Suzaku News #042: Updated background files for simulations

[US Suzaku GOF <suzakunews@bigbang.gsfc.nasa.gov>]

Dear Suzaku Cycle-3 proposers,

As you may have noticed the background files in the following
Suzaku AO-3 cycle proposal pages contained data of about 90 ks
exposures.

XIS: http://www.astro.isas.jaxa.jp/suzaku/proposal/ao3/xis_cxb/
     http://suzaku.gsfc.nasa.gov/docs/suzaku/prop_tools/xis_cxb.html
HXD: http://www.astro.isas.ac.jp/suzaku/proposal/ao3/hxd_mat/
     http://suzaku.gsfc.nasa.gov/docs/suzaku/prop_tools/hxd_mat.html

We have uploaded background files of longer exposures (about
800ks) for the HXD and we made a link to the night earth
database for the XIS in the above web pages.

For the HXD, the Poisson errors of the background files are
smaller than the systematic errors of the background.  So it
is not necessary to redo your simulations using the new
background in most cases, though the significance of signals
may increase a little bit.
However, we recommend to redo simulations, ONLY if you are
following the simulation recipe in section 5.5.2 of the technical
description AND if you use the absolute values of the chi^2 as
criteria of your observation.

For the XIS,  we recommend to redo simulations if the
exposure time is longer than about 100 ks and your statistics
are determined by background, i.e. the source is faint.
Since as in AO-2, we can provide only the long-exposure
night-earth data, please include the CXB and the galactic
emissions in your simulations as models.


Best regards,


Kazuhisa Mitsuda

Suzaku Project Manager
--------------------------------------------------
Department of High Energy Astrophysics
Institute of Space and Astronautical Science (ISAS)
Japan Aerospace Exploration Agency (JAXA)

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