Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/sas/8.0.0/doc/epnoisemap.ps.gz Дата изменения: Wed Jul 2 12:49:04 2008 Дата индексирования: Tue Oct 2 08:54:20 2012 Кодировка: Поисковые слова: 47 п п п п п п

XMM-Newton Science Analysis System Page: 1
epnoisemap
July 2, 2008
Abstract
This task makes a model image of the background due to PN double events (this
is greatest between 200 and 300 eV).
1 Instruments/Modes
Instrument Mode
PN Imaging
2 Use
pipeline processing yes
interactive analysis yes
3 Description
As in the abstract.
4 Parameters
This section documents the parameters recognized by this task (if any).
Parameter Mand Type Default Constraints
expcubeset yes dataset
Dataset which contains an exposure map cube. See the eexpchipmap task documentation for a descrip-
tion of the format of this le.
outputstyle no string sky sky|raw
If `sky', the noise map is output in sky coordinates, to the le referred to by parameter noiseimageset.
In this case a template set (templateset) is needed and the attstyle parameter is also read. If
xmmsas 20080701 1801-8.0.0

XMM-Newton Science Analysis System Page: 2
outputstyle=`raw' on the other hand the output is written to a cube (in the expcubeset format)
to the le pointed to by noisecubeset.
templateset yes dataset
This parameter is read if outputstyle=`sky'. This le should contain an image in the primary extension,
which is used to dene the pixel dimensions and World Coordinates of the output image.
noiseimageset no dataset noisemap.ds
An output image in sky coordinates is written to this le name if outputstyle=`sky'.
attstyle no string binnedset binnedset|template
This parameter is read if outputstyle=`sky'. To convert from chip to sky coordinates it is necessary to
know the spacecraft attitude. However the attitude is never completely stable and may vary signicantly
during an exposure. In this case the nett sky image must be a mosaic of components from dierent values
of the attitude. A time series of attitude values (such as that made either by attbin or evproject) can
be supplied to parameter binnedattset if attstyle is set to `binnedset'. If it is judged that the attitude
wander during the exposure did not exceed some small fraction of the image pixel dimensions, or if the
binned attitude set is not available, then the user may choose to set attstyle to `template' instead. In
this case a single xed value of attitude is read from * PNT keywords in the template image header.
binnedattset yes dataset
If attstyle=`binnedset' the user should supply to the present parameter the name of a dataset which
contains a time series of the spacecraft attitude variation during the exposure.
noisecubeset no dataset noisemapcube.ds
An output image cube in chip coordinates is written to this le name if outputstyle=`raw'.
selexprstyle no string userranges userranges|dss
Use of task epnoisemap implies that the user wishes to model the background component of a real
image. To do this properly it is necessary that the noise map and the image re ect the same selection of
events, because the PN noise varies markedly with event pattern and energy. It is therefore necessary to
provide details of the event selections used to construct the real image. Ideally the user should supply
these in the form of the Data Subspace (DSS) of the actual image by selecting selexprstyle=`dss' and
then supplying the le name of the image with the DSS to parameter dssset. However it has been found
convenient to also allow the user simply to choose to supply a set of energy ranges. This can be done by
selecting selexprstyle=`userranges' and then supplying lists of values to evlo and evhi. Note that in
this circumstance the assumption is made that the original image included double events.
evlo yes real list 0 I selexprstyle=`userranges', a set of lower energy bounds is read from this parameter. Note that evlo
and evhi must have the same (non-zero) number of elements; the elements of both parameters must
occur in increasing order; and no evlo value may be  than the respective evhi value.
evhi yes real list 0 I selexprstyle=`userranges', a set of upper energy bounds is read from this parameter. Note that evlo
and evhi must have the same (non-zero) number of elements; the elements of both parameters must
occur in increasing order; and no evlo value may be  than the respective evhi value.
dssset yes dataset
I selexprstyle=`dss', information about event selections is sought in a Data Subspace (DSS) of the
primary extension of this dataset.
xmmsas 20080701 1801-8.0.0

XMM-Newton Science Analysis System Page: 3
5 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.
dummy (error)
**********dummy
6 Input Files
1. (Mandatory) a dataset with an exposure cube (without vignetting) in the primary image
extension. The output of task eexpchipmap is suitable. A description of the cube format
can be found in the documentation of that task.
2. (Only mandatory if outputstyle=`sky') a FITS dataset, which contains an image in its
primary extension. The name of this dataset should be supplied to parameter templateset.
The output image (noiseimageset) is constructed so as to match templateset's pixel
dimensions and World Coordinates.
3. (Only mandatory if outputstyle=`sky' and attstyle=`binnedset') attbin output le, con-
taining a table ATT BINS with columns TSTOP, RA, DEC, PA and IS GOOD. The table should
also contain a TIMEZERO keyword.
4. (Only mandatory if dssstyle=`dss') A FITS dataset, the name of which should be supplied
to parameter dssset. The primary extension of this dataset should contain Data SubSpace
(DSS) information which describes any relevant event selections. Eg if you want to make a
background map to match the event selections used in the construction of an image, you will
probably want to supply this image to parameter dssset (provided that the image contains
the selection specication in the form of a DSS).
7 Output Files
 If outputstyle=`sky':
1. noiseimageset: an 2-byte-real-valued noise map, in sky coordinates, is contained in
the primary image extension.
This dataset contains the same keywords in the primary HDU as the template image, except
for DSS-related keywords. Extra extensions in the template image are not propagated.
 If outputstyle=`raw':
1. noisecubeset: a noise-map cube is contained in the primary image extension.
The format of this cube is described in the task documentation of eexpchipmap.
xmmsas 20080701 1801-8.0.0

XMM-Newton Science Analysis System Page: 4
8 Algorithm
**************Not yet written.
9 Comments
References
xmmsas 20080701 1801-8.0.0