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次毫米波陣列望遠鏡(SMA)

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Internal photos of Block Down Converter instrument: left - top view of RF brackets (x4), and monitor & control; right - bottom view of DC power supplies (x4), local oscillator plates (x2), and baseband plates (x4). Developed at the SMA project office by Derek Kubo, Ryan Chilson and John Kuroda for the SMA wideband upgrade project, this instrument provides signal conditioning and frequency translation of sixteen 8-12 GHz intermediate frequency channels from the eight SMA antennas. Two of these instruments were deployed to the Mauna Kea facility with a full suite of control software developed by Ranjani Srinivasan.

RF Block Down Converter Chassis, SMA Project

Photo of modified Hoffman enclosure cover with inlet fan at top and exhaust fan at bottom. The four smaller internal fans were oriented to circulate air within the enclosure in a circular direction. The silver upper air shield was installed to avoid direct cool air convection over the upper internal assemblies.

Antenna Hoffman Enclosure Cooling Cover, SMA Project

Top photo - eSMA control panel consisting of DC power supply, ADAM-6050 monitor and control module, and custom logic board. Bottom photo - Single-mode fiber splice trays with two black Newport SPDT optical switches at bottom.

eSMA Optical Fiber Switch, SMA Project

Photo of upgraded Correlator 1st Down Converter (C1DC) unit. This upgrade consisted of increasing the intermediate frequency (IF) signal bandwidth from 4-6 GHz to 4-16 GHz while maintaining the current function of the existing legacy correlator. The upgrade is visible as the rectangular metal plate near the bottom center of the photo. The upgrade consisted of two wide-band amplifiers, power divider, and filter along with a cooling fan.

Correlator 1st Down Converter Wideband Upgrade, SMA Project

(a) and (b): Color-composite image of SMA HCN(J = 4−3) tracing the circumnuclear disk in the Galactic center (blue; CND) and the 6 cm map tracing the mini-spiral (red). The B-field orientation of the JCMT data and the best-fit model are overlaid with the white segments in the (a) and (b), respectively. respectively. The SgrA* is labeled with the black cross. (c) The JCMT B-field segments (blue) and model (red) are overlaid on the CND (gray image) and the mini-spiral (contours). The B-field model is aligned with the CND well, which suggests that the same field lines, continuing inward, also align with the mini-spiral. (d) Azimuthal-plot of the B-field position angle (ΦB; red points) with the model overlaid (blue curve). The B-field shows a predominantly azimuthal field
being wrapped along with the CND. The systemetic deviation of the B-field in the NE-lobe (E), SW-lobe can be attributed to the accretion history. The clear connection of the neutral CND and ionized mini-spiral with the B-field is presented for the first time (Hsieh et al. 2018, accepted for publication in ApJ).

The Magnetic Field Revealing the Inflow Structures in the Central 2 pc of the Galactic Center

The photo-type of planar orthogonal-mode-transducer for wSMA 350 GHz band. The microstripline is fabricated on 25 um thick Si substrate. The size of ring structure is 200 um.

Photo of wSMA 350GHz band OMT

The performance of wSMA 240 mixer

Spiral-shell circumstellar pattern of CIT 6 is revealed in our SMA CO J=2-1 channel maps, in blue, shown atop the earlier VLA HC3N J=4-3 (Claussen et al. 2011) in red. In addition, non-spherical outflow in the central region is clearly seen at the edge velocity channels (i.e., about -20 km/s and 20 km/s). The channel center velocity with respect to the systemic velocity is labeled at the top left corner of each panel. The CO and HC3N beam sizes are denoted at the bottom right.

A Spiral and Bipolar Outflow in CIT 6: Unwinding the Mysteries of a Carbon Star

The SMA antenna built in Taiwan.

Left: Filamentary structure observed in the Orion Molecular Cloud obtained in the 850 µm continuum emission taken with the JCMT/SCUBA (Johnstone & Bally 1999) Right: SMA 850 µm continuum image (color) obtained with 85-pointing mosaic observations overlaid with the 850 µm continuum image taken with the JCMT/SCUBA (black contours)

The SMA successfully imaged the thermal dust emission at 0.85 mm from the 0.9 x 0.3 pc area of Orion Molecular Cloud-3 (OMC-3), which is located to the north of Orion nebula M42

One of the two SMA wideband 300GHz receiver inserts from ASIAA.
This is a new generation receiver with wider IF operation frequency from 4GHz to 12GHz. This receiver has shown fairly flat noise temperature performance between 4 to 12GHz, and the lowest noise contribution of this receiver has approached to 3 times quantum noise. (3hv/k)

New Generation SMA 300GHz Receiver

This is the new optical insert for SMA receiver. The local oscillator source is fixed on a 3-axes translation stage on the upper section of optical insert. Fine tune this translation stage can get maximum and stable LO power into receiver.

SMA optical insert

SMA 7-pixel array receiver co-polarization radiation pattern at 345 GHz. The peak value of each pixel is indicated. Each contour is 3dB apart.

Co-polarization radiation pattern of the 7-pixel array receiver optics design for SMA

2003年11月次毫米波陣列(SMA)在夏威夷的毛納基峰上正式啟用並運轉至今。本陣列是全世界第一座次毫米波干涉陣列，提供了在此波段最高的角解析力。這組獨特先進的望遠鏡由本所與美國史密松天文台合作興建。

次毫米波陣列包括八座6米的天線，其中兩座由本所（相關的電子及接受系統）提供建造。目前次毫米波陣列有4個觀測波段，代表頻率為230GHz、350GHz、400GHz及690GHz。其基線可到達509公尺，觀測溫濃厚雲氣塵埃在次毫米的頻譜可達到 0.1 弧秒的高解析度。次毫米波陣列具備各式光譜儀器，特別適合觀測冷星際物質，可分析緊臨年輕或老年恆星的低溫雲氣、形成恆星或行星的吸積盤、以及外星系中的恆星劇增區。

在藉由次毫米波陣列觀測而發表的約533篇論文中，本所同仁與其中約231篇，其中本所同仁為第一作者的有108篇。自啟用以來獲得許多非常重要且令人振奮的研究成果。其中包括透過數條在不同激發能態的分子譜線，研究年輕恆星HH211與HH212的拱星環境。較高激態的譜線可以探知更靠近中央恆星的區域，能讓我們了解高能量物質是如何以雙極噴流的形式噴出。這些是史上最佳的分子噴流影像，而分子噴流被認為是拱星盤物質被吸積至中央恆星時，釋放出多餘的角動量的憑藉。

本所在夏威夷希洛有一常駐團隊擔負起次毫米波陣列的運轉維修工作。本所科學家及工程師除了時常造訪外，也可在台北運用遠端操作次毫米波陣列進行觀測。