The Submillimeter Array

Call for Standard Observing Proposals -2020B Semester

We wish to draw your attention to the latest Call for Standard Observing Proposals for observations with the Submillimeter Array (SMA). This call is for the 2020B semester with observing period 16 Nov 2020 - 15 May 2021.

Standard Observing Proposals

Submission deadline:

      10 September 2020 (US)/11 September 2020 (Taiwan)

Proposal Information and Submission

The SMA is a reconfigurable interferometric array of eight 6-m antennas on Maunakea jointly built and operated by the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics. The array operates in the 230, 345 and 400 GHz bands, observing simultaneously with two orthogonally polarized receivers, one in the 230 GHz or 345 GHz band and the other in the 240 GHz or 400 GHz band (with full polarimetric observations available using the 230+240 or 345+400 band combinations).

The SMA configurations include antenna separations ranging between 9m and 508 m. The small antennas allow access to low spatial frequencies (with projected baselines as short as 6-m) in the sub-compact configuration, and at the other extreme, the finest angular resolution with the very extended configuration at 345 GHz is ~ 0.25". The compact and extended configurations complete the range. The characteristics, performance and sky coverage of the SMA are both similar and complementary to those of the stand-alone Atacama Compact Array (ACA) component of ALMA, while providing full access to the northern sky.

The heart of the SMA backend is the SWARM correlator, currently expanding to process 12 GHz bandwidth (IF coverage of 4 to 16 GHz) for each receiver in each sideband, for a total of 48 GHz total covered bandwidth, at a uniform 140 kHz resolution. Our delayed start to semester 2020A has pushed the expansion check out back a bit, but we are right now in the final steps of science validation and are confident in its availability in a matter of weeks.

The SMA can tune the orthogonal receiver combinations independently, resulting in a very flexible frequency coverage capability. For example, observations can be made at 1.3mm and 870 micron simultaneously (with many other configurations possible). One popular configuration allows 12 GHz/sideband/receiver frequency coverage to be interleaved, allowing a 44 GHz continous spectral coverage (with 4 GHz of dual polarization coverage), where the tuning ranges overlap for the two orthogonally polarized receivers. Alternatively, the two receivers can be set with the same LO to cover the same 24 GHz (12 GHz in each sideband) of frequency space in the two orthogonal polarizations, allowing improved spectral line sensitivity. In such a case, full Stokes polarization measurements are also possible at 1.3mm and 870 microns.

The SMA provides flexible, wide band frequency coverage that delivers high continuum sensitivity and excellent spectral line capabilities. A full transit observation with the 12 GHz/sideband/receiver correlator coverage will offer continuum sensitivity down to 200 or 450 micro-Jy (1 sigma) at 230 or 345 GHz in good weather conditions (precipitable water vapor 2.5mm and 1.0mm, respectively). The corresponding line sensitivities at 1 km/s resolution are 35 and 80 mJy.

For more information about SMA capabilities, visit the SMA Observer Center website and explore the set of SMA proposing tools. Current and archived SMA Newsletters provide a sampling of the wide variety of science possible with the SMA.

For more details visit the SMA Observer Center: Proposing Observations


  • Submissions open: 13 August 2020 (on or before)
  • Submissions close: 10 September 2020 (US)/11 September 2020 (Taiwan)

Given the direct impact of nearly 3 months offline in response to the novel coronavirus pandemic and its potential for continued impact on array operations, current and expected investment in further upgrades to the SMA capabilities, and obligations to previous approved programs, the Large Scale Projects program (for projects requesting 100 to 1000 hours) will not be accepting proposals at this time.

Questions or comments regarding the Standard Observing Proposals can be addressed to

Mark Gurwell
Chair, Submillimeter Array Time Allocation Committee