Project > SMA

SAO/ASIAA Submillimeter Array (SMA)

SMA Website

Research Gallery

Click the image for more...

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

The Submillimeter Array (SMA) was dedicated on Mauna Kea in Hawaii during November 2003, and has been operational ever since. It is the only interferometer operating at submillimeer wavelengths, providing the highest angular resolution at this wavelength. This unique advanced telescope is a collaboration between the ASIAA and the Smithsonian Astrophysical Observatory (SAO) in the US.

SMA consists of eight 6-meter antennas, with two of them (including the associated electronics and receiver systems) delivered by ASIAA under close collaborations with university groups and industry in Taiwan. It operates at the frequencies of 230, 345, 400, and 690 GHz. It can be arranged into configurations with baselines as long as 509 m， allowing us to observe submillimeter emission from warm, dense gas and dust at unprecedented high resolutions of up to 0.1 arcsecond. The SMA targets the cold interstellar medium with a great assortment of spectroscopic tools, diagnosing cool regions in the immediate vicinity of both young and evolved stars, the disks from which stars and planets form, and the active star forming regions in galaxies.

Some 533 papers have been produced, 231 of which have ASIAA co-authors and 108 papers have ASIAA first authors. Some of the most important and exciting results obtained since the SMA dedication include the use of a number of molecular lines at different excitation energies to study the circumstellar environment of two young stars (HH211, HH212). The higher excited lines can probe much closer to the central star and reveal the manner in which energetic material is being ejected in the form of bipolar jets. These images are the best ones ever made for molecular ejection, which is now understood as the means by which a circumstellar disk can remove excess angular momentum to facilitate accretion of matter onto the central star.

As a partner of the SMA project, ASIAA contributes towards the maintenance and operation of the array on Mauna Kea. ASIAA has a small local staff residing in Hilo, Hawaii. In addition, the scientific and engineering staff visits the site regularly, and conducts remote operation from Taipei.