OSETI with STACEE: A Search for Nanosecond Optical Transients from Nearby Stars

Hanna, D.; Ball, John A.; Covault, C. E.; Carson, J.; Driscoll, Donna M.; Fortin, P.; Gingrich, Doug; Jarvis, A.; Kildea, J.; Lindner, T.; Mueller, Carmen L.; Mukherjee, R.; Ong, R. A.; Ragan, K.; Williams, D. A.; Zweerink, J.

doi:10.1089/ast.2008.0256

Cited by 45 publications

(22 citation statements)

References 20 publications

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“…A diffraction-limited 10-meter diameter optic constitutes a reference fiducial laser beam launcher that is consistent with contemporary technology, as adopted by others (e.g. Ekers et al 2002, Howard et al 2004, Hanna et al 2009). The emitted solid angle (and the illuminated footprint area at the receiver) of such a beam launcher is proportional to the square of the wavelength, , of the laser light and inversely as the square of the diameter, D, of the emitting optic,  = (/D) 2 , allowing subsequent scaling to any envisioned wavelength and launch optic diameter.…”

Section: Discussionmentioning

confidence: 90%

“…These searches targeted both stars and galaxies, and more recently stars harboring known exoplanets (Siemion et al 2013). Searches for both continuously transmitting and short duration light pulses in the visible spectrum (optical SETI) have been conducted (Wright et al 2001;Reines and Marcy 2002;Howard et al 2004;Stone et al 2005;Howard et al 2007, Hanna et al 2009, Tellis & Marcy 2015, Abeysekara et al 2016. A unique search for near-infrared pulses has also begun (Wright et al 2014c, Maire et al 2014.…”

Section: Introductionmentioning

confidence: 99%

“…The detection thresholds in this survey can be translated to limits on searches for pulses of optical emission from extraterrestrial sources, such as the searches by Howard et al (2004), Hanna et al (2009), andWright et al (2014b). We may characterize optical pulses by the time separation between pulses, tsep, and the number of photons per unit area per pulse hitting Earth's atmosphere, Npulse.…”

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confidence: 99%

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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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Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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

Tellis¹,

Marcy²

2017

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“…While this is effective for sources that have sufficiently slow time variations, it becomes inefficient and eventually inadequate as the timescale of variation decreases. Optical searches for rapid variations in astronomical objects have been proposed and carried out, principally to search for extraterrestrial intelligence (Howard et al 2004;Stone et al 2005;Hanna et al 2009). They search for optical intensity pulses detected with fast electronics.…”

Section: Comparison With Other Optical Search Techniquesmentioning

confidence: 99%

Spectral signatures of ultra-rapidly varying objects in spectroscopic surveys

Borra¹

2010

A&A

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Context. Astronomy is an observationally-led subject where chance discoveries play an important role. The time domain is the least explored in astronomy. Aims. We alert spectroscopists, particularly those involved in surveys, that rapidly varying sources can induce periodic patterns in spectra. Methods. The analytical treatment is based on standard Fourier theory. It is used to predict the shapes of features introduced by intensity pulses in spectra. These are the shapes that one must look for in spectral surveys. The theoretical analysis is supported by published experiments that measured the spectral modulation, in the visible wavelength region, caused by pairs of 150 femtosecond laser pulses separated by time periods varying between 5 × 10 −13 s and 3 × 10 −11 s. Results. Detection of spectral signatures would allow the detection of new classes of objects that emit bursts of pulses separated by time intervals that are too short to be detected with conventional techniques. The principal advantage of the technique is that there is no need for specialized instruments or surveys: one must only incorporate algorithms capable of searching for periodic spectroscopic signals, such as those shown in a figure in this article, into existing data analyzis software and use it with standard spectroscopic surveys (including existing ones).

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“…Humanity started its search for extraterrestrial civilizations (SETI) even before the first crewed space flight (Cocconi & Morrison 1959). We are looking for communications such as optical pulses (Howard et al 2004(Howard et al , 2007Hanna et al 2009) and continuous waves (Tellis & Marcy 2015) or radio signals (Horowitz & Sagan 1993;Werthimer et al 2001;Siemion et al 2010). We are observing thousands of exoplanets (Winn & Fabrycky 2015), some of them potentially habitable (Quintana et al 2014;Kopparapu et al 2013;Dressing & Charbonneau 2015).…”

Section: Introductionmentioning

confidence: 99%

Interstellar Communication Network. I. Overview and Assumptions

Hippke¹

2020

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It has recently been suggested in this journal by Benford (2019) that "Lurkers" in the form of interstellar exploration probes could be present in the solar system. Similarly, extraterrestrial intelligence could send long-lived probes to many other stellar systems, to report back science and surveillance. If probes and planets with technological species exist in more than a handful of systems in our galaxy, it is beneficial to use a coordinated communication scheme. Due to the inverse square law, data rates decrease strongly for direct connections over long distances. The network bandwidth could be increased by orders of magnitude if repeater stations (nodes) are used in an optimized fashion. This introduction to a series of papers makes the assumptions of the communication scheme explicit. Subsequent papers will discuss technical aspects such as transmitters, repeaters, wavelengths, and power levels. The overall purpose is to gain insight into the physical characteristics of an interstellar communication network, allowing us to describe the most likely sizes and locations of nodes and probes.

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OSETI with STACEE: A Search for Nanosecond Optical Transients from Nearby Stars

Cited by 45 publications

References 20 publications

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

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

Spectral signatures of ultra-rapidly varying objects in spectroscopic surveys

Interstellar Communication Network. I. Overview and Assumptions

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