&lt;title&gt;Berkeley radio and optical SETI programs: SETI@home, SERENDIP, and SEVENDIP&lt;/title&gt;

Werthimer, Dan; Anderson, David P.; Bowyer, C. Stuart; Cobb, Jeff; Heien, E. M.; Korpela, E. J.; Lampton, M.; Lebofsky, Matt; Marcy, G. W.; McGarry, M. B.; Treffers, Dick

doi:10.1117/12.435384

Cited by 35 publications

(23 citation statements)

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“…The potential spectral similarity between anthropogenic radio-frequency interference (RFI) and extraterrestrial technological transmissions brings additional complications. The sheer immensity of the parameter space that must be explored is a potential explanation to the absence of radio detections of extraterrestrial intelligence, despite numerous previous efforts (Verschuur 1973;Tarter et al 1980;Bowyer et al 1983Bowyer et al , 1995Horowitz et al 1986;Steffes & Deboer 1994;Mauersberger et al 1996;Backus 1998;Werthimer et al 2000;Korpela et al 2011;Siemion et al 2013;Harp et al 2016;Gray & Mooley 2017).…”

Section: Introductionmentioning

confidence: 99%

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

Enriquez

Siemion

Foster

et al. 2017

ApJ

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142

335

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We report on a search for engineered signals from a sample of 692 nearby stars using the Robert C. Byrd Green Bank Telescope, undertaken as part of the Breakthrough Listen Initiative search for extraterrestrial intelligence. Observations were made over 1.1-1.9 GHz (L band), with three sets of five-minute observations of the 692 primary targets, interspersed with five-minute observations of secondary targets. By comparing the "ON" and "OFF" observations, we are able to identify terrestrial interference and place limits on the presence of engineered signals from putative extraterrestrial civilizations inhabiting the environs of the target stars. During the analysis, 11 events passed our thresholding algorithm, but a detailed analysis of their properties indicates that they are consistent with known examples of anthropogenic radio-frequency interference. We conclude that, at the time of our observations, none of the observed systems host high-duty-cycle radio transmitters emitting between 1.1 and 1.9 GHz with an Equivalent Isotropic Radiated Power of ∼10 13 W, which is readily achievable by our own civilization. Our results suggest that fewer than ∼0.1% of the stellar systems within 50 pc possess the type of transmitters searched in this survey.

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Section: Introductionmentioning

confidence: 99%

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

Enriquez

Siemion

Foster

et al. 2017

ApJ

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142

335

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“…Cocconi & Morrison 1959;Drake 1961;Horowitz & Sagan (1993) ;Tarter 2001;Howard et al 2007;Hanna et al 2009;Siemion et al 2013;Wright et al 2014a;Wright et al 2016;Lacki 2016)). Searches have been conducted at radio wavelengths with Arecibo, Green Bank telescope, Parkes radio telescope, and the Allen telescope array (Drake 1961;Werthimer et al 2001;Korpela et al 2011;Siemion et al 2013, Tarter et al 2011, and Harp et al 2015. These searches targeted both stars and galaxies, and more recently stars harboring known exoplanets (Siemion et al 2013).…”

Section: Introductionmentioning

confidence: 99%

A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars

Tellis¹,

Marcy²

2017

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We searched high resolution spectra of 5600 nearby stars for emission lines that are both inconsistent with a natural origin and unresolved spatially, as would be expected from extraterrestrial optical lasers.The spectra were obtained with the Keck 10-meter telescope, including light coming from within 0.5 arcsec of the star, corresponding typically to within a few to tens of au of the star, and covering nearly the entire visible wavelength range from 3640 to 7890 Å. We establish detection thresholds by injecting synthetic laser emission lines into our spectra and blindly analyzing them for detections. We compute flux density detection thresholds for all wavelengths and spectral types sampled. Our detection thresholds for the power of the lasers themselves range from 3 kW to 13 MW, independent of distance to the star but dependent on the competing "glare" of the spectral energy distribution of the star and on the wavelength of the laser light, launched from a benchmark, diffraction-limited 10-meter class telescope. We found no such laser emission coming from the planetary region around any of the 5600 stars. As they contain roughly 2000 lukewarm, Earth-size planets, we rule out models of the Milky Way in which over 0.1% of warm, Earth-size planets harbor technological civilizations that, intentionally or not, are beaming optical lasers toward us. A next generation spectroscopic laser search will be done by the Breakthrough Listen initiative, targeting more stars, especially stellar types overlooked here including spectral types O, B, A, early F, late M, and brown dwarfs, and astrophysical exotica.

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“…There were distinct advantages for either readout version: Geiger mode APDs offer high gains (M >10 [4][5] ), but have large quenching times of order of 0.1 -100 microseconds (Williams et al 26 ). In contrast, linear APDs have low quenching times (< 10 nanoseconds) but very low gains (M < 50).…”

Section: Selection Of Near-infrared Detectorsmentioning

confidence: 99%

“…Such a deviation from Poisson statistics can give strong suggestion of technological origin of the photons. For the optical SETI experiment at both Leuschner and Lick Observatory that use PMTs, it was determined that the optimal number of detectors that had good sensitivity and low false alarm rate was three (Werthimer et al 4 , Wright et al 5 ). For our near-infrared experiment using significantly different detectors, we re-explored the probability distribution of false alarm rate with the new near-infrared detectors, discussed in Maire et al, this conference.…”

Section: Conceptual Design Of "Optical Pulsed" Setimentioning

confidence: 99%

“…There has been growing interest in searches for fast (nanosecond) optical pulses emanating from transmitting beacons from extraterrestrial intelligence (e.g., Horowitz et al 3 , Werthimer et al 4 , Wright et al 5 , Reines & Marcy 6 , Howard et al 7 , Stone et al 8 , Howard et al 9 , Covault 10 ). Today's highest-powered pulsed lasers can outshine our Sun by at least 4 orders of magnitude in brightness, and may offer one of the best means for interstellar communication (as originally suggested by Schwartz & Townes 11 ).…”

Section: Introductionmentioning

confidence: 99%

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A near-infrared SETI experiment: instrument overview

Wright

Werthimer

Treffers³

et al. 2014

SPIE Proceedings

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We are designing and constructing a new SETI (Search for Extraterrestrial Intelligence) instrument to search for direct evidence of interstellar communications via pulsed laser signals at near-infrared wavelengths. The new instrument design builds upon our past optical SETI experiences, and is the first step toward a new, more versatile and sophisticated generation of very fast optical and near-infrared pulse search devices. We present our instrumental design by giving an overview of the opto-mechanical design, detector selection and characterization, signal processing, and integration procedure. This project makes use of near-infrared (950 -1650 nm) discrete amplification Avalanche Photodiodes (APD) that have > 1 GHz bandwidths with low noise characteristics and moderate gain (~10 4 ). We have investigated the use of single versus multiple detectors in our instrument (see Maire et al., this conference), and have optimized the system to have both high sensitivity and low false coincidence rates. Our design is optimized for use behind a 1m telescope and includes an optical camera for acquisition and guiding. A goal is to make our instrument relatively economical and easy to duplicate. We describe our observational setup and our initial search strategies for SETI targets, and for potential interesting compact astrophysical objects.

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<title>Berkeley radio and optical SETI programs: SETI@home, SERENDIP, and SEVENDIP</title>

Cited by 35 publications

References 0 publications

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars

A near-infrared SETI experiment: instrument overview

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