Interstellar scattering effects on the detection of narrow-band signals

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/170261· OSTI ID:5156214

Cordes, J M; Lazio, T J ^[1]

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1. Cornell University, Ithaca, NY (United States)

The detection and decoding of narrow-band radio signals are investigated after propagation through the turbulent, ionized interstellar medium. For most lines of sight through the Galaxy, spectral broadening due to scattering below about 0.1 Hz at 1 GHz occurs. Spectral broadening is therefore unimportant for the detection of hypothesized signals from extraterrestrial intelligence. Intensity scintillations, however, are of considerable importance. They both help and hinder detection: signals too weak to be detected without the scattering medium may be modulated above the detection threshold while, conversely, signals above threshold can be modulated below. In strong scattering (distances above about 100 pc at 1 GHz), multiple observations of a given target comprise a strategy that is superior to single observations even when the total time per target is held fixed. Decoding information carrying signals may encounter difficulties due to intensity scintillations. 49 refs.

• OSTI ID: 5156214
• Journal Information: Astrophysical Journal; (United States), Vol. 376; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
DETECTION
MILKY WAY
RADIOWAVE RADIATION
WAVE PROPAGATION
INTERSTELLAR SPACE
IONIZED GASES
LINE WIDTHS
PULSARS
SCATTERING
ELECTROMAGNETIC RADIATION
FLUIDS
GALAXIES
GASES
RADIATIONS
SPACE
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 - Astrophysics & Cosmology- Galaxies