Taming the Data

March 12, 2012 by Alberto Conti

Artist's concept of the Galaxy Evolution Explorer (GALEX)

My name is Alberto Conti and I am an astrophysicist and the James Webb Space Telescope (JWST) Innovation Scientist at the Space Telescope Science Institute (STScI). I’ve been at STScI since 2003.
I am going to use these posts to tell you a little bit about my interests, what inspires me and makes me come to work daily. In doing so, I will try to underscore how science in general, and astronomy in particular, has changed over the course of my lifetime in ways that still amaze me.
I came to STScI to contribute to the development of the archive for the Galaxy Evolution Explorer (GALEX) mission. As a space mission, GALEX was unique in many ways. GALEX brought us the first detailed look at the entire sky in ultraviolet light, a range of radiation just above the shortest wavelengths visible to the human eye. Led by the California Institute of Technology, GALEX conducted several first-of-a-kind surveys, contributing significantly to our understanding of the processes that give raise to galaxy formation and evolution. One of GALEX’s main goals was to analyze ultraviolet light from millions of distant galaxies, thereby providing key evidence for the history of star formation over 10 billion years of cosmic history — or about 70 percent of the life of our universe.
All data collected by GALEX is stored at STScI in Multimission Archive (MAST), which is NASA’s optical and ultraviolet data archive. MAST’s primary focus is to support the astronomical community by providing access tools to sets of data, or “datasets,” in the optical, ultraviolet, and near-infrared parts of the spectrum. MAST currently hosts data for over 20 missions, including the Hubble Space Telescope, the Kepler terrestrial planet finder telescope, and GALEX.
I have always been fascinated with how astronomical data is collected, stored, retrieved, visualized, and used to understand the properties of our universe or discover new, exciting ones. Over the past 25 years, astronomers have become much more efficient at collecting photons from distant galaxies with larger mirrors in space and on the ground. However, our ability to build larger telescopes has been outshined by the exponential growth of detectors. Thanks to advances in detector technology, a relatively small telescope like GALEX, for instance, was able to collect data on over 200 million ultraviolet sources.
As a result, astronomical data doubles every two years or so, and profound changes have occurred in the astronomical community as a result. While I had worked with moderately large datasets during my postdoctoral work at the University of Pittsburgh, GALEX was where my love (most would say obsession) for data really began.
Storing information on details such as brightness, size, distance, color and many, many other items for over 200 million GALEX sources required detailed planning. Imagine a spreadsheet with more than 200 million rows and 300 columns, and you’ll have an idea of the task at hand. Developing the tools to search, retrieve and visualize this data was only possible with the dedicated work of the whole MAST GALEX team. I look back at my time on GALEX as a very exciting part of my life. It seemed that our team was making data discovery possible, enabling the mining of millions of objects in a matter of seconds.
It was during this time that I learned about databases, data mining technologies, data visualization techniques, and the importance of preserving the integrity of the data for the community. Many of the lessons learned during this time still guide my judgment when thinking about the next generation data archives for JWST. I’ll elaborate on this in my future posts.
Astronomy is an elegant science because each instrument we use to reveal the nature of our universe is nothing but a small piece of a larger puzzle we are all working on. This is true for GALEX. As a mission it would not have been as successful if it were not for its surveying capabilities, which represent a great complement to other space-based missions such as the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer, but also for ground-based surveys like the Sloan Digital Sky Survey at optical wavelengths.
I use GALEX data to this day looking for transient object (object whose properties change over time), hot white dwarfs, and quasars in a long-standing collaboration with Johns Hopkins University astronomer Luciana Bianchi. I feel very privileged to be able to work in field so intellectually and professionally rewarding, but mostly I feel humbled to have the teammates I have, starting with my GALEX friends