1. The SETI@home, SERENDIP, SEVENDIP, Astropulse, and SPOCK SETI Programs
‘Dan Werthimer, Dave Anderson, Jeff Cobb,
Paul Demorest, Eric Korpela, Cecile Kim, Geoff Marcy
University of California, Berkeley

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4. NOT FUNDED 1

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6. NOT FUNDED 1

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8. NOT FUNDED 1

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10. Porno in space:
FUNDED! 1

11. Drake Equation N=R fs fp ne fl fi fc L
N = number of communicating civilizations in our galaxy

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14. Planet Detection

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20. First Radio SETI Nikola Tesla (1899) Guglielmo Marconi (1920)
Announces “coherent signals from Mars”
Guglielmo Marconi (1920)
Strange signals from ET
Frank Drake (1960)
Project Ozma
one channel, MHz

21. Signal Types 1. Artifact (radio, radar, ~TV, ????)
2. Deliberate (easy to decode, pictures, language lessons)
First civilization we contact is likely to be a billion years ahead of us.

22. Targeted Search Strategy:
Project Phoenix Seti Institute
Sky Survey Strategy:
Serendip, UC Berkeley
Beta Harvard
Southern Serendip Australia
Meta II Argentina
Seti Italia Medicina Obser.

23. Quick History of Berkeley SETI
Radio SETI
SERENDIP Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations
SERENDIP I-III ( )
SERENDIP IV (1997-)
SERENDIP V (2004-)

24. The Berkeley Radio SETI Family Tree
SERENDIP
SERENDIP II
OSU
SERENDIP III
SETI Italia
Data Recorder
Clients
SERENDIP IV
Southern
SERENDIP
HI Survey
AstroPulse
Pulse Survey II
Data Recorder II
Clients
SERENDIP V

25. SETI Programs at the University of California

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31. SERENDIP IV 168M channels 100 MHz Band centered on 1420 MHz
Photos Courtesy NAIC Arecibo Observatory, a facility of the NSF
168M channels
100 MHz Band centered on 1420 MHz
Carriage House 1 line feed
Operating since 1997

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36. Why SETI@home? Coherent Doppler drift correction
Narrower Channel Width->Higher Sensitivity
Variable bandwidth/time resolution
Search for multiple signal types
Gaussian beam fitting
Search for repeating pulses
Problem: Requires TFLOP/s processing power.
Solution: Distributed Computing

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40. The Client

41. Statistics
TOTAL RATE

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47. Structure of SETI@home
Tapes from
Arecibo
Online
Science
Database
3.8 Million Volunteers
The Internet
Work Unit Storage
Data splitters
Volunteer
Statistics
Master
Result Verification
Candidate Identification
Web Server
Data Server

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50. The Input and Output 1 Work-Unit=9.8 kHz x 220 samples (107 sec.)
256 Workunits across 2.5 MHz band centered on MHz.
Workunits overlap in time by ~25 sec.
Each workunit sent to multiple computers for result verification
Typically 4 TFLOP/workunit.
Output=Typically ~5 potential signals.

51. Spikes
Power distribution in the Fourier transformed data is exponential if no RFI.
SPIKE: Any bin in the spectrum above 22X the mean power (7.8x10-25 W/m2)

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54. Gaussians Weighted 2 fit to beam profile (vs time).
Gaussian must exceed a power and 2 threshold
Score inversely proportional to probability of arising due to noise
Sensitivity 8.4x W/m2

55. Triplets
Three evenly spaced spikes above 7.75X the mean power. (5.3X10-25 W/m2)

56. Pulses Modified Fast folding algorithm w/ dynamic threshold
Logarithmically spaced periods from 3ms to 35s
Sensitivity as low as J/m2

57. Candidate Identification
Candidate: A signal or group of signals
Within a positional window (~1 beamwidth typ.)
Within a frequency window (variable)
Above a score or power threshold (variable)
With time separation » typical transient RFI timescale
Score:
Relative ranking of a candidate’s probability of arising due to random noise.
Should be independent of signal type
Can also include probability of coincidence /w celestial objects

58. Gaussian Candidates

59. AstroPulse Sky survey Good time resolution DM range Sensitivity
Covers decs 0 to 30
~3 years of data recorded so far.
Good time resolution
Sensitive to 0.4 µs radio pulses at 21 cm
DM range
-100 to +100 pc/cm3
Sensitivity
10-18 W/m2 peak (Coherent de-dispersion)

60. Pulsed vs. CW
Concentrating power into short bursts can be more efficient than a “constantly on” transmitter.
Pulsed signals can be easier to see above background noise.

61. Dispersion … eventually becoming very weak.
However, we can correct for dispersion ...

62. AstroPulse
Only ~1.5 searches for single pulses on µs timescale before (O’Sullivan, Phinney)
Pulsar searches: ms time scales, folded
ms single pulses.
With interesting astrophysics as well as SETI applications.
Evaporating primordial black holes?
Pulsars, Other astrophysical exotica?

63. Conclusion: We need more computers!
Computation
… but it takes a lot of CPU time!
To search DMs up to 100 pc/cm3 in real time, we need about 500 GigaFLOPs.
(This would take ~1000 years of your PC working full time)
Conclusion: We need more computers!

64. BOINC Berkeley Open Infrastructure for Network Computing
General-purpose distributed computing framework.
Open source.
Will make distributed computing accessible to those who need it. (Starting from scratch is hard!)

65. AstroPulse/BOINC AstroPulse will be the first to use BOINC.
It is a good “beta-test” application:
Simple data analysis/reduction.
“Only” needs a few thousand computers.
Other projects which plan to use BOINC: II
Global climate modeling/prediction (Oxford)

66. AstroPulse Testing
Sample batch of data run through shows expected noise characteristics, and little else …
… so (hopefully) little RFI contamination for this type of signal.

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68. HI Column Density

69. OPTICAL SETI OPTICAL PULSE SEARCH
Pulsed laser power output continues to grow.
Petawatt pulses achieved at Livermore Labs. (Mjoule in 1nS)
can detect at earth technology at 1Kpc
little background noise, even from bright stars in whole visible band

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72. OSETI Detector 3-Photomultiplier fast coincidence detector
Sensitive to 1ns pulses
Low background
False alarm rate: 1 per 300 hours (10-6 Hz)
Double false alarm rate: 1 per 600 years!
Good sensitivity
10-8 W/m2 peak
10-19 W/m2 average

73. Optical SETI Uses Leuschner Observatory (UCB) Targeted Search
Automated 0.8m telescope
Targeted Search
Nearby F,G,K,M stars
~2,000 stars observed so far
Soon to include galaxies

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75. Amy Reines and Geoff Marcy
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76. 10-meter Keck Telescope Survey: 650 F8 – M5 V, IV Hipparcos V < 8.5
B-V > 0.55 (F8V)
Sep > 2 arcsec
Age > 2 Gyr

77. Doppler Instruments Echelle Spectrometer Resolution: 60,000
Iodine Abs. Cell.
Superimpose I2 lines
Wavelength Calib.

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80. Piggyback ALFA Sky Survey
SETI Instruments
Dedicated spectrometer (SERENDIP V)
300 MHz bandwidth, 2 pols, 7 beams
5 * 109 channels, 0.8 Hz resolution
II data recorder
10 MHz, 1 pol, 7 beams
Steps across 300 MHz band

81. Piggyback ALFA Sky Survey
Improved sensitivity
Tsys, integration time
Uniform sky sampling
galactic plane concentration
Multibeam RFI rejection
Larger Bandwidth

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86. Our Generous Sponsors The Planetary Society
The University of California
Sun Microsystems
Friends of
Network Appliance
Fujifilm
IBM
Quantum HP
Xilinx
The SETI Institute
Informix
EDT
Netscreen
Intel
O’Reilly & Associates
SpaceSounds
Dillon Engineering
NAIC, Arecibo Observatory
~4 million volunteers
Maybe, someday, the U.S. Government

87. SETI HAIKU

88. Seti.berkeley.edu