Call for SMA Science Observing Proposals

This Call for Proposals has been issued by the CfA/SAO SMA Time Allocation Committee. If you plan to propose to the ASIAA Time Allocation Committee, view the ASIAA Call for Proposals.

Proposal Deadline
SMA Observing Time and External Proposals
Proposal Evaluation
Number of Nights Available
Proposal Preparation
Accepted Proposals and SMA Observing

Proposal Deadline

Following the direction of the SMA steering committee, the CfA SMA Time Allocation Committee (TAC) solicits proposals for observations in the 230, 345, 400, and 690 GHz bands for the period 2008 Nov 16 - 2009 May 15. The deadline for submitting proposals is 2008 September 11 (16:00 EDT = 10:00 HST). In addition, large (legacy) proposals must be preceded by a brief "Notice of Intent" by 2008 September 4, 16:00 EDT.

SMA Observing Time and External Proposals

The time allocation ratios for the SMA partner institutions CfA:ASIAA:IfA are nominally 72:15:13, and up to 30 percent of the CfA time will be open to external principal investigators (PIs). The affiliation of the PI determines the designation of a proposal origin. The SMA is a complex instrument, and some capabilities are still under development. External PIs are required to have a CfA collaborator. If you are at the CfA and interested in collaboration with an experienced SMA user, or if you are an external PI and would like to find a CfA collaborator, please contact us well in advance of the proposal deadline at propose [at] sma [dot] hawaii [dot] edu. Note that ASIAA and IfA follow independent time allocation procedures. Collaborations among proposers from different institutions are encouraged; if a "joint proposal" is submitted to multiple institutions, then the time requested from each institution must be described explicitly.

Proposal Evaluation

Proposal selection is based on scientific merit (and technical feasibility). The TAC generally consists of a minimum of 3 CfA SMA staff members, 1 CfA staff member not affiliated with the SMA, 2 ASIAA staff members, and several representatives from the external community. The TAC assigns each proposal a numerical score and recommends an amount of time to be allocated. The proposals are ranked and grouped, with requested tracks falling into three categories: A (best effort to execute), B (may be executed as conditions permit), and C (will not be executed). Proposers are notified of their proposal rating by e-mail shortly after the TAC completes its work, typically within six weeks of the proposal deadline. Please see the TAC Procedures for more details of the TAC review process.

Number of Nights Available

On average, between five and six nights per week are expected to be allocated for routine science observations. Weather statistics suggest that approximately half of the useable time is suitable for observations for the 345 GHz band; perhaps 10 percent is suitable for the 690 GHz band. As a guide, taking account of time devoted to testing, overheads, and time lost to bad weather, CfA and external PIs might expect a total of 35 nights for the 230 GHz band, 28 nights for the 345 GHz band, and 7 nights for the 690 GHz band in the semester; the TAC will use these nominal values to set the approximate number of A-rated tracks. Several nights of Director's discretionary time are reserved for potential targets of opportunity and other use.

Proposers should keep in mind that the oversubscription rate as a function of target RA is far from uniform. The Figure below shows the distribution of target RA proposed in the past few semesters, with notable peaks at the RA of favorite parts of the sky, most prominently the inner Galactic Plane.

Proposal Preparation

Preliminary Considerations

SMA observations are generally executed at night, as the data quality is generally best from a few hours after sunset to sunrise when atmospheric phase noise is low. Observations are often continued into the morning daylight; observations in the afternoon hours are rare but not expressly prohibited. Proposers must provide clear justifications for the rms flux sensitivities, spectral resolutions, and antenna configuration(s) needed to achieve their science goals. Proposers must also show that suitable calibrator sources are available. For all proposals, and especially for 690 GHz observations or for any non-standard situations, calibration strategies must be described in sufficient detail to show project feasibility. For 2008 November - 2009 May observing, long tracks will be feasible during at least half the semester for sources in the range of roughly RA=4h to 16h. Sources outside this RA range will also be considered if adequate justification is provided. However, since the array configuration schedule is set to accomodate the A-rated proposals, such observations might not be possible.

Many projects do not need full tracks for adequate uv coverage and/or sensitivity, and the TAC strongly encourages requests for snapshots and partial tracks. Data from past SMA observations are archived by the CfA Radio Telescope Data Center and may be searched. The proprietary period for SMA data is generally 15 months, per CfA policy.

Technical Information and Tools

Please see Array Status and Technical Information for up-to-date technical information about the SMA, including antenna configurations, correlator setups, receiver status, and new or updated SMA capabilities. In addition, the SMA maintains several online tools for planning SMA observations, which are available on the Tools page. Proposers must use the Beam Calculator / Sensitivity Estimator to calculate nominal sensitivities for proposals. This tool now allows flexibility in the choice of precipitable water vapor. Standard values are 4.0, 2.5, and 1.0mm for <300, 300-420, and 600-700 GHz, respectively; proposers may use other values but must clearly justify their selection. The TAC uses these estimates to assess feasibility and risk; variations in weather may considerably impact actual sensitivities. The basic "compact" (70 meter) and "extended" (220 meter) antenna configurations are expected to be available at some point during the semester. The "very extended" (500 meter) and the "subcompact" (30 meter) antenna configurations are also available, depending on demand. The configuration schedule will mostly be determined only after the TAC process, to best fit the A-rated science projects. However, the SMA will likely be in the "compact" configuration at the start of the semester.

Proposal Forms and Proposal Submission

Proposers are required to have an "SMA Project Account" through which project proposal and execution will be performed. The project account will contain all information about an observer's proposals and projects, and will persist for reuse in future proposal cycles. All SMA project activities begin at the user's My SMA Projects page. Project accounts may be created from the login page if necessary. (Note: current SMAOC account holders do not need a separate project account)

Proposals must be submitted through the SMA Project Account, using the proposal submission facility which will open a few weeks prior to the proposal deadline. Each proposal consists of an on-line cover form and technical information forms, and an attached scientific justification in PDF format. Proposals may be saved and edited on-line as often as needed prior to final submission. The scientific justification is limited to a maximum of two US-letter sized pages of text (11pt or larger) plus two US-letter sized pages of figures, tables and references.

Notices of Intent to propose a legacy project must be submitted here.

Questions?

Please e-mail any questions about preparing and submitting proposals to propose [at] sma [dot] hawaii [dot] edu.

Accepted Proposals and SMA Observing

All accepted proposals are shared-risk, with no guarantee of observations, and no claim to observations in future proposal periods. Principal investigators of successful proposals should be prepared to provide an observer on Mauna Kea. Most proposals are queue scheduled to maximize return based on the prevailing weather conditions and instrument status. The SMA scheduler decides what project will be observed each night. It is unlikely that visiting observers will execute their own project when present on Mauna Kea. Data from SMA observations may be retrieved from the CfA's Radio Telescope Data Center archive for reduction. Proposals accepted but not observed due to time constraints will not be carried over and must be resubmitted to the TAC for future consideration.