“We have to be thoughtful about how we interpret our data as our lensing signal comes from the relatively rare coincidence of a supermassive black hole radiating huge amounts of energy and a massive foreground galaxy,” she said.
“Dark matter potentially explains everything, but we don’t have a dark matter particle hitting a detector, and there will always be a question mark in our minds until we have confirmation like that,” Nierenberg said. “The detection of the existence of structures made entirely of dark matter from their effects on gravitational lenses would potentially be the smoking gun we are looking for.”
Loebman’s $60,000 NASA grant allows her to analyze data from the HST to help her learn more about the clusters where stars are born.
Grants for time with the space telescopes is highly competitive — people from all over the world apply, and only about one in 10 of them succeed, which makes these two grants a point of pride for the Department of Physics at UC Merced. While Nierenberg will use her time for direct observations, Loebman’s work is computational and complementary to such observations.
“I hope this is going to be a legacy dark-matter project,” she said. Besides the observational time, the grant provides her with resources to analyze the data and support a postdoctoral researcher and a graduate student to help her do the work.
What she’s ultimately looking for is proof of completely “dark matter halos,” and if she can find that, she’d have definitive proof of dark matter, she said.
“We think most stars form in these open clusters and spread out over time,” Loebman said. “There is evidence that our sun formed in this sort of environment and could have solar siblings.”
There are many star clusters throughout the galaxy and in the nearby universe, but pictures only capture single moments in time. Through simulations, Loebman and her students can track star clusters over time and “turn on” different kinds of physics, such as magneto hydrodynamics, to impose different conditions.
“Our simulations help us see how time and environment affects where the clusters form and how this in turn shapes galaxies as they evolve,” she explained. “We have some good interpretations of current pictures, but simulations can show where the clusters form and how that is impacted by the varying conditions in the simulations.” With the $500,000 grant from the NSF, Loebman and her lab will work on detecting where spiral structures are forming in the nearby universe and try to gain more understanding of how spiral structures and star clusters affect each other.
“I’m really excited about this because we’ll have graduate and undergraduate students working with us through a collaboration with Bryn Mawr College, a women’s college,” she said. “The students will help us make pictures of these star clusters.” Both she and Nierenberg are interested in the building blocks, content and evolution of galaxies. The work she and the students will do helps set her lab up to track star clusters forward in time as they mix into galactic disks.
“I think this is the beginning of some great work at UC Merced,” Loebman said.