Data products from previous cycles will be available for use during Cycle 9. The specific products and their availability are described in detail in Appendices G and H.
Previous observations are summarized in the viewing plans or "timelines" for each previous cycle. Previous viewing plans, abstracts of previously approved programs, as well as additional information on sky exposure for EGRET and COMPTEL, are available on the Internet through the Compton GRO home page at http://heasarc.gsfc.nasa.gov/docs/cgro.
Observing timelines are most significantly constrained by spacecraft thermal and power considerations (location of the Sun) and by the requirement that likely discrete sources of gamma radiation be observable by the OSSE experiment. The OSSE detectors can rotate over a full range of 192o about the Y-axis, providing the capability to observe sources in the X-Z plane. For each Z-axis pointing of the spacecraft, an X-axis orientation is chosen to provide, ideally, two targets for OSSE to observe (refer to Figure 1 for definition of axes). The BATSE instruments provide continuous sensitivity to the entire unocculted sky and do not affect the viewing program.
Observing time will be allocated with no predetermined ratio between Guest Investigators and Instrument Team members. There are no targets reserved for the Instrument Teams, other than those uniquely related to the objectives described in section III.A.1 of Appendix C.
- EGRET, COMPTEL, AND OSSE
Excepting the specific topics for which these Instrument Teams have sole responsibility, as listed above in Appendix C, section III.A.1, Guest Investigators may propose observations without restrictions. Target conflicts will be taken into consideration in the selection process.
- BATSE
In addition to the gamma-ray burst and solar flare data discussed earlier, investigators may propose to analyze the data continuously obtained by the BATSE instrument. This includes temporal observations of hard x-ray sources performed using the Earth occultation technique, as well as observations of pulsating sources.
Excepting the any assigned solely to the BATSE Instrument Team, as described in Appendix C, Guest Investigators may propose BATSE observations without restrictions. Investigators wishing to work on the determination of burst positions by arrival time difference methods may contact the BATSE Team for a possible collaboration.
The specific observing modes and data products are detailed in Appendix G.
One of the important objectives of Compton GRO is the observation of transient phenomena such as supernovae, novae, solar flares, or AGN variability. In order to make such observations, it may be necessary to interrupt the viewing program and reorient the satellite. Because such reorientations place significant demands on project resources, at most four or five such observations will be allowed during Cycle 9. Investigators may propose to observe Targets of Opportunity (ToOs), either for individual objects or for classes of objects. If a candidate ToO occurs, the Project Scientist will determine whether or not a formal ToO declaration is made. Proposers should be as specific as possible in defining the trigger criteria for ToO activation. The peer review committees will be asked to carefully review these criteria and recommend changes as deemed warranted.
Data resulting from any peer-review approved ToO program will be the exclusive property of the proposer for the normal 3-month proprietary period. If an unproposed ToO candidate appears, and a decision is made to observe it, the data will be made available immediately after processing through the public archive at the Compton GRO Science Support Center.
ToO programs will generally not be funded until a ToO satisfying the proposer's trigger criteria occurs and a formal ToO declaration is made by the Project Scientist.
Correlative research (Type 3) proposals are welcome during Cycle 9, although they will generally be given a lower funding priority than observing (Type 2) or data analysis (Type 1) proposals. An exception to this policy will be made in the case of correlative observation programs utilizing the BACODINE system, or related methods, to search for counterparts to gamma-ray bursts discovered by Compton GRO at nongamma-ray wavelengths.
Service proposals (Type 4) are solicited during Cycle 9, although they will be given a lower funding profile than observing (Type 2) or data analysis (Type 1) proposals. Note the restrictions in Section III.B of Appendix C on what types of activities are eligible for support within service proposals under the Compton GRO Guest Investigator Program.
- Proposals requesting access to more than one Compton GRO instrument, either for observing time or for analysis of existing data, may be submitted under one cover.
- Multiyear proposals, which under certain conditions had been accommodated during previous cycles, will not be considered for Cycle 9 and beyond.
General information concerning Compton GRO Guest Investigator opportunities during Cycle 9 can be obtained from: Dr. Chris R. Shrader, Compton GRO Science Support Center, Code 661, NASA Goddard Space Flight Center, Greenbelt, Md. 20771-0001. (E-mail: shrader@grossc.gsfc.nasa.gov or Telephone: (301) 286-8434). Also see http://heasarc.gsfc.nasa.gov/docs/cgro on the Internet.