Reminder: RXTE proposals due August 4th

[Alan Smale <alan@osiris.gsfc.nasa.gov>]

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                  RXTE Cycle 6 Proposals Due August 4!
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This is a friendly reminder that you have only two and a half weeks to
complete and submit your RXTE proposals.

The text of the Announcement, plus the relevant Appendices, may be
obtained from the RXTE Guest Observer Facility pages at:

                      http://rxte.gsfc.nasa.gov/

(select "Proposals and Planning Tools" -> "NASA Research Announcements")



As you probably know, in May we lost the propane layer of PCU0, one of
the five PCA detectors.  Comparisons of rates in PCU0 versus the other
detectors show that the background in PCU0 is now about 8 cts/s, as
compared with 4 cts/s in each of the other PCUs (Std2, L1).  For
sources brighter than 10 mCrab this should have a minimal effect on
analysis. For longer observations of sources fainter than 10 mCrab,
new background models for PCU0 will be required to account for this
detector's higher, and more variable, background. Research is underway
to create these models.

Thus, the loss of the propane layer on PCU0 should have little impact
on the types of proposals that are accepted in Cycle 6.  In
particular, monitoring programs will continue, often with a single
detector rather than two, with minimum observing time of 1000 seconds.
(Note, however, that resource reductions may affect our ability to
schedule intensive monitoring programs with many pointings per day).
Observations that require the maximum available area (to study
variability, for example) may be done with all 5 detectors on for a
few orbits at a time.  Observations longer than 10-20 ks can have at
least 3 PCUs on almost all of the non-SAA and unocculted time, and up
to 5 PCUs for a few orbits per day.

For the final years of operations, it is important to focus on
scientific issues that only RXTE can address, to add value to its
legacy.  If you have any questions about the observing strategy you
have in mind, please consult us at xtehelp@athena.gsfc.nasa.gov.


	Jean Swank, RXTE Project Scientist
	Alan Smale, RXTE Guest Observer Facility
 
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