Up to top level
AO15   AO16   AO17   AO18   AO19   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 EPICpn/48859
Full headers

From: Alida.Wink@gmail.com
Subject: Can EPIC noise create a frequency peak at ~69s?
Compose reply
Download message
Move To:
2 replies: 1 2
1 followups: 1

Private message: yes  no

Notes:

Notification:


Date: Wed, 12 Oct 2011 08:57:51 GMT
From: Alida.Wink@gmail.com
To: xmmhelp@sciops.esa.int
Cc: Alida.Wink@gmail.com
Subject: Can EPIC noise create a frequency peak at ~69s?
Full_Name: Alida Odendaal
Submission from: (NULL) (146.182.9.9)


Hi

I have recently performed a period analysis on some archived XMM-Newton data
sets of an X-ray binary target.  I found a frequency peak in some (but not all)
of the power spectra at a period of about 69 seconds.  The peak shifts slightly
(~1 to 2 seconds) from data set to data set.  As such a periodicity was not
previously known for this source, I just want to make very sure that the
periodic signal is indeed from the target itself.

I am now trying to evaluate all possible periodic contributions to the data that
are *not* from the source, and that may generate such peaks.  I considered the
detector readout times and noise, but that does not seem to contribute on this
timescale?  The peak was detected on all the EPIC detectors at different stages
(strongest for pn, which also had the most counts) - the signal-to-noise ratio
for the RGS counts is very low for most of the data sets.  I also performed
timing analysis on the background (off-target) regions of each exposure to check
whether the periodicity arises from background noise, but that does not seem to
be the case.

Are there any detector features or properties of the data acquisition/storage
process that may introduce spurious periodic signals on these timescales, or
affect the timing analysis results adversely in any way?

Thank you for your help!

Kind regards
Alida Odendaal


Reply 1

Resend
From: Jan-Uwe Ness <xmmhelp@sciops.esa.int>
To: Alida.Wink@gmail.com
Subject: Re: Can EPIC noise create a frequency peak at ~69s? (PR#48859)
Date: Wed Oct 12 13:20:32 2011
Dear Alida Odendaal,

 frequency studies are always very tricky. If you don't see this frequency in
all but only in some observations, that is already a good sign that it may be
real. I will nevertheless investigate with the instrument teams and let you know
their thoughts.

 A way to confirm this period could be to observe with other instruments. Apart
from RGS, perhaps you can also search in the OM data if the fast read out mode
was employed. Such a frequency may for also be feasible to observe with other
missions such as Swift, Suzaku, or Chandra. But if the source is weak, XMM may
be the only mission that could detect this frequency and I will therefore
investigate and let you know.

 Best regards,
Jan-Uwe

--
Dr. Jan-Uwe Ness
XMM-Newton Science Operations Centre



> 
> Hi
> 
> I have recently performed a period analysis on some archived XMM-Newton
data
> sets of an X-ray binary target.  I found a frequency peak in some (but not
all)
> of the power spectra at a period of about 69 seconds.  The peak shifts
slightly
> (~1 to 2 seconds) from data set to data set.  As such a periodicity was
not
> previously known for this source, I just want to make very sure that the
> periodic signal is indeed from the target itself.
> 
> I am now trying to evaluate all possible periodic contributions to the data
that
> are *not* from the source, and that may generate such peaks.  I considered
the
> detector readout times and noise, but that does not seem to contribute on
this
> timescale?  The peak was detected on all the EPIC detectors at different
stages
> (strongest for pn, which also had the most counts) - the signal-to-noise
ratio
> for the RGS counts is very low for most of the data sets.  I also
performed
> timing analysis on the background (off-target) regions of each exposure to
check
> whether the periodicity arises from background noise, but that does not
seem
to
> be the case.
> 
> Are there any detector features or properties of the data
acquisition/storage
> process that may introduce spurious periodic signals on these timescales,
or
> affect the timing analysis results adversely in any way?
> 
> Thank you for your help!
> 
> Kind regards
> Alida Odendaal


Reply 2

Resend
From: Jan-Uwe Ness <xmmhelp@sciops.esa.int>
To: Alida.Wink@gmail.com
Subject: Re: Can EPIC noise create a frequency peak at ~69s? (PR#48859)
Date: Thu Oct 13 07:48:01 2011
Dear Alida Odendaal,

 I have checked back with the experts, and no instrumental effects are known
that could introduce a 69s period in the EPIC light curves. If it was detected
in the contemporaneous MOS and PN light curves, than you are very safe from the
instrumental point of view.

 Best regards,
Jan-Uwe


 
> Hi
> 
> I have recently performed a period analysis on some archived XMM-Newton
data
> sets of an X-ray binary target.  I found a frequency peak in some (but not
all)
> of the power spectra at a period of about 69 seconds.  The peak shifts
slightly
> (~1 to 2 seconds) from data set to data set.  As such a periodicity was
not
> previously known for this source, I just want to make very sure that the
> periodic signal is indeed from the target itself.
> 
> I am now trying to evaluate all possible periodic contributions to the data
that
> are *not* from the source, and that may generate such peaks.  I considered
the
> detector readout times and noise, but that does not seem to contribute on
this
> timescale?  The peak was detected on all the EPIC detectors at different
stages
> (strongest for pn, which also had the most counts) - the signal-to-noise
ratio
> for the RGS counts is very low for most of the data sets.  I also
performed
> timing analysis on the background (off-target) regions of each exposure to
check
> whether the periodicity arises from background noise, but that does not
seem
to
> be the case.
> 
> Are there any detector features or properties of the data
acquisition/storage
> process that may introduce spurious periodic signals on these timescales,
or
> affect the timing analysis results adversely in any way?
> 
> Thank you for your help!
> 
> Kind regards
> Alida Odendaal
> 
> 


Followup 1

Compose reply
Download message
Date: Thu, 13 Oct 2011 16:43:20 +0200
Subject: Re: Can EPIC noise create a frequency peak at ~69s? (PR#48859)
From: Alida Odendaal <alida.wink@gmail.com>
To: Jan-Uwe Ness <xmmhelp@sciops.esa.int>
--001517440fbe7104d604af2f298e
Content-Type: text/plain; charset=ISO-8859-1

Hi Jan-Uwe

Thank you so much for the thorough feedback and advice - it has been very
helpful and I appreciate it very much!

Kind regards
Alida


On 13 October 2011 09:48, Jan-Uwe Ness <xmmhelp@sciops.esa.int> wrote:

> Dear Alida Odendaal,
>
>  I have checked back with the experts, and no instrumental effects are
> known
> that could introduce a 69s period in the EPIC light curves. If it was
> detected
> in the contemporaneous MOS and PN light curves, than you are very safe from
> the
> instrumental point of view.
>
>  Best regards,
> Jan-Uwe
>
>
>
> > Hi
> >
> > I have recently performed a period analysis on some archived
XMM-Newton
> data
> > sets of an X-ray binary target.  I found a frequency peak in some (but
> not
> all)
> > of the power spectra at a period of about 69 seconds.  The peak shifts
> slightly
> > (~1 to 2 seconds) from data set to data set.  As such a periodicity
was
> not
> > previously known for this source, I just want to make very sure that
the
> > periodic signal is indeed from the target itself.
> >
> > I am now trying to evaluate all possible periodic contributions to the
> data
> that
> > are *not* from the source, and that may generate such peaks.  I
> considered
> the
> > detector readout times and noise, but that does not seem to contribute
on
> this
> > timescale?  The peak was detected on all the EPIC detectors at
different
> stages
> > (strongest for pn, which also had the most counts) - the
signal-to-noise
> ratio
> > for the RGS counts is very low for most of the data sets.  I also
> performed
> > timing analysis on the background (off-target) regions of each
exposure
> to
> check
> > whether the periodicity arises from background noise, but that does
not
> seem
> to
> > be the case.
> >
> > Are there any detector features or properties of the data
> acquisition/storage
> > process that may introduce spurious periodic signals on these
timescales,
> or
> > affect the timing analysis results adversely in any way?
> >
> > Thank you for your help!
> >
> > Kind regards
> > Alida Odendaal
> >
> >
>
>
> ================================================================================================
> 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.
>
> =================================================================================================
>
>

--001517440fbe7104d604af2f298e
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

Hi Jan-Uwe<br><br>Thank you so much for the thorough feedback and
advice - =
it has been very helpful and I appreciate it very much!<br><br>Kind
regards=
<br>Alida<br><br><br><div class=3D"gmail_quote">On
13 October 2011 09:48, J=
an-Uwe Ness <span dir=3D"ltr">&lt;<a
href=3D"mailto:xmmhelp@sciops.esa.int"=
>xmmhelp@sciops.esa.int</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin: 0pt 0pt 0pt 0.8ex; borde=
r-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear Alida Odenda=
al,<br>
<br>
=A0I have checked back with the experts, and no instrumental effects are kn=
own<br>
that could introduce a 69s period in the EPIC light curves. If it was detec=
ted<br>
in the contemporaneous MOS and PN light curves, than you are very safe from=
 the<br>
instrumental point of view.<br>
<br>
=A0Best regards,<br>
Jan-Uwe<br>
<div><div></div><div class=3D"h5"><br>
<br>
<br>
&gt; Hi<br>
&gt;<br>
&gt; I have recently performed a period analysis on some archived XMM-Newto=
n data<br>
&gt; sets of an X-ray binary target. =A0I found a frequency peak in some (b=
ut not<br>
all)<br>
&gt; of the power spectra at a period of about 69 seconds. =A0The peak shif=
ts<br>
slightly<br>
&gt; (~1 to 2 seconds) from data set to data set. =A0As such a periodicity =
was not<br>
&gt; previously known for this source, I just want to make very sure that t=
he<br>
&gt; periodic signal is indeed from the target itself.<br&

Message of length 7698 truncated

Up to top level
AO15   AO16   AO17   AO18   AO19   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