UAH researcher wins $750K EPSCoR grant to support STROBE-X explorations of gravitational wave sources, black holes and dark matter

HUNTSVILLE, Ala. (AUG. 5, 2024) – Dr. Sukanya Chakrabarti at The University of Alabama in Huntsville (UAH) has won a $750,000 Established Program to Stimulate Competitive Research (EPSCoR) award to support STROBE-X, a planned $1 billion probe-class NASA observatory that aims to unlock the secrets of some of the most extreme conditions in the universe. The researcher will be collaborating with an international team of scientists, including researchers at NASA's Marshall Space Flight Center (MSFC) in Huntsville, AL. Chakrabarti, the Pei-Ling Chan Endowed Chair in the College of Science at UAH, a part of the University of Alabama (UA) System, will head the effort to carry out a series of tests to assess the functionality and performance of the observatory's large area silicon drift detectors (SDDs).

Designed for X-ray timing and spectroscopy, the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays, or STROBE-X, is equipped with a huge collecting area to survey the X-ray sky. The mission is motivated by the high-priority goals of the Decadal Survey on Astronomy and Astrophysics (Astro2020). The goals of the initiative are widespread and potentially groundbreaking, such as better understanding of the precursors of gravitational wave sources, providing precise measurements of the spin of black holes and illuminating the nature of dark matter.

"It's hard to overstate the importance of this project and its potential impact on astronomy," Chakrabarti says. "STROBE-X is the planned next-generation time-domain X-ray facility. UAH and the Marshall Space Flight Center have long had an important role in supporting X-ray facilities. The detectors we will be testing are of broad relevance for aerospace-related research and will support a wide range of missions, from probe-class missions to CubeSats."

One way to study extreme phenomena is through X-ray timing, in which astronomers monitor and record changes in an object's X-ray emissions with a specially equipped telescope using solid-state silicon detectors that capture precise measurements of high-energy X-rays. The observatory's capabilities will significantly extend the reach of X-ray observations in the time-domain, a branch of astronomy that studies how astronomical objects change with time, especially variable objects beyond the Solar System.

"STROBE-X observations will increase our capability in X-ray timing, and will be transformative in helping us understand strong-field gravity, the gravitational field close to black holes," Chakrabarti notes. "These observations also have the potential to constrain the nature of dark matter. Much of my recent work focuses on characterizing dark matter and the gravitational potential from direct acceleration measurements. Some of my earlier work was on understanding how the very massive LIGO/Virgo black holes formed, and STROBE-X observations should give us a better picture of this."

The project is closely aligned not only with NASA MSFC, but also work being performed by teams at the United States Naval Research Laboratory and NASA's Goddard Space Flight Center.

"We will work closely with our collaborators at these institutions in testing the functionality of the SDDs," Chakrabarti says. "My co-investigator, Peter Jenke at UAH, has also done extensive work on X-ray detector hardware. My research group is keen to understand the formation of intermediate mass black holes – black holes that are more massive than stellar mass black holes and less massive than supermassive black holes – and this is another area where STROBE-X observations can be significant. We recently discovered the first stellar mass black hole from analysis of Gaia data, and STROBE-X observations of accreting stellar mass black holes will be complementary to what we can learn about black holes on wide orbits that do not interact with their companion

In addition, this program will benefit underserved students throughout the state of Alabama. The program includes a pilot STEM outreach teaming arrangement with the UAH Alabama Space Grant Consortium (ASGC). "We will work with Dr. Kathryn Williamson and the ASGC to target underserved students in the state. Our Science/Space Public Outreach Team (SPOT) workshops will be led by undergraduate and graduate students, and at UAH we will mentor minority students from the Alabama Louis Stokes Alliance for Minority Participation program (ALSAMP)," Chakrabarti says.

"We are aiming to create a collaborative bridge across North Alabama and will work with colleagues at Alabama A&M University in Huntsville and UA in Tuscaloosa to mentor under-represented students in research projects," the researcher says. "Our outreach is particularly unique."