Science Highlight




ALMA Science Verification Data

Science Verification is the process by which it is demonstrated that the data produced by ALMA are valid. The primary means of doing this is by observing sources that have already been observed by other telescopes and then comparing the ALMA results directly with those existing data sets.

The first two Science Verification data sets are now released. They consist of observations of the proto-planetary disk around TW Hya in band 7 and the merging galaxy NGC 3256 in band 3.

The data sets comprise both raw, uncalibrated data, together with the necessary calibration tables to allow users to try their hands on a complete data reduction process. Users also have access to already calibrated data, on which they can do data analysis and post-processing. In addition, reference images obtained from the reduced data sets are given as fits files.

In order to reduce and/or analyze the ALMA data, users need to use the Common Astronomy Software Applications (CASA) package. The CASA package can be accessed through http://casa.nrao.edu/. Associated with this ALMA Science Verification release are two tutorials (called CASA Guides). These provide step-by-step instructions for reducing the TW Hya and NGC3256 ALMA data sets.

The Science Verification data sets are available through the ALMA Science Portal. Go to ALMA Data --> Science Verification and select the source. Here you will also find links to the CASA Guides.