Fermi Science Support Center

The NRAO Cooperative Agreement

Radio observations using the NRAO facilities will be important to the scientific exploration by Fermi. Therefore, this Fermi-NRAO cooperative arrangement commits observing time on NRAO telescopes for coordinated observations of Fermi sources, to be awarded on a competitive basis. The scientific programs that will be supported within this program are those that are enhanced by the combination of Fermi observations with investigations using the radio facilities operated by NRAO. The philosophy of the approach, in keeping with the missions of both Fermi and NRAO, will be that of maximum data availability and maximum scientific return for the entire user community.

This cooperative arrangement includes two distinct types of collaborative observations and funding opportunities between NRAO and Fermi that will take place within the GI program. To distinguish these two opportunities, we call them the "Joint Proposal Opportunity" and the "Cooperative Proposal Opportunity," respectively. The two opportunities are described in turn below.

Background Description of NRAO Radio Telescopes

The NRAO operates the Very Long Baseline Array (VLBA), a milliarcsecond-resolution continent-wide interferometer array; the Jansky Very Large Array (VLA), an arcsecond-resolution centimeter-wave interferometer array; and the Robert C. Byrd Green Bank Telescope (GBT), a precise 100m single-aperture telescope. Proposers should note that all of these telescopes are evolving, with enhancements of the VLBA sensitivity, replacement of the VLA by the VLA, and new array receivers on the GBT; the "Astronomers" sections of the relevant web sites should be consulted for the most up-to-date information. In particular, the advent of the VLA means that joint Fermi - ELVA observations will henceforth be supported in Open Shared Risk Observing mode. NRAO is also the North American Executive of the Atacama Large Millimeter/Submillimeter Array (ALMA), presently under construction. The present agreement covers the GBT, VLA, and VLBA, with the potential of adding ALMA when it comes on line. The total amount of scientific observing time used on the operational NRAO telescopes ranges from 4000 to 6500 hours per year. The GBT, VLA, and VLBA are pointed telescopes generally allocated for PI proposals; their data proprietary period is 12 months, beginning at the time of the last observation associated with a proposal. NRAO also receives "Large Proposals" requesting at least 200 hours of NRAO observing time at each NRAO proposal deadline. NRAO is funded by NSF as a research facility that operates state-of-the-art telescopes in an "open skies" mode for the entire astronomical community.

Joint Proposal Opportunity

The first Fermi/NRAO opportunity is a Joint Proposal Opportunity, whereby potential radio observers submit proposals for Fermi funding and future NRAO observations through the Fermi GI portal. A range of telescope time will be made available by NRAO for the Fermi GI program. In turn, Fermi/NASA will make data-analysis funding available to successful U.S.-based investigators requesting NRAO observing time through the GI process. These proposals may include both NRAO and Fermi pointed observations, although pointed Fermi observations will be rare, and most successful proposals are expected to make use of Fermi survey data. The peer-reviewed GI proposal-evaluation process will identify programs with sufficient science justification to be allocated funding by Fermi, and those that fall within the agreed-on range of NRAO observing time will be allocated NRAO observing time without additional scientific review, provided they prove to be technically feasible.

Proposals for NRAO observing time submitted through the Fermi GI program are likely to be successful only if they make use of the unique capabilities of the NRAO telescopes; proposal evaluation will include an assessment of the radio telescope requirements, and those that are more appropriately done with other radio telescopes will be rejected. Only proposals equivalent to "regular" NRAO proposals, those requesting fewer than 200 hours of observing time, or those falling in the Triggered proposal category, will be eligible to be submitted for future observing time. NRAO Large Proposals (200 hours or more) will not be eligible because of their potential large impact on the available funding and observing time, but will be eligible for funding via the Cooperative Proposal Opportunity (see below). Some examples of NRAO observations that would be acceptable might include, but are not limited to, the following:

  • High-resolution rapid source surveys for spectral-energy distributions and candidate identification
  • High-resolution imaging to follow morphological evolution of flaring sources
  • Timing of weak millisecond pulsars to enable folding of the gamma-ray light curves with respect to the pulsar period
  • Multi-frequency spectral monitoring of radio-weak, flaring gamma-ray sources

The radio data will be the property of the proposers for the standard NRAO 12-month proprietary period.

The actual amount of NRAO observing time allocated via the Joint Fermi Process will depend on the amount of proposal pressure and the scientific quality of the proposals. We anticipate that a maximum of 10% of the NRAO scientific observing time would be made available on GBT, VLA, and VLBA, or up to 400-650 hours per year on each telescope. If there are very strong scientific proposals for more time, and the Fermi mission has funds available to support data analysis, the Fermi Project Scientist will request additional time from the NRAO Director, who will set up an NRAO mechanism to evaluate and respond to this request.

Accepted regular NRAO proposals may include observations that have some overlap with observations approved in the Fermi GI Cycle. NRAO and the Fermi mission will resolve such duplications on a case-by-case basis; the default resolution will be that a single observation will be made and the data shared among the respective teams. A team that has duplicate proposals (or portions of proposals) accepted by NRAO and Fermi will receive only one allocation of observing time.

Cooperative Proposal Opportunity

Direct proposals for NRAO observing time that will enhance the scientific return associated with the Fermi mission also may be eligible for NASA funding through the GI program. These proposals will be the NRAO Large Proposals (requesting 200 or more hours of NRAO observing time) and Director's Discretionary Time Proposals, which respond to time-critical transient events. NRAO receives and evaluates Large Proposals at each of its proposal deadlines, two times per year, whereas Target of Opportunity proposals are considered at any time. These proposals are distinguished from those of the Joint Proposal Opportunity because they would involve requests for Fermi GI funding that are made subsequent to NRAO approval of observing time. Proposers of NRAO observations who also intend to propose for Fermi funding via this route must indicate their intentions clearly in the NRAO proposal, and all information related to the NRAO review of successful proposals will be forwarded to the Fermi mission for their evaluation. Note that the award of NRAO observing time will not be a guarantee of Fermi funding; likewise the observing time is not contingent on Fermi funding in this case.

Credits and Attributions

For results obtained using Fermi and NRAO facilities, proper attribution to NRAO facilities must be included in all publications, conference proceedings, posters, abstracts and talks and colloquia, as in the following: "The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." Fermi attribution will be the same as for all other use of Fermi data products.