|
|
Observing Rules: 5. Targets of Opportunity |
|
5. Targets of OpportunityTargets of Opportunity (ToO) are transient phenomena whose timing and/or location on the sky are unpredictable. They include objects that can be generically identified before the onset of such phenomena (e.g., recurrent novae, variable stars) and predictable phenomena that can be expected, although whose precise timing cannot be specified a priori (e.g., newly discovered comets, novae, supernovae, gamma-ray bursts).Predictable phenomena whose exact timing may remain uncertain at the time of proposal submission should be submitted in response to a General Observer Call for Proposals (CP). Observations of completely unanticipated phenomena can be requested through Director's Discretionary Time (DDT) procedures. By its very nature, a ToO warrants urgent consideration and attention, and unique procedures to handle such observations are therefore accommodated within all categories of Spitzer observing programs. At the time of proposal submission, investigators will classify each ToO request, based on the degree to which the execution of such an observation affects normal scheduling and observing procedures (Section 5.1). A General Observer proposal must include a valid Astronomical Observation Request (AOR) for each predictable ToO observation. The AOR must be completed in as much detail as possible, lacking perhaps the precise target position (i.e., a "null target") and refined integration times. The proposal must present a detailed plan of observations that will be implemented if the specific event occurs. Moreover, it must also provide an estimate of the probability of occurrence of the specified event during the relevant Spitzer observing cycle(s). The SSC Director reserves the right to designate any ToO data for early release when such a release is deemed (by the Director) to be in the interest of the community.
Even if the date of the required observation can be determined well in advance, if ANY update to the observing sequence is required less than 5 weeks before execution then the observation must be submitted as a medium or high impact ToO. Apart from the overhead burdens applied to all Spitzer observations (Section 1), the SSC will impose no additional overheads on low-impact ToO observations. The SSC has developed separate calculations of Observatory overheads to be assessed against the high- and medium-impact categories of ToO observations. These special overhead burdens are described online within the Proposal Kit section of the SSC website and are subject to change in future CPs. Proposals must include these overheads in the total requested observation time. An investigator will self-determine the appropriate category, based upon the maximum delay (in their judgment) that is scientifically acceptable between the activation of an approved AOR and the execution of the observation. This information will be useful in permitting the SSC and the Time Allocation Committee (TAC) to scientifically assess the value of the ToO observation vis-a-vis other approved observations. The Principal Investigator of a "high-impact" ToO observation must include, as part of the observing proposal, strong justifications for a rapid turnaround of ToO data by the SSC and (if relevant) compelling evidence to support the need for rapid instrument changes. In general, the more disruptive the ToO observation is to normal scheduling and operations, the stronger the justification must be to approve the proposed observation. Any ToO proposals seeking multiple-instrument observations on timescales shorter than the normal instrument campaign (7-21 days) will be assessed special overheads in observing time by the SSC. These overheads will reflect the observing time estimated to be lost to other programs if the approved ToO observations are activated, and will be factored into the proposal review conducted by the TAC. Proposals must include these overheads in the total requested observation time.
An approved ToO observation will be executed only in the event that the
specified phenomenon actually occurs within the relevant observing cycle.
If the triggering event for an approved ToO observation does not occur
during the observing cycle, the AOR will be deactivated at the end of the
cycle. In the event that a ToO observation expires without execution,
the allotted observing time will be returned to the General Observer pool.
Go back to rules page or go on to Section 6: Generic Targets
|
help@spitzer.caltech.edu http://ssc.spitzer.caltech.edu/documents/rules/sec5.html
