The Atacama Large Millimeter Array Implications of a Potential Descope (2005) / Chapter Skim
Currently Skimming:
2 Technical Performance Specifications
2 Technical Performance Specifications
Pages 7-12
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 7... ...
So far, more than 30 galaxies have been detected in this manner beyond a redshift of z = 2. However, these detections have been limited to luminous objects that are unrepresentative of normal galaxy formation.
|
From page 8... ...
The committee notes, however, that even with this consideration, the implicit scientific goal of tracing star formation in galaxies up to z = 3 will not be met, because, unlike the case with carbon monoxide, the [CII] line does not directly trace the cold molecular component of the galaxies in a well-understood or systematic way.
|
From page 9... ...
It is the view of the committee that by working hard with real data, it would be possible to recover from a 60-antenna array the principal desired features, holes and gaps. However, this benchmark will be very difficult to achieve if the array size is reduced to 50, and achieving the benchmark may not be possible with a 40-antenna 2Although not unprecedented, 600 hours is an extremely long observation time.
|
From page 10... ...
Although imaging the gaps in continuum emission from dust is significant, observations in lines of the gas in the disks will be just as important in order to constrain the physical structure of the disk, the evolving chemistry, the location of the frost line, where water changes to ice, the origin of the outflowing winds, and the gas kinematics. It is the study of the gas that brings understanding of how planets form.
|
From page 11... ...
Much of ALMA's work will concern extended sources where the extremely high angular resolution needed to meet Requirement 2 is less crucial. The challenge will be to create images with high dynamic range so that faint components can be seen in the presence of bright components.
|
From page 12... ...
The committee concludes that two of the three level-1 requirements, involving sensitivity and high-contrast imaging of protostellar disks, will not be met with either a 40- or a 50-antenna array. It is not clear if the third requirement, on dynamic range, can be met with a 40-antenna array even if extremely long integrations are allowed for.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.