Science Highlight




ALMA Cycle 5 Pre-announcement

The Joint ALMA Observatory (JAO) will start the next cycle of observing (Cycle 5) in October 2017. A Call for Proposals with detailed information on Cycle 5 will be issued in March 2017, with a deadline for proposal submission in April 2017. This pre-announcement highlights aspects of the Cycle 5 proposal call that are needed to plan proposals.

General information

ALMA Cycle 5 will start in early October 2017 and span 12 months. It is anticipated that 4000 hours of 12-m Array time will be available for successful observations of approved projects, and 3000 hours will be available on the Atacama Compact Array (ACA), also known as the Morita Array.

The key dates for Cycle 5 are given below.

21 March 2017 Release of the ALMA Cycle 5 Call for Proposals and Observing Tool, and opening of archive for proposal submission
20 April 2017 Proposal deadline
End of July 2017 Result of the proposal review sent to Proposers
15 September 2017 Submission of Phase 2 by Proposers
October 2017 Start of ALMA Cycle 5 observations
September 2018 End of Cycle 5 observations

Proposal Types

Cycle 5 will offer the same proposal types as in Cycle 4.

Regular Proposals may request up to 50 hours of 12-m Array time or up to 150 hours of ACA stand-alone time. In previous cycles, the typical Regular Proposal requested approximately 5 hours of 12-m Array time. With the increasing number of hours available for science in Cycle 5, ALMA encourages the community to submit more Regular Proposals that request over 10 hours of 12-m Array time.

Large Programs may request more than 50 hours of 12-m Array time or more than 150 hours of ACA stand-alone time. Up to 600 hours of 12-m Array time and 450 hours of ACA stand-alone time will be allocated to Large Programs. Only standard observing modes (see below) are permitted for Large Programs. Additional guidance on preparing proposals for Large Programs will appear on the ALMA Science Portal by 1 February 2017.

Proposals will be accepted for Very Long Baseline Interferometry (VLBI) observations with ALMA in Bands 3 and 6 (wavelengths 3 mm and 1.3 mm) in the continuum only. ALMA VLBI observations will be made in concert with an existing VLBI network: the Global mm-VLBI Array (GMVA) at 3 mm and the NRAO/Event Horizon Telescope Consortium (EHTC) network at 1.3 mm. In addition to submitting an ALMA proposal, proposers of 3-mm VLBI observations must also submit a proposal to the GMVA by its 1 February 2017 deadline. Additional information about proposing with ALMA using the GMVA will be made available in the GMVA Call for Proposals in early January 2017. Additional information about proposing with ALMA using the NRAO/EHTC will appear in the ALMA Call for Proposals.

Anticipated Capabilities

Detailed information on the capabilities in Cycle 5 will be published in the Call for Proposals. The anticipated capabilities include:

Number of antennas

  • At least forty-three (43) antennas in the 12-m Array
  • At least ten (10) 7-m antennas (for short baselines) and three (3) 12-m antennas (for making single-dish maps) in the ACA


Receiver bands

  • Receiver bands 3, 4, 5, 6, 7, 8, 9 and 10 (wavelengths of about 3.1, 2.1, 1.6, 1.3, 0.87, 0.74, 0.44 and 0.35 mm, respectively)


12-m Array Configurations

  • Maximum baselines for the antenna configurations will vary from 0.15 km to 16 km; the planned configuration schedule will be released by 1 February 2017 and published in the Proposer’s Guide
  • Maximum baselines of 3.6 km for Bands 8, 9 and 10
  • Maximum baselines of 8.5 km for Band 7
  • Maximum baselines of 16 km for Bands 3, 4, 5 and 6
  • Files containing representative antenna configurations for both the 12-m and 7-m Arrays suitable for CASA simulations will be made available on the ALMA Science Portal by 1 February 2017


Spectral line, continuum, and mosaic observations

  • Spectral line and continuum observations with the 12-m Array and the 7-m Array in all bands
  • Single field interferometry (all bands) and mosaics (Bands 3 to 9) with the 12-m Array and the 7-m Array
  • Single dish spectral line observations in Bands 3 to 8



  • Single pointing, on axis, full (linear) polarization for continuum and full spectral resolution observations in Band 3, 4, 5, 6 and 7 on the 12-m Array. Note that the performance of the Stokes V is not yet verified. Due to the structure of ALMA’s data products, this is delivered but ALMA offers no warranty of the performance of Stokes V.


Cycle 5 observing modes will be classified as standard or non-standard. Standard modes have been well characterized and the observations are calibrated with the ALMA data reduction pipeline. Non-standard modes are not as well characterized and require manual calibration by ALMA staff. Up to 20% of the observing time in Cycle 5 will be allocated to proposals requesting non-standard modes, which include:

  • Band 8, 9 and 10 observations
  • Band 7 observations with maximum baselines > 5 km
  • Longest baseline configuration (16 km) in all Bands
  • All polarization observations
  • Spectral scans
  • Bandwidth switching projects (less than 1GHz aggregate bandwidths over all spectral windows)
  • Solar observations (Bands 3 and 6)
  • VLBI observations
  • User-specified calibrations


New in Cycle 5

In Cycle 5, the following opportunities will be available to Proposers for the first time.

Band 4 polarization: Proposals will be accepted for Band 4 observations in all available polarization modes.

Band 5 observations: Proposals will be accepted for spectral line (12-m, 7-m and Total Power arrays) and continuum (12-m and 7-m arrays) observations in Band 5. Proposals will be accepted for Band 5 observations in all available polarization modes. 

Update: for additional information, click on this link.