Call for SMA Science Observing Proposals
SMA Observing Time
Support for New Users
Number of Nights Available
Accepted Proposals and SMA Observing
The joint CfA-ASIAA SMA Time Allocation Committee (TAC) solicits
proposals for observations for the period
2014 Nov 16 - 2015 May 15. Proposals must be
Thursday, 7 August 2014, 10:00 HST (Hawaii)
Thursday, 7 August 2014, 16:00 EDT (Cambridge, MA)
Thursday, 7 August 2014, 20:00 GMT
Friday, 8 August 2014, 04:00 CST (Taipei)
The SMA is a joint project funded by the Smithsonian Astrophysical
Observatory (SAO) and the Academia Sinica Institute for Astronomy and
Astrophysics (ASIAA) and also includes the Institute for Astronomy (IfA) at the
University of Hawaii as a partner institution. As of the 2011-B semester, the CfA and
the ASIAA have merged their shares of time into a single pool on a trial basis. The time allocation ratios for
the three SMA partners,
CfA+ASIAA:IfA, are 85(72+13):15. Dedicated to excellence in scientific
research and cooperation in the scientific community, the CfA and the ASIAA allocate
their share of SMA observing time under an informal "open skies" policy.
The CfA+ASIAA share of the SMA time is open to astronomers worldwide and
is allocated by scientific merit.
In addition to regular proposal programs, SMA offers opportunity for large-scale projects in the
range of 100 to 1000 hours. Large-scale projects increase the
proposal oversubscription, especially, in the requested RA range. Currently, SMA is carrying out one large-scale
project in the RA of 17:30.
In spite of the merged CfA-ASIAA time shares, PIs from Taiwan should select ASIAA as
their proposal destination to facilitate book-keeping during the trial period.
Astronomers proposing for IfA time should submit proposals directly to the IfA,
following their independent procedures. Collaborations among astronomers from different
institutions are encouraged.
Several nights of Director's discretionary time are
reserved for potential targets of opportunity and other use. Please
contact the SMA project scientist, Eric Keto, TAC chair, Qizhou Zhang, or director, Ray Blundell
propose [at] sma [dot] hawaii [dot] edu.
The SMA staff offers support for observers who are not familiar with the SMA. We can provide support on different levels, from help getting started to full collaboration. Please contact us propose [at] sma [dot] hawaii [dot] edu for questions on proposal preparation, observing techniques and strategies, observing control scripts, and data analysis.
On average, between five and six nights per week are
allocated for routine science observations. Weather statistics
suggest that approximately half of the useable time is suitable for
observations in the 230 GHz and the 345 GHz bands each.
Taking account of time devoted to
testing, overhead, and lost to bad weather, the combined CfA+ASIAA share of the SMA time
averages about 41 nights each for the 230 GHz and the 345 GHz bands.
The TAC uses these averages to set the approximate number of
The oversubscription rate is a function
of target RA. The Figure below shows the distribution
of target RA proposed in the past few semesters with notable peaks
in the inner Galactic Plane.
Existing SMA data
Proposers should query the SMA archive before planning observations to see if existing SMA data suit their scientific goals. Data from past SMA observations are
archived by the CfA Radio Telescope Data Center and may be searched. SMA data are publicly available after a proprietary
period of 15 months.
RA range and UV coverage
SMA observations are generally executed at night
when the atmospheric
phase noise is low and often continued into the early morning.
Conditions are rarely suitable for afternoon observations.
For 2014 November
- 2015 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 accommodate the approved proposals, such
observations might not be possible.
The SMA operates in 4 configurations with maximum baselines of
30m ("subcompact"), 70m ("compact"),
220m ("extended"), and 500m ("very extended"). The
configuration schedule is determined after the TAC
process to best fit the approved projects; however, the SMA
will likely be in the "compact" configuration at the start of
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.
Technical Information and Tools
Starting from the 2013B semester, a new capability to cover a substantially larger bandwidth is available on a shared risk basis,
in the 230 and 345 GHz bands. This enhancement is enabled by the new SWARM correlator. In
addition to the 4 - 8 GHz IF range (2 X 4 - 6 GHz in the dual-Rx mode) covered by the legacy (existing) correlator,
the new coverages are 8-11 GHz for the 230 GHz band and 8-12 GHz for the 345 GHz band.
The SWARM correlator offers a fixed 140 kHz resolution across the IF band. This new capability is not yet available
for the 400 GHz Rx - and thus not available for dual-receiver polarization observations - as the 400 GHz Rx
has not yet been upgraded. See Array Status and Technical Information for more details.
As the SWARM correlator is being offered on a shared risk basis, proposals relying on the additional
continuum sensitivity or spectral coverage should address potential impact on the science goals
if the new capabilities are not realized.
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.
The SMA maintains several online tools for planning SMA observations,
available on the Tools page.
The Beam Calculator / Sensitivity
Estimator is a particularly useful tool to estimate angular resolution, UV coverage
and nominal sensitivities for different weather conditions (precipitable water vapor).
Variations in weather may considerably
impact actual sensitivities.
Generally, observations at lower frequencies can be done in atmospheric
conditions of higher
precipitable water vapor.
Standard values are < 4.0 and < 2.5mm of water vapor for observations in the frequency
ranges <300 and 300-420 GHz, respectively. Proposers must indicate and justify the atmospheric conditions
required for their scientific goals.
The SMA is more oversubscribed in
the weather conditions suitable for the 350 GHz band (< 2.5mm water vapor).
The Passband Visualizer and
Correlator Configuration Tool provides information on spectral line coverage and on configuring the SMA correlator to provide different spectral resolutions across the observing bandwidth.
SMA observations require calibrator sources for bandpass, gain, and flux calibration. Quasars are generally
used for bandpass and gain calibration; however, suitable calibrators may not be available for all parts of
the sky particularly at the higher frequencies. See The Submillimeter
Solar system bodies are generally used for flux calibration
but may not be available at all times of the year. Observers should show that their proposed observations
can be adequately calibrated.
Proposals should provide clear justifications for the rms flux
sensitivities, spectral resolutions, antenna configuration(s), weather conditions, and calibration strategies needed
to achieve their science goals.
Proposal Forms and Proposal Submission
Proposals are submitted through each individual PI's SMA Project Account.
The project account contains
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 Projects page. Project accounts may be
created from the login page if necessary. (current SMAOC account
holders do not need a separate project account)
Using the proposal submission facility, drafts may be created and edited at any
time, but may only be submitted within 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.
Proposal selection is based on scientific merit and technical
The TAC assigns each proposal a numerical score and
recommends an amount of time to be allocated. The proposals are ranked
and grouped 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 about ten weeks of the proposal deadline. Please see the TAC Procedures for more details
of the TAC review process.
All accepted proposals are shared-risk, with no guarantee of success.
Proposals accepted but not observed due to time constraints
will not be carried over and must be resubmitted in response to a future call for proposals.
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
Please e-mail any questions about preparing and submitting proposals to
propose [at] sma [dot] hawaii [dot] edu.
Last updated: 2014-Jul-12 by Qizhou Zhang