Engineering an Interstellar Communications Network by Deploying Relay Probes

Gertz, John; Marcy, Geoffrey W.

doi:10.48550/arxiv.2204.08296

Cited by 3 publications

(2 citation statements)

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“…Extinction in the ISM is lower at optical (compared with shorter) wavelengths (Rather 1991) and lower background is present at optical (compared with radio) wavelengths both from Earth and cosmic interference sources (Ross et al 2011). It has been shown that, even under the limitations of current human technology, transmission and detection of lasers over interstellar distances would be possible (Tellis & Marcy 2017;Clark & Cahoy 2018;Lipman et al 2019;Gertz & Marcy 2022). It is reasonable to hypothesize that intelligent civilizations, if present, might either intentionally direct lasers toward Earth as a means of communication, or else inadvertently signal their presence while using lasers for other purposes (e.g., telescope guiding, communication between spacecraft, or laser propulsion).…”

Section: Introductionmentioning

confidence: 99%

The Breakthrough Listen Search for Intelligent Life: A Laser Search Pipeline for the Automated Planet Finder

Zuckerman

Isaacson

et al. 2023

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The Search for Extraterrestrial Intelligence has traditionally been conducted at radio wavelengths, but optical searches are well-motivated and increasingly feasible due to the growing availability of high-resolution spectroscopy. We present a data analysis pipeline to search Automated Planet Finder (APF) spectroscopic observations from the Levy Spectrometer for intense, persistent, narrow-bandwidth optical lasers. We describe the processing of the spectra, the laser search algorithm, and the results of our laser search on 1983 spectra of 388 stars as part of the Breakthrough Listen search for technosignatures. We utilize an empirical spectra-matching algorithm called SpecMatch-Emp to produce residuals between each target spectrum and a set of best-matching catalog spectra, which provides the basis for a more sensitive search than previously possible. We verify that SpecMatch-Emp performs well on APF-Levy spectra by calibrating the stellar properties derived by the algorithm against the SpecMatch-Emp library and against Gaia catalog values. We leverage our unique observing strategy, which produces multiple spectra of each target per night of observing, to increase our detection sensitivity by programmatically rejecting events that do not persist between observations. With our laser search algorithm, we achieve a sensitivity equivalent to the ability to detect an 84 kW laser at the median distance of a star in our data set (78.5 ly). We present the methodology and vetting of our laser search, finding no convincing candidates consistent with potential laser emission in our target sample.

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Section: Introductionmentioning

confidence: 99%

The Breakthrough Listen Search for Intelligent Life: A Laser Search Pipeline for the Automated Planet Finder

Zuckerman

Isaacson

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Extinction in the ISM is lower at optical (compared with shorter) wavelengths (Rather 1991) and lower background is present at optical (compared with radio) wavelengths both from Earth and cosmic interference sources (Ross et al 2011). It has been shown that, even under the limitations of current human technology, transmission and detection of lasers over interstellar distances would be possible (Tellis & Marcy 2017;Clark & Cahoy 2018;Lipman et al 2019;Gertz & Marcy 2022). It is reasonable to hypothesize that intelligent civilizations, if present, might either intentionally direct lasers towards Earth as a means of communication, or else inadvertently signal their presence while using lasers for other purposes (e.g., telescope guiding, communication between spacecraft, or laser propulsion).…”

Section: Introductionmentioning

confidence: 99%

The Breakthrough Listen Search for Intelligent Life: A Laser Search Pipeline for the Automated Planet Finder

Zuckerman¹,

Ko²,

Isaacson³

et al. 2023

Preprint

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The Search for Extraterrestrial Intelligence (SETI) has traditionally been conducted at radio wavelengths, but optical searches are well-motivated and increasingly feasible due to the growing availability of high-resolution spectroscopy. We present a data analysis pipeline to search Automated Planet Finder (APF) spectroscopic observations from the Levy Spectrometer for intense, persistent, narrow bandwidth optical lasers. We describe the processing of the spectra, the laser search algorithm, and the results of our laser search on 1983 spectra of 388 stars as part of the Breakthrough Listen search for technosignatures. We utilize an empirical spectra-matching algorithm called SpecMatch-Emp to produce residuals between each target spectrum and a set of best-matching catalog spectra, which provides the basis for a more sensitive search than previously possible. We verify that SpecMatch-Emp performs well on APF-Levy spectra by calibrating the stellar properties derived by the algorithm against the SpecMatch-Emp library and against Gaia catalog values. We leverage our unique observing strategy, which produces multiple spectra of each target per night of observing, to increase our detection sensitivity by programmatically rejecting events which do not persist between observations. With our laser search algorithm we achieve a sensitivity equivalent to the ability to detect an 84 kW laser at the median distance of a star in our dataset (78.5 ly). We present the methodology and vetting of our laser search, finding no convincing candidates consistent with potential laser emission in our target sample.

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A search for transient, monochromatic light from the Galactic plane

Marcy

Tellis²

2023

Monthly Notices of the Royal Astronomical Society

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The Galactic Plane was searched for transient, monochromatic light at optical and near-IR wavelengths to detect pulses shorter than 1 sec. An objective-prism Schmidt telescope of 0.28-meter aperture and a CMOS camera were used to observe 973 square degrees, with 8864 exposures of 1-sec each, within a strip 2.1 deg wide along the Galactic Plane, from Galactic longitude -4 deg to +248 deg. All exposures were analyzed for transient, monochromatic sources using a “difference image” algorithm that yielded 11 candidate sources. All 11 sources were found to be associated with either astrophysical emission-line objects or aircraft with sub-second blinking lights. Our survey “rediscovered” many Wolf-Rayet stars, M dwarf flare stars, and planetary nebulae. It also identified an aircraft, of unknown type, that apparently had a nearly monochromatic lamp and a xenon lamp. This survey would have revealed optical and near-IR pulses having a power of ∼180 GW (wavelength dependent) if emitted by a 10-meter aperture laser located 1 kiloparsec away. These non-detections of laser pulses from the Galactic Plane, including a 10-degree region toward the Galactic Centre, add to the non-detections from more than 5000 nearby stars. Indeed, all-sky surveys for emission-line objects (e.g., ionized gas, supernovae remnants, and active galactic nuclei) would have revealed lasers of a wide range of average brightness, wavelength, and cadence. The absence of beacons reveals more of a SETI desert, notably at the intensely surveyed optical and radio wavelengths.

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Engineering an Interstellar Communications Network by Deploying Relay Probes

Cited by 3 publications

References 0 publications

The Breakthrough Listen Search for Intelligent Life: A Laser Search Pipeline for the Automated Planet Finder

The Breakthrough Listen Search for Intelligent Life: A Laser Search Pipeline for the Automated Planet Finder

The Breakthrough Listen Search for Intelligent Life: A Laser Search Pipeline for the Automated Planet Finder

A search for transient, monochromatic light from the Galactic plane

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