Radio Astronomy Transformed - Aperture Arrays: Past, Present & Future Prof. Michael Garrett ASTRON, the Netherlands Institute for Radio Astronomy Leiden University. Mike Garrett / NAC 1
Early Antenna Arrays My previous tests had convinced me that when endeavouring to extend the distance of communication, it was not merely sufficient to augment the power of the electrical energy of the sender, but that it was also necessary to increase the area or height of the transmitting and receiving elevated conductors - Marconi. Marconi Marconi s transmitter at Cornwall, Poldhu Mike Garrett / NAC 2
Professional Science community very sceptical of Marconi s attempts at over the horizon transatlantic communications... λ/4 Marconi room on Titanic RMS Titanic Mike Garrett / NAC 3
The first phased arrays : Phased arrays and radio astronomy (1950/60s) Braun et al. 1907 J.S. Hey et al. 1942 Jansky 1932, detects cosmic radio emission Friis & Feldman 1937 (Bell labs) - first phase shifted system. Mike Garrett / NAC 4
Aperture Array a lost technology : 1970-2010...?
Why dishes: 21cm - discovery of the 21cm HI line - interest in discrete radio sources and their identification - the need for resolution and development of long baseline interferometry interferome - Low frequencies hard : RFI, ionosphere etc. - reliability and flexibility of early phased arrays Mike Garrett / NAC 6
Jodrell Bank 1946: Mike Garrett / NAC 7
Jodrell Bank 1946: 1956: Mike Garrett / NAC 8
As a young PhD student at Jodrell Bank, G.K. Miley also very much part of this... Mike Garrett / NAC 9
As a young PhD student at Jodrell Bank, G.K. Miley also very much part of this... Mike Garrett / NAC 10
As a young PhD student at Jodrell Bank, G.K. Miley also very much part of this... Mike Garrett / NAC 11
One exception - Reber... visionary 1937: 1970s: Mike Garrett / NAC 12
Explosion of civilian and military applications using Aperture Arrays
Mid-frequency Aperture Array R&D at ASTRON (1995-2010) Aperture Arrays R&D focused on: - concept demonstration, - integration, - cost reduction. THEA, 2004 LOFAR EMBRACE, 2010 OSMA,1999 AAD,1997 Ardenne et al.
Mid-frequency Aperture Array R&D at ASTRON (1995-2010) Aperture Arrays R&D focused on: - concept demonstration, - integration, - cost reduction. THEA, 2004 LOFAR EMBRACE, 2010 OSMA,1999 AAD,1997 Ardenne et al.
LOFAR - Low Frequency Array LOFAR - L
Radio Astronomy Transformed (I) ICT capability explosion in: - direct sampling & digitisation - high speed data transport - super-computing - archive capacity - data mining Moore s Law Moore s Law Moore s Law
Radio Astronomy Transformed (II) 2) The emergence of a next generation Aperture Array adio telescopes - Software Telescopes! New antenna technologies: - Next Generation Aperture Array Software Telescopes Cheap & cheerful dipoles married to the new technologies:
Aperture Array concept firmly established as technology of choice at frequencies < 500 MHz: LOFAR LWA `LWA PAPER MWA
George s original proposal for LOFAR (1997):
EoR: ILT:
Miley Optimism:
Miley Optimism:
Inner core, near Exloo.
MSSS - LOFAR s first all-sky survey. LOFAR s huge field-of-view... LOFAR MSSS Heald et al. Heald et al. 2013
LOFAR s huge field-of-view... LOFAR 300 000 lj Heald et al. 2013
Heald et al. 2013 LOFAR 2 Mpc
Solar System Science Jupiter Sun Type III burst propogating via open B-field lines - Mann et al. Girard et al. Inter-planetary Scintillation. Fallows et al.
LOFAR: Pulsar discoveries Falke et al. LOFAR First Pulsars discovered by LOFAR (Dec. 2012 - Hessels et al.) Fallows et al. 2012
SKA Phase 1 (Low Frequency < 350 MHz): W. Australia 2020
ASTRON - 5 year plan 2012 t/m 2016 Current challenges Netherlands Institute for Radio Astronomy Extending aperture arrays to higher frequencies ~ 1420 MHz (neutral hydrogen) 13-06-2013 ASTRON is part of the Netherlands Organisation for Scientific Research (NWO) 32
SKA Phase 2 (< 1.4 GHz): S. Africa 2024
Annie Jameson Marconi RMS Titanic Mike Garrett / NAC 34
Annie Jameson Marconi Marconi room on Titanic RMS Titanic Mike Garrett / NAC 35
Annie Jameson Marconi Marconi room on Titanic RMS Titanic Mike Garrett / NAC 36
Thanks George! - from all your friends at ASTRON. Marconi room on Titanic RMS Titanic Mike Garrett / NAC 37