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| Paper: |
Demonstration of a Data Distribution System for ALMA Data Cubes |
| Volume: |
485, Astronomical Data Analysis Software and Systems XXIII |
| Page: |
7 |
| Authors: |
Eguchi, S.; Kawasaki, W.; Shirasaki, Y.; Komiya, Y.; Kosugi, G.; Ohishi, M.; Mizumoto, Y.; Kobayashi, T. |
| Abstract: |
The Atacama Large Millimeter / submillimeter Array (ALMA) is the world's
largest radio telescope in Chile. As a part of Japanese Virtual
Observatory (JVO) system, we have been constructing a prototype of data
service to distribute ALMA data, which are three or four dimensional
cubes and expected to exceed 2 TB in total size, corresponding to 75
days at world-averaged Internet bandwidth of 2.6 Mbps, in the next three
years. To utilize the limited bandwidth, our system adopts a higher
dimensional version of so-called "deep zoom": the system generates and
stores lower resolution FITS data cubes with various binning parameters
in directions of both space and frequency. Users of our portal site can
easily visualize and cut out those data cubes by using ALMAWebQL, which
is a web application built on customized GWT. Once the FITS files are
downloaded via ALMAWebQL, one can visualize them in more detail using
Vissage, a Java-based FITS cube browser. We exhibited our web and
desktop viewer “fresh from the oven” at the last ADASS conference
(Shirasaki et al. 2013). Improvement of their performance and
functionality after that made the system nearly to a practical level.
The performance problem of ALMAWebQL reported last year
(Eguchi et al. 2013) was overcome by optimizing the network topology and
applying the just-in-time endian conversion algorithm; the latest
ALMAWebQL can follow up any user actions almost in real time for files
smaller than 5 GB. It also enables users to define either a sub-region
or sub-frequency range and move it freely on the graphical user
interface, providing more detailed information of the FITS file. In
addition, the latest Vissage now supports data from other telescopes
including HST, Subaru, Chandra, etc. and overlaying two images. In this
paper, we introduce the latest version of our VO system. |
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