Texas Tech University

Looking for Insights from Our Nearest Star-Forming Galaxy

Doug Hensley

April 28, 2023

A Texas Tech astronomer is leading a team awarded a highly competitive Chandra program to study the stellar remnants in the Large Magellanic Cloud.

Image above: Taken by the Chandra Telescope
Vallia Antoniou
Vallia Antoniou

Vallia Antoniou, an assistant professor of practice in the Department of Physics and Astronomy at Texas Tech, has been awarded observing time on the powerful Chandra X-Ray Telescope to explore some of the deepest recesses of the universe.

It marks the second major Chandra program led by Antoniou, who is also a research associate with the Smithsonian Astrophysical Observatory.

Each year, astronomers from around the world follow a rigorously competitive process to receive Chandra time. The telescope was launched aboard the space shuttle Columbia in 1999 and orbits Earth, offering previously unavailable views of deep space at wavelengths that are not accessible from ground telescopes. During its more than two decades in space, the telescope has revolutionized the field of X-ray astronomy.

“The main idea is to study nearby star-forming galaxies,” Antoniou said. “It gives us an opportunity to study analogs of much more distant galaxies, yet obviously outside our Milky Way galaxy.”

Chandra telescope
Chandra Telescope
Courtesy: Harvard University

The program focuses on the Large Magellanic Cloud, the nearest star-forming galaxy which orbits the Milky Way at approximately 160,000 light-years from Earth.

Antoniou, also the director of the Preston Gott Skyview Observatory about 15 miles north of Lubbock, was awarded one mega-second of Chandra telescope time, which equates to roughly 11.5 days (a mega-second is 1 million seconds). 

Her proposal in the Very Large Program (VLP) category was approved for the specific viewing cycle in late June. Since the VLP category was first introduced in 2017, only seven VLPs have been awarded time from among the 64 proposed. 

Early findings should be available to the public late this summer, she said.

Her research focuses on understanding the formation and evolution of X-ray binaries in different galactic environments. The sheer distances involved can impede this work, making access to powerful telescopes necessary.

Large Magellanic Cloud
Large Magellanic Cloud
Courtesy: ESO/VMC Survey

“Chandra's proposal selection process is highly competitive, and Vallia's research program was the only VLP approved out of nine submitted in Cycle 24,” said Sung-Won Lee, chair of the physics and astronomy department. “This project is an international collaboration of scientists, and I am very pleased that our very own faculty is recognized internationally and will lead this important scientific mission.”

Antoniou said the awarded telescope time should give the team additional insights into the populations of stellar remnants such as pulsars and black holes and their behavior when they consume the stars orbiting them (so-called X-ray binaries).”

The team has selected 10 regions of the Large Magellanic Cloud, focusing on areas of the galaxy that they expect to have high X-ray binary formation rates, which in turn will provide a deeper understanding of the system and stars. The program completes an effort started by Antoniou studying the smaller sibling of the Large Magellanic Cloud, the Small Magellanic Cloud, which was awarded time as a Chandra X-Ray Visionary Program.

“This is another good example that our department is conducting very competitive research internationally,” Lee said.