≡ Menu

VERITAS: Strengthening the Optical SETI Search

Breakthrough Listen has just announced a new optical SETI effort in partnership with the VERITAS Collaboration. The news took me by surprise, for VERITAS (Very Energetic Radiation Imaging Telescope Array System) generally deals in high-energy astrophysics, with a focus on gamma rays, which signal their presence through flashes of Cherenkov radiation when they strike the Earth’s atmosphere. Here, the array is being used to look for technosignatures, as Andrew Siemion (UC- Berkeley SETI Research Center) explains:

“Breakthrough Listen is already the most powerful, comprehensive, and intensive search yet undertaken for signs of intelligent life beyond Earth. Now, with the addition of VERITAS, we’re sensitive to an important new class of signals: fast optical pulses. Optical communication has already been used by NASA to transmit high definition images to Earth from the Moon, so there’s reason to believe that an advanced civilization might use a scaled-up version of this technology for interstellar communication.”

Image: View of the Fred Lawrence Whipple Observatory basecamp and the VERITAS array. Credit: VERITAS.

So the search for faint optical flashes that could signal the presence of an extraterrestrial civilization deepens, complementing the optical SETI work currently underway at Breakthrough Listen as well as its ongoing survey at radio frequencies. VERITAS brings four 12-meter telescopes located at the basecamp of the Fred Lawrence Whipple Observatory on Mount Hopkins in Arizona into the mix. This is quite an exoplanet venue: The observatory has facilities at different elevations, including exoplanet arrays for HAT (Hungarian-made Automated Telescope), the MEarth project and MINERVA, all three of these robotic.

In the Breakthrough Listen effort, VERITAS will be looking for pulsed optical beacons with durations as short as several nanoseconds, for at timescales like these, an artificial beacon could outshine any stars located in the same region of sky. All four telescopes will be used simultaneously, which should assist the effort in screening out false positive detections.

Although I hadn’t realized it until looking further into VERITAS, the array has already seen use in a search of Boyajian’s Star for such pulses (see Abeysekara et al., “A Search for Brief Optical Flashes Associated with the SETI Target KIC 8462852,” abstract here). You’ll recall that this star has received intense scrutiny because of its unusual pattern of dimming, which did not correspond to planetary transits and raised questions about the source of the lightcurve variations.

Now VERITAS goes to work on stars not already found on Breakthrough Listen’s primary star list. The numbers are striking: Breakthrough Listen calculates that if a laser delivering 500 terawatts in a pulse lasting a few nanoseconds were located at the same distance as Boyajian’s Star (an F3V-class object in Cygnus approximately 1470 light years away) and pointed in our direction, VERITAS would be able to detect it.

Most stars in the Breakthrough Listen target list, however, are considerably closer. Hence the VERITAS search will be sensitive to pulses a factor 100 – 10,000 times fainter still. Thus an array built with the purpose of studying very-high-energy gamma rays proves adaptable to a search for technosignatures, with UC-Santa Cruz physicist David Williams, one of the effort’s leaders, saying “It is impressive how well-suited the VERITAS telescopes are for this project.” Williams will work in collaboration with Jamie Holder (University of Delaware) and Andrew Siemion’s Breakthrough Listen team at UC-Berkeley’s SETI Research Center (BSRC).

While we’re on the topic of SETI, let me also call your attention to a new resource that Penn State’s Jason Wright and Alan Reyes have created. Go to the NASA ADS site and include in your search terms ‘bibgroup:SETI’. I just searched, for example, using ‘author:”maccone” bibgroup:SETI’ and came up with 56 hits. SETI has been short on bibliographical resources, so this is promising stuff. You’ll need to familiarize yourself with the search syntax, but it’s not at all difficult, and will reward those looking to firm up a citation or check on the status of a particular scientist’s work. Wright and Reyes have submitted a paper on the bibliography to JBIS. For more, see Towards a Comprehensive Bibliography for SETI.

Image: Penn State’s Jason Wright. Credit: PSU.


Comments on this entry are closed.

  • Harry R Ray July 25, 2019, 9:56

    The key question to this endeavor is whether or not Breakthrough listen can access ARCHIVAL RECORDS from VERITAS and use them to FOCUS their attention on areas of the sky where interesting(i.e not provable byt not unprovable EITHER)Technosignature Candidate Signals(or TCS’s: Paul, please ask Dr Wright if this moniker for such interesting signals has already been coined). The reason I am bringing this up is the NEW “most mysterious star in the galaxy”, HD 139139(or EPIC249706694)otherwise known as The Random Transiter. This system is composed of two stars. a 1 to 2 billion year old(to be)sun-like star and a 61 CygniB-C – like star of undetermined age separated by 400 AU. Without coing into any more specifics(to GET them, google HD 139139 and click on Wikipedia or Rappaport and Vandenberg’s paper). Since the randomly transiting objects could ALL be transiting the sun-like star, ALL be transiting the red dwarf star, or some could be transiting one star and others could be transiting the other one. Keep in mind is that Boyajian’s Star is ALSO a “random transiter” but what differentiates HD 139139 is the FREQUENCY of the transits(28 0ver an 84 day period. Back to VERITAS: Any interestig archived signals in the region of the sky where HD 139139 is located should spark an intense follow-up campaign using more conventional OSETI instruments on telescopes dedicated to the ongoing OSETI search! HD 139139 WAS added to the list of targets for the Green Bank radio telescope. I assume that initial observations have already been made and are currently being analysed. STAY TUNED(pardon the pun)!

  • Harry R Ray July 25, 2019, 14:27

    OOPS: I meant 61 CygniA-B, NOT 61 CygniB-C.

  • ljk July 29, 2019, 12:20

    In case anyone thinks that Breakthrough Listen is covering all aspects of SETI or that searching for intelligent aliens is now funding secure:


  • ljk August 7, 2019, 12:08

    It is the 21st Century. SETI really needs to branch out based on what we know and especially now that this field is no longer the exclusive domain of a few radio astronomers:


  • ljk August 8, 2019, 9:35

    Freeman Dyson has this to say about SETI efforts, even when they don’t find aliens…

    Freeman Dyson’s First Law of #SETI Investigations:

    Every search for alien civilizations should be planned to give interesting results even when no aliens are discovered.


    Further quote:

    I think Freeman himself means this as a counterpoint to radio or laser SETI, which has the benefit of working against low natural background but this apparent disadvantage that they are unlikely to discover new natural phenomena in the course of their searches. I think this perspective is often overstated—radio SETI is closely aligned with pulsar and FRB astrophysics, and generates great science along the way, and there are natural sources of very brief optical flashes, too.

  • ljk August 9, 2019, 8:59


    The Nine Axes of Merit for Technosignature Searches

    Sofia Z. Sheikh

    (Submitted on 31 Jul 2019)

    The diverse methodologies and myriad orthogonal proposals for the best technosignatures to search for in SETI can make it difficult to develop an effective and balanced search strategy, especially from a funding perspective.

    Here I propose a framework to compare the relative advantages and disadvantages of various proposed technosignatures based on nine “axes of merit”.

    This framework was first developed at the NASA Technosignatures Workshop in Houston in 2018 and published in that report. I give the definition and rationale behind the nine axes as well as the history of each axis in the SETI and technosignature literature.

    These axes are then applied to three example classes of technosignature searches as an illustration of their use. An open-source software tool is available to allow technosignature researchers to make their own version of the figure.

    Comments: Submitted, waiting for review

    Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP); Popular Physics (physics.pop-ph)

    Cite as: arXiv:1908.02683 [astro-ph.IM]
    (or arXiv:1908.02683v1 [astro-ph.IM] for this version)

    Submission history

    From: Sofia Sheikh [view email]

    [v1] Wed, 31 Jul 2019 21:45:40 UTC (3,348 KB)


  • ljk August 9, 2019, 9:01


    Towards a Comprehensive Bibliography for SETI

    Alan Reyes, Jason T. Wright

    (Submitted on 1 Aug 2019)

    In this work, we motivate, describe, and announce a living bibliography for academic papers and other works published in the Search for Extraterrestrial Intelligence (SETI).

    The bibliography makes use of bibliographic groups (bibgroups) in the NASA Astrophysics Data System (ADS), allowing it to be accessed and searched by any interested party, and is composed only of works which have a presence on the ADS.

    We establish criteria that describe the scope of our bibliography, which we define as any academic work which broadly:

    1) advances knowledge within SETI, 2) deals with topics that are fundamentally related to or about SETI, or 3) is useful for the better understanding of SETI, and which has a presence on ADS.

    We discuss the future work needed to continue the development of the bibliography. The bibliography can be found by using the bibgroup field (bibgroup: SETI) in the ADS search engine.

    Comments: 7 pages, accepted to the Journal of the British Interplanetary Society The SETI bibliography on ADS can be accessed at this https URL

    Subjects: Digital Libraries (cs.DL); Instrumentation and Methods for Astrophysics (astro-ph.IM)

    Cite as: arXiv:1908.02587 [cs.DL]
    (or arXiv:1908.02587v1 [cs.DL] for this version)

    Submission history

    From: Alan Reyes [view email]

    [v1] Thu, 1 Aug 2019 14:36:37 UTC (125 KB)


  • ljk August 9, 2019, 9:04


    Searches for Technosignatures: The State of the Profession

    Jason T. Wright

    (Submitted on 18 Jul 2019)

    The search for life in the universe is a major theme of astronomy and astrophysics for the next decade. Searches for technosignatures are complementary to searches for biosignatures, in that they offer an alternative path to discovery, and address the question of whether complex (i.e. technological) life exists elsewhere in the Galaxy.

    This approach has been endorsed in prior Decadal Reviews and National Academies reports, and yet the field still receives almost no federal support in the US.

    Because of this lack of support, searches for technosignatures, precisely the part of the search of greatest public interest, suffers from a very small pool of trained practitioners.

    A major source of this issue is institutional inertia at NASA, which avoids the topic as a result of decades-past political grandstanding, conflation of the effort with non-scientific topics such as UFOs, and confusion regarding the scope of the term “SETI.”

    The Astro2020 Decadal should address this issue by making developing the field an explicit priority for the next decade. It should recommend that NASA and the NSF support training and curricular development in the field in a way that supports equity and diversity, and make explicit calls for proposals to fund searches for technosignatures.

    Comments: Submitted as an APC white paper to the Astro2020 Decadal process

    Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)

    Cite as: arXiv:1907.07832 [astro-ph.IM]
    (or arXiv:1907.07832v1 [astro-ph.IM] for this version)

    Submission history

    From: Jason Wright [view email]

    [v1] Thu, 18 Jul 2019 01:29:32 UTC (379 KB)


  • ljk August 9, 2019, 9:06


    Searching for Extraterrestrial Intelligence by Locating Potential ET Communication Networks in Space

    Ross Davis

    (Submitted on 10 Jul 2019 (v1), last revised 23 Jul 2019 (this version, v2))

    There have been periodic efforts in recent decades to search for extraterrestrial intelligence (SETI), especially by trying to find an extraterrestrial (ET) radio signal or other technosignature in space. Yet, no such technosignatures have been found. Considering the vastness of space, finding such technosignatures has been described as trying to find a needle in a cosmic haystack.

    To help resolve this, two hypotheses are proposed to aid SETI researchers in narrowing the search for ET technosignatures, based on a network analysis approach to locate where in space potential ET communication networks would most likely be.

    A potential ET communication network can use exoplanets as communication access points (e.g., placing a communication satellite into planetary orbit, or an antenna on a planetary surface).

    The approach uses a topology where exoplanets are represented as nodes, and the lines of average distance (generalized communication paths) between adjacent exoplanets are represented as edges; the nodes and edges form local and wide planetary networks. Using the approach and data visualization on exoplanet databases can highlight locations of potential ET communication networks in space.

    The first hypothesis posits that an ET technosignature would more likely appear in a potentially habitable solar system containing a high concentration of planets, wherein the planets function as communication access points to facilitate a potential ET communication network.

    The second hypothesis posits that an ET technosignature would more likely appear in a highly concentrated cluster of potentially habitable solar systems.

    Contributions to the SETI field can be increased accuracy in finding ET technosignatures, increased accuracy in reaching a Schelling point (a mutual realization of how we and an ET intelligence can find each other), and promoting interdisciplinary SETI research.

    Comments: 15 pages

    Subjects: Popular Physics (physics.pop-ph)

    Cite as: arXiv:1907.05259 [physics.pop-ph]
    (or arXiv:1907.05259v2 [physics.pop-ph] for this version)

    Submission history

    From: Ross Davis [view email]

    [v1] Wed, 10 Jul 2019 01:48:02 UTC (197 KB)
    [v2] Tue, 23 Jul 2019 05:13:23 UTC (197 KB)


  • ljk August 9, 2019, 9:08


    SETI in the Spatio-Temporal Survey Domain

    James. R. A. Davenport

    (Submitted on 9 Jul 2019)

    Traditional searches for extraterrestrial intelligence (SETI) or “technosignatures” focus on dedicated observations of single stars or regions in the sky to detect excess or transient emission from intelligent sources.

    The newest generation of synoptic time domain surveys enable an entirely new approach: spatio-temporal SETI, where technosignatures may be discovered from spatially resolved sources or multiple stars over time.

    Current optical time domain surveys such as ZTF and the Evryscope can probe 10-100 times more of the “Cosmic Haystack” parameter space volume than many radio SETI investigations. Small-aperture, high cadence surveys like Evryscope can be comparable in their Haystack volume completeness to deeper surveys including LSST.

    Investigations with these surveys can also be conducted at a fraction of the cost of dedicated SETI surveys, since they make use of data already being gathered. However, SETI methodology has not widely utilized such surveys, and the field is in need of new search algorithms that can account for signals in both the spatial and temporal domains.

    Here I describe the broad potential for modern wide-field time domain optical surveys to revolutionize our search for technosignatures, and illustrate some example SETI approaches using transiting exoplanets to form a distributed beacon.

    Comments: 8 pages, 3 figures, AJ submitted

    Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

    Cite as: arXiv:1907.04443 [astro-ph.IM]
    (or arXiv:1907.04443v1 [astro-ph.IM] for this version)

    Submission history

    From: James RA Davenport [view email]

    [v1] Tue, 9 Jul 2019 22:29:55 UTC (106 KB)


  • ljk August 9, 2019, 9:10


    The Breakthrough Listen Search for Intelligent Life: Public Data, Formats, Reduction and Archiving

    Matthew Lebofsky, Steve Croft, Andrew P.V. Siemion, Danny C. Price, J. Emilio Enriquez, Howard Isaacson, David H.E. MacMahon, David Anderson, Bryan Brzycki, Jeff Cobb, Daniel Czech, David DeBoer, Julia DeMarines, Jamie Drew, Griffin Foster, Vishal Gajjar, Nectaria Gizani, Greg Hellbourg, Eric J. Korpela, Brian Lacki, Sofia Sheikh, Dan Werthimer, Pete Worden, Alex Yu, Yunfan Gerry Zhang

    (Submitted on 18 Jun 2019)

    Breakthrough Listen is the most comprehensive and sensitive search for extraterrestrial intelligence (SETI) to date, employing a collection of international observational facilities including both radio and optical telescopes.

    During the first three years of the Listen program, thousands of targets have been observed with the Green Bank Telescope (GBT), Parkes Telescope and Automated Planet Finder. At GBT and Parkes, observations have been performed ranging from 700 MHz to 26 GHz, with raw data volumes averaging over 1PB / day.

    A pseudo-real time software spectroscopy suite is used to produce multi-resolution spectrograms amounting to approximately 400 GB hr^-1 GHz^-1 beam^-1.

    For certain targets, raw baseband voltage data is also preserved. Observations with the Automated Planet Finder produce both 2-dimensional and 1-dimensional high resolution (R~10^5) echelle spectral data.

    Although the primary purpose of Listen data acquisition is for SETI, a range of secondary science has also been performed with these data, including studies of fast radio bursts.

    Other current and potential research topics include spectral line studies, searches for certain kinds of dark matter, probes of interstellar scattering, pulsar searches, radio transient searches and investigations of stellar activity.

    Listen data are also being used in the development of algorithms, including machine learning approaches to modulation scheme classification and outlier detection, that have wide applicability not just for astronomical research but for a broad range of science and engineering.

    In this paper, we describe the hardware and software pipeline used for collection, reduction, archival, and public dissemination of Listen data.

    We describe the data formats and tools, and present Breakthrough Listen Data Release 1.0 (BLDR 1.0), a defined set of publicly-available raw and reduced data totalling 1 PB.

    Comments: 25 pages, 15 figures, submitted to PASP, comments welcome

    Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

    Cite as: arXiv:1906.07391 [astro-ph.IM]
    (or arXiv:1906.07391v1 [astro-ph.IM] for this version)

    Submission history

    From: Matt Lebofsky [view email]

    [v1] Tue, 18 Jun 2019 05:51:57 UTC (5,525 KB)


  • ljk November 20, 2019, 18:27

    Space Alien Research Could Get Its First Grad Program

    Scientists aim to make the search for extraterrestrial intelligence academically respectable

    By Sarah Scoles on November 18, 2019