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Dome A THz Astronomy

Workshop on Progress in Theoretical and Observational Cosmology Nov. 7-9, 2011, IHEP, Beijing. Dome A THz Astronomy. Ji Yang Purple Mountain Observatory, Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, China jiyang@pmo.ac.cn. Outlines.

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Dome A THz Astronomy

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  1. Workshop on Progress in Theoretical and Observational Cosmology Nov. 7-9, 2011, IHEP, Beijing Dome A THz Astronomy Ji Yang Purple Mountain Observatory, Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, China jiyang@pmo.ac.cn

  2. Outlines • Science Drive and Dome A THz Conditions • Dome A 5m THz Telescope Concept • Challenges to the THz Development • Technological Availability & International Collaboration

  3. Major Challenges in Astronomy End of Dark Age and Formation of First Generation Stars Precision Cosmology dominated by Dark Energy & Dark Matter Origin of Planetary Systems & Life Ecology in the Universe: ISM, Stars, Galaxies

  4. THz Wavelengths: New Windows for Observing the Universe  Cosmic SED peak at FIR/THz：THz as an important tracers to the distribution, structure, and motion at different levels.  Intensive lines carrying important information on the origin of the universe, celestial bodies, and life. Dole, H. et al. 2006; Driver, et al. 2008 Credit: Herschel Team

  5. World Trends and Challenges in Ground based Astronomy (Optical, NIR, THZ) • World trends for large fields of view, high sensitivities, high resolution and multi-wavelength coverage； • Finding best sites for large facilities to achieve the best performance； • Or, to put telescopes into space, under the cost of money and technological risks! • Difficulty in finding world-class sites for optical/NIR/THz within China; • Dome A as an potential opportunity for China was widely recognized.

  6. Dome A:The Site • Dome A，altitude 4100m(60km10km), a plateau of small fluctuation。Lowest Temp -83ºC。 • Site surveys under Panda Program suggest ：Dome A is a promising site for astronomy, particularly in THz & IR. • 2005.1.18Chinese inland expedition team reached Dome A. • Astronomy follows on from 2007/2008 , by the 24th Chinese Antarctic Expedition)

  7. The Pre-HEAT Collaboration(The High Elevation Antarctic Terahertz Telescope) Pre-HEAT measured the transparency of the sky above Dome A at submillimeter wavelengths using a high frequency heterodyne receiver at 0.66 THz. Installed by Chinese 25th antarctic expedition team and data were collected from Jan 24, 2008. Major Collaboration Institutes: University of Arizona, Exeter University, University of New South Wales, Polar Research Institute of China, & Purple Mountain Observatory.

  8. The Pre-HEAT Measurements Mauna Kea at Hawaii Stable over several weeks !!! best 25% weather at Mauna Kea 国际大科学工程ALMA台址 350-200 mm windows Dome A (partial time) • Dome A (4000m, -83C) • Measurement（2007-2008, Pre-HEAT • The best site ever knew • New THz windows over 150-800 m Yang, H. et al. 2010, PASP, 122, 490

  9. Measurement of Atmospheric THz Transmission by FTS (Shi, S.-c., et al. , 2011, in preparation) • In 2009，a FIR/THz FTS was developed & installed to measure the atmospheric transmission over 0.75-15 THz, under the collaboration among PMO, CfA, and NAOJ, with remote operation support from NSWU. • The results，combined with 660GHzradiometer measurement by Pre-HEAT，strongly suggest that Dome A is a unique site for ground-based THz observations. •  THz facilities for 200-350 micron windows should be planned.

  10. Uniqueness of Dome A Astronomy • Site：Excellent • Science： Unique & Competitive • Facility: Synergy in Wavelengths • Technology：Feasible • Targeted Science Drivers • Time Domain- The Legacy of a Dynamic Universe • Large FOV+High Resolution- Revealing the Dark Universe • New THz/IRWindow- Star Formation, Young Galaxies, Early Universe, & Origin of Celestial Life

  11. Concepts for Dome A Observatory Phase I • Taking the advantage of Dome A superior site conditions to build optical/IR, THz observing facilities, and to build efficient international collaborations; • Two telescopes with competitive observing capabilities, proposed as National Mega-Science Facilities; • Major science goals on dark energy and dark matter, exo-planets, time-domain sciences, formation & evolution of stars and galaxies; • Self-supported observing mode under remote control; • On-site bulk data storage, partially send back for timely analysis and follow-up observations； • Instrument maintenance/upgradeand data retrieval by summer traverse.

  12. Dome A Observatory: A Mega-Science FacilityProposed for 2011-2015 Construction • 2.5m Optical/NIR Telescope • 5m THz Telescope • Antarctic Support Platform • Transportation & Logistics • On-Site Assembly • Remote Operation

  13. Dome A Observatory Development: A Roadmap 2006- 2008 Site Survey & Small Telescope +Site Testing & Middle-size Telescope 2009- 2011 2011- 2015 Dome A Observatory Phase I 5m THz DATE5 2.5m Opt/NIR KDUST 2016- 2025 Dome A Observatory Phase II 6-8m Opt/NIR 15m THz

  14. Dome A THz Explorer（DATE5） DATE5System Diagram DATE5Toy Model Ant Optics THzReceivers Backend Spectral Proc. THzMixers（Band1 &2） IF Proc. （6chs） Relay Optics Ant THzDigit LO（Band1 &2） Control & DAC DATE5Specs

  15. The Extreme Site Conditions as The Major Challenges to Dome A THz Development • High altitude: 4000m; • Low pressure: 570hPa; • Extremely low temperature& large temp difference: -58.4 C , (-10 C ~ -83 C); • Harsh weather conditions： snow, ice,radiation; • Transportation: complicated • Installation/testing：limited working time/facilities; • Operation: low-bandwidth communication; • Logistics:limited summer support, no winter-over.

  16. 1995- 2000-2005 1980s 13.7m-100GHz, Delignha POST 30cm-492GHz SMACollaboration（0.2-0.9THz，Mauna Kea/Hawaii） ALMA THz Astronomy Development at PMO 2005-2009 Dome A THz Development 2006-

  17. The Superconducting Spectroscopic Array (SSAR):A mm-wave multi-beam receiver recently finished for Delingha 14m Telescope Sideband Separation SIS 3x3 beams, 18 IFs All digital System

  18. DATE5: Conceptual Studies on Ant & Relay Optics (Lou, Z. et al. 2011) Far-field distribution for Band1(14)& Band2(12) beams, calculated by Physical Optics through numerical methods based on GPU Roof mirror partition scheme for dividing the incoming beam into receivers of two bands Focal plane distribution for Band 1&2, calculated by GO

  19. DATE5 Prototype SIS Mixers Developed by Shi, S. et al & International Collaborations Original design initiated from 790-850GHz band design during ALMAR&D collaborations Band2HEBmixer prototype chip & measured FTS Response 1.3THzNbNSISmixer chip & measured I-Vcurve

  20. Prototype 2GHzDigital FFT Spectrometer based on FPGA (Yang, J. et al., 2011, under development) real-time pipeline FFT algorithm based on FPGA, 32k points • Bandwidth：2GHz • Freq Resolution：61kHz • Dynamic Range：≥ 30dB • Stability：≥ 1000s Function diagram for 2GHzreal-time digital FFT spectrometer, as a prototype back-end signal processing solution to the Dome A THz telescope

  21. Herschel Blue Array 2048 pixels Requirement for THz Focal Plane Imaging DetectorsCall for International Collaboration • background limit • NEP  10-16 W/ Hz at Dome A • Full sampling at Focal Plane • Undergoing Collaboration with world institutes • Demo device available with next few years

  22. Summary • Stimulated by Polar Research activities, the site surveys at Dome A demonstrate its excellent observing conditions for ground-based astronomy; • Small-scale instruments have been used at Dome A for continuing site survey and astronomical observations; • Dome A was selected as one of the major goals of development for Chinese astronomy for the next decade; Major Instruments, including 5m THz telescope & 2.5m Opt/IR telescope, have been proposed; • Dedicated teams are organized to study the 5m telescope and key technologies on receiver systems; • International collaboration has been successful and should be encouraged in future for Dome A THz astronomy.

  23. Acknowledgements • Part of the materials in this talk was contributed by Chinese Center for Antarctic Astronomy (CCAA) and The International Partner Group on Cosmic Star Formation. CCAA is a center jointly initiated by Chinese institutes and universities, including Purple Mountain Observatory, Nanjing Institute of Astronomical Optics and Technology, Polar Research Institute of China, Polar Research Institute of China, National Astronomical Observatories of Chinese Academy of Sciences, and Chinese universities. CCAA is based at Purple Mountain Observatory, Chinese Academy of Sciences. The International Partner Group on Cosmic Star Formationis a program supported by NSFC and CAS and affiliated to Purple Mountain Observatory. • Materials of this talk are also based on international collaborators including UNSW, UoA, CfA, NAOJ, etc.

  24. Antarctic Support Platforms for Remote Operation : Joint Developments 2007-2009 AUS、CHN、US、UK Joint PLATO Function：To supply power, communica-tion, remote operation and data storage/ manipulation capabilities. Results：PLATO operated over 204days in 2008，and full winter over 2009-2010。 New design of ASP by PMO-SEU: higher power output & larger data storage, testing in Tibet in 2010 summer. 2010 PMO-SEU Joint ASP

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