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XMM-Newton Science Analysis System Page: 1
etimeget
March 18, 2004
Abstract
A procedure to generate source and background time series.
1 Instruments/Modes
Instrument Mode
EPIC IMAGING, TIMING
2 Use
pipeline processing yes
interactive analysis yes
3 Description
etimeget is a metatask which runs evselect to extract time series from an XMM-EPIC observation.
The essential input parameters are the name of the XMM events table and a selection expression for the
source and optionally background areas, e.g. srcexp="((DETX,DETY) IN circle(572,-635,1340))"
backexp="((DETX,DETY) IN circle(2572,-1635,1340))". The minimum selection required in the source
and background expressions is the spatial region, which may be specied in sky (X/Y) or detector
coordinates. Other selections are defaulted as shown in Table 1. These defaults may be further re-
stricted by including additional selections in the input expressions, e.g. srcexp="((DETX,DETY) IN
circle(572,-635,1340))&& PATTERN==0". NB: The source and background expressions should use the
same pattern and ag selections. The expressions must be compliant with the selectlib standard.
4 Time series binning
The bin width of the light curve is controlled by two input parameters timebinstyle and timebinwidth.
If timebinstyle is set to intrinsic then the light curve is binned at the frame time of the observation.
This may be overridden by setting timebinstyle=parameter in which case the bin width is taken from
the timebinwidth parameter, e.g. for a 10 second binning
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Table 1: Default event selections
Parameter Camera
MOS PN
PATTERN 0{12 0{4
FLAG XMMEA EM a 0
a The selection #XMMEA EM represents a conglomerate of ags; see evatt.
etimeget timebinstyle=parameter timebinwidth=10
For EPIC-pn observations the frame time is set using the observing mode and a look-up table (taken
from A&A, 365, L20). The relationship between frame time and observing mode is not constant for the
MOS and so the frame time is read from the keyword FRMTIME present in the EXPOSU extensions of
the event le.
4.1 Examples
4.1.1 A light curve with 10 second binning
etimeget filestem=myagn srcexp="((DETX,DETY) IN circle(572,-635,800))"
table=P0129360201M1S004MIEVLI0000.FIT timebinstyle=parameter timebinwidth=10
This command line produces the le myagn srcrate.lc and myagn bgdrate.lc
4.1.2 Setting the output lenames explicitly
The names of the output les may be set individually by:
etimeget srcexp="((DETX,DETY) IN circle(572,-635,800))"
table=P0129360201M1S004MIEVLI0000.FIT srcrateset='Mylightcurve.li"
bckrateset="Mybackgnd.li"
4.1.3 Using the intrinsic frame time as a bin width
etimeget filestem=myhmxb srcexp="((X,Y) IN circle(25572,-24635,1200))"
backexp="((X,Y) IN circle(23000,-28000,1340))"
table=P0129360201PNS020PIEVLI0000.FIT timebinstyle=intrinsic
This command will produce a source and background time series binned at the frame time of the obser-
vation, e.g. 0.07336 seconds for Full Frame EPIC-pn.
4.1.4 Dening the patterns and ags to use
etimeget filestem=myagn
srcexp="FLAG==0&&PATTERN==0&&((DETX,DETY) IN circle(572,-635,1340))"
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backexp="FLAG==0&&PATTERN==0&&((DETX,DETY) IN annulus(572,-635,1600,3000))"
table=P0129360201M1S004MIEVLI0000.FIT
This will create source and background light curves from events of pattern zero having FLAG=0. Restricting
the pattern range to 0 can be useful when the source is piled up.
4.1.5 Dening the spatial area with a region le
etimeget filestem=myagn srcexp="(region(src.reg,X,Y))"
backexp="(region(bck.reg,X,Y))"
table=P0129360201M1S004MIEVLI0000.FIT:EVENTS
A region le (e.g. created by the command regions or ds9) may be used to specify the spatial selection.
5 Parameters
This section documents the parameters recognized by this task (if any).
Parameter Mand Type Default Constraints
withlestem no boolean yes
Whether to specify the output le names using the filestem parameter.
lestem no string lcurve
Stem for the output lenames. A value "lcurve" will produce the les, lcurve srcrate.lc, lcurve bgdrate.lc
srcrateset no string srcrate.lc
Name of the output source light curve. This is only used if withfilestem is false in which case it becomes
mandatory.
bckrateset no string bckrate.lc
Name of the output background light curve. Only used if withfilestem is false in which case it becomes
mandatory.
srcexp yes string
Expression for extracting the source events.
backexp yes string
Expression for extracting the background events.
table yes table
specier
event list table speci-
er
A table specier which must point to an event list table in a data set. It must be in either of the forms
setname or setname:tableid where setname must be the name of an existing data set and tableid the
name of a table in the specied data set. If the rst form, setname, is used, the event data are sought in
the rst block of the named data set.
timebinstyle no string intrinsic intrinsic,parameter
How to dene the time bin widths. Set to "intrinsic" this tells the task to bin the light curve at the
resolution of the frame time. Set to "parameter" it tells the task to use the value in the parameter
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timebinwidth to dene the bin width.
timebinwidth no real 1.0
The bin width for the light curve in seconds. This is only used if timebinstyle=parameter.
6 Errors
This section documents warnings and errors generated by this task (if any). Note that warnings and
errors can also be generated in the SAS infrastructure libraries, in which case they would not be docu-
mented here. Refer to the index of all errors and warnings available in the HTML version of the SAS
documentation.
InvalidExpression (error)
The input expression for this spatial region was not valid.
InvalidTimebinstyle (error)
The parameter timebinstyle contains an unrecognised value
invalidInstrument (error)
The Epic camera description contained in the INSTRUME keyword isn't recognised
NoEventsTable (error)
The input table didn't contain an EVENTS extension
UnknownModeString (warning)
If the spectrum contains an observing mode (in the keyword SUBMODE) which is not
recognised then the software assumes that the common PrimeFullWindow mode was in use.
The observing mode is used to calculate the frame time for PN observations
corrective action:
7 Input Files
 an EPIC calibrated events list from the pipeline, the e*proc or e*chain tasks.
8 Output Files
 A source light curve of name filestem srcrate.lc or srcrateset
 A background light curve of name filestem bgdrate.lc or bckrateset
9 Algorithm
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set output filenames: src_rate, bck_rate
depending on values of and related params.
Create a source time series
expression = + PATTERN + FLAG selections
evselect table= expression=
withrateset=yes rateset=src_rate
Create a background time series
expression = + PATTERN + FLAG selections
evselect table= expression=......
withrateset=yes rateset=bck_rate
10 Comments
References
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