News and Events
Image: The slumbering giant galaxy at the center of this image is 10 billion light-years away.
Credit: ESA/Hubble & NASA, A. Newman, M. Akhshik, K. Whitaker
For more info, see: Running on Empty: Research by UMass Amherst Astronomers Solves the 12-Billion-Year-Old Mystery of Stalled Galaxies
“The most massive galaxies in our universe formed incredibly early, just after the Big Bang happened, 14 billion years ago,” says Kate Whitaker, professor of astronomy at UMass Amherst. “But for some reason, they have shut down. They’re no longer forming new stars.” Star formation is one of the key ways that galaxies grow, and they’re said to have gone quiescent when they cease forming stars. Astronomers have known that these early, massive galaxies had gone quiescent, but until now, no one knew why.
To find the answer, Whitaker’s team, which includes Alexandra Pope, professor of astronomy, and Christina C. Williams, who received her Ph.D. in astronomy at UMass, devised an innovative pairing of telescopes. They used the Hubble Space Telescope, which sees ultraviolet to near-infrared light, including the light we can see with our own eyes, to detect these distant galaxies, which are so far away that we’re only just now seeing the light they emitted 10 billion to 12 billion years ago, when the universe was in its infancy. In effect, Whitaker’s team is looking into the deep past.
See also:
"Astronomers mark the change of seasons as the moment when the sun crosses over the celestial equator from the northern hemisphere of the sky to the southern hemisphere. This year the exact minute of the autumnal equinox is 3:21 p.m. Eastern Daylight Time on Sept. 22. At that moment, fall begins in the Northern Hemisphere and spring in the Southern. On the day of the equinox, an observer located on Earth’s equator will see the sun pass directly overhead at local noon. It also marks the beginning of six months of daylight at the South Pole and six months of nighttime at the North Pole."
View A Time-Lapse Video of the Equinox Here: http://videos.umass.edu/invideo/detail/videos/umass-in-video/video/55894...
The Thesis Defense will be held Wednesday, August 25, 2021 3:00pm via Zoom.
Abstract:
The propagation and evolution of cold galactic winds in galactic haloes is crucial to galaxy formation models. However, modeling of this process in hydrodynamic simulations of galaxy formation is over-simplified owing to a lack of numerical resolution and often neglects critical physical processes such as hydrodynamic instabilities and thermal conduction. In this thesis, I propose an analytic model, Physically Evolved Winds (PhEW), that calculates the evolution of individual clouds moving supersonically through a uniform ambient medium. The model reproduces predictions from very high resolution cloud-crushing simulations that include isotropic thermal conduction over a wide range of physical conditions. I also describe the implementation of this model into cosmological hydrodynamic simulations of galaxy formation as a sub-grid prescription to model galactic winds more robustly both physically and numerically.
It is with immense pleasure that we announce Dr. Alexandra Pope's promotion to Full Professor. Congratulations Prof. Pope!
New research discloses details of violent phenomena in the center of our galaxy.
The Center for Teaching and Learning (CTL) announces the selection of the 2021-22 Lilly Fellows for Teaching Excellence.
Sinclaire's research focuses on studying the enigmatic population of dusty star-forming galaxies in the early Universe.
"The Goldwater Scholarship Program, one of the oldest and most prestigious national scholarships in the natural sciences, engineering,and mathematics in the United States, seeks to identify and support college sophomores and juniorswho show exceptional promise of becoming this Nation’s next generation of research leaders in these fields."
