Astronomers scan the skies for nanosecond pulses of light from interstellar civilizations

In 2015, Russian-Israeli billionaire Yuri Milner and his nonprofit Breakthrough Initiative launched the largest SETI (Extraterrestrial Intelligence Exploration) project. Known as ‘Breakthrough Listen’, his SETI project uses the world’s most powerful radio telescopes and advanced analytics to search for potential evidence of technological activity, aka ‘technosignatures’. The 10-year project will study the nearest million stars, galactic centers, entire galactic planes, and the 100 closest galaxies to the Milky Way.

In 2018, the company partnered with the high-energy radiation imaging telescope array system VERITAS. The collaboration is a gamma-ray telescope ground system operating at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins in southern Arizona. In a recent article, the VERITAS Collaboration shared the results of the first year (2019-2020) of their search for “Hikari Techno Signature.” Their discovery is an important proof-of-concept of how light pulses can be incorporated into the catalog of technosignatures in the search for future extraterrestrial civilizations.

The VERITAS collaboration includes researchers from FLWO, the Harvard-Smithsonian Center for Astrophysics (CfA), the Arthur B. McDonald Canadian Institute for Astrophysics and Particle Physics, the German Electron Synchrotron (DESY) Research Center, and the NASA Goddard Space Flight. It is an international effort to participate in. Center and several universities and research institutes are involved. An article describing their findings titled “VERITAS/Breakthrough Listen Search for Optical Technosignatures” was recently accepted for publication in the Astronomical Journal and is available on the preprint server arXiv.

For the past 60 years, beginning with Project Ozma, the search for ETI has focused almost exclusively on finding evidence of radio communications. In recent years, scientists have discovered directed energy communications, radio and light leaks from technological civilizations, infrared emissions from megastructures, spectral evidence of industrial pollutants in exoplanet atmospheres, and even spacecraft and their We are expanding our quest to include techno-signatures that may contain other potential techno-signatures, such as debris inside. our solar system.

These and other potential examples of extraterrestrial technology are detailed in the NASA Technosignature Workshop Report published in 2018. The integration of the VERITAS array, consisting of four 12-meter (approximately 40-foot) optical Cerenkov reflectors for gamma-ray astronomy, is a breakthrough as the search for optical technosignatures, especially detectable nanosecond light pulses, expands. Listen is now possible. beyond interstellar distances. Dr. Gregory Foote, a candidate in the Department of Physics and Astronomy at the University of Delaware (UD) and co-author of the VERITAS article, told his Universe Today in an email:

“Traditional wireless technology signatures have been searched, but we don’t know what wavelength band the signal is coming from, whether the signal is pulsed or stationary. It makes sense to do.” Our techno signature. We’re looking for pulsed lasers, which can be easily detected (in principle) with today’s technology and transmitted up to 1000 light-year distances.

Completed in 2007, the VERITAS array effectively complements the Fermi Gamma-ray Space Telescope (FRGST) with its larger collection area and larger collection area. Enhanced sensitivity to gamma rays, in collaboration with NASA and Fermi’s partner, the Large Area Telescope (LAT). In fact, like the primary mirror of the James Webb Space Telescope (JWST), the VERITAS segmented reflector telescope has the highest sensitivity of any telescope in the VHE band (very high energy band), with a maximum sensitivity of 100 giga-electronvolts. (Gev) ~ 10 tera electrons. Volts (TeV).

These capabilities were tested when the collaboration team searched his Breakthrough Listen target catalog for signs of high-energy light pulses. Foote said:

“We started with the Breakthrough List target catalog released in 2017 and then removed everything that was inappropriate for VERITAS operations. About 506 target candidates remained, and they were ranked as near, faint, and others.” B. Exoplanets. This ranking selected only the highest-ranking planets observable on a given moon, making it a great tool for choosing which planets to observe. A total of 30 hours of observations were made, each observation lasting approximately 15 minutes. In the end, 136 targets were observed because some observations spanned multiple objects.

In addition, the collaboration team examined his 2012 VERITAS archive data. The team then calculated which targets were observed during the same period from the VERITAS breakthrough list catalog. Due to limited computing time, it was decided to spread the archive analysis across different targets and analyze only the first he hour of high-quality data. “This gave him 249 observations from his 119 non-overlapping fields, including his 140 randomly-acquired targets,” said Foote.

Their analysis found no evidence of nanosecond light pulses, but this The study provided an important proof-of-concept that will inform the future. Search. A limit is also set on the number of stars that can host broadcast civilizations, which narrows exploration and increases the chances of future discoveries. Foote also said the study could have significant implications for existing and planned gamma-ray observatories. These include the Panoramic All-Sky Near-Infrared and Optical Techno-Signature Finder (PANOSETI) making observations in conjunction with Veritas Observatory:

“I think the biggest impact on the broader field is that this technosignature can be searched for by piggybacking off of existing gamma-ray observatories, including VERITAS, and ones which have yet to be built. This also goes the other way too, as observatories being purpose-built for this technosignature, like PANOSETI, can have some gamma-ray science piggyback off of it. This is a unique intersection between fields which hasn’t been greatly explored until now.”