Transcript SETI on the SKA - Arecibo Observatory

SETI on the SKA
US SKA Consortium Meeting
Feb 28, 2000
Jill Tarter
Bernard M. Oliver Chair
SETI Institute
For SETI, We Don’t Know...
• Where To Look
• At What
Frequency
• When To Look
• For What Signal
• From How Far
For SETI, We Don’t Know...
• Where To Look
• At What
Frequency
• When To Look
• For What Signal
• From How Far
• Stars!
For SETI, We Don’t Know...
• Where To Look
• At What
Frequency
• When To Look
• For What Signal
• From How Far
As Much Of The
Spectrum As
Possible
(Terrestrial Wave
Window, Optical, IR)
For SETI, We Don’t Know...
• Where To Look
• At What
Frequency
• When To Look
• For What Signal
• From How Far
Multiple Looks
(Scintillation, and
Time Varying Signals)
For SETI, We Don’t Know...
• Where To Look
• At What
Frequency
• When To Look
• For What Signal
• From How Far
Technology Nature
(Compressed In
Frequency Or Time)
For SETI, We Don’t Know...
• Where To Look
• At What
Frequency
• When To Look
• For What Signal
• From How Far
All The Sensitivity We
Can Get!!!
SETI On Telescopes Today
• Sky Surveys
• Targeted Searches
SERENDIP IV
Project Phoenix
( SETI@home )
[BETA]
META II
So. SERENDIP
Project Argus
10 micron IR
Harvard Optical
Berkeley Optical
Columbus OSETI
SERENDIP IV At Arecibo
• UC Berkeley SSL
• Piggyback (commensal)
• Almost 4 years of data
• 1420 MHz +/- 50 MHz
• 0.6 Hz resolution
• 12 seconds per beam
• Simple threshold @ 15 
• 2.5 MHz time series data
to SETI@home
David Anderson
Dan Werthimer
Project Phoenix At Arecibo
• Microwave search from 1.2 to 3 GHz
Real Time Signal Detection
Frequency
M
Fully sample
frequencytime plane
N
Drifting CW
detection
algorithm
MN2 
MN logN
Real Time Signal Detection
Frequency
Thresholded
Sparse
Data Set
Triplet
Pulse
Detection
Algorithm
Unique to Project Phoenix
2 Antennas
linked as a
pseudointerferometer
Unique to Project Phoenix
• Original selection of
candidate signal is based
on power detection with
spectral resolution of 1Hz
• Coherent integration on
follow up with spectral
resolution that may be as
fine as 0.01 Hz
• Differential Doppler
signature is key to RFI
excision
Current Status of Project Phoenix
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•
•
•
Arecibo and Jodrell Bank
12 am +/- 6 hr, 40 d/yr
500 stars down, 500 to go
BW = 20 MHz  100 MHz
(RCP and LCP)
• Sensitivity limits
1012 W EIRP @ 155 lt yr
8x10-27 W/m2  1 Jy
Coverage of the Cosmic Haystack
How, Most Comprehensive??
• Hard to compare targeted searches with sky surveys
• If you assume stars are what matters
(not interstellar spacecraft between the stars)
• Can use sensitivity of the various searches to
calculate the number of stars that are “accessible”
within any given beam on the sky for both TS & SS
• Comparison can then be made for any ETI power
Figure = # of Stars x BW x log(Fhi/Flo) x (1+ log q)
of Merit
where q = number of looks
SERENDIP IV
searches for
intrinsically
strong sources
in sky visible
from Arecibo
)stta w( PRIE sv tireM
9
xineohP
T k1
7
VI S
SS Th1
5
)tir eM(gol
3
1
181
61
41
21
)PRIE(gol
01
8
6
Phoenix
seaches for
faint sources
nearby and
intrisically
strong sources
in the background
Coverage of the Cosmic Haystack
Results:
We Need
aNothing
Better
Telescope!
To Date
The First Step
The One Hectare Telescope (1hT)
Notes Added After Meeting:
The next slide is VERY IMPORTANT!
It shows that no matter where on the sky YOU ARE LOOKING
there will be multiple SETI target stars in the large field of view of
a small dish. Therefore for the cost of the beam-forming and
backend SETI processing systems, SETI can observe all the time
without interfering with scheduled observations of traditional
radio astronomy sources. (There would have to be some small
accommodation so that the field of view is not changed while an
interesting candidate signal is being pursued, but that will be
an infrequent conflict.)
Target Stars per Beam (5m dish)
1hT Speeds Up SETI
Multiplexing
100
90
80
70
100000 stars
60
1000000 stars
50
40
30
20
10
0
0
2
4
6
8
10
12
For a target list of
1 million stars
(from GAIA mission)
there will be more
than 1 star in the field
of view of a 5m (or
smaller) dish up to 10
GHz
and
Frequency in GHz
Increased BW
TS SETI Observations with 1hT
•
•
•
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•
# of targets = 100,000 stars •
•
•
100 m equivalent
Number of beams = 3
Bin width = 0.01 Hz
Integration time = 400 sec
Threshold = 9 sigma
= 1.7 E-23 W
Processing bandwidth = .5 GHz
Frequency range = 1 to 3 GHz
Number of relooks = 3
Total time for search = 6.3 years
TS SETI Observations with 1hT
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•
# of targets = 100,000 stars •
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•
100 m equivalent
Number of beams = 12
Bin width = 0.01 Hz
Integration time = 400 sec
Threshold = 9 sigma
= 1.7 E-23 W
Processing bandwidth = .5 GHz
Frequency range = 1 to 10 GHz
Number of relooks = 3
Total time for search = 8 years
SS SETI Observations with 1hT
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•
•
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+30 to +60 Declination
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•
100 m equivalent
Number of beams = 100
Bin width = 0.01 Hz
Integration time = 150 sec
Threshold = 25 sigma
= 9.3 E-23 W
Processing bandwidth = 1GHz
Frequency range = 1 to 3 GHz
Number of relooks = 1
Total time for search = 11 years
Improved Search Space
Merit vs EIRP(watts)
)stta w( PRIE sv tireM
In 20 year array
lifetime, the
1hT can do both:
9
xineohP
Phoenix
S IV
S IV
1hT TS
1hT SS1hT TS
1hT SS
7
VI S
SS Th1
5
)tir eM(gol
log(Merit)
(Merit)
Log
TS with 12 beams
SS with 100 beams
T k1
BETAmax
3
1
-1
6
81
8
61
10
41
12
21
log(EIRP)
)PRLog
IE(go(EIRP)
l
14
01
16
8
18
6
For SETI, We Don’t Know...
• Where
ThisToIsLook
a
• At What
Job For
Frequency
SKA
• When To Look
• For What Signal
• From How Far
• Stars! A Million
Or More
All The Sensitivity We
Can Get!!!
SETI Observations with SKA
• Factor of 100 in sensitivity over the 1hT
observations
• Factor of 100 decrease in transmitter EIRP
for current target star list
• Factor of 10 in distance or 1000 times as
many stars for current limit of 1012 W EIRP
SETI Issues
• Targeted searches prefer large FOV
– multiplexing advantage
• Sky surveys prefer all sky imaging
– tiles or Luneberg lenses
– probably can’t afford high resolution processing
– transients are attractive possibility
(OSS for strong transients - 1020 ops)
SETI Issues
• Targeted searches prefer large FOV
• Sky surveys prefer all sky imaging
• 1-10 thousand km maximum baselines? OK
– pencil beams all too small for background stars
• Maximum instantaneous BW
• Frequency range 0.5-10 GHz
Bets on Moore’s Law
SETI Observations with SKA
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Bin width = 0.01 Hz
Integration time = 1000 sec
Threshold = 11 sigma = 1.2 E-23 W
Processing bandwidth = 9 GHz
Number of beams = 10
Frequency range = 1 to 10 GHz
Number of relooks = 3
Total time for search = 10 years
Total number of targets = 1,000,000
Conclusions:
Merit vs EIRP(watts)
A sensitive
search of a
million nearby
stars will take
about 10 years
with the SKA
10
Phoenix
1SKA
kT
8
1hT TS
log(Merit)
6
4
2
0
6
8
10
12
log(EIRP)
14
16
It can be done
in parallel with
traditional RA,
assuming 10 beams
9 GHz BW