Prof. Steven Tingay (ICRAR, Curtin University) Workshop on East-Asian Collaboration on the SKA Daejeon, Korea, November 30 – December 2, 2011 A long baseline SKA that connects Asia and Oceania:

Reprise of presentation from: Advances in Asia and Oceania Toward Very Long Baseline Interferometry in the Age of the Square Kilometre Array Perth, Australia: May 4 – 6, 2011

SKA context SKA project enters “pre-construction” phase in Some partners on board, some yet to come on board. Exact scope and design to be defined over next three to four years. Open questions in science case and technical requirements. High angular resolution science for the SKA has great potential beyond the nominal 3000 km baseline (Memo #135); What are the opportunities to extend SKA beyond 3000 km? –Science case? –Telescope locations? Existing telescopes? –Network connectivity?

Science case for long baselines Godfrey et al. 2011, PASA, in press arXiv: Pulsars – key driver for SKA Phase 1 ; Galactic magnetic fields; Proto-planetary disks at cm wavelengths; Resolving AGN and star formation in galaxies; The first generation of AGN jets; X-ray binary systems; Mapping high mass star formation; ………..

Pulsars are the stand-out science for SKA long baselines ~3000 km baseline ~9000 km baseline Increases number of pulsar parallaxes with better than 20% error by ~4500 (50%) Smits, Tingay, Wex, Kramer & Stappers, 2011, A&A, 528, 108 Parallax distances to pulsars: Pulsar binary systems. Tests of GR limited by availability of independent measurements of distance (Deller, Bailes & Tingay, 2009, Science, 323, 1327); SKA Phase 1 pulsar timing will need SKA sensitivity long baseline astrometry. Mapping the ionised galactic medium and galactic magnetic fields from pulsar DM measurements and distance measurements; And many other aspects of pulsar science….

Geographic advantage and Maximum Discovery An SKA built in Australia and New Zealand (Oceania) couples two significant geographic advantages: –A Southern Hemisphere radio quiet site that can support a full range of baseline lengths from 0 km to 5500 km; –Proximity to the fastest growing region in the world in terms of radio astronomy capability, encompasing China, Japan, India, Korea (Asia). Connecting Oceania and Asia could very effectively extending SKA baselines to ~9000 km.

The Asian capacity Existing and planned/proposed Chinese, Indian, Japanese and Korean facilities total over 100,000 m 2, comparable to the total collecting area for the SKA remote stations. Australian Institute of Aboriginal and Torres Strait Islander Studies Perth Indian, Chinese, Japanese and Korean radio telescopes >20 m in diameter.

Australia and New Zealand SKA δ= -30 δ =0 + China (3) + Japan/Korea (2) + India (1) ν=1.4 GHz; Δν=350 MHz. ~25% fractional bandwidth (u,v) coverages by Dr Leith Godfrey. Take six SKA stations from Australia and place them in Asia?

Networks and data transport 10 Gbps intercontinental networking is required, and is on the way

Australia’s $43b National Broadband Network

e-VLBI as an SKA trail-blazar June China, Japan, Australia. ~1 Gbps First ever VLBI using the GMRT, 2011 Australia – India. ASKAP first e-VLBI – June 2011 KVN – EVN, Oct 2011

Questions/challenges What science would an extended Asia-Oceania SKA excel at? How many telescopes would be needed, how large and with what geographic distribution? Existing telescopes or SKA stations? What coordination in international networking is required?

Summary SKA Phase 1 science driver for pulsars calls for long baseline astrometry – the longer the baselines the better; An Oceania (Australia – New Zealand) SKA naturally connects to Asia (China, Japan, Korea, and India). These countries can derive direct benefits from involvement in the SKA project. Requires an extension of the e-VLBI technique to 10 Gbps and beyond, which looks feasible in the near future – SKA may help drive international research connectivity.