Up to top level
AO15   AO16   AO17   AO18   Backgrounds   Calibration   Conference   Data   Docs   EPICMOS   EPICpn   Feedback   Gallery   Misc   OM   Pending   PhD_Theses   Publications   RGS   RadMonitor   SAS_Hardware   SAS_WS   SASv16.0   SASv16.0_Installation   SASv16.1   SASv16.1_Installation   SASv17.0   SASv17.0_Installation   SASv18.0   SASv18.0_Installation   SciSim   Simulators_other   Suggestions   Trash   Visibility   XMM-bouncing   XMM-news   XRPS   XSA   esas   incoming  

Logged in as guest

Viewing SASv16.0/81932
Full headers

From: reham.m.ayoub@gmail.com
Subject: pipeline spectra
Compose reply
Download message
Move To:
2 replies: 1 2
2 followups: 1 2

Private message: yes  no

Notes:

Notification:


Date: Sun, 2 Jul 2017 21:49:27 GMT
From: reham.m.ayoub@gmail.com
To: xmmhelp@sciops.esa.int
CC: reham.m.ayoub@gmail.com
Subject: pipeline spectra
Full_Name: Reham Mostafa
Submission from: (NULL) (105.40.94.196)


I downloaded several pipeline spectra from 3XMM-DR4 and I wonder if all pipeline
spectra of 3XMM-DR4 are binned. And if that can I unbinned these spectra?


Reply 1

Resend
From: Jan-Uwe Ness <xmmhelp@sciops.esa.int>
To: reham.m.ayoub@gmail.com
Subject: Re: pipeline spectra (PR#81932)
Date: Mon Jul  3 06:51:35 2017
Dear Reham Mostafa,

 spectra are always binned there is no such thing as an unbinned spectrum. You
perhaps mean whether you can get spectra with a smaller bin size? The bin size
at which spectra are created is a choice that depends on various factors, e.g.,
the brightness of the source that determines how much light you will have in
each spectral channel. The instrument capabilities determine the minimum
possible bin size below which the instrument is not able to deliver more
information.

Rigorous binning to smallest bin sizes has to be done with care as some spectral
channels may end up containing zero counts with zero errors. Fitting a model
with standard chi^2 statistics crashes on such spectra because of dividing by
zero. All spectral channels have to contain at least 25 counts for chi^2
statistics to be valid. Spectra with smaller bin sizes that contain few counts
in at least one bin require usage of cash statistics, see, e.g., the xspec
manual for more information:
   https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/node293.html

The 3XMM-DR4 may not be binned at the smallest possible binsize for every
source, thus for very bright sources smaller bin sizes are under certain
circumstances possible. Unfortunately, the pipeline spectra cannot be rebinned
to smaller bin sizes as the information has already been lost during the
standard processing. To get higher-resolution spectra, you will need to process
them from scratch.

Best wishes,
Jan-Uwe


> I downloaded several pipeline spectra from 3XMM-DR4 and I wonder if all
pipeline
> spectra of 3XMM-DR4 are binned. And if that can I unbinned these spectra?

--
   Dr. Jan-Uwe Ness
   XMM-Newton User Support Group
   European Space Astronomy Centre


Followup 1

Compose reply
Download message
From: Reham Mostafa <reham.m.ayoub@gmail.com>
Date: Mon, 3 Jul 2017 11:24:14 +0400
Subject: Re: pipeline spectra (PR#81932)
To: "Pedro M. Rodriguez Pascual" <xmmhelp@sciops.esa.int>
--001a11401c30730f16055364a7bb
Content-Type: text/plain; charset="UTF-8"

Dear Dr.Jan-Uwe Ness,

Actually I want to model these spectra using cash statistics and so I have
to bin them to 1 count/bin. So should I first unbinned these spectra and
then binned to 1 count/bin?

Best regards,
Reham

On Jul 3, 2017 8:51 AM, "Jan-Uwe Ness" <xmmhelp@sciops.esa.int> wrote:

Dear Reham Mostafa,

 spectra are always binned there is no such thing as an unbinned spectrum.
You
perhaps mean whether you can get spectra with a smaller bin size? The bin
size
at which spectra are created is a choice that depends on various factors,
e.g.,
the brightness of the source that determines how much light you will have in
each spectral channel. The instrument capabilities determine the minimum
possible bin size below which the instrument is not able to deliver more
information.

Rigorous binning to smallest bin sizes has to be done with care as some
spectral
channels may end up containing zero counts with zero errors. Fitting a model
with standard chi^2 statistics crashes on such spectra because of dividing
by
zero. All spectral channels have to contain at least 25 counts for chi^2
statistics to be valid. Spectra with smaller bin sizes that contain few
counts
in at least one bin require usage of cash statistics, see, e.g., the xspec
manual for more information:
   https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/node293.html

The 3XMM-DR4 may not be binned at the smallest possible binsize for every
source, thus for very bright sources smaller bin sizes are under certain
circumstances possible. Unfortunately, the pipeline spectra cannot be
rebinned
to smaller bin sizes as the information has already been lost during the
standard processing. To get higher-resolution spectra, you will need to
process
them from scratch.

Best wishes,
Jan-Uwe


> I downloaded several pipeline spectra from 3XMM-DR4 and I wonder if all
pipeline
> spectra of 3XMM-DR4 are binned. And if that can I unbinned these spectra?

--
   Dr. Jan-Uwe Ness
   XMM-Newton User Support Group
   European Space Astronomy Centre

This message and any attachments are intended for the use of the addressee
or addressees only.
The unauthorised disclosure, use, dissemination or copying (either in whole
or in part) of its
content is not permitted.
If you received this message in error, please notify the sender and delete
it from your system.
Emails can be altered and their integrity cannot be guaranteed by the
sender.

Please consider the environment before printing this email.

--001a11401c30730f16055364a7bb
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"auto"><div>Dear Dr.Jan-Uwe Ness,</div><div
dir=3D"auto"><br></d=
iv><div dir=3D"auto">Actually I want to model these spectra using cash
stat=
istics and so I have to bin them to 1 count/bin. So should I first unbinned=
 these spectra and then binned to 1 count/bin?</div><div
dir=3D"auto"><br><=
/div><div dir=3D"auto">Best regards,</div><div
dir=3D"auto">Reham<br><div c=
lass=3D"gmail_extra" dir=3D"auto"><br><div
class=3D"gmail_quote">On Jul 3, =
2017 8:51 AM, &quot;Jan-Uwe Ness&quot; &lt;<a
href=3D"mailto:xmmhelp@sciops=
.esa.int" target=3D"_blank">xmmhelp@sciops.esa.int</a>&gt;
wrote:<br type=
=3D"attribution"><blockquote class=3D"m_-6704058771986245624quote"
style=3D=
"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Reham =
Mostafa,<br>
<br>
=C2=A0spectra are always binned there is no such thing as an unbinned spect=
rum. You<br>
perhaps mean whether you can get spectra with a smaller bin size? The bin s=
ize<br>
at which spectra are created is a choice that depends on various factors, e=
.g.,<br>
the brightness of the source that determines how much light you will have i=
n<br>
each spectral channel. The instrument capabilities determine the minimum<br=
>
possible bin size below which the instrument is not able to deliver more<br=
>
information.<br>
<br>
Rigorous binning to smallest bin sizes has to be done with care as some spe=
ctral<br>
channels may end up containing zero counts with zero errors. Fitting a mode=
l<br>
with standard chi^2 statistics crashes on such spectra because of dividing =
by<br>
zero. All spectral channels have to contain at least 25 counts for chi^2<br=
>
statistics to be valid. Spectra with smaller bin sizes that contain few cou=
nts<br>
in at least one bin require usage of cash statistics, see, e.g., the xspec<=
br>
manual for more information:<br>
=C2=A0 =C2=A0<a href=3D"https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/n=
ode293.html" rel=3D"noreferrer" target=3D"_blank">https://heasarc.gsfc.nasa=
.<wbr>gov/xanadu/xspec/manual/<wbr>node293.html</a>&l

Message of length 6683 truncated


Reply 2

Resend
From: Jan-Uwe Ness <xmmhelp@sciops.esa.int>
To: reham.m.ayoub@gmail.com
Subject: Re: pipeline spectra (PR#81932)
Date: Mon Jul  3 09:09:54 2017
Dear Reham,

 once a spectrum is binned to 100eV bin size, there is unfortunately no way back
to smaller bin sizes. The only way is to start with the events file in the
pipeline products and the region files associated to the sources you are
interested in following the threads for MOS and pn:
https://www.cosmos.esa.int/web/xmm-newton/sas-thread-mos-spectrum
https://www.cosmos.esa.int/web/xmm-newton/sas-thread-pn-spectrum

 Best wishes,
Jan-Uwe

> Dear Dr.Jan-Uwe Ness,
> 
> Actually I want to model these spectra using cash statistics and so I have
> to bin them to 1 count/bin. So should I first unbinned these spectra and
> then binned to 1 count/bin?
> 
> Best regards,
> Reham
> 
> On Jul 3, 2017 8:51 AM, "Jan-Uwe Ness" <xmmhelp@sciops.esa.int>
wrote:
> 
> Dear Reham Mostafa,
> 
>  spectra are always binned there is no such thing as an unbinned spectrum.
> You
> perhaps mean whether you can get spectra with a smaller bin size? The bin
> size
> at which spectra are created is a choice that depends on various factors,
> e.g.,
> the brightness of the source that determines how much light you will have
in
> each spectral channel. The instrument capabilities determine the minimum
> possible bin size below which the instrument is not able to deliver more
> information.
> 
> Rigorous binning to smallest bin sizes has to be done with care as some
> spectral
> channels may end up containing zero counts with zero errors. Fitting a
model
> with standard chi^2 statistics crashes on such spectra because of dividing
> by
> zero. All spectral channels have to contain at least 25 counts for chi^2
> statistics to be valid. Spectra with smaller bin sizes that contain few
> counts
> in at least one bin require usage of cash statistics, see, e.g., the xspec
> manual for more information:
>    https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/node293.html
> 
> The 3XMM-DR4 may not be binned at the smallest possible binsize for every
> source, thus for very bright sources smaller bin sizes are under certain
> circumstances possible. Unfortunately, the pipeline spectra cannot be
> rebinned
> to smaller bin sizes as the information has already been lost during the
> standard processing. To get higher-resolution spectra, you will need to
> process
> them from scratch.
> 
> Best wishes,
> Jan-Uwe
> 
> 
>> I downloaded several pipeline spectra from 3XMM-DR4 and I wonder if
all
> pipeline
>> spectra of 3XMM-DR4 are binned. And if that can I unbinned these
spectra?
> 
> --
>    Dr. Jan-Uwe Ness
>    XMM-Newton User Support Group
>    European Space Astronomy Centre


Followup 2

Compose reply
Download message
From: Reham Mostafa <reham.m.ayoub@gmail.com>
Date: Tue, 4 Jul 2017 00:01:39 +0400
Subject: Re: pipeline spectra (PR#81932)
To: "Pedro M. Rodriguez Pascual" <xmmhelp@sciops.esa.int>
--001a114a7ff032215005536f3c9c
Content-Type: text/plain; charset="UTF-8"

Thank you for your reply.

On Jul 3, 2017 11:09 AM, "Jan-Uwe Ness" <xmmhelp@sciops.esa.int> wrote:

> Dear Reham,
>
>  once a spectrum is binned to 100eV bin size, there is unfortunately no
> way back
> to smaller bin sizes. The only way is to start with the events file in the
> pipeline products and the region files associated to the sources you are
> interested in following the threads for MOS and pn:
> https://www.cosmos.esa.int/web/xmm-newton/sas-thread-mos-spectrum
> https://www.cosmos.esa.int/web/xmm-newton/sas-thread-pn-spectrum
>
>  Best wishes,
> Jan-Uwe
>
> > Dear Dr.Jan-Uwe Ness,
> >
> > Actually I want to model these spectra using cash statistics and so I
> have
> > to bin them to 1 count/bin. So should I first unbinned these spectra
and
> > then binned to 1 count/bin?
> >
> > Best regards,
> > Reham
> >
> > On Jul 3, 2017 8:51 AM, "Jan-Uwe Ness" <xmmhelp@sciops.esa.int>
wrote:
> >
> > Dear Reham Mostafa,
> >
> >  spectra are always binned there is no such thing as an unbinned
> spectrum.
> > You
> > perhaps mean whether you can get spectra with a smaller bin size? The
bin
> > size
> > at which spectra are created is a choice that depends on various
factors,
> > e.g.,
> > the brightness of the source that determines how much light you will
> have in
> > each spectral channel. The instrument capabilities determine the
minimum
> > possible bin size below which the instrument is not able to deliver
more
> > information.
> >
> > Rigorous binning to smallest bin sizes has to be done with care as
some
> > spectral
> > channels may end up containing zero counts with zero errors. Fitting a
> model
> > with standard chi^2 statistics crashes on such spectra because of
> dividing
> > by
> > zero. All spectral channels have to contain at least 25 counts for
chi^2
> > statistics to be valid. Spectra with smaller bin sizes that contain
few
> > counts
> > in at least one bin require usage of cash statistics, see, e.g., the
> xspec
> > manual for more information:
> >    https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/node293.html
> >
> > The 3XMM-DR4 may not be binned at the smallest possible binsize for
every
> > source, thus for very bright sources smaller bin sizes are under
certain
> > circumstances possible. Unfortunately, the pipeline spectra cannot be
> > rebinned
> > to smaller bin sizes as the information has already been lost during
the
> > standard processing. To get higher-resolution spectra, you will need
to
> > process
> > them from scratch.
> >
> > Best wishes,
> > Jan-Uwe
> >
> >
> >> I downloaded several pipeline spectra from 3XMM-DR4 and I wonder
if all
> > pipeline
> >> spectra of 3XMM-DR4 are binned. And if that can I unbinned these
> spectra?
> >
> > --
> >    Dr. Jan-Uwe Ness
> >    XMM-Newton User Support Group
> >    European Space Astronomy Centre
>
>
> This message and any attachments are intended for the use of the addressee
> or addressees only.
> The unauthorised disclosure, use, dissemination or copying (either in
> whole or in part) of its
> content is not permitted.
> If you received this message in error, please notify the sender and delete
> it from your system.
> Emails can be altered and their integrity cannot be guaranteed by the
> sender.
>
> Please consider the environment before printing this email.
>
>
>

--001a114a7ff032215005536f3c9c
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"auto">Thank you for your reply.=C2=A0</div><div
class=3D"gmail_=
extra"><br><div class=3D"gmail_quote">On Jul 3, 2017 11:09 AM,
&quot;Jan-Uw=
e Ness&quot; &lt;<a
href=3D"mailto:xmmhelp@sciops.esa.int">xmmhelp@sciops.e=
sa.int</a>&gt; wrote:<br type=3D"attribution"><blockquote
class=3D"gmail_qu=
ote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex=
">Dear Reham,<br>
<br>
=C2=A0once a spectrum is binned to 100eV bin size, there is unfortunately n=
o way back<br>
to smaller bin sizes. The only way is to start with the events file in the<=
br>
pipeline products and the region files associated to the sources you are<br=
>
interested in following the threads for MOS and pn:<br>
<a href=3D"https://www.cosmos.esa.int/web/xmm-newton/sas-thread-mos-spectru=
m" rel=3D"noreferrer"
target=3D"_blank">https://www.cosmos.esa.int/<wbr>web=
/xmm-newton/sas-thread-mos-<wbr>spectrum&l

Message of length 9409 truncated

Up to top level
AO15   AO16   AO17   AO18   Backgrounds   Calibration   Conference   Data   Docs   EPICMOS   EPICpn   Feedback   Gallery   Misc   OM   Pending   PhD_Theses   Publications   RGS   RadMonitor   SAS_Hardware   SAS_WS   SASv16.0   SASv16.0_Installation   SASv16.1   SASv16.1_Installation   SASv17.0   SASv17.0_Installation   SASv18.0   SASv18.0_Installation   SciSim   Simulators_other   Suggestions   Trash   Visibility   XMM-bouncing   XMM-news   XRPS   XSA   esas   incoming  

Logged in as guest


Please make your (short) question the subject of your request!


Web interface using JitterBug ... back to the XMM home page