Keeping an Eye on the Universe
The night sky is filled with objects such as asteroids that dash across the sky and others -- such as exploding stars and variable stars -- that flash, dim, and brighten. Studying such phenomena can help astronomers better understand the evolution of stars, massive black holes in the centers of galaxies, and the structure of the Milky Way.
These types of objects also were essential for the recent discovery of dark energy -- the mysterious energy that dominates the expansion of the universe -- that earned last year's Nobel Prize.
Using images obtained by the UA's asteroid-hunting Catalina Sky Survey, the Catalina Real-Time Transient Survey, or CRTS, lets CalTech astronomers systematically scan the heavens for these dynamic objects, resulting in an unprecedented data set that will allow scientists worldwide to pursue new research.
"Exploring variable objects and transient phenomena like stellar explosions is one of the most vibrant and growing research areas in astrophysics," said S. George Djorgovski, professor of astronomy at Caltech and principal investigator on the CRTS. "In many cases, this yields unique information needed to understand these objects."
The new data set is based on observations taken with the 0.7-meter telescope on Mt. Bigelow in Arizona. The observations were part of the Catalina Sky Survey, a search for Near-Earth Objects, or NEOs --asteroids that may pose a threat to Earth -- conducted by astronomers at the UA.
By repeatedly taking pictures of large swaths of the sky and comparing these images to previous ones, the CRTS is able to monitor the brightness of about half-billion objects, allowing it to search for those that dramatically brighten or dim. In this way, the CRTS team identified tens of thousands of variables, maximizing the science that can be gleaned from the original data.
The new data set contains the so-called brightness histories of a total of 200 million stars and other objects, incorporating more than 20 billion independent measurements.
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