Measurements of metal abundances in galaxies present a conundrum: compared to expectations, there are not nearly enough metals observed within galaxies. New observations of a nearby dwarf galaxy may help us understand where this enriched material went. Continue Reading
Measurements of metal abundances in galaxies present a conundrum: compared to expectations, there are not nearly enough metals observed within galaxies. New observations of a nearby dwarf galaxy may help us understand where this enriched material went.BENEFACTORS can be too generous. Exploding stars in a small galaxy called Leo P pumped out heavy elements with such vigour that most of them sailed off into space.
“It’s tough being a little galaxy,” says Kristen McQuinn at the University of Texas at Austin. Not only does a dwarf galaxy’s feeble gravity fail to retain debris from supernovae that explode within it, but giant galaxies such as the Milky Way can also raid the dwarf of stars and gas. Continue Reading
Using one of the world’s premier telescopes, University of Minnesota astrophysicists Evan Skillman and Kristen McQuinn have discovered a priceless relic of the Big Bang in the Milky Way’s back yard. They are part of an international team that found Leo P, a tiny galaxy in the constellation Leo that contains relatively few stars, but has large clouds of hydrogen and helium. The ratio of elements in those clouds is of great interest because it is believed to mirror conditions in the first few minutes after the Big Bang. Continue Reading
Tiny, faint Leo P may point to additional galaxies hidden in our corner of the cosmos.
In recent years astronomers have extended their view almost to the very edge of the observable universe. With the venerable Hubble Space Telescope researchers have spotted a handful of galaxies so faraway that we see them as they appeared just 400 million years or so after the Big Bang.
But even as astronomers peer ever deeper into the Universe to explore the cosmic frontier, others are finding new realms to explore in our own backyard. Such is the case with Leo P, a dwarf galaxy that astronomers have just discovered in the Milky Way’s vicinity. At a distance of some five million or six million light-years from the Milky Way, Leo P is not quite a next-door neighbor, but on the vast scales of the Universe it counts as a neighbor nonetheless. Continue Reading
Starbursts in Dwarf Galaxies are a Global Affair
2009 Hubble Space Telescope News Center
Bursts of star making in a galaxy have been compared to a Fourth of July fireworks display: They occur at a fast and furious pace, lighting up a region for a short time before winking out. But these fleeting starbursts are only pieces of the story, astronomers say. An analysis of archival images of small, or dwarf, galaxies taken by NASA's Hubble Space Telescope suggests that starbursts, intense regions of star formation, sweep across the whole galaxy and last 100 times longer than astronomers thought. The longer duration may affect how dwarf galaxies change over time, and therefore may shed light on galaxy evolution. Continue Reading
Astronomy: Twinkle, Twinkle, Lots of Stars
2009 Nature 458, 810 Research Highlights
Starbursts, periods of intense star formation in galaxies, have long been thought to be short and frenetic, lasting just several million years or so. But it turns out those episodes were just isolated 'flickers', say Kristen McQuinn of the University of Minnesota in Minneapolis and her colleagues, who measured starbursts in three nearby dwarf galaxies.
They found the flickers to be interconnected parts of longer starbursts, spread out across each galaxy, and sustained for 200 million - 400 million years. These larger, longer starbursts could be responsible for galactic superwinds, which are suspected of being responsible for carrying chemically enriched compounds into intergalactic space.
Long Voyage to the Stars: The Unlikely Odyssey of Kristen McQuinn
2009 University of Minnesota
Astronomy graduate students are an intrepid bunch. They must have a good command of math and physics in order to master the science, and lord knows they pull a lot of all-nighters. From the word go, they are steeped in a graduate school culture that demands utter devotion to study and research.
Kristen McQuinn knew that as she faced the University of Minnesota’s director of graduate studies (DGS) in astronomy. Since college she had spent 12 years out of academia, she had two kids in diapers, and she was asking to be admitted to doctoral study–heresy of heresies–part time. Continue Reading