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Suzaku News #067: AO-6 Information/Attitude instability/Call for volunteers

November 4, 2010


[1] AO-6 deadline reminder
[2] Joint Fermi-Suzaku proposal opportunity
[3] AO-6 Technical Description and tools
[4] Increased attitude instability
[5] Call for volunteers for the US peer review


[1] AO-6 deadline reminder

Suzaku AO-6 proposals are due on Friday, November 19, 2010.  For further
details, please consult the appropriate agency's web pages:

JAXA: http://www.astro.isas.jaxa.jp/suzaku/proposal/ao6/
NASA: http://suzaku.gsfc.nasa.gov/docs/suzaku/aehp_prop_tools.html
ESA:  http://www.rssd.esa.int/index.php?project=ASTROE2&page=AODocs


[2] Joint Fermi-Suzaku proposal opportunity

The Suzaku and Fermi project have an agreement in place for joint
Fermi-Suzaku proposals.  Investigators who plans a joint analysis of
Fermi and Suzaku data will have the opportunity to submit a single
proposal to Fermi Cycle 4 (deadline: January 21, 2011).  This agreements
allows the Fermi proposal peer-review, in conjunction with a technical
review by the Suzaku project, to award up to 250 ks of Suzaku observing
time through such joint proposals.  Further details will be published
on the Fermi Science Support Center web site in due course.



[3] AO-6 Technical Description and Tools

We have updated the Technical Description document for AO-6 proposals,
and it is now available.  As of this writing, however, there are
several missing and rotated figures in the HTML version (no such
problems exist for the PDF and gzipped PostScript versions).  We
are working to fix these issues with the HTML version.

In addition, response and background files for simulation are now
ready for use, and these have been propagated into WebPIMMS and

We apologize for the delay in providing these to the community.


[4] Increased attitude instability

Since 2009 December 18, the stability of Suzaku attitude in the
detector X direction has become worse, on average by a factor of 2.
Moreover, there is a significant scatter in the degree of instability
from observation to observation.  Moreover, the attitude files for
observations taken between 2009 December 18 and 2010 June 15 fail to
reproduce the wobbles.  Since 2010 June 15, while the instability
remains in the attitude control, the attitude files reflect this

The effect of this instability on the data quality depends on several
factors, not the least the actual degree of instability for the
particular observation.  An important factor is the aim point.
Observations in which a point source is placed at the HXD nominal
aim point are far more strongly affected than those taken at the XIS
nominal aim point.  This is because the source stays at the flat
part of the vignetting curve when the XIS nominal aim point is used.
With the HXD nominal pointing, the source location changes in a region
where the vignetting curve has a noticeable slope and curvature.
This leads to count rate variations even when the source flux is
constant.  This can also lead to significant cross-normalization
issues among the XIS units.  Observations at the HXD nominal position
with a window option are the worst affected, as the fraction of source
flux within the window in XIS1 changes due to the attitude wobble.

For these reasons, we no longer recommend the use of the HXD nominal
aim point for all future observations.

Further details are contained in three Suzaku memos (2010-04, 2010-05,
and 2010-06).  They are available via



[5] Call for volunteers for the US peer review

We plan to hold the US peer review for Suzaku Cycle 6 proposals on
January 24 & 25, in or near Greenbelt, MD.  US-based scientists who
are willing to serve in this review are invited to e-mail


Please note that we are constrained to use only those scientists
who are affiliated with a US institution during the relevant period.
Please also note that, in all likelihood, we can only use some of
the volunteers, in order to assemble review panels that have the right
set of expertise without undue number of conflict of interest cases.

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