Science Highlight




ALMA Cycle 6 Pre-announcement

The Joint ALMA Observatory (JAO) will start the next cycle of observing (Cycle 6) in October 2018. A Call for Proposals with detailed information on Cycle 6 will be issued in March 2018, with a deadline for proposal submission in April 2018. This pre-announcement highlights aspects of the Cycle 6 proposal call that are needed to plan proposals.

General information

ALMA Cycle 6 will start in early October 2018 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 6 are given below.

18 December 2017

Cycle 6 pre-announcement

1 February 2018

Additional information on configuration schedule

20 March 2018

Release of the ALMA Cycle 6 Call for Proposals and Observing Tool, and opening of archive for proposal submission

19 April 2018

Proposal deadline

18-23 June 2018

Proposal Review meeting

End of July 2018

Result of the proposal review sent to Proposers

6 September 2018

Deadline for Phase 2 submission by Proposers

October 2018

Start of ALMA Cycle 6 observations

September 2019

End of Cycle 6 observations


Proposal Types

Cycle 6 will offer the same proposal types as in Cycle 5.

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 5-7 hours of 12-m Array time. ALMA continues to encourage 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 2018.

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 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 2018 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 EHTC will appear in the ALMA Call for Proposals.

Anticipated Capabilities

Detailed information on the capabilities in Cycle 6 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 2018 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
  • The Cycle 6 antenna configuration files needed for CASA simulations are available here. The representative antenna configurations in Cycle 6 are the same as in Cycle 5.


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 and circular polarization for both continuum and full-spectral-resolution observations in Band 3, 4, 5, 6, and 7 on the 12-m Array. The field of view of both linear and circular polarization observations is limited to the inner 1/3 of the primary beam.


Cycle 6 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 6 will be allocated to proposals requesting non-standard modes, which include:

  • Band 9 and 10 observations
  • Band 7 observations with maximum baselines > 5 km
  • All polarization observations
  • Spectral scans
  • Bandwidth switching projects (less than 0.9375 GHz aggregate bandwidths over all spectral windows)
  • Solar observations (Bands 3 and 6)
  • VLBI observations
  • User-specified calibrations
  • Astrometry


New in Cycle 6

In Cycle 6, the following opportunities will be available to Proposers for the first time.

Circular polarization: proposals will be accepted for Bands 3, 4, 5, 6, and 7 in all (including circular) polarization modes for continuum and spectral-line observations. The minimum detectable degree of circular polarization, defined as three times the systematic calibration uncertainty, is currently 1.8% of the peak flux for both TDM and FDM observations. Additional information on the circular polarization capabilities will be presented in the 1 February 2018 announcement on the ALMA Science Portal.

Band 8 standard mode: Band 8 will become a standard mode starting in Cycle 6.

Band 8 ACA Standalone: Band 8 can be requested on the ACA in standalone mode.

Band 6 IF extension: The Band 6 IF bandwidth has been increased by 0.5 GHz to extend from 4.5 to 10 GHz. This will enable 12CO, 13CO, and C18O J=2-1 to be observed simultaneously with broader spectral windows for galactic sources and nearby galaxies.