)[] ?
This parameter controls the value written as the exposure time in the
output file. The allowed values are:
{a numerical value}
- where the entered value (assuming it can be parsed as a real), is
written to the output dataset. The value will be assumed to be in
units of seconds. At the current time, numerals of the form 1E04
or 1E-04 are NOT supported.
{an input filename}
- whereby the exposure time read from the specified input file is
written to the output dataset
CALC
- where the exposure time is calculated from the input expression
by substituting each filename with its exposure time, and performing
the specified calculation.
NULL
- where an exposure of 1 second is written to the output dataset
Exposure time flag/value ({value},{file},CALC,NULL or ?)[] NULL
Number of comment strings to be added (up to 4)[1]
Comment 1[] This is a ratio of spectrum1.pha/spectrum2.pha
...... processing file: spectrum1.pha
...... processing file: spectrum2.pha
... performing algebra in units of COUNTS
** FILOP 2.0.0 WARNING:
... Poissonian errors with N<20 assumed for:
...... channels 1.- 7.
...... channels 201.- 201.
...... channels 205.- 208.
...... channels 210.- 213.
...... channels 216.- 256.
** FILOP 2.0.0 WARNING:
... Divide-by-zero encountered for:
...... channels 1.- 7.
...... channels 252.- 252.
...... channels 256.- 208.
... These channels have been set bad, and value DIVZERO inserted
... written the PHA data Extension
** MATHPHA 3.0.3 Finished
This made a ratio of two spectra, the user can plot the output file using FPLOT (use FSTRUCT and FLCOL to examine the file first, so you know what column names to give to FPLOT).
Particle background spectra are required for use in background
subtraction of extended sources, or in any case where the background must be
estimated using a significantly different part of the PSPC detector than
the region where the source data were taken. The sky X-rays have a
different radial dependance than the particle background, so simply
correcting the background spectrum for the different vignetting effect is
inadequate
pcparpha generates a 256-channel PHA spectrum of the particle
background in the ROSAT PSPC from the parameterization of Plucinsky
etal (1993 ApJ 418, 519)
Example:
pcparpha
** PCPARPHA 2.0.1
O/p PHA filename[particle_spectrum.pha]
EVR filename[rp100000.evr]
GTI filename[rp100000.fits] (the events file)
WMAP/Off-axis histogram filename[target.pha]
No. pixels in source region (or '%' or '?')[%] ?
... This parameter is the number of pixels for which the
particle background spectrum is to be calculated.
This information should also be in the Off-axis histogram
dataset. Enter "%" to use the stored values or enter
an integer to override the stored values. In the
latter case, you will be prompted for the pixel size next.
No. pixels in source region (or '%' or '?')[?] %
.... No. theta bins to process: 20
... No. EVR events to process: 323
theta weight (%)
...... finished theta bin 1 (1.5000 , 0.000000)
... written the PHA data Extension
** PCPARPHA 2.0.1 Finished