AARTFAAC Project John Swinbank [email protected]

AARTFAAC Amsterdam ASTRON Radio Transients Facility And Analysis Centre “All the sky, all the time” (Well, nearly)

LOFAR ANTENNAE HUGE FIELD OF VIEW (“ALL SKY” IN THE LOW BAND)

LONG BASELINES: TRADE NETWORKING FOR RESOLUTION ➔ STATION-LEVEL (& TILE-LEVEL) BEAMFORMING; SO MUCH FOR FIELD OF VIEW.

The Superterp ➡ 6 stations ➡ 576 low band antennae (288 usable at a time) ➡ 288 high band tiles ➡ ~300 metres ➡ Fast networking The plan: Directly correlate all the antennae on the Superterp. Make images & search for transients in real time.

Some Numbers Low Band Field of view ~10000 sq. deg. RMS 1 Jy (1 s) Resolution 40 ’ High Band Field of view ~300 sq. deg. RMS 0.05 Jy (1 s) Resolution 16 ’

THE CORRELATOR: UNIBOARD DISTRIBUTED: 2 UNIBOARDS PER STATION CORRELATE 1/6 OF TOTAL BANDWIDTH

“SKA scale” correlator Number of visibilities 166176 576 (288x2); dual polarisation Total bandwidth 6.9 or 13.8 MHz 8 or 16 bit Subband width 24 kHz Subbands 288 or 575 Dump time 0.1 or 1.0 seconds Data rate 1.5-30 Gb/s Estimate

Imaging Pipeline Pelican Pipeline Antenna Antenna Antenna Antenna Antenna Monitoring and control Pelican Server Image cube Inspect Calibrate Distributed Correlator Pelican Pipeline Inspect Image Postprocess Write to image cube Pelican Pipeline Inspect Image Postprocess Write to image cube Transients Pipeline ➡ Image “real time”: latency < 1s. ➡ Based on Pelican framework (Oxford). ➡ High-performance computing challenge: use of GPUs.

Transients Pipeline Derived from the standard TKP/LOFAR system. See talk by Evert. MonetDB Database Imaging Pipeline Image Cube Source Finding Lightcurve Storage Transient & Variability Analysis Source Association Archive Database Classification & Analysis Response Scheduling Send External Alert Re-run Image Analysis Schedule New Observation Other Observatories Receive External Alert Real-time Processing Off-line & External Systems LOFAR On-line Systems Visibility Data

Data products ➡ Calibrated image cubes ➡ HDF5 format ➡ Following the LOFAR ICD ➡ Lightcurve database ➡ Real-time alerts to the community

Initial experiment ➡ Dump data from Superterp dipoles to disk ➡ Limits us to 1 MHz total bandwidth ➡ Correlate offline, in software ➡ Provides test data for system validation, pipeline commissioning etc ➡ Is this the largest astronomical interferometer ever?! ➡ Happening “now”

Timeline Autumn 2010 ➡ Project start Spring 2011 ➡ Hardware design finalized ➡ Initial software planning Summer 2011 ➡ Initial Superterp correlation ➡ First pipeline code Autumn 2011 ➡ New team members joining project ➡ Hardware development Winter 2011/2 ➡ Correlator firmware available ➡ Basic imaging pipeline usable Summer 2012 ➡ Full distributed correlator installed ➡ Regular real-time imaging ongoing

The Team Principal Investigator Ralph Wijers (University of Amsterdam) Co-Investigator Michael Wise (ASTRON) Hardware Project Manager Andre Gunst (ASTRON) Software Project Manager John Swinbank (University of Amsterdam) Amsterdam Lars Bähren (PhD) Dario Carbonne (PhD) Yvette Cendes (PhD) Alexander van der Horst (Postdoc) Peeyush Prasad (Postdoc/Developer) Thijs van Putten (PhD) Antonia Rowlinson (Postdoc) ASTRON Marco de Vos (Managing Directory) Ronald Nijboer (Head of R&D Software Group) Arwash Orwang (PhD) Oxford Software Development Stef Salvini Fred Dulwich Ben Mort Oxford Hardware Development Kris Zarb-Adami Griffin Foster