Presentation on theme: "Dome A THz Astronomy Ji Yang Purple Mountain Observatory, Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, China"— Presentation transcript:
Dome A THz Astronomy Ji Yang Purple Mountain Observatory, Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, Nanjing , China Workshop on Progress in Theoretical and Observational Cosmology Nov. 7-9, 2011, IHEP, Beijing
Outlines Science Drive and Dome A THz Conditions Dome A 5m THz Telescope Concept Challenges to the THz Development Technological Availability & International Collaboration
Origin of Planetary Systems & Life Ecology in the Universe: ISM, Stars, Galaxies Precision Cosmology dominated by Dark Energy & Dark Matter Major Challenges in Astronomy End of Dark Age and Formation of First Generation Stars
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. 2008Credit: Herschel Team
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. 5
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. Dome A: The Site Chinese inland expedition team reached Dome A. Astronomy follows on from 2007/2008, by the 24 th Chinese Antarctic Expedition)
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 25 th antarctic expedition team and data were collected from Jan 24, Major Collaboration Institutes: University of Arizona, Exeter University, University of New South Wales, Polar Research Institute of China, & Purple Mountain Observatory.
Dome A (4000m, -83 C) Dome A (4000m, -83 C) Measurement （ , Pre-HEAT Measurement （ , Pre-HEAT The best site ever knew The best site ever knew New THz windows over m New THz windows over m The Pre-HEAT Measurements Stable over several weeks !!!best 25% weather at Mauna Kea 国际大科学工程 ALMA 台址 Dome A (partial time) Mauna Kea at Hawaii Yang, H. et al. 2010, PASP, 122, m windows
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 THz, under the collaboration among PMO, CfA, and NAOJ, with remote operation support from NSWU. The results ， combined with 660GHz radiometer measurement by Pre-HEAT ， strongly suggest that Dome A is a unique site for ground-based THz observations. THz facilities for micron windows should be planned.
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/IR Window- Star Formation, Young Galaxies, Early Universe, & Origin of Celestial Life
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/upgrade and data retrieval by summer traverse.
Dome A Observatory: A Mega-Science Facility Proposed for Construction 2.5m Optical/NIR Telescope 5m THz Telescope Antarctic Support Platform Transportation & Logistics On-Site Assembly Remote Operation 12
Dome A Observatory Development: A Roadmap Site Survey & Small Telescope Site Testing & Middle-size Telescope Dome A Observatory Phase I Dome A Observatory Phase II 2.5m Opt/NIR KDUST 6-8m Opt/NIR 5m THz DATE5 15m THz
Dome A THz Explorer （ DATE5 ） DATE5 Toy Model Ant Relay Optics Ant OpticsTHz Receivers THz Mixers （ Band1 &2 ） IF Proc. （ 6 chs ） THz Digit LO （ Band1 &2 ） Back end Spe ctral Proc. Control & DAC DATE5 System Diagram DATE5 Specs OpticsSymmetric Cassegrain Main Reflector5m paraboloid Surface Accuracy 10 m (rms) Pointing2“ (rms) FoV 10′×10′ (350 m), 5′×5′ （ 200 m ） Receiver Superconducting Mixer ， Nb/NbN SIS&HEB Wavelength 350 m×6, 200 m×2 Power Consumption <= 3 kW
The Extreme Site Conditions as The Major Challenges to Dome A THz Development High altitude: 4000m; Low pressure: 570 hPa; Extremely low temperature & large temp difference: 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.
THz Astronomy Development at PMO1980s 13.7m-100GHz, Delignha POST 30cm-492GHz SMA Collaboration （ THz ， Mauna Kea/Hawaii ） ALMA Dome A THz Development
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
DATE5: Conceptual Studies on Ant & Relay Optics (Lou, Z. et al. 2011) Roof mirror partition scheme for dividing the incoming beam into receivers of two bands Far-field distribution for Band1(1 4) & Band2(1 2) beams, calculated by Physical Optics through numerical methods based on GPU Focal plane distribution for Band 1&2, calculated by GO
DATE5 Prototype SIS Mixers Developed by Shi, S. et al & International Collaborations 1.3THz NbN SIS mixer chip & measured I-V curve Original design initiated from GHz band design during ALMA R&D collaborations Band2 HEB mixer prototype chip & measured FTS Response
Bandwidth ： 2GHz Freq Resolution ： 61kHz Dynamic Range ： ≥ 30dB Stability ： ≥ 1000s Prototype 2GHz Digital FFT Spectrometer based on FPGA (Yang, J. et al., 2011, under development) Function diagram for 2GHz real-time digital FFT spectrometer, as a prototype back-end signal processing solution to the Dome A THz telescope real-time pipeline FFT algorithm based on FPGA, 32k points
Requirement for THz Focal Plane Imaging Detectors Call for International Collaboration background limit NEP W/ Hz at Dome A Full sampling at Focal Plane Undergoing Collaboration with world institutes Demo device available with next few years Herschel Blue Array 2048 pixels
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.
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 Formation is 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.
Antarctic Support Platforms for Remote Operation : Joint Developments Function：To supply power, communica- tion, remote operation and data storage/ manipulation capabilities. Results：PLATO operated over 204 days in 2008，and full winter over 。 New design of ASP by PMO-SEU: higher power output & larger data storage, testing in Tibet in 2010 summer AUS 、 CHN 、 US 、 UK Joint PLATO 2010 PMO-SEU Joint ASP