Appendices

Abbreviations, Acronyms, Definitions, and Useful URLs

AAT Archive Access Tool; https://data.nrao.edu
DDT Director’s Discretionary Time
LBO Long Baseline Observatory
LST Local Sidereal Time
NRAO Science Helpdesk https://help.nrao.edu/
Open Skies Open Skies observing time is when any scientist, regardless of nationality or residence, can apply for time on an instrument through a peer-reviewed process. The percentage of time that is considered Open Skies depends on the facility.
OPT Observation Preparation Tool; https://obs.vla.nrao.edu/opt/; requires login
PFT Proposal Finder Tool; https://library.nrao.edu/proposals
PI Principal Investigator
PST Proposal Submission Tool; https://my.nrao.edu; requires login
RCT Resource Catalog Tool; https://obs.vla.nrao.edu/rct; requires login
SCT Source Catalog Tool; https://obs.vla.nrao.edu/sct; requires login
Science Program https://science.nrao.edu/science/science-program and https://greenbankobservatory.org/science/gbt-observers/proposals/past-proposal-calls/
SRDP Science Ready Data Products
SRP Science Review Panel
TAC Telescope Time Allocation Committee
TTA Telescope Time Allocation
ToO Target of Opportunity
VLA Configuration

The antennas in the Karl G. Jansky Very Large Array (VLA) are placed in specific configurations. There are four basic antenna arrangements, called configurations, whose scales vary by the ratios 1 : 3.28 : 10.8 : 35.5 from smallest to largest. These configurations are denoted D, C, B, and A, respectively.

VLA configuration cycle; The VLA completes one cycle through all four configurations in an approximately 16 month period. See https://public.nrao.edu/vla-configurations/ for current and up-to-date configuration schedules and associated proposal deadlines.

Student Proposals and Dissertation Plans

The “Plan of Dissertation Research” should be submitted with their first proposal. This plan can be referred to in later proposals; instructions for how to upload or replace a plan are available here.

The Plan of Dissertation is important in the proposal review process and should be well written; it is not a placeholder and should not be a replica of the proposal. The plan must be compliant with the follow requirements:

  • It must follow the Observatory's Plan of Dissertation Research template. The template is available below in word or latex formats:
  • The section headers in the template should not be changed but the instructional text within the template should be replaced.
  • It must be uploaded as a Portable Document Format (pdf).
  • It is a maximum of two (2) pages.
  • There is a minimum of one inch margins on all sides and the pages are US letter size.
  • The minimum font size is 11 point, which includes the font in figure captions, table captions, table headers, content, and references. Fonts in rescaled figures should be legible.
  • All sections of the plan must be authored by the student.

The plan provides some assurance against a dissertation being impaired by adverse referee comments on one proposal, when the referees do not see the full scope of the project. Students should keep their expected graduation date in the user profile (Section 2.1) and in the thesis time line updated, as the date of data acquisition must fall within the timeline of the PhD. If the observing semester occurs after the student intends to graduate, then it is not appropriate to indicate that the proposal is for a dissertation. While not a guarantee, the Observatory allows reviewers to consider elevating the proposal in the rankings if it is associated with an acceptable Plan of Dissertation. This is given in consideration to the time constraints students typically operate under, as having to resubmit a proposal due to minor criticisms may not be possible within the scope of their studies. Therefore, it is advantageous for students to provide a thoughtful and thorough Plan of Dissertation if their PhD research is reliant on the proposal data.

Note, the PST does not validate Plans of Dissertations.

 

Definition of Duplicate Observation

A proposed observation is considered a duplicate of another observation if all of the following conditions are met:

  • Target field location
    • For a single-field, the proposed position coincides within the half-power beam width of the
      other observation. Moving objects (e.g., Solar System objects) will be identified by name.
    • For mosaic observations, more than 50% of the proposed pointings are within the half-power beam width area covered by the other observation.
    • For evolving or variables sources, the duplication is not scientifically justified.
    • For GBT monitoring programs, no two active programs can monitor the same proposed position that coincides within the half-power beam width of the other observation. Moving objects (e.g., Solar System objects) will be identified by name.
  • Angular Resolution
    • The proposed angular resolution differs by a factor of ≤ 2 from the other observation.
  • Spectral Windows
    • For the VLA and VLBA,
      • Continuum: The requested sensitivity (rms) for the aggregate bandwidth is better by a factor of ≤ 2 from the other observation and the requested frequency is within a factor of 1.3.
      • Spectral line: If the central frequency in any requested correlator window is encompassed by the other observation and the sensitivity per spectral channel, after smoothing to the same spectral resolution, is better by a factor of ≤ 2. Or, if the spectral resolution, as justified by the science case, is better by a factor of ≤ 2.
    • For the GBT,
      • Continuum: The requested sensitivity (rms) for the aggregate bandwidth is better by a factor of ≤ 2 from the other observation and the requested frequency is within a factor of 1.3.
      • Spectral Lines: Within the largest beam size of two receivers with overlapping frequency ranges, any spectral line being the same while taking into account velocity/redshift.

Solar observations will not be checked for duplication.

Commensal Observing

Commensal observations can be an effective way to maximize observing hours on Observatory telescopes, by allowing multiple experiments or systems to run simultaneously, when resources allow. The Observatory may support two kinds of commensal observing: commensal observing projects, and commensal systems.

Commensal observing projects refer to peer-reviewed, PI science projects which can be done simultaneously on Observatory telescopes using Observatory backends to conduct two different experiments concurrently. Investigators wishing to carry out commensal observing projects submit independent science proposals as separate primary and secondary proposals, which go through the normal time allocation processes, and are subject to standard data policies.

Commensal systems may be backends or data pipelines which have been approved to run on Observatory telescopes while some PI science experiments are running. Commensal observing systems which are currently on the VLA are described at the proposing page.

A primary proposal controls the telescope pointings and requests the full amount of telescope hours required to fulfill the science objectives detailed in the proposal. Secondary proposals are to run commensally with the primary pointings but make no formal request for an allocation of telescope time. However, when preparing a secondary commensal proposal, please ensure that a nominal amount of time is requested for a session (e.g., 0.1 hrs), even if it is a dummy session. Each proposal must contain estimates of the full resources needed (correlator setup, data rates, etc.) to carry out their specific part of the project.

During the proposal review and time allocation process it will be determined if the combination of the observing set-up and the positions by the primary or secondary proposals conflict with any approved projects. In the case of a conflict, some data restrictions may be applied to the primary and/or the secondary commensal proposal. If the primary and secondary proposals use the same back-end resources (e.g., VLA-WIDAR) it may be necessary for technical reasons to require that the investigators on both primary and commensal projects be given full access to all data.

The Observatory wishes to ensure that peer-reviewed, open-skies PI science projects which are approved via review processes are protected, and that ownership of data is defined. The concept of a “PI science project” includes the science goals and the data produced from PI-specified observing setups. The operation of all commensal systems on Observatory telescopes is subject to the below policy:

Peer-reviewed, open-skies PI science, and the associated output from standard observatory backends, take priority over commensal observing systems. Commensal observing systems may run at all times during open-skies PI science, except when they conflict directly with such science, or cannot run because of technical incompatibility. Conflict is defined by a commensal system reproducing, or being able to reproduce, any part of the PI data approved by the Observatory’s Telescope Time Allocation Committee. The Observatory requires that all commensal systems provide sufficient technical information so that determinations can be made as to whether they will conflict with PI science. The primary project science PI may choose to allow a conflicting commensal system to run; in this eventuality, the commensal system may run alongside the PI science project, subject to technical compatibility. The data produced by a commensal system are controlled by the associated commensal project team.

Observatory telescopes and backends are sufficiently flexible in many cases to allow two experiments to run commensally. To the degree that this enhances science return from the telescopes, Observatory wishes to support commensal projects subject to resource and scheduling constraints. The operation of commensal systems during other (non-open-skies) observing time is subject to the details of relevant contracts or agreements. Groups wishing to carry out commensal observations should submit independent science cases as separate primary and secondary proposals.

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