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Delingha 13.7-m mm-Wave Telescope

Delingha 13.7-m mm-Wave Telescope. Yingxi Zuo , Ji Yang Purple Mountain Observatory, CAS. Sino-German workshop on radioastronomy Sep 13, 2005 Urumqi. OUTLINE. Site Overview Telescope Description Technical Upgrade Activities Future Plans Science Activities.

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Delingha 13.7-m mm-Wave Telescope

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  1. Delingha 13.7-m mm-Wave Telescope Yingxi Zuo, Ji Yang Purple Mountain Observatory, CAS Sino-German workshop on radioastronomy Sep 13, 2005 Urumqi

  2. OUTLINE • Site Overview • Telescope Description • Technical Upgrade Activities • Future Plans • Science Activities

  3. Site Overview -- General Information • Location: • 35km from Delingha City, Qinghai, China • Longitude: 9733.6E • Latitude: 3722.4N • Altitude: 3200 m • Dry & Cold in Winter Delinha Nanjing

  4. Site Overview-- Atmospheric Opacity @ fLO=112.6 GHz

  5. Telescope Description – System Block Diagram Be able to observe CO(1-0) and its isotopes simultaneously

  6. Antenna Performance Enclosed in a High-Transparency Radome (85-90%) Diameter: 13.7 m Pointing Accuracy: < 10” over the whole sky Beamwidth (HPBW): ~60” Aperture Efficiency: 39% Main Beam Efficiency: 77% Surface Accuracy: ~0.1 mm Telescope Description --Current Status (1)

  7. Receiver 85 to 115 GHz SIS Receiver TSYS: typically ranging from 180 to 250K (DSB @EL=60°) Backends Continuum backends (Bandwidth 800MHz) Total Power (TP) Chopping Modulation (SP) Spectrum Backends AOS1: Center 70MHz / BW 43MHz / 1024 chs AOS2: Center 70MHz / BW 43MHz / 1024 chs AOS3: Center 225MHz / BW 145MHz / 1024 chs Observation Mode Position-Switch, spectral mapping 12CO (J=1-0), 13CO (J=1-0), C18O (J=1-0) observation simultaneously Fast beam switching (chopper-wheel modulating), continuum mapping Telescope Description --Current Status (2)

  8. Upgrade Activities (1)-- Multi-Line System (2002) • Observing 12CO, 13CO, C18O (J=1-0) lines simultaneously, Because of the DSB Receiver 115.27 GHz ⇓ AOS3 109.78 GHz ⇓ AOS1 110.20 GHz ⇓ AOS2 Set to 112.6 GHz

  9. Upgrade Activities (1)-- Multi-Line System An example of simultaneously observations of CO(J=1-0) and its isotopes, toward NGC 2264. The on-source integration time is 60 seconds and Tsys=248K.

  10. Upgrade Activities (2)-- SIS Mixer Stability Improvement Below 100 GHz (2004) • The SIS mixer is designed to operate in the range of 90-115 GHz, but … • Below 100 GHz, the pumped quantum steps are too flat to stably bias (very large dynamic resistance at the step) • DC bias is very sensitive to noise and interference • Solution:putting a shunt resistance in the DC bias circuit of the mixer, parallel to the SIS junction. Reducing the dynamic resistance Pumped I-V curve @90GHz, Without any shunt resistance in the DC bias circuit Pumped I-V curve @90GHz, with a 36W resistance paralleled to the SIS junction

  11. Upgrade Activities (2)-- SIS Mixer Stability Improvement Below 100 GHz (2004) After putting a shunt resistance, the stability improved significantly, in the range of 85-115 GHz (fLO). See the red points. Theblack points indicate the case before (without any shunt resistance).

  12. Upgrade Activities (2)-- SIS Mixer Stability Improvement Below 100 GHz (2004) Source: R-CAS Line:SiO (n=1, J=2-1) It is possible to take five-point mapping observations toward SiO maser sources at 86.243GHz to verify the telescope pointing on the northern hemisphere Five-point mapping toward an SiO(J=2-1) maser source at 86.243GHz, to verify telescope pointing on the northern sky

  13. Upgrade Activities (3)-- Near Field Receiver Beam Measurement System (2004) • Measuring the receiver (including all the optical components) beam pattern to determine • Whether all the optical components are well aligned or not • Receiver beam axis (other than the mechanical axis) • Antenna illumination, edge taper

  14. Upgrade Activities (3)-- Near Field Receiver Beam Measurement System (2004) • A probe source is mounted on an x-y motion stage • Probe scanning area: 500×500 mm • The scanning measurement should be taken at (at least) two different distances from the receiver to determine the beam axis. Then using a laser beam memorizes the axis for further aligning the receiver with the sub-reflector. • Scalar measurement, only measured the power, the phase information may included in the future

  15. Upgrade Activities (3)-- Near Field Receiver Beam Measurement System (2004) x scan @2m The red circle indicates the sub-reflector edge. The edge taper is about –10dB y scan @2m Map @1.5m

  16. Upgrade Activities (4)-- Subreflector Real-Time Control (2004) • The subreflector is relatively large (1.08m) and heavy • It will tilt and drop down a bit with EL getting low due to gravity, affecting the alignment (between subref. and Rx, and between subref. and main dish) • This can be corrected by re-positioning the subref. • Re-position Z1 axis and Y axis simultaneously while EL changes

  17. Upgrade Activities (4)-- Subreflector Real-Time Control (2004) • Measured 2-D beam pattern EL=71° Saturn map EL=35° Jupiter map

  18. Future Plans • Antenna servo system updating • Digital Spectrometer with 500MHz BW • Joining east-Asia mm-wave VLBI network

  19. Science Activities • Physical structure study of Galactic molecular clouds • High-velocity outflows from young stellar objects • Interstellar chemistry • Molecular gas distributions in the Galactic star form regions • Galactic dynamics • Star evolution and molecular gas of late stars • Large-scale molecular line survey for cold IRAS sources in the Galaxy • ……

  20. Recent Selected Publication (I)-- Molecular Clouds & Star form Regions Ao, Yiping; Yang, Ji; Sunada, Kazuyoshi, 13CO, C18O, and CS Observations toward Massive Dense Cores, AJ, 128...1716A, 2004 Qin S.L., Wu Y.F., et al, Star Formation in Molecular Cloud Associated with IRAS 07028-1100，2004，Chinese Physics Letter，Vol.21 No.8, 1677 J. Sun, et al., A study of molecular clouds with compact HII regions in Galactic Science in China (A), 2001 Y. Xu, D. Jiang, X. Zheng, M. Gu, Z. Yu, C. Pei High-Velocity H2O Maser Associated Massive Star Formation Regions Chin. Phys. Lett., 18(12), 1663-1665(2001) J. Sun, Y. C. Sun, New detected CO(J=1-0) emission from planetary nebulae Science in China (Series A), 43(2), 217, (2001) Y. Wu, J. WU, and J. Wang, A search for massive dense cores with 13CO J=1-0 line A&A, 2001, December 12

  21. Recent Selected Publication (II)-- Molecular Outflow Xu Y., Yang J., Zheng X.W., et al, Discovery of Multiple outflows in IRAS06056+2131,2004，Chin. Phys. Lett., Vol.21, No.10, 2071-2072 SUN K.F., WU Y.F.,A New High-velocity Molecular Outflow of IRADS 19282+1814，2003，Chinese Astronomy and Astrophysics，27, 73-78 Y. Xu, D. R. Jiang, C. Y. Yang et al., High-velocity gas associated ultra-compact HII regions. Science in China(A), 32, 177-184, 2002 S. Qin, Y. Wu New high-velocity bipolar outflows in S39 and IRAS 06306+0232 Science in China (Series A), 2001 Y. Wu, C. Yang, Y. Li, et al. High-velocity molecular outflows near massive young stellar objects Science in China (Series A), 42(7), 732, (1999)

  22. Recent Selected Publication (III)-- Survey of Molecular Lines from IRAS Sources J. Yang, Z. Jiang, M. Wang, B. Ju, & H. Wang A Large-Scale Molecular Line Survey for Cold IRAS Sources in the Galaxy: I. The CO (J=1-0) Data ApJS, v141,157, (2002). J. Yang, Z. Jiang, M. Wang, H. Wang, R. Mao, B. Ju, &Y. Ao Molecular Line Studies of Galactic Young Stellar Objects APRM2002_OHP (invited talk)，Japan, 2002 Ji Yang Galactic Star Forming Regions: Local and Distant in Proceedings of 3rd OCPA3(invited talk)，2000

  23. Recent Selected Publications (IV)– Other Topics Wu Y.F.，Wang J.Z.，Wu J.W., A Search for Extremely Young Stellar Objects，2003，Chin. Phys. Lett.，Vol.20, No.8, 1409 Y. Xu, X. Zheng, D. Jiang, et al, An H2O flare in GGD25, Chinese Science Bulletin, 46(1), 35-38(2001) J.J. Zhou and X.W. Zheng, Short Time Variability of the Water Masers in W51M, Astrophysics and Space Science, 275, 431-439(2001) Y. Xu, X. W. Zheng , et al, Rapid time variation of water maser emission in W3(OH) and NGC6334C, Astronomy and Astrophysics, 364（2000），232. Y. Wu, Wang, Wu, Yan, Lei, Sun, Wang, A 13CO mapping study for massive molecular cloud cores, Science in China (A), 44(4), 536-544(2001) C. C. Pei, R. Q. Mao, Q. Zeng, Molecular lines and continuum from W51A, Science in China (A), 44(9), 1209-1215(2001) Y. Wu，H. Yan，J. Wu，Y. Zhao, A mapping study for massive dense cores, Imaging at radio through sub-millimeter wavelengths, ASP Conference Series, 217(2000),96.

  24. Sample Spectral LinesObtained from the 13.7-m Telescope • Besides CO, 13CO and C18O, the telescope can be used to observe many other molecular lines in the 3mm band, such as HCO+, N2H+, CN, CS, CH3CN, SO, HC3N, CH3OH, OCS, SiO, HCN, CH13CN, …, from molecular clouds and circumstellar envelope. • Following are some examples of molecular transition spectra obtained from our telescope.

  25. HC3N Line Toward IRC+10216

  26. CH3OH Line Toward Orion

  27. CN Hyperfine TransitionsToward Orion

  28. N2H+ Lines Toward L134N

  29. HCO+(1-0) Line Toward S140

  30. H13CN (1-0) Line Toward OrionA

  31. Welcome to Delinghahttp://www.pmodlh.ac.cnOpen Time: September 1 – May 31Proposal submission (all over the year)proposal@pmodlh.ac.cn

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