Twenty-four thousand hours of GREENBURST observations with the GBT

A. P. V. Siemion; A. Turan; D. Adair; D. Agarwal; D. R. Lorimer; E. Craver; E. Fonseca; E. Mayfield; F. Crawford; Fengqiu Adam Dong

arxiv: 2601.20143 · v2 · submitted 2026-01-28 · 🌌 astro-ph.HE · astro-ph.IM

Twenty-four thousand hours of GREENBURST observations with the GBT

J. W. Kania , S. Paine , G. M. Doskoch , S. Tabassum , S. Sirota , M. Flanagan , K. Halley , D. R. Lorimer

show 18 more authors

E. Mayfield M. A. McLaughlin E. Fonseca D. Agarwal M. P. Surnis F. Crawford T. Jespersen E. Craver M. Golden A. Turan J. Muyskens D. Adair Fengqiu Adam Dong A. P. V. Siemion G. Golpayegani M. B. Mickaliger K. M. Rajwade I. H. Stairs

This is my paper

Pith reviewed 2026-05-16 11:06 UTC · model grok-4.3

classification 🌌 astro-ph.HE astro-ph.IM

keywords pulsarsfast radio burstsradio transientsGreen Bank Telescopecommensal observationsnulling pulsarrepeating FRBsdispersion measure

0 comments

The pith

A 24,186-hour commensal search on the Green Bank Telescope detected 50 pulsars including one new slow pulsar and three previously known repeating fast radio bursts.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper reports outcomes from the GREENBURST project, which searched for dispersed radio pulses in data taken during other observations on the Green Bank Telescope. Across more than 24,000 hours the effort recorded 50 pulsars and three fast radio bursts. One pulsar had not been seen before; follow-up timing shows a 2.2-second spin period, a characteristic age of roughly 2 million years, and a nulling fraction of 70 to 80 percent. The three fast radio bursts were all known repeating sources already under monitoring. The authors emphasize that a single-beam receiver makes it difficult to separate genuine astronomical pulses from terrestrial radio-frequency interference, a point illustrated by one candidate pulse that later appeared to belong to a longer narrow-band signal of uncertain origin.

Core claim

We present the results from the first 24,186 hours of the GREENBURST search for dispersed radio pulses with the Green Bank Telescope. To date, GREENBURST has detected a total of 50 pulsars and three FRBs. One of the pulsars, PSR J0039+5407, has a period of 2.2 s and was previously unknown. Using follow-up observations with the Canadian Hydrogen Intensity Mapping Experiment, we found a timing solution for this pulsar which shows it to have a characteristic age of 2 Myr. Additional GBT observations show the pulsar has a very high nulling fraction (~70-80%). All three of the FRBs are repeating sources that were previously known and were being monitored by the GBT as part of other projects. A ma

What carries the argument

The GREENBURST single-beam receiver and pulse-detection pipeline on the Green Bank Telescope, which identifies dispersed pulses but must rely on post-processing filters to separate celestial signals from local interference.

If this is right

The newly discovered pulsar PSR J0039+5407 has a characteristic age of about 2 million years and nulls 70 to 80 percent of the time.
All fast radio bursts found in this survey were already-known repeating sources.
Single-beam searches accumulate large total observing time but require extra follow-up to confirm new transients.
Commensal use of large facilities can locate new pulsars without dedicated allocations.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

Extended commensal programs at major telescopes can steadily add to the known pulsar population even when transients are not the primary goal.
Better real-time or post-facto methods for rejecting narrow-band terrestrial signals would raise the chance that single-beam systems discover new fast radio bursts.
Continued monitoring of the narrow-band candidate pulse could reveal whether it repeats with a consistent dispersion measure or remains confined to a single frequency band.

Load-bearing premise

Pulses that survive the interference filters, including the new pulsar and the case-study event, are produced by astronomical sources rather than terrestrial radio-frequency interference.

What would settle it

Repeated multi-beam or multi-site observations that either recover a stable timing solution and dispersion measure for PSR J0039+5407 across independent sessions or show the ambiguous narrow-band pulse to lack astronomical dispersion and to recur without the expected frequency sweep.

read the original abstract

In addition to fast radio burst (FRB) searches carried out using dedicated surveys, a number of radio observatories take advantage of commensal opportunities with large facilities in which observations for other projects can be searched for FRBs and other transient sources. We present the results from one such effort, the first 24,186 hours of the GREENBURST search for dispersed radio pulses with the Green Bank Telescope (GBT). To date, GREENBURST has detected a total of 50 pulsars and three FRBs. One of the pulsars, PSR J0039+5407, has a period of 2.2 s and was previously unknown. Using follow-up observations with the Canadian Hydrogen Intensity Mapping Experiment, we found a timing solution for this pulsar which shows it to have a characteristic age of 2 Myr. Additional GBT observations show the pulsar has a very high nulling fraction ($\sim70-80\%$). All three of the FRBs are repeating sources that were previously known and were being monitored by the GBT as part of other projects. A major challenge for GREENBURST in the discovery of new FRBs is its single beam. This makes it hard to distinguish some of the pulses from sources of radio frequency interference. We highlight this problem with a case study of an FRB-like pulse that initially passed our interference filters. Upon closer inspection, the event appears to be part of a longer-duration narrow-band source of unknown origin. Further observations and monitoring are required to determine whether it is terrestrial or celestial.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

GREENBURST logs 24k hours, adds one new pulsar with solid follow-up, but stays incremental on FRBs and flags the single-beam RFI issue plainly.

read the letter

This paper is a straightforward report on 24,186 hours of GREENBURST commensal data from the GBT. They detected 50 pulsars in total and three known repeating FRBs. The standout new result is PSR J0039+5407, a 2.2 s pulsar with a CHIME-derived timing solution giving a 2 Myr characteristic age and additional GBT data showing 70-80% nulling. The survey numbers and that one discovery are what is actually new here. The work does well on the observational side by including the follow-up timing and by walking through the case study of the ambiguous pulse that looks like RFI rather than a celestial source. That section is transparent about the single-beam limitation and does not overclaim. The data handling and external confirmation look reliable with no circularity or unsupported steps. The soft spot is that the paper is mostly descriptive. The FRBs were already known, the methods extend existing programs without major changes, and the overall yield does not address bigger open questions in the field. With that much integration time the discovery rate is modest but typical for these searches. This is useful for teams running or planning commensal pulsar and FRB surveys who need real numbers and practical notes on RFI. The thinking is clear and the limitations are handled honestly. I would send it to peer review.

Referee Report

1 major / 3 minor

Summary. The paper reports results from the first 24,186 hours of the GREENBURST commensal search for dispersed radio pulses with the Green Bank Telescope. It claims detection of 50 pulsars (including the new PSR J0039+5407 with 2.2 s period) and three previously known repeating FRBs. Follow-up CHIME timing yields a 2 Myr characteristic age for the new pulsar, with additional GBT data indicating a ~70-80% nulling fraction. The manuscript transparently discusses single-beam limitations via a case study of an ambiguous FRB-like pulse that appears to be narrow-band RFI of unknown origin.

Significance. This observational report adds to the sample of pulsars and FRBs found through commensal GBT observations. The new pulsar discovery with supporting multi-telescope timing and nulling characterization is a concrete contribution, and the explicit treatment of the single-beam RFI ambiguity provides a useful cautionary example for similar searches. The work is primarily catalog-oriented rather than discovery-driven but strengthens the case for continued commensal monitoring.

major comments (1)

The nulling fraction of ~70-80% for PSR J0039+5407 is presented as a key property, yet the text does not specify the total number of pulses or observing sessions used in the estimate; this detail is needed to assess the robustness of the high-nulling claim.

minor comments (3)

Abstract: the sentence on the ambiguous pulse could explicitly state the observing frequency band to aid quick assessment of the RFI case study.
The manuscript refers to 'additional GBT observations' for the new pulsar without citing the specific project codes or dates; adding these would improve traceability.
Figure captions for the pulse profiles should include the number of averaged pulses to allow readers to judge signal-to-noise directly.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their positive recommendation and constructive comment. We address the major comment below.

read point-by-point responses

Referee: The nulling fraction of ~70-80% for PSR J0039+5407 is presented as a key property, yet the text does not specify the total number of pulses or observing sessions used in the estimate; this detail is needed to assess the robustness of the high-nulling claim.

Authors: We agree that the manuscript would benefit from explicit details on the data used for the nulling fraction. The ~70-80% value was derived from the additional GBT follow-up observations of PSR J0039+5407. In the revised manuscript we will add the total number of pulses examined and the number of observing sessions (and total integration time) on which the estimate is based. revision: yes

Circularity Check

0 steps flagged

No significant circularity; purely observational reporting

full rationale

The manuscript reports raw survey results from 24,186 hours of GREENBURST commensal observations: 50 pulsar detections (including the newly discovered PSR J0039+5407 with its 2.2 s period, CHIME-derived timing solution, 2 Myr characteristic age, and ~70-80% nulling fraction) plus three previously known repeating FRBs. All claims rest on direct pulse detection, external follow-up timing, and explicit discussion of single-beam RFI limitations via one case study. No equations, parameter fits, predictions, ansatzes, or uniqueness theorems appear; the derivation chain is absent and the results are externally falsifiable via independent telescopes. This is the standard non-circular outcome for an observational catalog paper.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an observational report with no theoretical derivations, fitted parameters, or invented entities central to a claim.

pith-pipeline@v0.9.0 · 5720 in / 1007 out tokens · 29531 ms · 2026-05-16T11:06:18.114579+00:00 · methodology

discussion (0)

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

IndisputableMonolith/Cost/FunctionalEquation.lean washburn_uniqueness_aczel unclear

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unclear
Relation between the paper passage and the cited Recognition theorem.

GREENBURST data acquisition and analysis pipeline... jess_gauss.py Jarque-Bera filter... Heimdall... FETCH... weighted zero-DM subtraction
IndisputableMonolith/Foundation/DimensionForcing.lean reality_from_one_distinction unclear

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unclear
Relation between the paper passage and the cited Recognition theorem.

24,186 hours... 50 pulsars... PSR J0039+5407... three repeating FRBs

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