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VLBA Proposal Preparation and Submission

by Gustaaf Van Moorsel last modified Apr 17, 2019 by Emmanuel Momjian
VLBA Proposal Preparation and Submission

Call for Proposals

The Call for Proposals details the general capabilities being offered for the Very Long Baseline Array (VLBA).  Proposals for time on the VLBA need to be prepared using the Proposal Submission Tool (PST), which is also used to submit proposals for the Very Large Array (VLA) and the Green Bank Telescope (GBT).

In addition to these general capabilities, NRAO offers a VLBA Resident Shared Risk Observing (RSRO) program for those who would like to push the capabilities of the instrument beyond those offered for general use.  Details are available on the web at the VLBA RSRO Program page.

The NRAO Proposal Submission Tool (PST) is accessed via the NRAO Interactive Services.  Documentation is available in the NRAO Proposal Submission Guide. For a comprehensive description of the VLBA instrument we refer to the VLBA Observational Status Summary (OSS).

For questions on the proposal submission process or problems with the NRAO PST please submit a ticket through the NRAO Helpdesk.

How to Propose

  1. Develop rationale: Before writing a proposal, the proposer must develop the scientific rationale for the program, develop a source list, decide on the observing band(s) to be used, and estimate the expected source strengths and their detectability. For spectral-line sources, the proposer also must decide on the desired velocity resolution, and convert that to a spectral resolution.
  2. Create Proposal in the Proposal Submission Tool (PST): After logging into NRAO Interactive Services, click on "Proposals" and then "New Proposal" on the top to the far right of the screen. Then Click on VLBA/HSA and "Create" (again on top to the far left). A proposal template will be created for you, click on the proposal number and this will open the proposal for you. There are seven screens to choose from and edit (there is an additional screen where you can find your disposition letter after the proposal has been reviewed).
    1. General: Title, abstract, proposal type, etc.. Edit this page by clicking on the "edit" button to top to the far right.
    2. Authors: List of authors and contact information. You can add an author by clicking on the "Add" button to the right on the page. Then search for your co-authors and if they are not in the database you can add them.
    3. Scientific Justification: Upload a pdf or txt of your scientific justification, no more than 4 pages in length for a Regular proposal (including figures, tables and references) with an 11pt font, or 10 pages for a Large (200 hours or more) proposal.
    4. Technical Justification: An important part of the proposal to be submitted is the Technical Justification.  Previously merely a required section in the Scientific Justification, it is now a separate element of each proposal.  Instead of the free format used in the Scientific Justification, we ask proposers to supply information on a number of standard topics, covering the wide range of technical issues of importance.  We have found that this reduces the likelihood that information is left out needed by the Technical Reviewers to judge the feasibility of the project as proposed. Follow the links in the form to obtain more information on the individual topics.  Click here to see an example.  Note that, with technical information contained on this page, space is freed up in the Science Justification.
    5. Sources: List of sources to observe. One slightly confusing thing here is that you have to create a "New Source Group" to add sources (button on upper right). After creating a group you can either add sources to it by hand or search for them with NED/SIMBAD. Adding sources to this section does not mean any time has been requested for them, they must be linked to a telescope resource in Sessions.  Except for proposals where the sources are not known a priori (e.g. triggered proposals), all target sources must be included in the source list.
    6. Resources: Resources requested from the VLBA (antennas, frequencies, bit rates, correlator, etc.).  To add a resource click "add" on the right.  If proposing for the VLBA/HSA then the "Socorro-DiFX" correlator should be used. Set which telescopes are being requested and then set the "Observing Parameters" and "Correlation Parameters" based on the scientific goals of the project. For most continuum experiments you will want the highest sustainable aggregate bit rate (currently 2 Gbps; see the relevant section of the OSS), i.e., the largest bandwidth and therefore the highest sensitivity.  For spectral line observations choose the number of baseband channels and their widths based on the expected frequency coverage of the lines, leaving some continuum on either side available for calibration.  If bandwidths narrower than 1 MHz are required, see the spectral resolution section of the OSS.
    7. Sessions: Describes the amount of time requested, and how it should be divided among the various sources and resources. Click on "New Session", this is where you actually request time on your sources at different frequencies.
  3. Examine and Submit: Go back to "My Proposals" and click on the printer icon (looks like a printer) next to the proposal code to see what the proposal will look like to a reviewer.  Once you are satisfied click the submit (large arrow) button to submit the proposal.