Transcript Delingha 13.7-m mm

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
Site Overview
-- General Information

Location:
– 35km from Delingha City,
Qinghai, China


Longitude: 9733.6E
Latitude: 3722.4N
Altitude: 3200 m
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Dry & Cold in Winter

Delinha
Nanjing
Site Overview
-- Atmospheric Opacity @ fLO=112.6 GHz
Atmospheric Opacity @ fLO=112.6 GHz
0.5
0.4
Mean=0.25
rms=0.07
o
0.3
0.2
0.1
0.0
25-Nov 23-Dec 12-Jan
4-Feb
9-Mar
29-Mar 18-Apr
Date (from 4-Nov-2004 to 24-Apr-2005)
Telescope Description – System Block Diagram
Vacuum Pump
&
4K Cryocooler
Be able to observe CO(1-0)
and its isotopes simultaneously
SIS & HEMT
Bias Supply
70/70MHz
IF Amp.,
SISMIX HEMT
Center
2.64GHz/
BW 800MHz
Power
Devider
&
Frequency
Convertor
AOS1
70/70MHz
225/245MHz
AOS3
Lock-in Amplifier
1790/800MHz
Phase-Locked
Gunn
Oscillator
Power
Detector
Chopper Wheel Controller
Synthesizer
AOS
Controller
AOS2
Telescope-Control Computer
TP/SP
Telescope Description -- Current Status (1)

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 (2)

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
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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
Upgrade Activities (1)
-- Multi-Line System (2002)

Observing 12CO, 13CO, C18O (J=1-0) lines simultaneously,
Because of the DSB Receiver
Frequency
C18O
109.78 GHz
13
CO
110.20 GHz
⇓
⇓
AOS1
AOS2
LO
Set to
112.6 GHz
12
CO
115.27 GHz
⇓
AOS3
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.
Upgrade Activities (2)
-- SIS Mixer Stability Improvement Below 100 GHz (2004)
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
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
Upgrade Activities (2)
-- SIS Mixer Stability Improvement Below 100 GHz (2004)
35
2003/08/20 Data
2004/08/08 Data
Relative Stability (+% )
30
25
20
15
10
5
0
85
90
95
100
105
110
115
Frequency£¨GHz£©
After putting a shunt resistance, the stability improved significantly,
in the range of 85-115 GHz (fLO). See the red points. The black
points indicate the case before (without any shunt resistance).
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 fivepoint 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
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
Upgrade Activities (3)
-- Near Field Receiver Beam Measurement System (2004)
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
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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
Upgrade Activities (3)
-- Near Field Receiver Beam Measurement System (2004)
7
6
4
3
2
1
0
0
100
200
300
400
500
X (mm)
x scan @2m
7
6
5
Amplitude (V)
Amplitude (V)
5
4
3
2
1
0
0
100
200
300
400
Y (mm)
y scan @2m
500
The red circle indicates the sub-reflector
edge. The edge taper is about –10dB
Map @1.5m
Upgrade Activities (4)
-- Subreflector Real-Time Control (2004)

– Re-position Z1 axis and Y axis simultaneously while EL changes
0.9
1.0
Z1 Position
Z1=0.359+0.497cos(EL)
0.5
0.8
0.7
0.0
0.6
-0.5
0.5
-1.0
Y Position
-1.5
0.4
Y=0.9267-2.328cos(EL)
0
20
40
60
EL (deg)
80
0.3
100
Z1 Position (LVDT outputs)

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.
Y Position (LVDT outputs)

Upgrade Activities (4)
-- Subreflector Real-Time Control (2004)

Measured 2-D beam pattern
EL=71° Saturn map
EL=35° Jupiter map
Future Plans
Antenna servo system updating
 Digital Spectrometer with 500MHz BW
 Joining east-Asia mm-wave VLBI
network
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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
 ……
--
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
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)
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
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), 3538(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.
Sample Spectral Lines
Obtained 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.
HC3N Line Toward IRC+10216
0.8
Source:IRC+10216
Formula:HC3N
Freq:109174.212MHz
Quatum number: 12-11
0.6
T(K)
0.4
0.2
0.0
-0.2
-0.4
109155
109160
109165
109170
109175
109180
Frequency(MHz)
109185
109190
109195
CH3OH Line Toward Orion
0.8
SOURCE:ORIONA
Formula:CH3OH
Freq:108894.663MHz
Q.n:0(0)-1(-1)E
0.6
T (K)
0.4
0.2
0.0
-0.2
-0.4
108880
108885
108890
108895
Frequency (MHz)
108900
108905
108910
CN Hyperfine Transitions Toward Orion
3.0
b
SOURCE:ORIONA
Formula:CN
2.5
T(K)
2.0
1.5
a
1.0
c
d
113500
113510
0.5
0.0
-0.5
113470
113480
113490
Frequency (MHz)
a:Freq:113488.618MHz
b:Freq:113491.467MHz
c:Freq:113500.137MHz
d:Freq:113509.456MHz
Quantum
Quantum
Quantum
Quantum
number:1-0
number:1-0
number:1-0
number:1-0
J=3/2-1/2
J=3/2-1/2
J=3/2-1/2
J=3/2-1/2
F=3/2-1/2
F=5/2-3/2
F=1/2-1/2
F=3/2-3/2
113520
N2H+ Lines Toward L134N
HCO+(1-0) Line Toward S140
H13CN (1-0) Line Toward OrionA
Welcome to Delingha
http://www.pmodlh.ac.cn
Open Time: September 1 – May 31
Proposal submission (all over the year)
[email protected]