Dark galactic region nicknamed ‘the brick’ explained with Webb’s discoveries

In a study led by University of Florida astronomer Adam Ginsburg, groundbreaking discoveries have shed light on a mysterious dark region at the center of the Milky Way. The turbulent gas cloud, playfully nicknamed “the brick” because of its opacity, has sparked heated debate within the scientific community for years.

To decipher its secrets, Ginsburg and her research team, including UF graduate students Desmond Jeff, Savannah Gramze and Alyssa Bulatek, turned to the James Webb Space Telescope (JWST). The implications of their observations, published in The Astrophysics Journal, are monumental. The results not only reveal a paradox at the center of our galaxy, but also indicate a critical need to reevaluate established theories regarding star formation.

The Brick is one of the most intriguing and widely studied regions of our galaxies, thanks to its surprisingly low rate of star formation. For decades, it has defied scientists’ expectations: as a cloud filled with dense gas, it should be ripe for the birth of new stars. However, this demonstrates a surprisingly low rate of star formation.

Using JWST’s advanced infrared capabilities, the research team peered into the brick and discovered a substantial presence of frozen carbon monoxide (CO). It harbors significantly more CO ice than previously thought, which has profound implications for our understanding of star formation processes.

No one knew how much ice there was in the Galactic Center, according to Ginsburg. “Our observations convincingly demonstrate that ice is very widespread there, to the point that every future observation will have to take this into account,” he said.

Stars generally emerge when the gases are cold, and the significant presence of CO ice should suggest a thriving area for star formation in the brick. Yet despite this CO richness, Ginsburg and the research team found that the structure exceeded expectations. The gas inside the brick is hotter than comparable clouds.

These observations challenge our understanding of CO abundance at the center of our galaxy and the critical gas/dust ratio there. According to the results, both measures appear lower than previously thought.

“With JWST, we are opening new avenues for measuring molecules in the solid (ice) phase, where previously we were limited to studying gas,” Ginsburg said. “This new view gives us a more complete picture of where molecules exist and how they are transported.”

Traditionally, CO observation is limited to gas emissions. To reveal the distribution of CO ice within this vast cloud, the researchers needed intense backlight from stars and hot gas. Their results go beyond the limits of previous measurements, which were limited to around a hundred stars. The new results encompass more than ten thousand stars, providing valuable information on the nature of interstellar ice.

Since the molecules present in our solar system today were likely, at one time, ice on small dust grains that combined to form planets and comets, this discovery also marks a step forward towards understanding the origins of the molecules that shape our cosmic environment.

These are just the team’s first findings from a small fraction of their JWST observations of Brick. Looking ahead, Ginsburg aims for more in-depth study of celestial ices.

“We do not know, for example, the relative quantities of CO, water, CO₂and complex molecules,” Ginsburg said. “With spectroscopy, we can measure them and get a sense of how the chemistry progresses over time in these clouds.”

With the advent of JWST and its advanced filters, Ginsburg and her colleagues are presented with the most promising opportunity yet to expand our cosmic exploration.