NRAO eNews
Volume 4, Issue 7
June 30, 2011

  • Download PDF
  • Contact the Editor
  • Subscribe
RSS News Feed Twitter Facebook YouTube

NRAO eNews
Volume 4, Issue 7  •  June 30, 2011

NRAO Call for Proposals: Semester 2012A

The NRAO announces the Call for Proposals for the 1 August deadline for Semester 2012A. The call is open now and will close on 1 August 2011 at 17:00 EDT (21:00 UTC).

Proposal preparation and submission are via the NRAO Proposal Submission Tool (PST) available through the NRAO Interactive Services. Several modifications to the PST have been made and will be in place starting 12:00 EDT (16:00 UTC) Thursday, 30 Jun 2011. (See PST_Release_Notes_Jun_2011 for details of recent changes.) The principal investigator, the contact author for scheduling and any students who will use the proposed observations for their dissertation thesis must be registered users. On the registration form you will be asked for contact information that will be used for notification about proposal status, telescope scheduling, student funding, etc. We encourage proposers to register early.

General News for Proposers

Full Implementation of the Semester-Based Proposal Cycle

NRAO has fully migrated from the old trimester-based proposal cycle to the new semester-based proposal cycle, with each semester lasting six months. Proposal submission deadlines are on 1 February and 1 August each year. At each deadline, proposers may request time on the GBT (Green Bank Telescope), the VLBA (Very Long Baseline Array) and/or the EVLA (Expanded Very Large Array). The 1 February deadline applies to requests for time from 1 August through 31 January, and the 1 August deadline applies to requests for time from 1 February through 31 July.  At either proposal deadline, requests can be made for an EVLA configuration linked to a future proposal deadline. Consult the EVLA Configuration Plans when planning such requests. Further details about proposal submission, proposal evaluation, and time allocation are available here.

Tips for Proposers

The new NRAO proposal evaluation and time allocation process, now occurring on a semester basis, is panel based. That is, members of the scientific community are responsible for reviewing proposals based on their scientific merit through eight Science Review Panels. As a means of broadening the scientific perspective of its reviewers, and of increasing the participation of the wider astronomy and astrophysics community in the science program of NRAO facilities, SRP membership was deliberately selected to include some colleagues that are not necessarily experts in radio observational techniques. This being the case, we encourage proposers to consider the following when preparing their proposals:

  1. avoid the use of radio astronomy jargon
  2. do not assume the reader is familiar with a particular observing technique - explain it briefly
  3. do not assume the reader is familiar with an earlier rationale for a developing line of research - provide adequate historical context and connect the dots as necessary
  4. describe previous observations and publications relevant to the proposed observations
  5. if a particular point source or brightness temperature sensitivity is required, justify it

Filler Time

The Observatory would like to point out that there are opportunities for so-called "filler" programs on all of its telescopes, particularly the VLBA (see below). Observing programs that exploit frequencies <10 GHz (X band and below), do not have strong scheduling constraints, and could benefit from short observing tracks of 30-60 min, are encouraged to propose for such opportunities. The proposal should make clear in the abstract and early in the science justification that "filler" time (scheduling priority C) is being requested, not scheduling priority A or B.

High Risk Proposals

As a means of maximizing its scientific impact through cutting edge observations, the Observatory also encourages the submission of high-risk/high-reward proposals. Such proposals may involve unusual targets, nonstandard observing techniques, new post-observing data reduction and analysis, or supplementary hardware or new back ends. Please contact Observatory Science Operations prior to submitting such proposals to discuss anticipated resource requirements. Observers contemplating such proposals may also wish to consider submitting an Exploratory Proposal to request Director's Discretionary Time as a means of demonstrating a proof of concept.

ALMA Preparatory Science Programs on NRAO Telescopes

With ALMA early science operations slated to begin in 2011, we continue to encourage the community to propose for ALMA Preparatory Science observing programs on the GBT, the VLBA and the EVLA. Proposals will be considered for all NRAO telescopes, and for all proposal types (Large, Regular and Triggered). There will be no limits on the fraction of time that NRAO will allocate for these proposals. Such proposals should be identified as ALMA preparatory science in the proposal title or in the abstract. These proposals will be subject to the normal evaluation process.

Opportunities for Joint Observations with Fermi or Chandra

We remind the community that it is possible to propose for observing time on NRAO facilities through the Fermi Gamma-ray Space Telescope Joint Proposal Opportunity or the Cooperative Proposal Opportunity. For Fermi, which is primarily in sky-survey mode, potential observers may propose for NRAO observations that make use of the Fermi survey data even without re-pointing of the Fermi satellite. The actual amount of NRAO observing time allocated via the Joint Fermi Process depends on the amount of proposal pressure and the scientific quality of the proposals. A maximum of 10% of the NRAO scientific observing time is made available on the GBT, the VLBA and the EVLA, or up to 400-650 hours per year on each telescope. Details about joint observations with Fermi and the GBT, the VLBA or the EVLA may be found here. The next Fermi proposal deadline is in January 2012.
Similarly, the community may propose for observing time on NRAO facilities through a joint program with the Chandra X-ray Observatory. For Chandra, proposals must be for observations that require both Chandra pointing and NRAO observations to carry out a scientific investigation. The NRAO has allocated up to 3% of the observing time on the EVLA, the VLBA, and the GBT for Chandra joint proposals. Section 4.5.5 of the Chandra call for proposals gives specifics of the joint NRAO/Chandra program. The next Chandra proposal deadline is in March 2012.

PhD Dissertations using NRAO Facilities

Students planning to use one or more NRAO telescopes for their PhD dissertation must submit a "Plan of Dissertation Research" of no more than 1000 words with their first proposal. This plan can be referred to in later proposals. At a minimum the plan should contain a thesis time line and an estimate of the level of NRAO telescope resources needed. The plan provides some assurance against a dissertation being impaired by an adverse review of a proposal when the full scope of the thesis is not seen. The plan can be submitted via NRAO Interactive Services. Students are reminded to submit their plan comfortably in advance of the proposal deadline.

Beginning with the proposal deadline of 1 August 2011, new thesis plans must be in pdf format so science reviewers can easily access the plans. Students who have not yet graduated but have plans on file should consider updating those plans to a pdf format if they are not already in that form.

Student Observing Support Program

NRAO maintains a program to support research by students, both graduate and undergraduate, at U.S. universities and colleges. This program is intended to strengthen the proactive role of the Observatory in training new generations of telescope users. Regular or Triggered proposals submitted for the EVLA, the VLBA and the GBT are eligible. Large proposals for the EVLA, the VLBA, the GBT, and any combination of these telescopes are also eligible. New applications to the program may be submitted along with new observing proposals at any proposal deadline. A general overview of the program can be found here; additional details can be found here.

Key Science Projects

The NRAO Time Allocation Committee (TAC) automatically considers proposals for time on the GBT, the VLBA and the EVLA for designation as Key Science Projects. Key Science Projects should be those that have have high science impact, addressing forefront issues in astronomy and astrophysics. Key Science Project status will be based on scientific rank, recommendation by the TAC and approval by the NRAO Director.

EVLA Proposals

Observing Capabilities for EVLA Early Science

The 1 August 2011 deadline involves the observing period 27 January 2012 through 27 August 2012 (Semester 2012A), corresponding to the C, CnB and B configurations. However, proposals to use all future EVLA configurations through the end of the A configuration in January 2013 will also be considered. See the EVLA Configuration Plans for further information.

All antennas now employ EVLA-style electronics, and most of the new receiver systems will be installed by the beginning of the EVLA C configuration. EVLA Early Science is enabled by two programs for the user community: the Open Shared Risk Observing (OSRO) program and the Resident Shared Risk Observing (RSRO) program. These programs have been announced previously in NRAO eNews. For this cycle, the capabilities offered for the OSRO program are identical to the previous proposal cycle with additional receiver availability; the RSRO program offers enhanced correlator capabilities. Both programs' capabilities are described in detail on the OSRO and RSRO web pages. In addition, the EVLA Observational Status Summary has been updated and provides a reference to the capabilities for those interested in proposing. We remind users that access to the EVLA is on a shared-risk basis, and that the EVLA is undergoing commissioning through end of 2012. Nevertheless, NRAO will make every effort to ensure high-quality EVLA data during this period.

For this proposal cycle, we will be offering continuous frequency coverage from 1 to 50 GHz for the majority of the antenna systems (i.e., the extended EVLA tuning ranges at L, S, C, X, Ku, K, Ka, and Q-bands). Some L-band systems are "interim," which means they use old VLA polarizers. The ranges outside the nominal VLA frequencies for L-band have poor sensitivity and polarization performance for the interim receivers, as compared with the nominal VLA frequencies. New EVLA-style X-band receivers are included in astronomical observations along with the existing narrow-band VLA (8-8.8 GHz; see the following table) receivers as soon as they have been tested. During this cycle, the majority of antennas will have the new wide-band receivers; however, observers should continue to assume the tuning range of the VLA receivers at X-band if all antennas are required. For those bands whose receivers support the wide bandwidths, the two IF pairs may independently be placed anywhere in the tuning range shown in the table below, except for special limitations on the tuning of the IFs for the Ka-band receiver. Please consult the EVLA Observational Status Summary for frequency setting restrictions and details on the sensitivity as a function of frequency.

The numbers of receiver systems available at the beginning of the EVLA C configuration are approximately as follows:

Band Tuning range Receiver availability: Jan 2012
L 1-2 GHz 20 (EVLA) + 7 (interim)
S 2-4 GHz 22
C 4-8 GHz 27
X 8.0-12.0 (8.0-8.8) GHz 17 (EVLA) + 10 (VLA)
Ku 12.0-18.0 GHz 18
K 18-26.5 GHz 27
Ka 26.5-40 GHz 27
Q 40-50 GHz 27

OSRO observers will be able to use two independently-tuned basebands, each up to 1 GHz wide. Each baseband comprises up to 8 contiguous sub-bands, with sub-band bandwidths selectable in powers of two between 31.25 kHz and 128 MHz. RSRO observers have considerably more flexibility in the correlator setups (number of sub-bands, varying bandwidths, independent tuning and channelization); correlator recirculation, enabling options for millions of spectral channels, is also being commissioned through the RSRO program. In addition, a subset of antennas (approximately 7 in February increasing to 22 in August) will be equipped with 3-bit samplers, enabling up to 8 GHz of instantaneous bandwidth; we expect to ready these for availability for RSRO programs in the second quarter of 2012. These features will be made available to the general community at the beginning of the next configuration cycle in January 2013.

Subarrays, phased array, pulsar and VLBI observing modes will not be available in Semester 2012A except through the provision of RSRO commissioning effort to enable these modes. No proposals to use frequencies lower than 1 GHz will be considered for this call. Users will be notified when these observing modes have been fully commissioned.

All EVLA observations are set up using the Observation Preparation Tool (OPT). Use of the OPT requires registration in the NRAO User Database. Most, if not all, projects will be observed dynamically so users should submit scheduling blocks early in the configuration to maximize the opportunity of them being observed.

Proposal preparation and submission are via the Proposal Submission Tool at NRAO Interactive Services. The different capabilities available for the OSRO and RSRO programs may be selected in the "resources" section of VLA proposals.

Questions about EVLA capabilities, observing strategies, or proposal submission should be directed to the NRAO Helpdesk.

GBT Proposals

The 1 August 2011 deadline is for the Semester 2012A observing period: 1 February 2012 through 31 July 2012. Proposals will be considered for the following receivers: 290-920 MHz (PF1), 910-1230 MHz (PF2), 1.15-1.73 GHz (L), 1.73-2.60 GHz (S), 3.8-6.1 GHz (C), 8.0-12.0 GHz (X), 12.0-15.4 GHz (Ku), 18.0-26.0 (KFPA), 26.0-39.5 GHz (Ka), 38.2-49.8 GHz (Q) receivers, MUSTANG (80-100 GHz Bolometer Array) and shared-risk 68-92 GHz (W).

Available observing modes include spectral line (including cross-polarization), continuum, pulsar, and VLBI/VLBA. The VLBA back end with Mark5A disk recorder may be used as a high-time resolution (> 2 ns) backend for single-dish observing.

Details of all GBT observing modes are in the GBT Proposer's Guide. Proposers should also consult the more general document "The Performance of the GBT: A Guide for Planning Observations."

4mm Receiver: The new 68-92 GHz 4mm (W-band) receiver will be commissioned in the fall of 2011. The receiver should available for shared-risked observations in the 12A semester. Note that observations with this receiver are expected to be limited to night-time only. Also, the pointing/tracking stability of the GBT is currently 2-3 arcseconds, which is a large fraction of the 4mm beam. For more information see the GBT 4mm Receiver web page.

4mm VLBI: We will consider shared-risk proposals to use the new 4mm receiver for VLBI observations in the 12A semester.

VErsatile GBT Astronomical Spectrometer (VEGAS): A new FPGA spectrometer is under development for the GBT. Shared-risk proposals to use VEGAS will be considered for the 12A semester. Please see the GBT Proposer's Guide for more information on VEGAS.

New Sensitivity Calculator: All proposers should use the new and improved GBT Sensitivity Calculator. Please see the GBT Sensitivity Calculator User's Guide for further instructions. The new Sensitivity Calculator results can be cut and pasted into the Technical Justification section of the proposal. This will streamline the creation of your Technical Justification and will increase your chances of getting a positive technical review.

Proposers requesting GBT participation in High Sensitivity Array (HSA), Very Long Baseline Array (VLBA), or global Very Long Baseline Interferometry (VLBI) observations should consult the "VLBA, HSA, and VLBI" section below.

The GBT will be scheduled by the Dynamic Scheduling System (DSS) in Semester 2012A. Note that the DSS will result in no change to the proposal preparation and submission process: when the review process is complete, project investigators will be contacted on how to modify any information brought over from the PST which they desire to have changed before the semester begins. GBT staff will, as always, be available to help observers in working with the observing information in the DSS database and also with understanding the new dynamic scheduling scheme. Note that the DSS alters only the scheduling process for the GBT and will not affect the observing interface (e.g. Astrid) in any way. The GBT observing policies describe the remote observing restrictions.

Technical questions or questions about the proposal process may be addressed to Toney Minter (+1-304-456-2275 or Questions about the PST should be sent to the NRAO helpdesk.

VLBA, HSA, & VLBI Proposals

The 1 August 2011 deadline applies to regular and triggered observing proposals requesting:

This deadline also applies to large observing proposals requesting the VLBA, alone or with other NRAO resources.

The observing period is February 1, 2012 through July 31, 2012.

Please see here for further details and proposal submission instructions for VLBA, HSA, and global VLBI proposals.

2-Gbps Wideband Observing Capability

As at the February 1, 2011, proposal deadline, we are soliciting proposals to use the new 2-Gigabit per second (Gbps) recording rate, corresponding to 256 MHz bandwidth per IF input in a typical 2-IF case. In its current implementation, this wideband mode is relatively inflexible, supporting only a fixed configuration that produces fifteen contiguous 32-MHz sub-bands from each of two IF inputs (a sixteenth sub-band in each IF does not contain usable data). Fully flexible selection of any sixteen of these thirty sub-bands for 2-bit requantization and recording at 2 Gbps is now available. We expect the two main configurations that will be selected to be eight dual-polar, and sixteen single-polar sub-bands.

A substantial pool of recording media is available to support 2-Gbps recording for most proposed wideband observations. However, since it will not be possible to support sustained 2 Gbps recording for all observations, proposals requesting this capability should justify its use.

Wideband observing is selected via a checkbox labelled "Wideband Observing System" in the NRAO Proposal Submission Tool's resources section. That checkbox causes the appropriate fixed values to be filled throughout the resource segment, with the only exception being that either single- or dual-polar modes can also be specified. Alternatively, proposals not requiring the wideband capability can request use of the original VLBA data acquisition system in the same manner as previously.

Scientific commissioning of the new equipment continues. The tenth VLBA station was outfitted at the end of May, and installation at the GBT was completed at the end of March, with correct operation validated in several recent tests. Proposals to use the GBT in 2-Gbps HSA observations with the VLBA will be considered at this deadline; other HSA telescopes will be included as they become available, but should not be assumed for this deadline.

C-Band Upgrade Progress

The first receiver has been upgraded to the new, wider band and higher sensitivity configuration, and re-installed on the array. Recent measurements showed a noise temperature on the sky of about 22 Kelvin. Since the downconverter module required to support the entire range of frequencies is not yet available, temporary filters limit the operation of the new receiver to the old system's range, which should be assumed for proposals at this deadline. Outfitting of the remaining stations is expected to proceed at about one per month, with the upgrade reaching completion by mid-2012. During this period the number of available C-band receivers on the VLBA is expected to be 8 or 9 at any one time, possibly as few as 7 for brief intervals. Requirements for eight or more stations may require special scheduling, and should be justified in the proposal.

VLBA "RSRO" Program

The VLBA currently has several development projects planned or underway that would benefit from contributions by community experts for their commissioning and delivery. We are now offering a program similar to the EVLA's successful "Resident Shared Risk Observing" (RSRO) concept, to give users an opportunity to assist NRAO with these projects in return for early access to the corresponding new capabilities. Users are invited to propose areas in which they would be willing to contribute two months or more (subject to negotiation) of concentrated effort. A RSRO option is now available in the VLBA Resources page of the Proposal Submission Tool for entry of a brief description of the proposed RSRO resources and technical set-up. Further details on the VLBA RSRO program, including some areas of particular interest to NRAO, are listed on a separate NRAO website page. Proposals for any area of user interest are welcome.

VLBA Observational Status Summary

An updated version of the VLBA Observational Status Summary is available in html, pdf, or postscript formats.

Please Use the NRAO Helpdesk!

Investigators requiring assistance in proposal submission, observation preparation, or data processing should use the NRAO Helpdesk, rather than sending communications directly to members the VLBA support staff. Please log in using the same user ID and password as when accessing the Proposal Submission Tool. EVLA and ALMA users will already be familiar with this system.

Filler Time Available

We continue to encourage the submission of proposals that can use short scheduling blocks, poor weather, or fewer than the maximum ten VLBA stations (see the NRAO eNews, September 15, 2010).

Staff  |   Policies  |   Diversity