24A Semester

24A Proposal Call

The Green Bank Observatory (GBO) invites scientists to
participate in the 2024A Semester
Call for Proposals for the Green Bank Telescope (GBT).

The submission deadline for Semester 2024A proposals is
Wednesday, 2 August 2023, at 17:00 EDT (21:00 UTC).

The deadline is for the 24A semester observing period on the GBT:
1 February 2024 – 31 July 2024

The GBO would like to highlight the following:

  1. Low frequency (< 8 GHz) projects are encouraged
    • Up to 200 hours per source or field is reasonable
  2. Joint proposals with NICER(new), XMM-NewtonChandraHSTSwift, and Fermi
  3. Expected hours available: ~1700-2800 hours
    • Planned shutdown May-September 2024 (except for one week per month) for infrastructure work
    • Other shutdowns for infrastructure work may occur as necessary
    • ≤ 100 hours available for ν ≥ 50 GHz
    • Monitoring observations cannot be guaranteed cadence through shutdowns
  4. X-band and UWBR remain shared risk
    • UWBR available for short, week long campaigns at irregular intervals
  5. S-band will not be available
  6. New policy manual available here
    • Proposal deadline now Wednesday nearest Feb 1 and Aug 1
      • For example: 24B deadline will be January 31, 2024
    • New page limits
      • Regular: 4 pages
      • Large proposals: 6 pages
      • DDT proposals: 2 pages

A detailed timeline for the 24A Proposal Call is available here and summarized in the table below:

29 June 2023GBO/NRAO Call for Proposals
2 August 2023GBO/NRAO Proposal Deadline @ 21:00 UTC
31 August 2023Individual Science Reviews Completed
15 September 2023Science Review Panel (SRP) Meetings Completed
16-17 October 2023Telescope time allocation committee (TAC) meeting
7 November 2023Disposition Letters Sent

The GBO 2024A Call for Proposals is for observations with the GBT; the corresponding call for the VLBA/HSA/GMVA and VLA can be found at the NRAO Call for Proposals.

What’s New in 24A?

  • Proposal Deadline Dates. Starting in 24A, the deadline dates will be the closest Wednesday to 1 February (B semesters) or 1 August (A semesters).  For example, the 24A deadline date will be Wednesday, 2 August 2023 at 17:00 EDT and for 24B, the deadline will be Wednesday, 31 January 2024 at 17:00 EST.
  • Large Proposals. Starting in 24A, the page limit for the scientific justification of Large proposals will be reduced from 10 pages to 6 pages. 
  • Director’s Discretionary Time.  Proposals that are time critical or request target of opportunity observations that require the flexibility to allocate observing time on short notice should be submitted as DDTs.  Also, we strongly encourage the community to submit DDT requests for high-risk-high-reward investigations or exploratory time to test new, innovative ideas.  DDTs can also be submitted in support of Education and Public outreach.  Starting with the announcement for the Call for Proposals for 24A, the page limit for the scientific justification of DDTs will be reduced from 4 pages to 2 pages.
  • NICER. Starting in 24A, joint proposals may be submitted requesting time on the Neutron Star Interior Composition Explorer (NICER).  A maximum time of 250 ksec can be allocated per year on NICER.
  • Users’ Policies.  The NRAO users’ policies have been reviewed and updated by the science support and research department.  All users’ policies are located off the NRAO science website here.  The policies listed at this new location supersede policies listed elsewhere.

Proposal Process and Opportunities

Joint GBO and NRAO Telescope Time Allocation Process

Proposals to the Green Bank Observatory (GBO) and the National Radio Astronomy Observatory (NRAO) for the scientific use of its telescopes are evaluated on the basis of scientific merit and technical feasibility using a panel-based proposal review system.  This joint process is run by the NRAO in accordance with its policy of non-discrimination and inclusion.

The GBO 2024A Call for Proposals is for observations with the GBT; the corresponding call for the VLBA/HSA/GMVA and the VLA can be found at the NRAO Call for Proposals.

Low Frequency Science Opportunities

Low frequency (below 8 GHz) projects, especially those that may require significant amounts of observing time per source or field, are strongly encouraged.  Observations up to 200 hours per source or field at low frequencies is not unreasonable for the less subscribed LST ranges.  Please see the LST pressure plots in the Proposal Results for previous semesters located here.

New Opportunity

Joint Observations with NICER and GBO: Starting with the 24A semester joint observations requesting time on both NICER and the NRAO may be requested.  For more details see the Joint Proposal page.

Expected GBT time available in 24A

The GBT is expected to be shut down from May 2024 through the end of September 2024, except for one week per month.  During this shutdown repairs to the GBT infrastructure will be performed.  This includes azimuth wheel replacement, painting, and track, foundation and grout work.

Other shutdowns for infrastructure work may occur as necessary and with little warning.

As a result of the expected infrastructure work shut downs, we expect only 50% of the available observing time to be for open skies projects.  It is expected that there will be about 1700-2800 hours of A and B ranked observing time that can be assigned to new projects.  It is also expected that less than 100 hours of excellent weather high frequency time that can be assigned to new projects.

We cannot guarantee that monitoring projects can be scheduled through the summer of 2024 due to the planned infrastructure work.

Receiver Availability

X-band and Ultra-wideband shared risk

The X-band receiver is undergoing commissioning observations in the summer of 2023.  Shared risk proposal to use this receiver will be accepted for the 2024A proposal call.

The new Ultra-wideband Receiver (UWBR) is undergoing engineering changes and commissioning in the summer of 2023.  Unfortunately, the UWBR will not be available for regular monitoring observations in the 23B and 24A semesters.  We still anticipate that the UWBR could become available for some observations in the near future.  This would be for short, week-long campaigns occurring on irregular basis.
The UWB receiver is optimized for high-precision pulsar timing and wide-band observations of fast transients.  VEGAS will support coherent and incoherent dedispersion, and pulsar searching and timing modes over the full bandwidth of the receiver. 
For more information on the UWBR please visit here.

S-band not available

The S-band receiver will not be available in the 24A semester.

Receivers available only during campaigns

The Prime Focus 342 and 800 MHz feeds, the UWBR, and Q, W, Ka and Ku-band receivers will only be available for campaigns during the 24A semester.  The 800 MHz feed will be available on a monthly basis.

Receiver available during entire semester

It is expected that the L, C, X-band, KFPA, Argus and Mustang2 receivers will be available during the entire 24A semester.

Continuing Opportunities

Joint Observing program

Access to the Joint Observing program will continue for the GBT, VLA, and VLBA for semester 24A.  This includes joint observations with NICER, the XMM-Newton Project, the Chandra X-ray Observatory, the Hubble Space Telescope (HST), the Swift Gamma-Ray Burst Mission, and the Fermi Gamma-ray Space Telescope.  For more details see the Joint Proposal page.

Director’s Discretionary Time Including Education and Public Outreach

Proposals for Director’s Discretionary Time (DDT) may be submitted at any time. They must be submitted through the PST. DDT proposals are intended to address targets of opportunity, high-risk/high-return exploratory time, or other science opportunities deemed sufficiently urgent to justify prompt action. 

DDT proposals may also be submitted for the purpose of education and public outreach—for example, to image an iconic source or to support an educational opportunity for students. Such proposals should clearly justify the requirements for the requested time allocation and observing mode on any given instrument, and should describe the anticipated impact of the observation.  

While there is not an a priori limit to time that can be requested via DDT, it is expected that no more than 5% of the available science time on each telescope will be allocated for this purpose.

Other Proposal Opportunities

The GBO would like to make users aware that there are additional proposal opportunities as follows:

  • High Risk Proposals: As a means of maximizing its scientific impact through cutting-edge observations, the Observatory encourages the submission of high-risk/high-reward proposals.  That the proposal is high risk/high reward should be designated both in the abstract and the science justification.
  • Triggered Proposals: Observations for unknown sources that would be triggered by a celestial event (e.g., near Earth asteroid discovery, comet discovery, fast radio burst, etc.) can be submitted as a triggered proposal.  Any accepted triggered proposal will have proprietary rights to observations over any Director’s Discretionary Time (DDT) proposal.
  • Filler Programs: Some programs are not time critical or do not require highly subscribed LST ranges can request designation as a “filler program.”. Such programs may be able to take advantage of gaps in the GBT schedule.   The proposal should make clear in the abstract and early in the science justification that “filler” time is being requested.  Filler time requests will be ineligible for scheduling priority A or B.

New User’s Policy

The new User’s Policy Manual is available here. Important changes include moving the proposal deadlines to the nearest Wednesday to the 1st of February and the 1st of August (e.g., the 24B proposal deadline will be January 31, 2024), creation of scheduling priority D (formerly C-minus), and new pages limits (6 pages for large proposals and 2 pages for DDT proposals).

GBT Proposal Guide

All proposals should state why the GBT is necessary for the requested observations in both the abstract and science justification.

Virtual Proposal Planning Office Hours will be held July 26, 27 and 31.

Proposers are encouraged to look at past proposal call results, especially the LST pressure plots, which can be found in the TAC proposal result reports.  This information can be found here.

GBT Proposal Preparation

All proposers, including pulsar proposers, should use the GBT Sensitivity Calculator. The 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 lessen the chances for error. 

If you are planning on making maps with the GBT, you should use the GBT Mapping Calculator tool.

The GBT observing policies describe the telescope’s remote observing restrictions.

Proposers requesting GBT participation in High Sensitivity Array (HSA), Very Long Baseline Array (VLBA), or Global Millimeter Very Long Baseline Interferometry (GMVA) observations should consult the VLBA, HSA, and GMVA Proposal Call.

GBT Capabilities

The GBO encourages proposals that take advantage of the GBT’s unique capabilities across 0.29 to 116.2 GHz frequency range.  (Coverage is not available for 15.8-18.0 GHz, and 50.5-67.0 GHz).

Key science areas include, but are not limited to:

  • low column density HI (NHI ≈1017 cm-2 galactic and extragalactic)
  • star formation
  • fast radio bursts
  • galaxy and cluster evolution
  • pulsars (searches and timing)
  • cosmology
  • radio recombination lines
  • astrochemistry
  • solar system science

Details of all GBT observing modes are inThe Proposer’s Guide for the Green Bank Telescope. Proposers should also consult the more general document The Performance of the GBT: A Guide for Planning Observations.

Large Proposals

The GBT only accepts large proposals once per year for the B semester proposal deadlines.  Large GBT proposals are not accepted at the A semester proposal deadlines.  This policy ensures equality for the reviews of all large proposals that can be scheduled across a full year.

Recall that all large proposals are restricted to using no more than 50% of the open skies time available under any weather category (poor, good, excellent) at any LST during any semester.

Regular and Large proposal size definitions for the GBO are as follows:

  • 0-8 GHz (Any weather)
    • Regular:  < 400 hours and lasting ≤ 1 year
    • Large: ≥ 400 hours or lasting >1 year
  • 8-18 and 27.5-50 GHz (Good weather)
    • Regular:  < 200 hours and lasting ≤ 1 year
    • Large: ≥ 200 hours or lasting >1 year
  • 18-27.5 and > 50 GHz (Excellent weather)
    • Regular:  < 100 hours and lasting ≤ 1.5 year
    • Large:  ≥ 100 hours or lasting >1.5 year
  • Fixed and Monitoring proposals
    • Regular:  < 200 hours and lasting ≤ 1 year
    • Large:  ≥ 200 hours or lasting >1 year

Proposers submitting Large Proposals should read the Large Proposal Policy to ensure that they address all of the mandatory requirements.

Currently Large proposals comprise 50% of the available time for excellent weather projects.  We do not anticipate accepting any Large proposals for excellent weather projects at the 24B proposal deadline.

High Frequency Observations

There are approximately 1000 hours of excellent weather (18-27.5 and > 50 GHz) available each semester for both open skies and sponsored time.    Prior commitments typically account for slightly more than half of this time which leaves only 420 hours available to be scheduled each semester.  Due to mechanical issues encountered in the 22B and 23A semester, we expect the amount of high frequency carry over time to be larger than normal for the 24A semester.  We anticipate that ≤ 100 hours of high frequency time will be available for new proposals in the 24A semester.

Starting with the 23B proposal, all A ranked excellent weather projects will be considered for scheduling for 3 semesters.


The GBT receivers, backends, and observing modes that are available in Semester 2018B are listed in Tables 1 and 2 below.

ReceiverFrequency RangeExpected AvailabilityNote
Prime Focus 1290 – 395 MHzshort campaigns with irregular intervals between
Prime Focus 1680 – 920 MHzMonthly 2-3 week campaigns
Prime Focus 1385 – 520 MHz
510 – 690 MHz
high rank proposal demand only
Prime Focus 2910 – 1230 MHzhigh rank proposal demand only
UWBR700 – 4200 MHzshort campaigns with irregular intervals betweenshared-risk in the 24A semester
L-band1.15 – 1.73 GHzentire semester
S-band1.73 – 2.60 GHznot available
C-band3.8 – 8.0 GHzentire semesterlinear only, see below
X-band5 – 11.6 GHzentire semester
Ku-band12.9 – 15.4 GHzcampaigns (Feb-Mar, Jun-Jul)
K-band Focal Plane Array (KFPA)18 – 26.5 GHzentire semester7-pixel array
Ka-band26 – 39.5 GHzcampaigns (Feb-Mar)
Q-band38.2 – 49.8 GHzcampaigns (Apr-May)
W-band67 – 93.3 GHzcampaigns (Apr-May)
Argus75 – 115.3 GHzentire semester16-pixel array
MUSTANG-290 GHzentire semestershared-risk, private PI instrument
Table 1
BackendObserving ModeNote
VEGAScontinuum, spectral line, pulsar
CCBcontinuumKa-receiver only
MARK6 Disk RecorderVLBI
JPL Radar backendradarPrivate PI instrument, open for public use
Breakthrough ListenPrivate PI instrument, shared risk
Table 2

Permission required for instruments not listed as being available: Anyone requesting a receiver or instrument not listed as being available in the proposal call must have permission from the site director before the proposal is submitted.

C-band Polarization: Proposals wishing to use the GBT C-band receiver should only use linear polarization outputs.  The circular polarization of the receiver is currently not performing correctly and we will not accept any proposals to use the circular polarization output of this receiver.

VLBI including the HSA and GMVA: Proposers should clearly justify the need for the GBT in the text of the proposal.  All Very Long Baseline Interferometry (VLBI) proposals requesting the GBT should include any needed setup and overhead time in the time request of their proposals. 
Proposals requesting the GBT as part of High Sensitivity Array (HSA), and Global 3mm VLBI Array (GMVA) should be submitted through the Very Long Baseline Array’s call (available here).

C-band VLBI on the GBT: The GBO will only accept proposals using the GBT C-band receiver for VLBI Stokes I continuum observations (the observations will need to be done using full Stokes just to calibrate Stoke I).  Please see the HSA section of the Long Baseline Observatory call (available here) for proposals for more details.

MUSTANG-2: The GBO will accept proposals for shared risk observations using the MUSTANG-2 instrument at the proposal deadline.  More information on MUSTANG-2 can be found here.  The GBO cannot guarantee that MUSTANG-2 will be cold at the start of scheduled observing due to low observing elevations or rotations of the turret from prior observations.  All MUSTANG-2 proposals must have permission from the instrument development team – contact Emily MoravecSimon Dicker or Brian Mason

Breakthrough Listen backend: The Breakthrough Listen project is making its backend available for shared-risk observations during the 2024A semester.  The instrument consists of a cluster of 64 Titan X and 1080 GPU-based servers capturing 8-bit baseband voltages over up to 12 GHz of instantaneous bandwidth.  Data rates are typically tens of TB/hr but a pipeline is available to generate spectra with adjustable frequency (> 3 Hz) and time (> 350 μs) resolutions, with possible science applications including fast radio transients, pulsar observations, stellar flares, SETI, etc.  Before submitting a proposal, proposers must obtain permission from the Breakthrough Listen team at Berkeley SETI Research Center.  The team will consult on proposal preparation and data analysis.  Any data acquired using the backend will be proprietary to the proposer per the standard GBO policies.
More information including a technical description of the backend and team contact details can be found here.

Continuum Observations: Proposers wishing to perform continuum observation should consult with a GBO scientist.  Some information on continuum observations can be found here.

Observing and Scheduling Constraints

Session lengths: Proposers should be aware that long scheduling blocks (more than ~6 hours) are difficult to schedule.  Proposers must clearly state in the technical justification section how their project could be scheduled in smaller observing blocks that would more easily fit within the GBT scheduling constraints.   This is especially critical for proposals that require fixed or coordinated observing dates, e.g., VLBI observations, pulsar monitoring, radar, etc.

Mapping: If you are considering mapping with the GBT such that there are major turns or moves (end of rows in raster map, petals in daisy maps, changes in position for pointed maps, etc.) that occur with a cadence faster than every 30 seconds, you will need to consult with a GBT support scientist to ensure that the GBT can safely withstand the stresses induced by the mapping motions.

Fixed, Windowed and Temporally Constrained Observations: Due to varied pressures on the GBT’s scheduling, fixed time observations (e.g., VLBI, pulsar transit observations, etc.), windowed observations (e.g., monitoring observations) and temporally constrained observations (pulsar phase connection, orbit phase constraints, etc.) will likely have to be ranked at least in or near the top 10-25% of all AUI telescope proposals in order to be accepted.

Observing Team Members: We would like to remind all project teams of the Green Bank Observatory policy that all observers must be listed as a member of the project team in the GBT Dynamic Scheduling System. 
Also, we would like to remind all observers that they should not log into any GBO computing system using another person’s account.  Co-Is and students are required to have their own GBO login and account if they are to participate in observing and data reduction. 

Scheduling Increments: Please note that the GBT is scheduled in 15 minute (0.25 hour) increments and that all proposals should request time appropriately.   Time requests will be rounded down to the nearest 0.25 hour increment. 


The most recent RFI monitoring scans for the GBT can be found here.  These scans provide information on the frequencies that may encounter RFI.  Note that a Green Bank computing account is required to be able to view this information.  If you do not have a computing account please contact the helpdesk to request the desired RFI plots.

Schools and Workshops

Observer Training Workshops: The Green Bank Telescope (GBT) Remote Observer Training Workshop will provide the essential skills and knowledge needed to use the GBT and maximize its scientific output. It is intended for experienced astronomers who need to learn the specifics of observing with the GBT. After completing the workshop, an attendee will be certified to use the GBT as a remote observer. The workshop will focus on hands-on training in the observing techniques most relevant to participants (e.g. high frequency map, continuum, pulsar, etc.).
These workshops will be held several times a year and will complement traditional on-site training.  The next workshops will be held Feb 06-08, 2024. More information can be found here.

Single Dish Training School: The Green Bank Telescope (GBT) Single Dish Training School will provide graduate students, post-docs, and experts in other fields of astronomy with both knowledge and practical experience of the techniques and applications of single-dish radio astronomy using the GBT as the primary example. The school will be based around an intensive series of lectures from experts, as well as hands-on radio-astronomy projects and tutorials. Topics to be covered include radio telescope fundamentals, key single-dish science areas, observing and calibration techniques, the impact of weather, the GBT observing procedures and software, and data reduction.
The school will be held once per year. An intensive GBT remote observer training workshop will be held immediately following the school for those who wish to obtain remote observing certification.  The next school is tentatively set to occur in the summer or fall of 2024.

Joint Proposals

Joint Proposals Between the GBT, VLBA and VLA

Observing programs that require combinations of the GBT, VLBA, and/or the VLA should submit a proposal for each of the requested telescopes, with a clear justification for each, as has been the case to date. The proposals will be reviewed as before and considered jointly by the Time Allocation Committee. VLBI proposals which request the GBT or VLA (or the HSA, for example) as elements of the VLBI array do not need separate proposals—those telescopes can be selected as separate VLBI stations from a VLBA/HSA proposal.

Joint Proposals with External Facilities

Here we list opportunities for joint proposals with several external (non-AUI) facilities.  Agreements for Joint Observations with external facilities were made at different times across the boundaries when the NRAO was split into multiple observatories (NRAO, GBO, and LBO) in 2017, and when the LBO was reintegrated back into the NRAO in 2019.  Therefore, the agreements below will sometimes mention various combinations of the NRAO, GBO, and LBO.  Regardless, access to the Joint Observing program will continue for the VLA, VLBA, and GBT for semester 24A.

  • Joint Observations with NICER: By  agreement between the GBO and NASA, detailed in a Memorandum of Understanding, the GBO can award up to 250 ksec of NICER observing time per year.  In return, NICER can award up to 5% of the GBT open skies observing time.  See the Joint Observations with NICER page for details.
  • Joint Observations with XMM-Newton: By agreement with the Green Bank Observatory, detailed in a Memorandum of Understanding, the XMM-Newton Project may award up to 3% of GBT open skies observing time. Similarly, the GBT Time Allocation Committee may award up to 150 ks of XMM-Newton time per year. See the Joint Observations with XMM-Newton page for details.
  • Joint Observations with Chandra X-ray Observatory: In previous semesters, the community has had the opportunity to propose for observing time on NRAO facilities through a joint program with the Chandra X-ray Observatory. The Green Bank Observatory will continue with this program and will allocate up to 3% of the open skies time to highly ranked proposals that request time on both Chandra and the GBT.  Proposers to the GBO will have the opportunity to request time on Chandra, to be awarded on the recommendation of the GBO Telescope Allocation Committee (TAC) and approved by the GBO Director. Up to 120 ksec will be made available to GBO/NRAO proposers annually. 
    Due to Chandra’s increasingly challenging thermal constraints, the amount of Chandra exposure time available for High Ecliptic Latitude (HEL) targets with |bGal| > 55deg is extremely limited.  If you request joint time on Chandra, please avoid long exposures on such targets if at all possible.  You must note explicitly the requested amount of Chandra HEL time in the body of your science justification.
    N.B., Chandra ToO proposals are not supported under the Chandra-NRAO joint program.  See the Joint Observations with Chandra page for details.
  • Joint Observations with the Hubble Space Telescope (HST): By agreement between the NRAO (and continued honoring by GBO) and the Space Telescope Science Institute, STScI will be able to award up to 3% of the available open skies time to highly ranked proposals that request time on both HST and the GBT.  In return, STScI has offered 30 orbits per year of HST time for allocation by the GBO/NRAO TAC.   See the Joint Observations with HST page for details.
    N.B., HST “Snapshot” observations are not supported under the HST-NRAO Joint program since there is no guarantee that Snapshot targets will be completed.
  • Joint Observations with Swift Gamma-Ray Burst Mission: To foster correlative observations, a joint Swift/NRAO observing program was established, detailed in a Memorandum of Understanding. The GBO will continue to honor this agreement.  By this agreement, the Swift Program permits GBO/NRAO to award up to 300 kiloseconds of Swift observing time per year.   Similarly, GBO/NRAO permits the Swift Guest Investigator (GI) Program to award GBO observing time.  See the Joint Observations with Swift page for details.
  • Joint Observations with Fermi Gamma-ray Space Telescope: We remind the community that it is possible to propose for observing time on the GBT through the Fermi Gamma-ray Space Telescope Joint Proposal Opportunity or the Cooperative Proposal Opportunity.  See the Joint Observations with Fermi page for details.

GBO and NRAO User’s Policy

The new user’s policy manual is available here.

Tips for Proposers

Scientific Justification

The NRAO proposal evaluation and time allocation process is panel based. That is, members of the scientific community are responsible for reviewing proposals based on their scientific merit through the 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 is 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:

  • Avoid the use of radio astronomy jargon.
  • Do not assume the reader is familiar with a particular observing technique – explain it briefly.
  • 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.
  • Describe previous observations and publications relevant to the proposed observations.
  • If a particular point source or brightness temperature sensitivity is required, justify it.

Source Lists

The Observatory requires proposers to specify their source lists in full. This enables the Observatory to identify potential conflicts between observing programs and to better understand scheduling pressure on the instruments it operates. It may be the case that the final target list has not been selected at the time a proposal is submitted. In such cases, all potential targets and fields should be listed. The only exceptions to this requirement are for Triggered proposals to observe targets that are unknown a priori. Proposal source lists are not made public by the Observatory.

Dissertation Plans

Students proposing to use the GBT for their PhD dissertation must submit a “Plan of Dissertation Research” if they check the thesis box on the PST. The plan should be no more than 1000 words, and submitted with their first proposal. This plan can be referred to in later proposals.  The Plan of Dissertation is important in the proposal review process and should be well written; it is not a placeholder.  At a minimum it should contain:

  • A summary of thesis science and goals.
  • The role played by GBT observations being proposed.
  • A thesis time line.
  • The adviser’s name and institution.
  • An estimate of the total GBT telescope resources needed.

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. This requirement applies to all three of the AUI major instruments: GBT, VLBA, and VLA.

The Plan of Dissertation Research can be uploaded either from the Author’s page or from the student’s user profile at: Profile > My Profile > User Preferences. The Plan of Dissertation Research is associated with an Author which can then be used in one or more proposals. The Plan of Dissertation Research field here is only used to display the current status. For example, if there are no students listed on the proposal who are observing for their thesis the text box will display: Dissertation Research Plan(s) not required’.

24A Proposal Call Results

A total of 61 proposals requesting NSF funded “open skies” time were submitted to the Green Bank Observatory’s Robert C. Byrd Green Bank Telescope (GBT) for semester 24A. Proposals are reviewed on a competitive basis with a panel review system (see Proposal Review System). Below are the statistics by proposal count and hours. The oversubscription is the ratio of the number of submitted proposals to the number of approved proposals. The pressure is the ratio of the requested time to the available time in hours. Here we only include proposals submitted for the 24A semester that have been reviewed by the Green Bank Observatory Telescope Allocation Committee (TAC).

A description of the 24A proposals accepted can be found in our NSF Open Skies Science Program section below.

Total Proposals61
Statistics by Proposal Count
Requested Time3209 h
Available Time2626 h
Approved1622 h
Filler472 h
Rejected1115 h
Statistics by Proposal Hours

GBT Pressure Plots

Observations in high frequency bands require better weather conditions than observations in lower frequency bands. The GBT uses three weather categories:

  • poor – for observations below 8 GHz
  • good – for observations between 8-18 GHz and 26.5 – 50 GHz
  • excellent – for observations in the 18-26.5 GHz band and above 50 GHz

The first three figures below show the pressure plots for each these weather categories.  The last figure includes all weather categories.  The grey horizontal line shows the total available hours.  The letters A, B, and C correspond to the priorities assigned by the TAC where A and B are approved time and C is filler time.  Carryover is time allocated by a TAC from a previous semester that is being executed in the 24A semester.

GBT Observation Preparation

Please use the GBT Dynamic Scheduling System (DSS) to enable observing sessions, select observers for your project, and enter your blackout dates. The DSS Home Page has additional information about the DSS.  See GBT Observing for information about how to prepare for your observations.

Please note that the DSS uses the average Right Ascension (RA) and Declination (Dec) of all sources within a session.  The average RA and Dec will be used to determine when the session can be scheduled.  You will need to carefully check the RA and Dec, along with the minimum and maximum session lengths, to make sure that these values are satisfactory and will allow all your sources to be observed before enabling the session.

24A Science Program

A total of 61 proposals requesting NSF funded “open skies” time were submitted to the Green Bank Observatory’s Robert C. Byrd Green Bank Telescope (GBT) for the August 2, 2023 semester 24A deadline . The table below summarizes the approved observing programs. Listed are the PI name, proposal ID, proposal title, maximum hours approved and proposal type (Regular, Triggered, Large or External).

Proposals from previous semesters that were awarded time in the 24A semester are included. The table also includes HSA and GMVA proposals that were awarded time on the GBT as a VLBI station as well as proposal accepted via external agreements with CHANDRA, Hubble Space Telescope, FERMI, Swift, and XMM.

For each approved program, the Proposal Finder Tool will have access to its author, title, abstract and total approved hours.

A description of the Time Allocation Committee report for 24A can be found in the Proposal Call Results section above.

Alexander, KateGBT23A-273Monitoring the Exceptional Jetted Tidal Disruption Event AT2022cmc17.5Regular
Andreon, StefanoGBT24A-100Seeing warm gas accretion at the time when first galaxy clusters assemble32Regular
Bolatto, AlbertoGBT21B-024GBT EDGE: A Representative Survey of the z=0 Universe with Full IFU Spectroscopy300Large
Burton, CharlesGBT24A-329Milky Way Galactic Bar Dust Lanes21Regular
Busch, MichaelGBT24A-144Probing the structure of the diffuse molecular ISM–mixed or clumped?216Regular
Butterfield, NatalieGBT23B-202BARFLYS: Investigating the Star Forming Potential of the Galactic Bar Dust Lanes227.5Large
Cameron, AndrewGBT24A-211Continued observations of an eccentric, relativistic binary pulsar.15.75Regular
Cromartie, ThankfulGBT24A-400A GBT Search for Gaia-Selected Binary Pulsars16Regular
Dai, ShiGBT24A-055Monitoring the active repeater FRB 20190520B24Regular
Demorest, PaulGBT21B-285The North American Nanohertz Observatory for Gravitational Waves98Large
Dicker, SimonGBT24A-291Quantifying biases in selection functions of Sunyaev-Zel’dovich Effect surveys.16Regular
Di Gennaro, GabriellaGBT23B-120SZ observations of MaDCoWS clusters with diffuse radio emission at z=0.8-1.3414Regular
Di Teodoro, EnricoGBT23A-131Measuring 12CO(1-0) emission in the Milky Way’s Nuclear Wind6.5Regular
Gao, ShijieGBT24A-092Search for Radio Pulsations from Non-interacting Compact Star Binaries with GBT47.5Regular
Ginsburg, AdamGBT23A-268From ACES to TENS: The Central Molecular Zone with MUSTANG6Regular
Gomez, Jose L.GMVA23B-152Imaging supermassive binary black hole candidate OJ287 with GMVA+ALMA14Regular
Gusinskaia, NinaGBT23B-240Continued Timing of a Millisecond Pulsar in a Stellar Triple System51Regular
Gupta, HarshalGBT21B-316Molecular Exploration of the Diffuse Interstellar mediUM (MEDIUM)285.75Large
Huertas-Roldan, TeresaGBT24A-184Searching for fullerene-related species in space with the GBT132Regular
Jiao, SihanGBT24A-161A GBT pilot study of Anomalous Microwave Emission in M3131.75Regular
JNHS, AdityaVLBA24A-069Neutral gas in the nuclear regions of PKS 0428+2015Regular
Karunakaran, AnanthanGBT24A-120HI Observations of Dwarf Galaxies at the edge of the Local Group and Beyond68Regular
Kramer, MichaelGBT23B-227Timing and General Relativity in the Double Pulsar System82Regular
Ladu, ElisabettaVLBA23A-234Evidence for a new disk maser in the LINER galaxy IC485.8Regular
Ladu, ElisabettaGBT24A-278Monitoring of the water megamaser in IC485: weighing the BH of a LINER galaxy12Regular
Lockman, FelixGBT24A-319A Search for H2CO in Molecular Clouds Entrained in the Nuclear Wind19Regular
Lynch, RyanGBT24A-396Continuing a Pilot GBT Pulsar Survey of the Galactic Plane214Regular
Maan, YogeshGBT24A-201A Deep Search for Radio Pulsars in Faint and Compact Steep-spectrum Sources17.25Regular
Mall, GeetamGBT24A-303A scintillometric analysis of the relativistic binary pulsar B1534+1219.5Regular
Maureira, Maria JoseGBT22B-180CO freeze-out across a filamentary dense cloud forming a quadruple system25.5Regular
McGuire, BrettGBT23A-047Closing the Loop: PAHs Toward Cyg OB2-126Regular
McGuire, BrettGBT24A-232The Dark Carbon Falls – An ARKHAM Pilot Project192Regular
McKee, JamesGBT24A-255Broadband observations of giant pulses from PSR J0218+42328Regular
Michail, JosephVLBA24A-105Simultaneous Radio and Millimeter Monitoring of Sgr A* with JWST and EHT21Regular
Minter, AnthonyGBT24A-237A Search for Dust-free Clouds in the Galactic Disk205.75Regular
Moravec, EmilyGBT23B-005Characterizing the Highest Redshift Shock in a Merging Galaxy Cluster35Regular
Parent, EmilieGBT24A-172Pinpointing the onset of radio pulsations in a new transitional pulsar candidate4Triggered
Park, JonghoGMVA23B-067Peering into M87’s black hole in multiple colors28Regular
Patil, Swarali ShivrajGBT24A-394Searching for Scintillation Arcs in NANOGrav Binary Pulsars12Regular
Pearlman, AaronGBT24A-246Multiwavelength Studies of Nearby Repeating FRB Sources in the Local Universe20Triggered
Perez, KarenGBT24A-351Establishing the Energetics of the Luminous Gamma-Ray Redback: PSR J0212+532122Regular
Pineda, JaimeGBT23A-199Ions vs Neutrals in a Dense Core – copy18Regular
Possenti, AndreaGBT24A-023The magnetar-FRB link: simultaneous Radio/X-Ray monitoring of active magnetars21Triggered
Ransom, ScottGBT24A-375Long Term Timing of 76 Recycled Pulsars in Bulge Globular Clusters35Regular
Remijan, AnthonyGBT24A-114What is Happening With the HNCNH Maser in Sgr B2(N)? – A Monitoring Campaign2.5Regular
Remijan, AnthonyGBT24A-115Mapping the Large Scale Spatial Distribution of Complex Molecules towards Sgr B25.5Regular
Remijan, AnthonyGBT24A-124A Deep Targeted Line Survey of TMC-1 at X-band – A Pilot Study193.5Regular
Robishaw, TimothyGBT24A-397Confirmation of Magnetic Field Detection in CRRL Emission from DR 2141Regular
Romero, CharlesGBT23A-086SZ Constraints of Shocks in CIZA J2242.8+530140Regular
Salas, PedroGBT22A-437SC: GBT Diffuse Ionized Gas Survey at Low frequencies – GDIGS-Low826Large
Salas, PedroGBT23B-143The Partially Ionized Medium around HII Regions — the low frequency complement49Regular
Sarazin, CraigGBT23A-028Bridges of Intergalactic Gas Connecting ACT Cluster Pairs35Regular
Schmiedeke, AnikaGBT23A-360Exploring the kinematics in a filamentary infrared dark cloud40Regular
Schmiedeke, AnikaGBT22B-191Feeding a super-critical filament in a subsonic core17.5Regular
Scibelli, SamanthaGBT22A-435SC: Q- Band Chemical Complexity Survey of Prestellar Core L1544647Large
Sengar, RahulGBT24A-405The GBT 820MHz & GBNCC Survey: Pulsar Timing & Candidates Confirmation10Regular
Shroyer, JordanGBT23B-262Polarized Ku-Band Observations near G107.2+5.20 for CMB Foregrounds Study55Regular
Singal, JackGBT19A-083How Bright is the Radio Sky? A 310 MHz Absolute Map30Regular
Song, YiqingGBT22B-248Mapping HCN and HCO+ in Local Luminous Infrared Mergers19.5Regular
Spekkens, KristineGBT22B-139Atomic Gas in the Host Galaxies of Gravitational Wave Events – LVK O440Triggered
Spezzano, SilviaGBT22B-040Exploring the chemistry of Sulfur towards the young starless core L1521E18Regular
Squillace, ReynierGBT23A-263A Survey of 15-Nitrogen Fractionation in Prestellar Cores36Regular
Stephens, IanGBT23A-288Mapping Ammonia in Bones: Understanding our Magnetized Spiral Potential132Regular
Thomas, Reshma AnnaGBT24A-415Observation of an FRB skewering the M31 halo10.5Regular
Tu, TianyuGBT23B-090Probing the cosmic-ray-ionized dense gas associated with supernova remnant HB912Regular
Urquhart, JamesGBT23A-350Search of Hypercompact HII Regions Towards Methanol Masers56.25Regular
van Marrewijk, JoshiwaGBT24A-249Resolving SZ-selected clusters in the epoch of most rapid cluster growth42Regular
Yang, ChentaoGBT22B-020Confirming the nature of a 380GHz H2O maser disk in a lensed quasar at z=3.9114Regular
Yusef-Zadeh, FarhadGBT24A-116The Nature of the Extremely Broad 2200 km/s H56a line emission from Sgr A*4.75Regular

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