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arxiv: 1907.05263 · v1 · pith:EHZDCQTQnew · submitted 2019-07-11 · 🌌 astro-ph.IM

Commensal, Multi-user Observations with an Ethernet-based Jansky Very Large Array

Jack Hickish , Tony Beasley , Geoff Bower , Sarah Burke-Spolaor , Steve Croft , Dave DeBoer , Paul Demorest , Bill Diamond
show 7 more authors
Vishal Gajjar Casey Law Joseph Lazio Jason Manley Zsolt Paragi Scott Ransom Andrew Siemion
This is my paper

Pith reviewed 2026-05-24 22:55 UTC · model grok-4.3

classification 🌌 astro-ph.IM
keywords commensal observingJansky VLAEthernet data distributionradio astronomy instrumentationSETItransient surveysmulti-user observations
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The pith

Ethernet data sharing lets the VLA run multiple independent science programs at the same time.

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

The paper shows that falling costs of consumer computing hardware now make it practical to connect radio telescopes directly to Ethernet networks that feed raw data to many users simultaneously. This setup turns wide-bandwidth, wide-field instruments like the Jansky VLA into platforms that can pursue several goals in parallel, such as searches for technological signals and surveys for radio transients, without needing separate pointings or schedules. The authors describe a concrete project to install an Ethernet-based commensal mode on the VLA and explain how it would support a large-scale effort to map the occurrence of advanced life while also serving other programs and future instrument tests.

Core claim

By routing raw telescope data over Ethernet, a single VLA observation can supply independent data streams to multiple science teams at once, allowing commensal programs that do not require unique cadence or direction to run together and thereby multiply the telescope's scientific return.

What carries the argument

Ethernet interconnect that naturally permits multiple subscribers to a single raw data stream from the telescope.

If this is right

  • A continuous commensal search for radio emission from technology can run on the VLA to place new limits on the distribution of advanced life.
  • Radio transient surveys and other time-domain programs can operate alongside the SETI effort without dedicated scheduling.
  • The same raw data streams can support technology development and testing for next-generation processing systems.
  • Consumer-grade hardware upgrades become straightforward because the Ethernet interface decouples the data distribution from specific instrument designs.

Where Pith is reading between the lines

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

  • Existing radio arrays without Ethernet distribution could gain similar productivity gains by adding comparable data-sharing layers.
  • Shared raw data streams create opportunities for new combinations of science goals that were previously scheduled separately.
  • The approach lowers the hardware barrier for small teams to access high-bandwidth observations without building dedicated instruments.

Load-bearing premise

Many science programs do not need exclusive control over where the telescope points or when it observes.

What would settle it

A set of simultaneous observing requests in which two programs require incompatible pointings or cadences that cannot be reconciled without one program losing data.

Figures

Figures reproduced from arXiv: 1907.05263 by Andrew Siemion, Bill Diamond, Casey Law, Dave DeBoer, Geoff Bower, Jack Hickish, Jason Manley, Joseph Lazio, Paul Demorest, Sarah Burke-Spolaor, Scott Ransom, Steve Croft, Tony Beasley, Vishal Gajjar, Zsolt Paragi.

Figure 1
Figure 1. Figure 1: Adapted from [18], the transmitter rate limit, [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: A SWIB interface card (b) will be added to the spare output connector of each of the [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: A Clos network is a well-known architecture that allows large switching networks to be [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: The 40 Gb Ethernet infrastructure used in the MeerKAT array feeds data between 64 dig [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: A tentative timeline for the execution of the project and activities described herein, [PITH_FULL_IMAGE:figures/full_fig_p011_5.png] view at source ↗
read the original abstract

Over the last decade, the continuing decline in the cost of digital computing technology has brought about a dramatic transformation in how digital instrumentation for radio astronomy is developed and operated. In most cases, it is now possible to interface consumer computing hardware, e.g. inexpensive graphics processing units and storage devices, directly to the raw data streams produced by radio telescopes. Such systems bring with them myriad benefits: straightforward upgrade paths, cost savings through leveraging an economy of scale, and a lowered barrier to entry for scientists and engineers seeking to add new instrument capabilities. Additionally, the typical data-interconnect technology used with general-purpose computing hardware -- Ethernet -- naturally permits multiple subscribers to a single raw data stream. This allows multiple science programs to be conducted in parallel. When combined with broad bandwidths and wide primary fields of view, radio telescopes become capable of achieving many science goals simultaneously. Moreover, because many science programs are not strongly dependent on observing cadence and direction (e.g. searches for extraterrestrial intelligence and radio transient surveys), these so-called "commensal" observing programs can dramatically increase the scientific productivity and discovery potential of an observatory. In this whitepaper, we detail a project to add an Ethernet-based commensal observing mode to the Jansky Very Large Array (VLA), and discuss how this mode could be leveraged to conduct a powerful program to constrain the distribution of advanced life in the universe through a search for radio emission indicative of technology. We also discuss other potential science use-cases for the system, and how the system could be used for technology development towards next-generation processing systems for the Next Generation VLA.

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.

Referee Report

1 major / 0 minor

Summary. The manuscript is a whitepaper proposing the addition of an Ethernet-based commensal observing mode to the Jansky Very Large Array (VLA). It claims that Ethernet's natural support for multiple subscribers to a single raw data stream, when combined with the VLA's broad bandwidths and wide fields of view, will enable multiple independent science programs (e.g., SETI searches for technosignatures and radio transient surveys) to run in parallel without conflicting with primary observations, thereby increasing overall scientific productivity and supporting technology development for the ngVLA.

Significance. If the proposed mode can be realized, it would offer a cost-effective way to multiply the VLA's scientific output by leveraging commodity hardware and existing data distribution infrastructure for commensal programs that are insensitive to cadence and pointing. The emphasis on a SETI program as a flagship application is a concrete example of how such a system could address high-impact questions about the distribution of advanced life. The approach aligns with trends toward general-purpose computing in radio astronomy instrumentation.

major comments (1)
  1. [Project description (as referenced in the abstract)] The central technical claim—that Ethernet multi-subscriber access can sustain full-rate delivery to several concurrent pipelines at VLA correlator output rates without packet loss, added latency, or resource contention—is load-bearing for the productivity gains asserted in the abstract, yet the manuscript supplies no quantitative estimates of data rates, required network bandwidth, multicast implementation details, or processing isolation.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their constructive review and positive assessment of the proposed Ethernet-based commensal observing mode. We address the single major comment below and will revise the manuscript to incorporate additional quantitative context where feasible.

read point-by-point responses

  1. Referee: [Project description (as referenced in the abstract)] The central technical claim—that Ethernet multi-subscriber access can sustain full-rate delivery to several concurrent pipelines at VLA correlator output rates without packet loss, added latency, or resource contention—is load-bearing for the productivity gains asserted in the abstract, yet the manuscript supplies no quantitative estimates of data rates, required network bandwidth, multicast implementation details, or processing isolation.

    Authors: We agree that the whitepaper would benefit from order-of-magnitude estimates to better support the central claim. In the revised version we will add a short subsection (likely in Section 2 or 3) that provides: (1) approximate VLA correlator output rates based on published 8-bit, 3 GHz bandwidth configurations (~ tens of Gbps aggregate); (2) the network bandwidth required to support multicast distribution to a small number of independent subscribers; and (3) a high-level description of standard Ethernet multicast (IGMP/PIM) and how commodity switches can isolate traffic. We will explicitly note that detailed packet-loss, latency, and isolation measurements lie beyond the scope of this conceptual whitepaper and would be addressed in a subsequent engineering study. These additions will be kept concise so as not to change the document's character as a science-driven proposal. revision: yes

Circularity Check

0 steps flagged

No circularity: proposal document contains no derivations or fitted quantities

full rationale

The document is a forward-looking whitepaper proposing an Ethernet-based commensal mode for the VLA. It contains no equations, no parameter fitting, no predictions derived from data, and no load-bearing self-citations. All claims rest on stated general properties of Ethernet networking and observing strategies (e.g., independence of certain science programs from cadence), which are presented as external facts rather than derived within the paper. No step reduces by construction to its own inputs.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an instrumentation proposal with no mathematical model, data analysis, or theoretical derivation; therefore the ledger contains no entries.

pith-pipeline@v0.9.0 · 5873 in / 1043 out tokens · 21691 ms · 2026-05-24T22:55:23.532883+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

35 extracted references · 35 canonical work pages · 3 internal anchors

  1. [1]

    An Astrobiology Strategy for the Search for Life in the Universe

    Engineering National Academies of Sciences and Medicine. An Astrobiology Strategy for the Search for Life in the Universe. The National Academies Press, Washington, DC, 2019

    work page 2019

  2. [2]

    Detecting Earth-like Biosignatures on Rocky Exoplanets around Nearby Stars with Ground-based Extremely Large Telescopes

    Mercedes Lopez-Morales et al. Detecting Earth-like Biosignatures on Rocky Exoplanets around Nearby Stars with Ground-based Extremely Large Telescopes. Astro2020 Science White Paper, 2019

    work page 2019

  3. [3]

    Searches for Technosignatures in Astronomy and Astrophysics

    Jason Wright. Searches for Technosignatures in Astronomy and Astrophysics. Astro2020 Science White Paper, 2019

    work page 2019

  4. [4]

    Radio technosignatures

    Jean-Luc Margot. Radio technosignatures. Astro2020 Science White Paper, 2019

    work page 2019

  5. [5]

    Bayesian approach to SETI

    Claudio Grimaldi and Geoffrey W Marcy. Bayesian approach to SETI. In Proceedings of the National Academy of Sciences, pages E9755–E9764. Ecole Polytechnique F´ed´erale de Lausanne claudio.grimaldi@epfl.ch; geoff.w.marcy@gmail.com, National Academy of Sciences, October 2018

    work page 2018

  6. [6]

    M Lacy, S A Baum, C J Chandler, S Chatterjee, T E Clarke, S Deustua, J English, J Farnes, B M Gaensler, N Gugliucci, G Hallinan, B R Kent, A Kimball, C J Law, T J W Lazio, J Marvil, S A Mao, D Medlin, K Mooley, E J Murphy, S Myers, R Osten, G T Richards, E Rosolowsky, L Rudnick, F Schinzel, G R Sivakoff, L. O. Sjouwerman, R Taylor, R L White, J Wrobel, A ...

    work page 2019

  7. [7]

    SETI surveys of the nearby and distant universe employing wide-field radio interferometry techniques

    M A Garrett. SETI surveys of the nearby and distant universe employing wide-field radio interferometry techniques. arXiv.org, October 2018

    work page 2018

  8. [8]

    Applications of data science

    Anamaria Berea. Applications of data science. Astro2020 Science White Paper, 2019

    work page 2019

  9. [9]

    Observing the Earth as a communicating exoplanet

    Julia DeMarines et al. Observing the Earth as a communicating exoplanet. Astro2020 Science White Paper, 2019

    work page 2019

  10. [10]

    Scientific implications of (non-)detection

    Jacob Haqq-Misra et al. Scientific implications of (non-)detection. Astro2020 Science White Paper, 2019

    work page 2019

  11. [11]

    Radio Time-Domain Signatures of Magnetar Birth

    Casey Law et al. Radio Time-Domain Signatures of Magnetar Birth. Astro2020 Science White Paper, 2019

    work page 2019

  12. [12]

    Fast Radio Burst Tomography of the Unseen Universe

    Vikram Ravi et al. Fast Radio Burst Tomography of the Unseen Universe. Astro2020 Science White Paper, 2019. 1

    work page 2019

  13. [13]

    Twelve Decades: Probing the Interstellar Medium from kiloparsec to sub-AU scales

    Dan Stinebring et al. Twelve Decades: Probing the Interstellar Medium from kiloparsec to sub-AU scales. Astro2020 Science White Paper, 2019

    work page 2019

  14. [14]

    The Virtues of Time and Cadence for Pulsars and Fast Transients

    Ryan Lynch et al. The Virtues of Time and Cadence for Pulsars and Fast Transients. Astro2020 Science White Paper, 2019

    work page 2019

  15. [15]

    realfast: Real-time, Commensal Fast Transient Surveys with the Very Large Array

    C J Law, G C Bower, S Burke-Spolaor, B J Butler, P Demorest, A Halle, S Khudikyan, T J W Lazio, M Pokorny, J Robnett, and M P Rupen. realfast: Real-time, Commensal Fast Transient Surveys with the Very Large Array. The Astrophysical Journal Supplement Series, 236(1):8, May 2018

    work page 2018

  16. [16]

    K W Bannister, A T Deller, C Phillips, J-P Macquart, J X Prochaska, N Tejos, S D Ryder, E M Sadler, R M Shannon, S Simha, C K Day, M McQuinn, F O North-Hickey, S Bhandari, W R Arcus, V N Bennert, J Burchett, M Bouwhuis, R Dodson, R D Ekers, W Farah, C Flynn, C W James, M Kerr, E Lenc, E K Mahony, J O’Meara, S Osłowski, H Qiu, T Treu, V U, T J Bateman, D C...

    work page internal anchor Pith review Pith/arXiv arXiv 1906

  17. [17]

    Fast Radio Burst 121102 Pulse Detection and Periodicity: A Machine Learning Approach

    Yunfan Gerry Zhang, Vishal Gajjar, Griffin Foster, Andrew Siemion, James Cordes, Casey Law, and Yu Wang. Fast Radio Burst 121102 Pulse Detection and Periodicity: A Machine Learning Approach. The Astrophysical Journal, 866(2):149, October 2018

    work page 2018

  18. [18]

    Danny C Price, J Emilio Enriquez, Bryan Brzycki, Steve Croft, Daniel Czech, David DeBoer, Julia DeMarines, Griffin Foster, Vishal Gajjar, Nectaria Gizani, Greg Hellbourg, Howard Isaacson, Brian Lacki, Matt Lebofsky, David H E MacMahon, Imke de Pater, Andrew P. V . Siemion, Dan Werthimer, James A Green, Jane F Kaczmarek, Ronald J Maddalena, Stacy Mader, Jam...

    work page 2019

  19. [19]

    P., Comoretto, G., Webber, J

    Escoffier, R. P., Comoretto, G., Webber, J. C., Baudry, A., Broadwell, C. M., Greenberg, J. H., Treacy, R. R., Cais, P., Quertier, B., Camino, P., Bos, A., and t, A. W. Gun. The ALMA correlator. A&A, 462(2):801–810, 2007

    work page 2007

  20. [20]

    Hampson, A

    G. Hampson, A. Brown, S. Neuhold, J. Bunton, A. Macleod, J. Tuthill, and R. Beresford. Askap advancements in beamformer and correlator optical backplane technology. In 2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM), pages 1–1, Jan 2013

    work page 2013

  21. [21]

    S. M. Dougherty and Rick Perley. The Expanded Very Large Array. Bulletin de la Societe Royale des Sciences de Liege, 80:491–495, Jan 2011

    work page 2011

  22. [22]

    Refined EVLA WIDAR Correlator Architecture

    Brent Carlson. Refined EVLA WIDAR Correlator Architecture. NRC EVLA Memo Series, 4, 10 2001. 2

    work page 2001

  23. [23]

    David H. E. MacMahon, Danny C. Price, Matthew Lebofsky, Andrew P. V . Siemion, Steve Croft, David DeBoer, J. Emilio Enriquez, Vishal Gajjar, Gregory Hellbourg, and Howard Isaacson. The Breakthrough Listen Search for Intelligent Life: A Wideband Data Recorder System for the Robert C. Byrd Green Bank Telescope. Publications of the Astronomical Society of th...

    work page 2018

  24. [24]

    M. A. Clark, P. C. La Plante, and L. J. Greenhill. Accelerating Radio Astronomy Cross-Correlation with Graphics Processing Units. arXiv e-prints, page arXiv:1107.4264, Jul 2011

    work page internal anchor Pith review Pith/arXiv arXiv 2011

  25. [25]

    A GPU-based Correlator X-engine Implemented on the CHIME Pathfinder

    Nolan Denman, Mandana Amiri, Kevin Bandura, Jean-Franc ¸ois Cliche, Liam Connor, Matt Dobbs, Mateus Fandino, Mark Halpern, Adam Hincks, and Gary Hinshaw. A GPU-based Correlator X-engine Implemented on the CHIME Pathfinder. arXiv e-prints, page arXiv:1503.06202, Mar 2015

    work page internal anchor Pith review Pith/arXiv arXiv 2015

  26. [26]

    Magro, K

    A. Magro, K. Zarb Adami, and J. Hickish. GPU-Powered Coherent Beamforming. Journal of Astronomical Instrumentation, 4:1550002–336, Jun 2015

    work page 2015

  27. [27]

    MeerKAT Science: On the Pathway to the SKA, Jan 2016

    work page 2016

  28. [28]

    African star joins the radio astronomy firmament

    Fernando Camilo. African star joins the radio astronomy firmament. Nature Astronomy, 2:594–594, Jul 2018

    work page 2018

  29. [29]

    A scalable packetised radio astronomy imager

    Jason Ryan Manley. A scalable packetised radio astronomy imager. PhD thesis, University of Cape Town, 2015

    work page 2015

  30. [30]

    S Pete Worden, Jamie Drew, Andrew Siemion, Dan Werthimer, David DeBoer, Steve Croft, David MacMahon, Matt Lebofsky, Howard Isaacson, Jack Hickish, Danny Price, Vishal Gajjar, and Jason T. Wright. Breakthrough Listen - A new search for life in the universe. Acta Astronautica, 139:98–101, October 2017

    work page 2017

  31. [31]

    Buch, Sandeep C

    Jack Hickish, Zuhra Abdurashidova, Zaki Ali, Kaushal D. Buch, Sandeep C. Chaudhari, Hong Chen, Matthew Dexter, Rachel Simone Domagalski, John Ford, and Griffin Foster. A Decade of Developing Radio-Astronomy Instrumentation using CASPER Open-Source Technology. Journal of Astronomical Instrumentation, 5(4):1641001–12, Dec 2016

    work page 2016

  32. [32]

    SETI State of the Profession

    Jason Wright. SETI State of the Profession. Astro2020 APC White Paper, 2019

    work page 2019

  33. [33]

    Steve Croft, Andrew P. V . Siemion, James M Cordes, Ian S Morrison, Zsolt Paragi, Jill Tarter, , U C Berkeley, Radboud University, SETI Institute, Cornell University, Curtin University, and JIVE. Science with an ngVLA: SETI Searches for Evidence of Intelligent Life in the Galaxy. arXiv.org, October 2018

    work page 2018

  34. [34]

    David H. E. MacMahon, Danny C. Price, Matthew Lebofsky, Andrew P. V . Siemion, Steve Croft, David DeBoer, J. Emilio Enriquez, Vishal Gajjar, Gregory Hellbourg, and Howard Isaacson. The Breakthrough Listen Search for Intelligent Life: A Wideband Data Recorder System for the Robert C. Byrd Green Bank Telescope. Publications of the Astronomical Society of th...

    work page 2018

  35. [35]

    Price, David H

    Danny C. Price, David H. E. MacMahon, Matt Lebofsky, Steve Croft, David DeBoer, J. Emilio Enriquez, Griffin S. Foster, Vishal Gajjar, Nectaria Gizani, Greg Hellbourg, and et al. The breakthrough listen search for intelligent life: Wide-bandwidth digital instrumentation for the csiro parkes 64-m telescope. Publications of the Astronomical Society of Austral...

    work page 2018