Photo of orbits of the G objects at the center of our galaxy

Astronomers discover class of strange objects near our galaxy’s enormous black hole

Photo of orbits of the G objects at the center of our galaxy

Orbits of the G objects at the center of our galaxy, with the supermassive black hole indicated with a white cross. Stars, gas and dust are in the background. Photo: Anna Ciurlo, Tuan Do/UCLA Galactic Center Group

Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered a new class of bizarre objects at the center of our galaxy, not far from the supermassive black hole called Sagittarius A*. They published their research in the Jan. 16 issue of the journal Nature.

“These objects look like gas and behave like stars,” said co-author Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and director of the UCLA Galactic Center Group.

The new objects look compact most of the time and stretch out when their orbits bring them closest to the black hole. Their orbits range from about 100 to 1,000 years, said lead author Anna Ciurlo, a UCLA postdoctoral researcher.

Ghez’s research group identified an unusual object at the center of our galaxy in 2005, which was later named G1. In 2012, astronomers in Germany made a puzzling discovery of a bizarre object named G2 in the center of the Milky Way that made a close approach to the supermassive black hole in 2014. Ghez and her research team believe that G2 is most likely two stars that had been orbiting the black hole in tandem and merged into an extremely large star, cloaked in unusually thick gas and dust.

“At the time of closest approach, G2 had a really strange signature,” Ghez said. “We had seen it before, but it didn’t look too peculiar until it got close to the black hole and became elongated, and much of its gas was torn apart. It went from being a pretty innocuous object when it was far from the black hole to one that was really stretched out and distorted at its closest approach and lost its outer shell, and now it’s getting more compact again.”

“One of the things that has gotten everyone excited about the G objects is that the stuff that gets pulled off of them by tidal forces as they sweep by the central black hole must inevitably fall into the black hole,” said co-author Mark Morris, UCLA professor of physics and astronomy. “When that happens, it might be able to produce an impressive fireworks show since the material eaten by the black hole will heat up and emit copious radiation before it disappears across the event horizon.”

But are G2 and G1 outliers, or are they part of a larger class of objects? In answer to that question, Ghez’s research group reports the existence of four more objects they are calling G3, G4, G5 and G6. The researchers have determined each of their orbits. While G1 and G2 have similar orbits, the four new objects have very different orbits.

Ghez believes all six objects were binary stars — a system of two stars orbiting each other — that merged because of the strong gravitational force of the supermassive black hole. The merging of two stars takes more than 1 million years to complete, Ghez said.

“Mergers of stars may be happening in the universe more often than we thought, and likely are quite common,” Ghez said. “Black holes may be driving binary stars to merge. It’s possible that many of the stars we’ve been watching and not understanding may be the end product of mergers that are calm now. We are learning how galaxies and black holes evolve. The way binary stars interact with each other and with the black hole is very different from how single stars interact with other single stars and with the black hole.”

Ciurlo noted that while the gas from G2’s outer shell got stretched dramatically, its dust inside the gas did not get stretched much. “Something must have kept it compact and enabled it to survive its encounter with the black hole,” Ciurlo said. “This is evidence for a stellar object inside G2.”

“The unique dataset that Professor Ghez’s group has gathered during more than 20 years is what allowed us to make this discovery,” Ciurlo said. “We now have a population of ‘G’ objects, so it is not a matter of explaining a ‘one-time event’ like G2.”

The researchers made observations from the W.M. Keck Observatory in Hawaii and used a powerful technology that Ghez helped pioneer, called adaptive optics, which corrects the distorting effects of the Earth’s atmosphere in real time. They conducted a new analysis of 13 years of their UCLA Galactic Center Orbits Initiative data.

In September 2019, Ghez’s team reported that the black hole is getting hungrier and it is unclear why. The stretching of G2 in 2014 appeared to pull off gas that may recently have been swallowed by the black hole, said co-author Tuan Do, a UCLA research scientist and deputy director of the Galactic Center Group. The mergers of stars could feed the black hole.

The team has already identified a few other candidates that may be part of this new class of objects, and are continuing to analyze them.

Ghez noted the center of the Milky Way galaxy is an extreme environment, unlike our less hectic corner of the universe.

“The Earth is in the suburbs compared to the center of the galaxy, which is some 26,000 light-years away,” Ghez said. “The center of our galaxy has a density of stars 1 billion times higher than our part of the galaxy. The gravitational pull is so much stronger. The magnetic fields are more extreme. The center of the galaxy is where extreme astrophysics occurs — the X-sports of astrophysics.”

Ghez said this research will help to teach us what is happening in the majority of galaxies.

Other co-authors include Randall Campbell, an astronomer with the W.M. Keck Observatory in Hawaii; Aurelien Hees, a former UCLA postdoctoral scholar, now a researcher at the Paris Observatory in France; and Smadar Naoz, a UCLA assistant professor of physics and astronomy.

The research is funded by the National Science Foundation, W.M. Keck Foundation and Keck Visiting Scholars Program, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, Lauren Leichtman and Arthur Levine, Jim and Lori Keir, and Howard and Astrid Preston.

In July 2019, Ghez’s research team reported on the most comprehensive test of Einstein’s iconic general theory of relativity near the black hole. They concluded that Einstein’s theory passed the test and is correct, at least for now.

► Watch a four-minute film about Ghez’s research

►View an animation below of the orbits of the G objects, together with the orbits of stars near the supermassive black hole. Credit: Advanced Visualization Lab, National Center for Supercomputing Applications, University of Illinois

This article originally appeared in the UCLA Newsroom.

Photo of group of volunteers at first mobile health clinic.

Student launches mobile health clinic to increase access to care

Photo of group of volunteers at first mobile health clinic.

Ahmad Elhaija, center, with International Collegiate Health Initiative medical staff, volunteers and student team members at the organization’s first mobile health clinic. Photo: Reed Hutchinson/UCLA

On a sunny autumn Saturday at the Southeast-Rio Vista YMCA in the city of Maywood, kids colored drawings and played Jenga while their parents and other family members underwent basic health screenings conducted by volunteer nurses.

After their bloodwork and other tests were done, the people met with doctors from medical centers in southeast Los Angeles County to discuss their results. Aided by Spanish-language translators, the doctors also gave advice about everything from medications to old injuries — anything the patients wanted to know.

The free event, attended by about 40 community members plus their children, was the first mobile community health clinic hosted by the International Collegiate Health Initiative. Founded two years ago by UCLA junior psychobiology major Ahmad Elhaija, the initiative aims to increase access to affordable, high-quality medical care in low-income and refugee communities in Los Angeles through mobile community health clinics and social advocacy.

“I thought, what can we do here that’ll make a big impact, where we can affect the statistics of a community, their health outcomes?” he said.

Elhaija drew inspiration for the project from two aspects of his youth in Anaheim — growing up frequently sick without consistent health insurance and his volunteer work assisting Arab and Muslim refugees.

Given the need for this kind of service, Elhaija applied for the annual Donald A. Strauss Foundation scholarship to help implement his vision. Each year, the Strauss Foundation awards 10 to 15 students from across 14 California colleges a $15,000 scholarship which is divided between the student’s educational costs and a grant for the public service project they propose in their application.

Elhaija was the only UCLA student to win the $15,000 scholarship in 2019. In 2018, two UCLA students won the Strauss scholarship; their projects helped transfer students prepare for doctoral programs, and provided therapy and support for K-12 students who stutter.

Photo of Ahmad Elhaija

Ahmad Elhaija Photo: Reed Hutchinson/UCLA

As part of the scholarship, Elhaija was assigned a mentor to advise him on his project. Elhaija’s mentor, Marc Anthony Branch, is a program officer for sustainable development for the United Methodist Committee on Relief and an expert in grant writing. Elhaija relied on Branch’s knowledge to improve his grant writing skills.

“I set him up with my grant-writing team, and he was really pivotal in actually getting us moving forward,” Elhaija said. “Before him, we didn’t really have much progress in grant writing, so having him on board and him giving his expertise was really cool. He knows what grant-giving organizations are looking for and he has some good contacts in that realm as well.”

Growing up in a low-income neighborhood in Anaheim, Elhaija was frequently sick from asthma and a rare blood disorder called cyclic neutropenia. His family didn’t always have health insurance, and although they worked hard to support and care for him, they were often left with high hospital bills.

While his family’s difficulty navigating his health care opened his eyes to the importance of providing affordable care, as a teenager Elhaija also volunteered at the nonprofit Access California Services, which provides support and resources to Arab and Muslim refugees in Anaheim. He said that volunteering with the organization and seeing the services for refugees that were still lacking inspired him to think of ways he could help.

So when Elhaija got to UCLA in 2017, he formed the International Collegiate Health Initiative with the goal to provide medical care to refugees in countries like Syria and Palestine. Through his volunteer work and visiting his own family in the Middle East, Elhaija learned that college campuses would be the safest places to provide medical services in the region.

However, finances and logistics made it more productive for Elhaija to focus his efforts on refugee and low-income communities closer to home. So he switched the initiative’s focus to offering mobile community health clinics in southeast Los Angeles.

The initiative is managed by a team of 20 students, a board of directors and professional advisers who offer guidance and medical services for the clinics. The clinic in Maywood, held on Nov. 16, was the organization’s first mobile health clinic. Another is planned for the city of Bell in February.

The ICHI’s ultimate goal is to raise enough money for a mobile clinic van, and to expand to other cities in California or even overseas.

“The idea is that we could have our full blown mobile clinic running in the fall of next year, where we can provide basically every type of care that a standard clinic can provide,” Elhaija said.

This article originally appeared in the UCLA Newsroom.