TUSCALOOSA, Ala. — A project led by an astronomer at The University of Alabama that includes amateur astronomers will use gaps in the schedule of the Hubble Space Telescope to get a better look at oddities found in the sky.
Dr. William C. Keel, UA professor of physics and astronomy, led an effort to use Hubble to investigate unusual objects found by volunteer astronomers in a crowd-sourced astronomy project, Galaxy Zoo, and its companion Radio Galaxy Zoo.
The Space Telescope Science Institute, or STScI, which conducts Hubble science operations, started the Enhanced HST Schedule Gap Program to fill in small breaks of less than 25 minutes between focusing the telescope on larger projects, but Keel said many will likely be closer to 12-15 minutes.
STScI called for proposals for objects Hubble could quickly view without changing the telescope’s current settings. Hubble takes about 94 minutes to orbit the Earth, and it can capture an image for about 50 minutes of that time. Some observations use more than one orbit, and some smaller projects use about half an hour for an observation.
Keel has long been involved with Galaxy Zoo and its offshoots, such as Radio Galaxy Zoo, to investigate oddities found by the volunteer astronomers. He assembled a team that includes scientists from other institutions and volunteers from three continents and proposed a list of more than 1,100 objects where Hubble exposure could give a better picture.
STScI informed Keel earlier this month that the proposal was selected for the gap program, but he needed to whittle the list to no more than 300 objects.
“This lets us potentially address a range of studies that happen very rarely to galaxies,” Keel said. “The volunteers, after filtering through a million galaxy images, have found a handful where there are weird things. We need the Hubble data to confirm this is happening. Each one of them might not be enough for an individual study, but when you put them all together it adds up to an interesting study.”
Galaxy Zoo began in 2007 enlisting the public to help classify more than a million galaxies catalogued in the Sloan Digital Sky Survey, but it has since expanded to other data sets. Along the way, people have found objects not easily classified, prompting professional astronomers, sometimes in partnership with Galaxy Zoo participants, to investigate further with different techniques, such as Hubble.
For this project, which Keel calls Gems of the Galaxy Zoos, objects includes oddities and rarities that could help in understanding how the universe formed and interacts with itself, such as extreme starbursts called green pea galaxies, spiral arms of a galaxy and backlit dust structures, among other objects.
One example is an image of a merging pair of galaxies, catalogued as UGC 4052. It appears from ground-based telescopes to be forming a new disk of stars and gas around the remnant cores of both galaxies, which are normally violent events that make motions too chaotic for such a disk. If this happens often, it changes the understanding of the history of galaxies, Keel said.
Hubble data would clear the image to see if something in the background is playing tricks on the image, he said.
“What we study depends on what mix of galaxies Hubble is able to view,” Keel said. “Whenever a 20-minute schedule gap comes up, the software will go to the list to see what is closest.”
Hubble’s operators will schedule the objects in the gaps over the next few years, and the images will be publicly available as soon as they are captured. However, Keel and the science team will be notified when one of their images is viewed, allowing for further research.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy Inc., in Washington, D.C.
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