Science Highlight




Resubmission of unfinished Cycle 1 and 2 proposals for the Cycle 3 proposal review

Proposers of active Cycle 1 and Cycle 2 B- or C-graded projects should consider that these projects may not be completed before the end of Cycle 2.  If they wish to observe the same targets in Cycle 3 they must specify whether or not the cycle 3 observations will duplicate the former ones. If so, the proposers must specify if the duplicating observations need to be repeated in Cycle 3 even if they have been successfully completed by the end of Cycle 2. Such repetition, if deemed necessary, must be scientifically justified.

Cycle 2 observations will start again at the end of March with the array in the compact configuration (C34-1/2), and will continue with observations scheduled in blocks of two weeks followed by a week of EOC (Extension and Optimization of Capabilities). During the two-week observation blocks, 24h/day observing runs will take place during the weekends. Array re-configurations will mainly be done during the EOC weeks. The Cycle 2 tentative array reconfiguration schedule is as follows (note that changes can be made due to unforeseen circumstances that prevent array re-configurations such as snow storms etc.):

Array Configuration

Start date

Night time LST range


March 31



May 12



June 2



June 23



Aug 4



Aug 25



Numbers in parenthesis means that the configuration is expected to contain sufficient baselines to approximate either configuration.

Due to the array configuration schedule there are in particular a number of projects that are unlikely to be observed:

  1. High frequency projects (Bands 8, and 9) in the compact configurations (C34-1 and C34-2) have a low chance to be observed during the remaining time in April due to poor anticipated atmospheric conditions (see Figure 1 of the ALMA Proposer’s Guide).
  2. High frequency projects that can only be scheduled during daytime (Bands 7, 8, and 9), regardless of configuration, are less likely to be observed due to the poorer atmospheric stability, higher system temperatures, and worse antenna pointing accuracy during the day.

The PIs of the projects meeting these criteria will be contacted by their ARC support personnel to suggest they resubmit their proposal for Cycle 3.