SETI with SKA1 and SKA2

Transcription

1 SETI with SKA1 and SKA2 Alan Penny1, Heino Falcke2, Mike Garrett3 1 University of St Andrews and South African Astronomical Observatory PI: LOFAR Early Access Program LEA070 'A SETI Pilot Program' 2 Raboud University 3 ASTRON and Leiden University AAVP2010 U Cambridge 8-10 December 2010

2 What a radio SETI search looks for A narrow (perhaps1 Hz wide) spectral line

3 Sections 1. SETI 2. Experience of SETI with LOFAR and WSRT 3. SETI and SKA - needs

4 Sections 1. SETI 2. Experience of SETI with LOFAR and WSRT 3. SETI and SKA - needs

5 What a radio SETI search looks for A narrow (perhaps1 Hz wide) spectral line

6 SETI Scientific Activity Searches 101 significant searches major (thousands of hours) Papers Search for phrase extraterrestrial intelligence NASA ADS text Google Scholar 658 1,990 A number of these are minor articles and comments, but there are many hundreds of real papers

7 The National Science Foundation Decadal Review ''The most promising signatures of life on planets around other stars are features in the atmospheric spectra of planets around other stars, such as the red edge arising from photosynthesis. Less definitive is molecular oxygen, which is locked up in oxidized surface minerals unless continually replenished either by life (as on Earth) or catastrophic loss of surface water followed by photolysis Of H2O in the atmosphere (as on early Venus). The presence of both water and methane in a planetary atmosphere is a more reliable biosignature of water-based organic life than that of one or the other alone. A different approach is to look for signals produced by technologically advanced entities elsewhere in our galaxy.''

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9 SKA Design Reference Mission The Cradle of Life The existence of life elsewhere in the Universe has been a topic of speculation for millennia. In the latter half of the 20th Century, these speculations began to be informed by observational data, including organic molecules in interstellar space, and proto-planetary disks and planets themselves orbiting nearby stars. With its sensitivity and resolution, the SKA will be able to observe the centimeterwavelength thermal radiation from dust in the inner regions of nearby proto-planetary disks and monitor changes as planets form, thereby probing a key regime in the planetary formation process. On larger scales in molecular clouds, the SKA will search for complex prebiotic molecules. Finally, detection of transmissions from another civilization would provide immediate and direct evidence of life elsewhere in the Universe, and the SKA will provide sufficient sensitivity to enable, for the first time, searches for unintentional emissions or leakage.

10 The Four Facts of SETI FACT IMPLICATION 1) We are here ETI is possible 2) Other Earths exist ETIs are possible 3) 'We' happened at the end ETI is rare? - The Anthropic Principle 4) 'They' are not here - The Fermi Paradox No ETI?

11 Methods of Searching Distant EM radiation - radio optical/ir X-ray gamma-ray gravity lensing Artefact - object - pattern Gravity waves Alfven waves Nearby Particles (beams) - neutron - molecule - bacteria - neutrino - charged particle - dark matter - supersymmetry particle Exotica - tachyon - worm hole - telepathy - Earth Earth orbit Moon Earth-Moon system asteroid belt planets and moons Solar System Buried message Invitation Waiting

12 What a radio SETI search looks for A narrow (perhaps1 Hz wide) spectral line

13 Radio Sky Background Ghz 1m 10 cm 1 cm 10 mm

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15 Moore's law in SETI spectral channels

16 Project Dorothy Nov sites

17 ATA observations Eps Eri 10 mins 277 channels out of 64M 277 Hz MHz (SETI Insitute, Harp and Ackermann)

18 ATA observations Eta Are 10 mins 277 channels out of 64M 277 Hz MHz (SETI Insitute, Harp and Ackermann)

19 Sections 1. SETI 2. Experience of SETI with LOFAR and WSRT 3. SETI and SKA - needs

20 Using LOFAR and WSRT/Apertif Time allocated EoI accepted

21 (Tied) A ybreraam LOFAR - Different Beams LOFAR Array Station-Beam ntam e e-rbe h ctoion n Ia St Station AntennaBeam Antennae

22 ATA many SETI beams in one pointing

23 SETI surveys with LOFAR In Progress 1) LEA 070: A SETI Pilot Program in LOFAR Commissioning Time Planned 1) Tied-Beam survey of nearby stars 2) All-sky search derived from Transients KSP 3) Piggyback - One Second All Sky Survey - Incoherent beam transients - Transients Key Project - Cosmic Rays Key Project

24 Detection limits - BMEWS radar - 1 month obs - EIRP - 8kHz bandwith

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26 1 Hz spectral resolution with LOFAR Flux (0.004% of data) Frequency (MHz) (Zarka, Griessmeier, Girad)

27 60 1 Hz spectral resolution with LOFAR Time (secs) 5 db Frequency (MHz)

28 Sections 1. SETI 2. Experience of SETI with LOFAR and WSRT 3. SETI and SKA - needs

29 SKA Design Reference Mission The Cradle of Life Finally, detection of transmissions from another civilization would provide immediate and direct evidence of life elsewhere in the Universe, and the SKA will provide sufficient sensitivity to enable, for the first time, searches for unintentional emissions or leakage. But no discussion of SETI needs in the DRM

30 SETI possibilities and needs for SKA1 - Many millions of narrow 1 Hz wide channels - Very large data handling and storage rates - For AA - Tied-beams (many) - All-sky mode - Signal triggering - For dish array - Tied-beams (many) - FPAs - Spigots for both

31 Radio Sky Background Ghz 1m 10 cm 1 cm 10 mm

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33 SETI further possibilities s for SKA - Transient pulses - Time scales - Signal spectral widths - Fish-eye modes - ATA-type piggy-back spigots

34 Immediate tasks for SETI-SKA study 1) Do SETI needs lie outside present DRM? 2) A detailed investigation of h/w and s/w needs for many millions of channels of 1 Hz width - extra h/w and s/w - data flow and storage - analysis software - pointed and all-sky modes 3) Possible less ultimate modes in the near future

35 The End What a radio SETI search looks for A narrow (perhaps1 Hz wide) spectral line

36 The End