EMILIO ENRIQUEZe.enriquez@berkeley.edu

LOFAR AS AN INSTRUMENT FOR SETI:a case study on the Solar Neighborhood

ANDREW SIEMIONSANDER TER VEENVLAD KONDRATIEV

HEINO FALCKE

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Low Band Antenna (LBA)10-90 MHz

van Haarlem (2013)

High Band Antenna (HBA)110-240 MHz

van Haarlem (2013)

Low Frequency ArrayAreciboGreen Bank

TelescopeInfrared Spatial Interferometer

Optical Telescopes

THE LOFAR FREQUENCY RANGE

! First LOFAR SETI experiment done at a wide range of low frequencies

! Covering radio leakage regions (AM & FM)

van Haarlem (2013)

Station Cabinets

• Bullet one here, with some text discussing something important. So important there will be more detail here.

• Bullet two here, with some more text

• Bullet point three is going here, bam.

• Bullet one here, with some text discussing something important. So important there will be more detail here.

• Bullet two here, with some more text

• Bullet point three is going here, bam.

LOFAR DIGITAL TELESCOPE

LOFAR MULTI-BEAM: EXCELLENT RFI REJECTION

MULTI-BEAM RFI REJECTION

! Example high resolution data with 1.49 Hz per channel

SETI WITH LOFAR

How sensitive is the LOFAR Core?

Enriquez, et.al., In prep.

! HAARP-IRI (EIRP:8 GW)

! Arecibo Planetary Radar

! (EIRP:2x1013 W)

(tintegration = 10 min, SNR = 5) FOR A TRANSMITTER AT 5 PC

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SETI ON NEARBY STARS WITH LOFAR

! LOFAR core beamform observations ! Volume limited sample at 5 pc ! Observations of the 30 nearest stars ! Spectral type independent ! Covering the full frequency coverage of LOFAR (10-250 MHz; 5 sets of 40 MHz) ! Total of 24 hrs at 12 min int.

! Using bright nearby pulsars for diagnostics ! Two station beams with two TAB per station beam ! Stored raw voltage data at 21 Gbps (Total 140 TBs)

SETI LOFAR PROCESSING PIPELINE

Enriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptx

NARROWBAND SEARCH OF DRIFTING SIGNAL

GOOD RFI CONDITIONS

WELL, YOU GET THE POINT…

NARROW BAND SEARCH

! Narrow band searches at high frequency resolution (1.49 Hz)

! Range of +/- 10 Hz/s

! At 250 MHz equivalent to +/- 56 Hz/s at 1.4 GHz (any solar system object)

! At 20 MHz equivalent to +/- 700 Hz/s at 1.4GHz (theoretical limits on rotation)

! Total number of hits: 2,411,879 > 5 sigma ! Total number of hits: 389,307 > 10 sigma

RESULTS ARROW BAND SEARCH

RESULTS ARROW BAND SEARCH

RFI REJECTION

RFI REJECTION

RFI REJECTION

MULTI-BEAM

MULTI-BEAM

RFI REJECTION

RFI REJECTION

SLIDE FOR WHEN WHITE BACKGROUND IS REQD.

RFI EXCISION: HITS FREQUENCY DISTRIBUTION

RFI EXCISION: HITS DRIFT RATE DISTRIBUTION

RESULTS ARROW BAND SEARCH

How sensitive is the LOFAR Core?

Enriquez, et.al., In prep.

! HAARP-IRI (EIRP:8 GW)

! Arecibo Planetary Radar

! (EIRP:2x1013 W)

(tintegration = 10 min, SNR = 5) FOR A TRANSMITTER AT 5 PC

SEFD AS FUNCTION OF FREQ AND ELEVATION

RESULTS

! Multi-beam RFI excision shows to be very promising for SETI work. Only a few top hits are left after the RFI excision.

! Place limits to the nearest stars to EIRP 1011-1012 W

! Sky coverage not so great with TABs (100-800 arcsec)

FUTURE SETI PROJECT WITH THE LOFAR CORE

! One step improvement:

! Multi step effort:

! TAB + SAP muti-beam analysis ! SAP beam width ~ 470 v-1

51deg2 (250MHz) or 645 deg2 (20MHz) ! Can use TAB to do RFI excision to the SAP

! Fly’s Eye observations increases the FOV greatly ! With 24 stations you can do full sky below 18 MHz

Enriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptx

Enriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptx

Enriquez.SETI.AAS.2017.pptxEnriquez.SETI.AAS.2017.pptx

Observing Strategy! Using Bright Pulsars for

Diagnostics

! Multi-beaming: Excellent RFI Rejector!

! Astronomical Sources Appear Only in a Single

! Beam Interference in Many Beams

(tintegration = 10 min, SNR = 15) FOR AN EXTRATERRESTRIAL TRANSMITTER @ 50 LY

SETI ON THESETI ON THESETI ON THESETI SETI SETI ONONONON THETHETHETHE

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LOFAR Single Subband !- Dedoppler search unit

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Pulsar Detection Dependence on frequency

! PSR 2310+42

! 210 – 217 MHz

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Pulsar Detection Dependence on frequency

! PSR 2310+42

! 117 – 124 MHz

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Pulsar Detection Dependence on frequency

! PSR 2310+42

! 56 – 63 MHz

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! Pulsar detection based on a single band of 7MHz.

! Increased sensitivity by adding the full bandwidth of 41 MHz. This done after processing with a different pipeline only on few selected targets.LBA1 LBA2 HBA1 HBA2 HBA3

[20MHz -- > 240 MHz]

Pulsar Detection Dependence on frequency 49

Multi-beam RFI Rejection

! Threshold search with 5 sigma ~ 10 hrs per subband.

! Threshold search with 3 SNR ~ 8 days!!

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! Detection Threshold for a Star at 5pc (phased NL-core, SEFD 60 Jy w/ HBA, 1200 Jy LBA)

How sensitive is the LOFAR Core?Enriquez, et.al., In prep.

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SETI in the Solar neighborhood !with LOFAR

! Observations of all stars systems within 5pc (16ly)

! 10 - 250 MHz (LBA and HBA)

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HadoopGrid

LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

HadoopGrid LTA

! Search of known pulsars

!RFI diagnostic " rejection with > 75% RFI

Analysis Pipeline

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Current Status

! Processing data through GRID pipeline.!100% complete.!Used ~ 80k CPU hours

! Initial number of signals 3.0 Million (not yet candidates)

HadoopGrid

LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

HadoopGrid LTA

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LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

Current StatusHadoopGrid

LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

HadoopGrid LTA

! Ongoing development of mutibeam rejection pipeline

! From a 25 SNR threshold, the rejection rate from multi-beam is about 99.8%

! We are looking into other techniques to search the remaining 0.2 %

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Current Status

LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

HadoopGrid LTA

! Using SURFSara computing facilities (in Amsterdam)

! Awarded ! 100k hours Grid + 50 TB storage ! 100K Hadoop + 30 TB storage

Grid (SURFsara) Hadoop

Number of cores (nodes) 5600 Xeon cores at 2.2 to 2.6 GHz

768 cores(107 nodes)

Total mem 41 TB 5.25 TB

Disk storage (tape) 7.8 PB (17.6 PB) 1.7 PB

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LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

Current Status

! Observations 100% complete

! 12 min recording of Complex Voltage data = 100TB!

! Tied-array Mode with Core Stations (inner 2km)

12 min recording of Complex Voltage data = 100TB!

HadoopGrid

LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

HadoopGrid LTA

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LOFAR Observations

Low ResolutionAnalysis(Pulsar Search;

RFI diagnostic)

High ResolutionAnalysis

(Dedoppler)

Multibeam Analysis

Other Analysis(Stellar

Astrophysics)

Analysis Pipeline

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Analysis Pipeline

LOW FREQUENCY RADIO SETI - LEAKAGE

See also: Loeb and Zaldarriaga, 2006

!768 kW @ 217 MHz (originally 108 MHz)

!EIRP ~1010 W

!120º x 1.5’ Fan Beam (3000 times the solid angle of Arecibo Planetary Radar)

! United States Air Force Space Surveillance System “Space Fence”