Radio Astronomy Transformed

Transcription

1 Radio Astronomy Transformed - Aperture Arrays: Past, Present & Future Prof. Michael Garrett ASTRON, the Netherlands Institute for Radio Astronomy Leiden University. Mike Garrett / NAC 1

2 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

3 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

4 The first phased arrays : Phased arrays and radio astronomy (1950/60s) Braun et al J.S. Hey et al Jansky 1932, detects cosmic radio emission Friis & Feldman 1937 (Bell labs) - first phase shifted system. Mike Garrett / NAC 4

5 Aperture Array a lost technology : ?

6 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

7 Jodrell Bank 1946: Mike Garrett / NAC 7

8 Jodrell Bank 1946: 1956: Mike Garrett / NAC 8

9 As a young PhD student at Jodrell Bank, G.K. Miley also very much part of this... Mike Garrett / NAC 9

10 As a young PhD student at Jodrell Bank, G.K. Miley also very much part of this... Mike Garrett / NAC 10

11 As a young PhD student at Jodrell Bank, G.K. Miley also very much part of this... Mike Garrett / NAC 11

12 One exception - Reber... visionary 1937: 1970s: Mike Garrett / NAC 12

13 Explosion of civilian and military applications using Aperture Arrays

14 Mid-frequency Aperture Array R&D at ASTRON ( ) Aperture Arrays R&D focused on: - concept demonstration, - integration, - cost reduction. THEA, 2004 LOFAR EMBRACE, 2010 OSMA,1999 AAD,1997 Ardenne et al.

15 Mid-frequency Aperture Array R&D at ASTRON ( ) Aperture Arrays R&D focused on: - concept demonstration, - integration, - cost reduction. THEA, 2004 LOFAR EMBRACE, 2010 OSMA,1999 AAD,1997 Ardenne et al.

16 LOFAR - Low Frequency Array LOFAR - L

17 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

18 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:

19 Aperture Array concept firmly established as technology of choice at frequencies < 500 MHz: LOFAR LWA `LWA PAPER MWA

20 George s original proposal for LOFAR (1997):

21

22 EoR: ILT:

23 Miley Optimism:

24 Miley Optimism:

25 Inner core, near Exloo.

26 MSSS - LOFAR s first all-sky survey. LOFAR s huge field-of-view... LOFAR MSSS Heald et al. Heald et al. 2013

27 LOFAR s huge field-of-view... LOFAR lj Heald et al. 2013

28 Heald et al LOFAR 2 Mpc

29 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.

30 LOFAR: Pulsar discoveries Falke et al. LOFAR First Pulsars discovered by LOFAR (Dec Hessels et al.) Fallows et al. 2012

31 SKA Phase 1 (Low Frequency < 350 MHz): W. Australia 2020

32 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) ASTRON is part of the Netherlands Organisation for Scientific Research (NWO) 32

33 SKA Phase 2 (< 1.4 GHz): S. Africa 2024

34 Annie Jameson Marconi RMS Titanic Mike Garrett / NAC 34

35 Annie Jameson Marconi Marconi room on Titanic RMS Titanic Mike Garrett / NAC 35

36 Annie Jameson Marconi Marconi room on Titanic RMS Titanic Mike Garrett / NAC 36

37 Thanks George! - from all your friends at ASTRON. Marconi room on Titanic RMS Titanic Mike Garrett / NAC 37