Summary

Here we summarize our major conclusions. For a number of topics, detailed recommendations are included in the appropriate sections of the report.

• The ASAC re-iterates its strong support for the participation of Japan in the ALMA project as a full partner. For the Enhanced ALMA resulting from such a partnership, the possibility of an Atacama Compact Array of 10-16 antennas of size 6-8 meter and adding complete frequency coverage have the highest priority because they both enable new science to be done. Other enhancement options are additional array antennas and an enhanced correlator. With regard to the Atacama Compact Array, we recommend studies of its imaging performance to determine optimum values for the size and number of its antenna elements.

• The project team working on the future correlator solicited ASAC input on a variety of items. Our recommendations are listed in section 3.2.

• Regarding calibration, the ASAC concludes that there should be no cold loads in the dewar. Current ideas, particularly the semi-transparent vane and the use of coherent signals should be developed further. A calibration accuracy of 1% is adequate.

• The ASAC very strongly encourages further work on developing a phase correction scheme using water-vapor radiometry at 183 GHz and 20 microns. Various efforts are under way and should be pursued concurrently.

• The ASAC confirms that the highest priority receiver bands to be initially installed are bands 3, 6, 7, and 9. Second priority bands are 1, 4, 8, and 10, while third priority is assigned to bands 2 and 5. The ASAC requests to be involved in all further discussions on prioritization of receiver bands. We again request a presentation at the next ASAC meeting of a detailed plan for the mass production, integration and testing of the ALMA Phase II receivers.

• A number of detailed recommendations concerning polarization are given in section 7.4.

• A thorough comparison of the Pampa la Bola and Chajnantor sites should be made using as much contemporaneous data as possible.