ARTEMIS

Aris Karastergiou

Transcript

1. The  Sun Pulsars Radio   Transients Interstellar   Medium Nanosecond   Astronomy Ionosphere Cosmic  Rays The  Unknown LOFAR  staAon Beamformed Data
2. What is ARTEMIS? A software/hardware backend to process streaming data, used for single-station science at LOFAR-UK, Nancay, Bonn + Onsala. Software: AMPP, the artemis modular pelican pipelines AMPP: prototype for streaming processing for the SKA and its pathfinders. 35 TB/day today. Tomorrow? Software: Pelican, a light and scalable framework for distributed streaming processing. Hardware: AMPP and Pelican have native CPU and GPU support AMPP is not a UDP packet recorder AMPP is not limited to LOFAR AMPP is documented and open to developers H5 data product that conforms to LOFAR standard
3. Can be used for 100% of the time
5. LOFAR international stations • Large collecting area (96 coherently added dipoles), high sensitivity. 9 international stations = superterp • Very fast sampling rate (5 ns), reduced to 5.12 µs for the station beams. • Large fields of view, 10 to 100s of square degrees. • Not used for all LOFAR KSPs.
6. Dispersion searches DM 0 N2 or N logN process per time sample (N > 1000 -- 10000+ samples/sec HPC computing
7. 6 MHz bandwidth HBA UK (ARTEMIS) 48 MHz bandwidth LBA superterp
8. Dell Poweredge C6100 Dell Poweredge C410x Stef Salvini Wes Armour Dalal Ait Allal Mike Giles Chris Williams Steve Roberts Fred Dulwich Ben Mort Alessio Magro Aris Karastergiou hardware
9. Frequency (MHz) Time (ms) 8000 8200 8400 8600 8800 9000 143 144 145 146 147 148 149 20 30 40 50 60 200 400 600 800 0 2000 4000 6000 8000 Time bin 40 60 100 200 300 400 500 600 700 800 900 dB Frequency channels Pulse
10. Frequency (MHz) Time (ms) 8000 8200 8400 8600 8800 9000 143 144 145 146 147 148 149 16 18 20 22 24 26 28 30 200 400 600 800 0 200 400 Time bin 22 24 26 100 200 300 400 500 600 700 800 900 dB Frequency channels
11. frequency intensity frequency intensity intensity frequency 1. Model the bandpass 2. Match model to data 3. Subtract model and filter 4. Store spectrum stats in ring buffer 5. Update model with running averages
12. dynamic noise modelling for effective RFI removal and transient detection DM time (s) GPU dedispersion: 4000 dispersion measures searched, only pulses from B0329+54 detected, no spurious signals filterbank noise pre-filtering filterbank noise post-filtering
13. Dispersion  measure  pc/cm3 Time  (s) Crab HAM SAT HAM SAT • Working  prototype  for  non-­‐image  processing • Real-­‐Bme  searches  for  Individual  Radio  Pulses  using  CPU/GPU • Dedispersion  over    4000  DMs  per  beam  in  real  Bme  with  GPUs • Pilot  survey  1:  6-­‐8  beams  tracking  circumpolar  targets • Pilot  survey  2:  6  beams  fixed  on  the  meridian  from  8o  to  28o  dec Pipeline  diagnosBc  plot  from  Pilot  survey  –  daily  summary  from  one  of  six  beams Receive  udp   stream Polyphase  filter Raw  to   Stokes RFI  removal Dedispersion output S/N DM Time  (s) Aris  Karastergiou  (aris@astro.ox.ac.uk) Crab
14. • Real time detection system which would easily detect RRATs and Lorimer burst as they happened. • Affordable and scalable hardware • Fastest ever dedispersion code on NVIDIA GPU • RFI rejection performing well in very contaminated environment Crab B1919+21 26 December 2011 drift scan with beam at Dec=+21º B1919+21 Crab time (s) ?? ? ?
15. http://www.oerc.ox.ac.uk/ research/artemis
16. Buffer of Stokes data
17. Unknown sources at DM 0.9, observed simultaneously at Chilbolton and Nancay
18. Buffer of beamformed voltage data PSR B1919+21 Onsala+Chilbolton
19. Buffer of beamformed voltage data PSR B1919+21 Onsala+Chilbolton Interferometric fringes!
20. The hundred tied-array-beams realtime processor LOFAR APERTIF MeerKAT SKA-I SKA-II RFI-excision dedispersion folding detection CPU - GPU cluster
21.