page title icon ALMA Science Archive remote visualization with CARTA

The Atacama Large Millimeter/submillimeter Array (ALMA) is a large interferometer radio telescope in Chile, one of the largest astronomy projects in existence, at least until the Square Kilometre Array is built. The ALMA Science Archive (ASA) contains the public and proprietary data of all ALMA observations. Through the Archive Query Interface, the user can constrain their search using various observational parameters, and then queue up the selected data for download. Up to now there has been no easy way to view the data products before fully downloading them. Images can range from a few megabytes to hundreds of gigabytes in size, thus making it a time consuming process.

CARTA, the Cube Analysis and Rendering Tool for Astronomy, is a next generation image visualization and analysis tool utilizing server-client architecture and designed for ALMA, VLA, and SKA pathfinders. CARTA has now been integrated into the ASA at all three locations, at ESO, NAOJ and NRAO.

Using server-client architecture, the heavy computation and data storage occurs remotely on powerful servers connected to high performance storage. The user interacts through the client interface running natively in their local web-browser (see Figure 1). Only essential data such as the rendered image, histogram data, and spectral profiles etc. are sent from the server to the client. This means that image cubes in terabyte sizes can be quickly and efficiently visualized without the need to download it first. As you can imagine, this makes it the ideal software to integrate with the ALMA Science Archive (ASA).

Figure 1: Example of the CARTA client interface. Here it is demonstrating the ‘catalog’ feature.

Now all 500,000+ ALMA science FITS files from the ASA can be viewed within seconds using CARTA (excluding Cycle 0). After selecting one or more projects in the ALMA Query Interface and navigating to the ALMA Request Handler page, expand a data product folder and look for the CARTA button associated with each FITS image (See Figure 2). Once clicked, CARTA will automatically open in a new web browser tab and display the image (Please allow the ASA to open pop-ups in your web browser first).

Figure 2: Example of the Request Handler page with the new CARTA button highlighted by the red circle. Clicking it will open the associated image, in this case, an image cube 2GB in size.

CARTA, originally an ALMA development project from 2014 to 2016, is now jointly developed by the Inter-University Institute for Data Intensive Astronomy (IDIA) with teams at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan, the National Radio Astronomy Observatory (NRAO) in the United States, and the Department of Physics, University of Alberta in Canada.

Visit the ALMA Science Portal to try CARTA integration with the ASA, or try CARTA on ilifu

For more information, please see the CARTA homepage.

Credit: CARTA (interface)/NASA Goddard/LAMBDA (science images).