NRA 99-OSS-02
Appendix C

I. Program Objective

The objective of the Compton Gamma Ray Observatory Guest Investigator Program is to maximize the scientific return from the Compton GRO mission by broadening the scientific participation in the analysis of data, expanding the scope of observations, and conducting correlative research that is closely tied to the Compton GRO observations.

II. Program Scope

Compton GRO is comprised of four distinctly different instruments which are optimized to perform simultaneous observations of specific targets or regions. NASA, with advice from the Compton GRO Users Committee, has accordingly defined various types of proposals and modes of participation in this Program. These allow proposers to structure their investigations to make the best use of the available resources, taking into account their own familiarity with the instruments and analysis techniques. The Compton GRO Guest Investigator (GI) program is generally structured in terms of four operational phases of the mission and four types of proposals that may be submitted by Guest Investigators. These structural elements are defined in the following sections.

This NRA applies only to Cycle 9 of the mission. This specific guidance for responding to this NRA is given in Appendix D. Subsequent NRA's are planned to be issued at intervals of approximately 12-18 months.

A. Data Types

Two broad categories of data will be generated at the Instrument Team institutions:
1. Low-level processed data: These data are products of "automatic" pipeline processing. They will generally be produced within a few months of acquisition. Examples of low-level data include: a) Burst and Transient Source Experiment (BATSE) gain-corrected pulse-height spectra and rates from normal telemetry stream (i.e., not burst memory readouts), rates and uncorrected spectra from burst memory, relative rates for determining approximate burst locations; b) Imaging Compton Telescope (COMPTEL) gain-corrected pulse height, pulse shape, position, and time-of-flight of individual events, raw spectra from burst detectors, shield rates; c) Energetic Gamma-Ray Experiment Telescope (EGRET) directions and energies of gamma-ray events, gain corrected pulse-height spectra for bursts and flares, anticoincidence shield rates; d) Oriented Scintillation Spectrometer Experiment (OSSE) gain corrected 2-minute spectra, event-by-event pulsar data, count rates from shields for burst and flare studies.

2. High-level processed data: These data are products of detailed processing, including instrumental calibrations and background corrections, which are expected to be produced several months after acquisition. Examples of these data include: a) BATSE time-resolved background-subtracted count and photon spectra of bursts and transients, high temporal resolution rate histories of bursts, good quality source locations; b) COMPTEL sky maps accumulated during two week observations, background-corrected photon spectra of selected objects in the field of view; c) EGRET sky maps accumulated during 2-week observations, photon spectra of selected sources in the field of view; d) OSSE background-subtracted count and photon spectra accumulated in intervals from several minutes up to 2 weeks.

   Detailed descriptions of the different data sets and their projected availability is provided in Appendix G (available electronically or in hardcopy upon request).

Four operational phases have been defined for the Compton GRO mission. Following deployment there was an initial period of approximately 40 days devoted to checking out the spacecraft and instruments, followed by the Phase 1, 2, and 3 observing periods. This NRA solicits proposals for Guest Investigations for a 1.5-year period of Phase 4, to be called Cycle 9. Opportunities during this cycle are described in more detail in Appendix D.

Phase 1: A period beginning May 16, 1991, ending on November 17, 1992. Observing time during this first phase was allocated exclusively to the Instrument Teams. Key activities during this phase included verification of the scientific performance of the instruments, performance of a comprehensive sky survey (EGRET and COMPTEL), and the conduct of observations of high-priority discrete and diffuse sources (OSSE, EGRET, and COMPTEL). During this period, the Instrument Teams developed and refined the initial data processing software and procedures. Opportunities available to Guest Investigators were primarily in the form of cooperative, correlative, and theoretical research projects in conjunction with the predefined observations of the Instrument Teams.

Phase 2: A 9-month period immediately following Phase 1, which ended on September 7, 1993. During this phase, 30% of the total observing time was allocated to Guest Investigators. In addition, a portion of the solar flare and gamma-ray burst data from the four instruments was made available for guest investigations.

Phase 3: A 12-month period immediately following Phase 2. In Phase 3, approximately 55 percent of the observing time was allocated to Guest Investigators. In addition, 60 percent of the Instrument Team data on randomly selected solar flares and cosmic gamma-ray bursts was made available.

Phase 4: The remainder of the mission. Observing time allocations between Guest Investigators and Instrument Teams for this period are not predetermined, but are decided completely on the basis of peer review.

C. Types of Proposals

Four types of proposals have been identified as being applicable to the Compton GRO Guest Investigator Program during Cycle 9. Funding priorities will be weighted so as to favor Types 1 and 2 over Types 3 and 4, although each proposal type will be considered for support. An important exception to this general rule will be correlative research programs that will attempt to identify gamma-ray burst counterparts at non-gamma-ray wavelengths via prompt observing campaigns utilizing BACODINE or related techniques. These proposals will receive comparable weighting to Type 1 and 2.

Type 1: Proposals for analysis or use of existing (archival) Compton GRO data.

Type 2: Proposals for observing time during Cycle 9, including Targets of Opportunity proposals, or for other analyses of proprietary Compton GRO data, such as BATSE data.

Type 3: Proposals for correlative research that are closely tied to Compton GRO observations. Correlative research involves data obtained by a Guest Investigator from observations in the same or other wavelength regions and/or from other spacecraft, rockets, or balloons that would be used in combination with Compton GRO observations of selected objects or phenomena³.

Type 4: Proposals to perform services to the community in direct support of Compton GRO related scientific research activities. Examples include the establishment of online databases or catalogs and the development of analysis software or data products complimentary or superior in some manner to that provided by the Compton GRO Science Support Center or the Instrument Teams.

Once Compton GRO data products reside in the pubic domain at Compton GRO Science Support Center, or some other archival research center, they are accessible to all users (see section III. D below). In this case, a response to this NRA is not necessary, provided that research funds are not to be requested.

III. Additional information

A. Data Policies

1. Proprietary Data Rights

   Data resulting from observations specifically approved as part of a peer reviewed proposal by any Investigator are considered proprietary for a period up to 3 months after receipt of the data by the investigator in a usable form.

   Data resulting from any peer-review approved Target of Opportunity (ToO) program (see Appendix D, section I.C) will be the exclusive property of the proposer for a 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.

   Information, including burst and other alerts, derived from nonproprietary Compton GRO data and relayed via various NASA and public networks, is considered published without constraints or pre-conditions on its use.

   With the exceptions enumerated below, all data that have not been specifically proposed and awarded on the basis of competitive peer review is public domain data. NASA will make every effort to ensure that these data are placed in accessible data bases permitting equal access to all interested scientists.

   In order to provide the astronomical community with timely access to complete, uniformly analyzed data sets, the Instrument Teams have the responsibility to produce catalogs of all detected sources and maps of all detected diffuse emission. These catalogs and maps will eventually incorporate all Compton GRO observations. Observations conducted by Guest Investigators will not be included in the Instrument Teams' catalogs and maps prior to the expiration of the 3-month proprietary period without the consent of the Guest Investigator.

   In addition to these general proprietary data, certain scientific research projects or sources have been identified as reserved for the Instrument Teams in recognition of their relationship to the originally proposed investigations and the special technical requirements of the analysis. These topics or sources are listed below for each of the Compton GRO instruments:

   The Oriented Scintillation Spectrometer Experiment (OSSE):

   The OSSE Team has been assigned the sole responsibility to carry out the following scientific investigations:
   

   • Observations up to 2 years after their discovery of new Galactic or local group supernovae
     
   • Performance of a comprehensive Galactic plane survey (not including proposed discrete source observations)
     
   Guest Investigators will have the opportunity to participate in the OSSE scientific teams to investigate these topics.

   The Imaging Compton Telescope (COMPTEL):

   The COMPTEL Team has been assigned the sole responsibility to carry out the following scientific investigations:
   

   • Preparation of an all-sky map of diffuse emission
     
   • Preparation of a complete catalog of discrete sources
     
   • Observations up to 2 years after their discovery of new Galactic or local group supernovae

   The Energetic Gamma Ray Experiment Telescope (EGRET):

   The EGRET Team has been assigned the sole responsibility to carry out the following investigations:
   

   • Preparation of an all-sky map of diffuse emission
     
   • Preparation of a complete catalog of discrete sources

   The Burst and Transient Source Experiment (BATSE):

   The BATSE Team has been assigned the sole responsibility to carry out the following investigations:

   • Preparation of a comprehensive catalog of cosmic gamma-ray bursts⁴

   Notwithstanding the above restrictions, all Compton GRO data will become accessible to the scientific community 3 months after production of these data in usable form.

   Other Items:

   1. BATSE Monitoring Reports

      Certain information derived from BATSE quick-look Earth-occultation and pulsar data analysis will be placed promptly in the public domain (via the Internet at MSFC and accessible through the Compton GRO Science Support Center at http://heasarc.gsfc.nasa.gov/docs/cgro). These data are intended primarily for planning purposes and are not recommended for use in detailed analysis leading to publication.

   2. Multiyear Programs

      Multi-year projects can no longer be supported and they should not be proposed. A number of multiyear programs of indefinite or 4-5 year duration were approved during Cycles 4 and 5. These programs will no longer be automatically carried over - they must be reproposed for Cycle 9 and annually thereafter.

   3. Parallel Data and Serendipitous Sources

      Two special attributes of the Compton GRO mission are the capability for simultaneous observations by the four instruments and the relatively wide fields of view of two of the pointed instruments (EGRET and COMPTEL). In many cases, this will permit two or three proposed and accepted scientific investigations to be accomplished concurrently. For times during which approved observations are underway involving one or two instruments, while unproposed data is being accumulated in parallel, the following rule will apply:

      If a serendipitous source is detected during routine pipeline data processing by the EGRET, COMPTEL, or OSSE Instrument Teams, the data will be placed promptly into the public domain. The Instrument Teams will use their normal criteria for source detection in this situation. Serendipitous sources found in the field of view of an approved target which are not detected during routine processing by the Instrument Teams may be claimed by the discoverer. Proprietary rights to that data for a 3-month period can then be established for the first claimant by contacting the Compton GRO Science Support Center.

   4. Solar Flare and Gamma Ray Burst Data

      The selection of solar flare and burst data available to Guest Investigators from OSSE, COMPTEL, and EGRET will, in general, be derived from events identified by BATSE. If an investigation so requires, data from a particular event will be made available from all instruments for analysis whenever possible.

   5. Calibration Data and Observations

      An allotment of observing time equivalent to one 2-week viewing period may be granted at the discretion of the project scientist for instrument calibration purposes. The specific plans for the use of this discretionary time will not be subjected to peer-review, but must be reviewed and approved by the project scientist. The expected mode of implementation would be through coordinated dialog between the 4 Instrument Teams, the Project Scientist, and the Compton GRO Timeline Committee. These activities will not be funded through the Guest Investigator Program.

      Additional or alternative calibration studies must, as in the past, be awarded through peer review, although it is our expectation that the needed calibration observations can be carried out within the allotted discretionary time allocation. Calibration studies selected through peer review are eligible for grant support.

   6. New Data Which Were Not Proposed For and Awarded through Peer Review

      Other data which may have been obtained during Cycle 9, but which were not specifically proposed for and awarded through peer review, will in general be made available upon request prior to the expiration of the normal proprietary period. Examples of such data might include off-axis COMPTEL or EGRET sources or OSSE secondary targets inserted into the viewing plan by the time-line committee to fill a void in the schedule. For BATSE, which has an uncollimated, full-sky view, all triggered gamma-ray bursts and solar flare events will be made promptly available to any interested party. Additionally, BATSE Earth-occultation or pulsar data products, for sources not already awarded through peer review, will be made available as well.

      All requests for data satisfying the above criteria should be directed to the Compton GRO Science Support Center shrader@grossc.gsfc.nasa.gov. Questionable cases, such as point sources which may be only marginally resolvable from approved point-source fields or requests requiring excessive data processing efforts, will be mediated on a case-by-case by the Compton GRO Project Scientist.

There are certain restrictions on what types of activities are eligible for support under the Type 4 Service Proposal category; specifically, tasks which have already been contracted through longstanding agreements to the Instrument Teams and the Compton GRO Science Support Center will not be supported. The Instrument Teams have contractual responsibilities to:

• Monitor instrument specific flight hardware and maintain flight software.
  
• Communicate with and advise flight operations team (FOT) on instrument specific issues.
  
• Perform basic processing of incoming data including manual inspection/screening as needed.
  
• Monitor instrument performance and maintain revise calibration parameters when warranted as the instruments age.
  
• Generate basic data products as outlined in Appendix H (e.g. photon event lists, exposure and counts maps, count spectra, response matrices) and deliver to the Compton GRO Science Support Center and/or guest investigators.

Anyone considering submitting a service proposal who is uncertain about these restrictions is encouraged to contact the Compton GRO Science Support Center for clarification.

The proposal review process will be directed by the Compton GRO Program Scientist at the Office of Space Science, NASA Headquarters. Proposals for investigations under the Compton GRO Guest Investigator program will be evaluated by a NASA-convened peer review panel derived from the international scientific community.

Proposals approved for pointed observations (Type 2 proposals for OSSE, EGRET, and COMPTEL) will be submitted to the Compton GRO Timeline Committee for scheduling following the peer review process. Targets will be scheduled taking into account the A, B, or C priority rankings assigned by the peer review. The Timeline Committee will include representation from the user community. Once an observation is scheduled, the proposer will be informed that his or her proposal has been accepted.

Some over selection of proposed pointed observations relative to the nominal time available will be made to allow for an optimal viewing plan to be constructed. An attempt will be made to carry over into the next cycle any scheduled priority A targets that are dropped from the timeline due to operational considerations or targets of opportunity. In such cases, consideration will be given to the net time loss incurred by the program and the assessed impact of the time loss to the scientific objectives of the proposed research. Targets which are unable to be scheduled, even if they are priority A, will not automatically carry over into the next cycle. Only proposals that are accommodated in the timeline will be considered for funding.

³Funds for correlative research will be used to cover operational expenses, data analysis, and expenses involved directly in collaborating with Compton GRO Investigators. Funds under this category will not generally be authorized for: The conduct of observations in other wavelength bands; the conduct of observations from other spacecraft, observatories, rockets, or balloons; procurement of observatory facilities; or development of flight hardware. The Agency may under certain circumstances consider exceptions to this policy.

⁴Note that this does not preclude the possibility to propose for data rights to individual bursts.