4273-18

Targeted and All-Sky Search for Nanosecond Optical Pulses at
Harvard-Smithsonian

by

Paul Horowitz

&

Charles Coldwell, Physics Dept, Harvard University
Andrew Howard, Physics Dept, Harvard University
David Latham, Center for Astrophysics
Robert Stefanik, Center for Astrophysics
Jonathan Wolff, SpaceDev Inc.
Joe Zajac, Center for Astrophysics

Abstract

We have built a system to detect nanosecond pulsed optical signals from a target list of some 10,000 sunlike stars, and have made some 20,000 observations during its two years of operation.  A beamsplitter feeds a pair of hybrid avalanche photodetectors at the focal plane of the 1.5m Cassegrain at Agassiz Station, with a coincidence triggering measurement of pulse width and intensity at sub-nanosecond resolution.  A flexible web-enabled database, combined with mercifully low background coincidence rates (~1 event per night), makes it easy to sort through far-flung data in search of repeated events from any candidate star.  An identical system is beginning observations, synchronized with ours, at the 0.9m Cassegrain at Princeton University.  These will permit unambiguous identification of even a solitary pulse.

We are planning an all-sky search for optical pulses, using a dedicated 1.8m f/2.4 spherical glass light bucket and an array of pixelated photomultipliers deployed in a pair of matched focal planes.  The sky pixels, 1.5 arcmin square, tesselate a two degree by half degree patch of sky in transit mode, covering the Northern sky in ~150 clear nights.  Fast custom IC electronics monitors corresponding pixels for coincident optical pulses of nanosecond timescale, trigerring storage of a digitized waveform of the light flash.

Keywords

Optical SETI, interstellar communication.

• The paper (author Web site)

Principal Author Biography

Paul Horowitz has been Professor of Physics at Harvard University since 1974, where he received the A.B. and Ph.D.  His research interests have included experimental astrophysics, x-ray and particle beam microscopy, the search for extraterrestrial intelligence, studies of the e.coli rotary engine, optical interferometry, the search for ultraheavy matter, radon measurement techniques, and the search for neutral hydrogen condensations in the early universe.  He is an author of some sixty scientific articles, reports, and book chapters, and (with W. Hill) "The Art of Electronics", as well as some ninety technical reports on topics in national security.

Principal Author Affiliation

Department of Physics Harvard University
Physics Department, Lyman
17 Oxford St
Cambridge , MA 02138
US
Phone: 617-495-3265
Fax: 617-496-5144
Email: horowitz@physics.harvard.edu

Correspondence for Secondary Authors

Charles Coldwell, Physics Dept, 17 Oxford St, Cambridge, MA 02138; tel 617-495-3037; fax 617-496-5144;
email coldwell@frank.harvard.edu

Andrew Howard, Physics Dept, 17 Oxford St, Cambridge, MA 02138; tel 617-495-3037; fax 617-496-5144;
email howard@frank.harvard.edu

David Latham, Center for Astrophysics, 60 Garden St, Cambridge, MA 02138; tel 617-495-7215; fax 617-495-7467;
email dlatham@cfa.harvard.edu

Robert Stefanik, Center for Astrophysics, 60 Garden St, Cambridge, MA 02138; tel 617-495-7070; fax 617-495-7070;
email rstefanik@cfa.harvard.edu

Jonathan Wolff, SpaceDev Inc, 13855 Stowe
Dr, Poway, CA 92064; tel 858-375-2034; fax 858-375-1050;
email wolff@spacedev.com

Joe Zajac, Center for Astrophysics, 60 Garden St, Cambridge, MA 02138; tel 617-495-7070; fax 617-495-7070;
email jzajac@cfa.harvard.edu