Dancing Galaxies: how to make new stars, feed massive black holes, and send out very fast electrons
When galaxies collide they take a couple of billion years to do so. Our Milky Way and Andromeda will merge in the distant future. If you had a few billion years to spare and stare at the night sky you would observe a slow and gracious dance. Stars, gas, dust, and dark matter of the two galaxies affected at first mostly by the gravity of their own galaxies, will change their orbits and structures as they become more affected by the gravity of two, now merging galaxies.
The changing gravitational potential pulls and compresses some of the cold gas which then clump quicker into dense disks that precede the formation of new stars. The new stars then transform their surroundings with impressive outputs of light, energetic particles, metals, and even tiny dust grains. While some gas will fuel star-formation, other gas will be forced to slow down its rotation, and swirl down into the central super-massive black hole.
In this presentation we will look at how this scenario was put together based on multi-wavelength, multi-epoch, multi-facilities observations of gravitationally interacting galaxies. We will also discuss some of the remaining burning questions about merging galaxies that keep extragalactic-astronomers glued to their data.
Presenter Bio - A. Petric immigrated from Romania to New York City at 14, graduated high-school at 16 with the misplaced hope that in college she will figure out how to extract energy from black-holes and also get a job at the United Nations to bring peace and equality for all. While those goals were not very well informed or feasible, Petric got her PhD in Astrophysics from Columbia University in 2008 studying cosmological dust: how it’s made, how we can find it between galaxies, and how it was not confusing our estimates of dark energy. After Columbia University, Petric went to the California Institute of Technology to study nearby, gravitationally interacting galaxies and identify which of them were harboring growing super-massive black holes at their cores. In 2013 Petric moved to Hawaii first as a Gemini Science Fellow and then as the UH resident astronomer at CFHT. Her current research focuses on how growing super-massive black holes affect the ability of their host galaxies to make new stars. She also has the privilege to teach undergraduate students at the University of Hawaii, Hilo and graduate students at University of Hawaii, Manoa. She also mentored several fantastic students in the last few years, several of whom have gone on to graduate school, and/or are now employed in Astronomy. In her spare time she volunteers for class-room visits, collaborates with local artists to come up with art-astronomy educational activities for kids and adults, works with the Big Island Giving Tree, tries hard not to be the last one in local swim races, and tries even harder to work with organizations that want to bring peace and equality for all.