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RXTE Cycle 15 "Dear Colleague" Letter RXTE

Below is the "Dear Colleague" letter released by NASA HQ, soliciting proposals for RXTE Cycle 15. For more information on Cycle 15, see the RXTE Cycle 15 Information Web page.

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

July 16, 2010

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). In consultation with the RXTE User's Group, we are issuing the present call ("Cycle 15") for observing proposals in the eventuality that NASA HQ can extend the mission past its nominal end currently set for February 28, 2011. Cycle 15 will be implemented in the same manner as Cycle 14.

Public Data

For Cycle 15 the data from all new observations will be immediately public, and 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 January 1 through September 2011. We emphasize that no funding to support guest investigations is available for Cycle 15.

Core Program

The Core Program was first proposed to the 2008 Senior Review, and became part of the observing plan for Cycle 13. It comprises 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 January 1 through September 30, 2011. While continued RXTE operations through September 30, 2011 have been proposed, at present there remains a possibility that the mission would end prior to this, so there is no guarantee that proposed observations will be completed. 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, September 16, 2010 (17:00 EDT).

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 15 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 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 via their feedback form:


Ilana Harrus
Program Scientist, RXTE

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