Call for Standard Observing Proposals for observations with the Submillimeter Array (SMA)

This call is for the 2020A semester with observing period 16 May 2020 – 15 Nov 2020.

Standard Observing Proposals

Submission deadline: 05 Mar 2020 21:00 UTC = 05 Mar 2020 16:00 EST = 06 Mar 2020 05:00 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 9 m 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, able to process 8 GHz bandwidth (IF coverage of 4 to 12 GHz) for each receiver in each sideband, for a total of 32 GHz bandwidth, at a uniform 140 kHz resolution. We are currently expanding the correlator coverage by 50%, to 12 GHz bandwidth (IF coverage from 4 to 16 GHz) for each receiver in each sideband, for 48 GHz total bandwidth, while maintaining the fine 140 kHz uniform resolution. While not yet fully commissioned, we are working toward offering this new capability in 2020A as a shared-risk opportunity.

The SMA can tune the orthogonal receiver combinations independently, resulting in a very flexible frequency coverage capability. For example, observations can be made at 1.3 mm and 870 micron simultaneously (with many other configurations possible). One popular configuration allows the current 8 GHz/sideband/receiver frequency coverage to cover up to 32 GHz contiguously, 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 16 GHz (8 GHz in each sideband) of frequency space in the two orthogonally polarizations, allowing improved spectral line sensitivity. In such a case, full Stokes polarization measurements are also possible at 1.3 mm and 870 microns. When our upgrade is completed to 12 GHz/sideband/receiver, the frequency coverage will be configurable to cover 44 GHz contiguously (with 4 GHz of overlap), or can be configured to cover the same 24 GHz (12 GHz in each sideband) with the same LO.

The SMA provides flexible, wide band frequency coverage that delivers high continuum sensitivity and excellent spectral line capabilities. A full transit observation with the current 8 GHz/sideband/receiver correlator coverage will offer continuum sensitivity of 250 or 600 micro-Jy (1 sigma) at 230 or 345 GHz in good weather conditions (precipitable water vapor 2.5 mm and 1.0 mm, respectively). When the correlator upgrade is fully commissioned this will improve the continuum sensitivities by 22% per unit time. 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 Proposal Information Page.

IMPORTANT DATES FOR STANDARD OBSERVING PROPOSALS

• Submissions open: 06 February 2020 (on or before)
• Submissions close: 05 Mar 2020 21:00 UTC = 05 Mar 2020 16:00 EST = 06 Mar 2020 05:00 Taiwan

Due to current and expected investment in further upgrades to the SMA capabilities, as well as 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 sma-propose@cfa.harvard.edu.