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RXTE Cycle 13 "Dear Colleague" Letter RXTE

Below is the "Dear Colleague" letter released by NASA HQ, soliciting proposals for RXTE Cycle 13. For more information on Cycle 13, see the RXTE Cycle 13 Information Web page.

Dr. Ilana Harrus
RXTE Program Scientist
Astrophysics Division, NASA HQ
202.358.1250 (voice)

September 19, 2008

Dear Colleague,

This letter is to call your attention to the opportunity to propose investigations requesting observing time on NASA's Rossi X-ray Timing Explorer (RXTE). NASA headquarters has approved continued operations of RXTE through September 2009, and we quickly need to produce an observing plan for this period. In light of the 2008 Senior Review recommendation of severely reduced funding for RXTE during Fiscal Year 2009, and in consultation with the RXTE Users' Group, we are issuing the present scaled-down call for observing proposals.

Public Data

In the upcoming observing period ("Cycle 13"), the data from ALL new observations, with the exception of uncompleted peer-reviewed Cycle 12 observations, will be immediately PUBLIC. For Cycle 13 two categories of observing programs, the "Core" and "Open-Time" programs have been defined. Only Open-Time programs will require proposal submission. The Open-Time program solicits proposals for the time frame from March through September 2009, however, we will likely select more observing time than can be done through September 30, 2009, so that we can schedule more efficiently and will have targets available if RXTE operations are extended beyond that time. We emphasize that NO funding to support guest investigations is available for Cycle 13.

Core Program

The Core Program was proposed to the 2008 Senior Review, and is comprised of observations uniquely suited to RXTE and in which RXTE has taken a lead role in the past. In general, observations of the type included within the Core Program are widely recognized to be of the highest priority for the mission, having passed a peer review in many successive observing cycles. A description and list of Core Program observations can be found here,


Please note that all of the data from the Core Program will be made public immediately upon processing. Proposal submission is NOT required for observations in this category.

Open-Time Program

The purpose of the Open-Time Program is to make RXTE observing time available to the international science community for science investigations not included in the Core Program. To request such observations, investigators must submit a short proposal and associated target forms as described below.

In order to maintain an innovative science program, this announcement solicits observing proposals for new science investigations or extensions of existing programs not covered by the Core Program. Such proposals may also involve coordinated RXTE observations of targets with other space-based and/or ground-based facilities. We emphasize that Open-Time proposals should NOT duplicate observations in the Core Program.


Proposers may submit requests for the observing period covering March 1 through September 30, 2009. While approaches for extending RXTE science operations beyond this period are currently being explored, the outcome of these investigations is still uncertain. Proposals for Open-Time observations must be submitted via HEASARC's Remote Proposal System (ARK/RPS),


The proposal must consist of the following,

  • Cover Page - containing basic information about the proposal
  • General Page - containing co-investigator information
  • Target Forms - containing target request information and instrument configurations
  • Scientific Justification and Feasibility

Proposals should establish the science case briefly, and describe how RXTE's unique capabilities will be exploited. Proposals must be submitted electronically using ARK/RPS and received by Thursday, October 30, 2008 (17:00 EST).

The scientific justification and feasibility are limited to ONE page, to be uploaded as a pdf file. Proposals must use a 10pt font or larger.

Evaluation Criteria

Cycle 13 proposals will be evaluated using the following criteria:

  • The suitability of using the RXTE observatory and data products for the proposed investigation;
  • The degree to which the investigation uses RXTE's unique capabilities;
  • The feasibility of accomplishing the objectives of the investigation within the time, telemetry, and scheduling constraints;
  • The feasibility of the proposed analysis techniques; and
  • The relevance to NASA's scientific objectives

Here, relevance to NASA's objectives includes the consideration of the potential contribution to NASA's mission as expressed in its most recent NASA strategy documents and to the objectives and goals of the RXTE mission.

Review and Selection

A peer review committee will be convened to evaluate proposals for Open-Time investigations, including recommendations concerning the approved observing targets and times.

Prospective proposers can get more information from the RXTE Guest Observer Facility's Web page:


Any additional questions should be addressed to the XTE Help Desk feedback form.

Ilana Harrus
Program Scientist, RXTE

If you have a question about RXTE, please send email to one of our help desks.

This page is maintained by the RXTE GOF and was last modified on Monday, 22-Sep-2008 09:28:05 EDT.