URSI January 5, 2009 Science at the ARO with ALMA-Style Frontends Lucy M. Ziurys R.W. Freund And the Staff of ARO A rizona O bservatory R adio A rizona O bservatory R adio 1.2 1.0 0.8 0.6 0.4 0.2 0.0 T A * (K) 232000.0 231800.0 231600.0 231400.0 231200.0 Frequency(M Hz) OCS 13 CS C 2 H 3 CN C 2 H 3 CN C 2 H 5 CN HCOOCH 3 C 2 H 3 CN CH 3 CH O + U CH 3 CH O + C 2 H 5 CN CH 3 C HO + C 2 H 3 CN CH 2 OH CH O + C 2 H 3 CN + C 2 H 5 CN U? D 2 C O? + H COOCH 3 ? HCOOCH 3 ? CH 3 CHO U HCOOH C 2 H 5 O H + (C H 2 OH) 2 CH 3 CHO + U HCOOCH 3 ? C 2 H 3 CN HCOOCH 3 ? (CH 3 ) 2 O U U CH 3 CHO C 2 H 5 OH C 2 H 5 OH C 2 H 5 CN? U C 2 H 5 OH CH 3 NH 2 NH 2 CHO C 2 H 5 CN HNCO (CH 3 ) 2 O C 2 H 3 C N + HCOOCH 3 C 2 H 3 CN C 2 H 3 CN C 2 H 5 CN U U + C 2 H 5 OH
The Arizona Radio Observatory • ARO: An independent research unit of Steward Observatory• Consists of two mm/sub-mm Single Dish Telescope Facilities Sub-millimeter Telescope (SMT) - 10 m dish on Mt. Graham, Arizona at 10,543 ft. - Surface accuracy: 15 μm rms - Pointing good to 1” rms - ηB ~80 % at 230 GHz; 49% at 490 GHz
- Operation at λ ≤ 1 mm One of world’s best antennas Kitt Peak 12 m - Kitt Peak site: 6,280 ft - ηB ~ 75 % at 70 GHz
- 2 and 3 mm workhorse Begun to equip facilities with ALMA-type receivers
SMT
12 m
URSI January 5, 2009
The New Technology of ALMA-Type Mixers
• New Type of SIS Mixers developed specifically for ALMA “Sideband-Separating”• Two mixers with RF and IF Quadrature Hybrids obtain upper and lower sideband simultaneously but separated
with good image rejection and two IF outputs 4 GHz instantaneous BW
per IF
Unequaled Stability Most sensitive SIS mixers
Dual polarization: 4 IF’s
Perfect Devices for Single-Dish Spectroscopy Emphasis of ARO
URSI January 5, 2009
New ALMA-Type Receivers at ARO1) 1 mm (210-280 GHz) Receiver: SMT
- Utilizes ALMA Band 6 Mixers (NRAO)
- Sideband-Separating
- Dual Polarization with 4 IFs
- Tsys as good 105 K, SSB, on sky
2) 0.4 mm (600 - 720 GHz) Receiver: SMT
- Utilizes ALMA Band 9 Mixers (SRON)
- Dual Polarization, currently DSB
- Upgrade planned to SBS Mixers
3) 3 mm (85 -116 GHz) Receiver: 12 m
- Uses ALMA Band 3 Mixers (HIA)
- Double Polarization
- Sideband-Separating
New CO detections: 0.4 mm
3 mm receiver at 12 m
URSI January 5, 2009
Mixer Block(from NRAO)
• Mixer in hand to working receiver Not a trivial task 1mm receiver as an example
Incorporation into “Insert”(one per polarization“Inserts” put into Dewar
Dewar incorporated Into Receiver package
URSI January 5, 2009
The Power of the ARO ALMA-type Receivers
• Sensitivity
• HCO+ J = 1→0 line at 89 GHz • Previous 3 mm receiver (NRAO vintage) with 63 hours integration
• Same spectrum• New ALMA-type 3 mm receiver with 4 hours integration
63 hours 4 hours
URSI January 5, 2009
PN M5-55 12CO:J=2→1 230 GHz
• Position-switched spectrum: 4° offset note the baseline…
• Stability
• Four IF Mode with steerable IF frequency• Dual polarization signals for 12CO and 13CO
Ability to detect new molecules• 1 mm receiver at SMT used for comparative spectral line survey of
circumstellar envelopes of IRC+10216 and VY CMa• IRC+10216: C-rich object at 150 pc• VY CMa: O-rich shell at 1.5 kpc• Continuous coverage 215-285 GHz• Compare O-rich and C-rich regimes• Most sensitive 1 mm survey
to date
• Typical Tsys < 200 K (SSB)
• Survey 70% complete
Science with ALMA-Type Receivers: New Molecules
URSI January 5, 2009
Survey Results thus far..
• Two new oxide species in VY CMa: PO and AlO
• Two phosphorus molecules in IRC+10216: PH3 and HCP
Tenenbaum et al 2007 Tenenbaum & Ziurys 2009
VY CMa
Tenenbaum & Ziurys 2008
URSI January 5, 2009
Re-discovering VY Canis Majoris• Record Sensitivity at 1 mm: enormous advantage• Discovered interesting new morphology and
chemistry in O-rich Shell of Supergiant VY CMa First new source of new interstellar molecules in
25 YEARS (after Orion, SgrB2, TMC-1, IRC+10216)
. ........
.....
5"
Arc I
Arc II
CNT
. ........
.....
5"
Arc I
Arc II
CNT
• Random sporadic mass loss from photospheric “supergranules”• Large convection cells in red giants, supergiants (Schwarzschild 1975)
URSI January 5, 2009
Complex Chemistry in Planetary Nebulae• Planetary Nebulae: Final Stage for Intermediate Mass Stars• Strong UV Radiation Field from Central White Dwarf Star
Destroy all Molecules• Study of oldest Planetary Nebula with ALMA receivers: HELIX NEBULA
Found numerous polyatomic species
• Detections of CCH, H2CO, C3H2
• Widespread distribution of HCO+
HelixNebula
~ 1000”
URSI January 5, 2009
(125, 185)
(390, -30)
(130, -180)
(-15, 270)
(-240, -100)
(-120, 240)
(-372, 0)
(-300, -200)
HCO+ J = 1 → 0:Helix Nebula
-80 -24 32
0.0
0.3
0.6
VLSR (km/s)
-80 -24 32
0.00
0.04
0.08TR
* (K
)
(130, -180) CO J= 1-0
HCO+
J = 1-0
VLSR (km/s)
-80 -24 32
TR
* (K
)
0.00
0.02
0.04
-80 -24 32
0.0
0.1
0.2 (125, 185) COJ = 1-0
HCO+J = 1-0
CO
CO
HCO+ thus far found at every position
URSI January 5, 2009
VLBI at 1 mm of SgrA*
SMT, JCMT/SMA,
CARMA
• Angular size of SgrA*: 37 (+16.9,-10.5) μsec
4 Schwarzschild radii
Density determined rules out alternatives to MBH• Probes size scales near Event Horizon
(Doeleman et al. Nature 2008)
SMT-JCMT
SMT-JCMT
SMT-CARMA
URSI January 5, 2009
In Conclusion…• Receivers utilizing ALMA-Type Sideband Separating Mixers• NRAO/HIA Design Offer a major step forward in sensitivity and stability• Have already been instrumental in:
Detecting new molecules at mK level
Unraveling new molecular content of “uninteresting” sources Key Factor in success of 1 mm VLBI
• Bright Future for Exciting New Scientific Discoveries using increase in
receiver performance with new ALMA Technology
Thank you to NRAO CDL, HIA, and SRONAlso Thank you to staff of ARO
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