From her perch in the student center at MIT, Dominika Ďurovčíková often finds herself dreaming about the cosmos. Surrounded by the bustle of Massachusetts Avenue, she wishes for just one hour when city lights could be turned off, apart from critical services like hospitals. “Let people gaze at the Milky Way or the stars. Experiencing such a sight can profoundly influence your perspective,” she muses. Even after years of studying the universe as a PhD candidate under the guidance of professors Anna-Christina Eilers and Robert Simcoe at MIT’s Kavli Institute for Astrophysics and Space Research, she still values the simple act of looking up at the night sky.
For Ďurovčíková, exploration often involves advanced technology and groundbreaking instruments. The James Webb Space Telescope (JWST) provides invaluable data from celestial bodies at the fringes of the observable universe, where she concentrates her research efforts. Leveraging data from JWST alongside information from the Magellan telescopes in Chile, she’s on a quest to identify distant quasars—ancient supermassive black holes that emit enormous amounts of light. The more remote these quasars are, the richer the information they yield about the early universe.
“These luminous objects act as beacons from the past, revealing insights about the universe at significant stages of its evolution,” she explains. “It’s almost like engaging in cosmic archaeology.”
Her research delves into a significant period—the Epoch of Reionization. This era marks the moment when radiation from quasars, stars, and galaxies broke through the dark hydrogen clouds leftover from the Big Bang, allowing light to permeate space. “During reionization, the substance surrounding galaxies underwent a phase transition, becoming transparent for the first time, which let us witness light previously absorbed by neutral hydrogen,” she notes.
One of her ambitious goals is to uncover the triggers behind the reionization process. Although the astrophysical community has established a rough timeline for when this occurred, numerous questions linger, and Ďurovčíková hopes her quasar investigations can provide clarity. “Understanding the timing of reionization could potentially reveal the sources that initiated it,” she explains. “We’re not there yet, but exploring quasars might illuminate the path forward.”
Exploring Cosmic Time and Distance
The quasars captivating Ďurovčíková’s interest are categorized as high-redshift—a term that describes the extent to which a light wave’s frequency has diminished. In the realm of astrophysics, redshift serves as a crucial tool for determining both the age and distance of light waves, in light of the universe’s expansion. “A higher redshift means we’re observing light closer to the universe’s beginnings,” she elaborates.
Research indicates that reionization initiated approximately 150 million years post-Big Bang, with full ionization of the intergalactic medium around 850 million years later. In her latest paper, Ďurovčíková analyzed a group of 18 quasars whose light began its journey from around 770 million to 950 million years after the Big Bang. Collaborating with scientists across four nations, they categorized the quasars into three distance-based “bins” to compare the levels of neutral hydrogen in the intergalactic medium during various epochs. This study helped refine the reionization timeline while confirming compatibility between quasar data and other celestial bodies.
“As of now, we understand that by redshift 5 or 6, the substance between galaxies was generally ionized, but it remains unclear which stars or galaxies primarily instigated this universal transition,” she shares.
A related aspect of her research—which she plans to delve deeper into while crafting her thesis—examines the origins of these quasars. Their substantial mass and age pose challenges to existing theories about the universe’s chronology. The light they emit arises from the prodigious gravitational forces acting on the plasma they absorb. If these quasars were massive enough to produce such light billions of years ago, when precisely did they begin to form? “These black holes appear too massive to have grown within the timeframe their spectra suggest,” she states. “Is there something obscuring our understanding of their growth? We’re exploring various methods to estimate their lifespans.”
Inspiring Future Astrophysicists
While pursuing her research, Ďurovčíková is equally passionate about inspiring future generations of astrophysicists. Fortunate to have had supportive parents and mentors who unveiled academic possibilities she hadn’t previously envisioned, she co-founded a nonprofit called Encouraging Women Across All Borders to guide students worldwide.
“In life, you’ll encounter various doors,” she reflects. “Some will be open to you while others remain shut. The real tragedy lies in the countless doors you’re unaware of.”
She understands this sentiment well; growing up in Slovakia, her educational options largely revolved around universities in Bratislava or neighboring Prague. Her affinity for math and physics led her to enroll in the International Baccalaureate program, where she met a teacher named Eva Žitná, who sparked ideas that ultimately guided her to Oxford for a master’s program.
“Participating in the IB program opened doors to opportunities I previously never considered,” she recalls. “It marked the beginning of an exciting journey.”
Guiding others along a similar path brings her great joy, but witnessing moments of realization about the vast universe is particularly fulfilling. Serving as co-director of MIT Astrogazers, she remembers hand out eclipse glasses at the Cambridge Science Festival before last October’s partial solar eclipse. Many people, young and old alike, looked upward with awe-filled expressions, sharing a moment of wonder.
“We often lose sight of life’s bigger picture,” she observes. “Everyday inconveniences—like traffic jams or transit delays—can easily consume our thoughts. Yet, when you gaze at the sky, you’re reminded of the incredible beauty and enormity of the universe around us.”
Photo credit & article inspired by: Massachusetts Institute of Technology
