Galaxies are often found grouped into clusters, which contain many ‘red and dead’ members that stopped forming stars in the distant past. Now astronomers have found that when galaxy clusters collide, the resulting shockwave can “wake up” these dormant galaxies and drive a new generation of star formation.
The international team that made the discovery is led by Andra Stroe of Leiden Observatory in the Netherlands and David Sobral of Leiden and the University of Lisbon, Portugal, and researchers Will Dawson and James Jee from UC Davis and the Lawrence Livermore National Laboratory, and David Wittman, associate professor of physics at UC Davis. The work is published April 24 in two papers in the journal Monthly Notices of the Royal Astronomical Society.
Full post: Cosmic collisions wake up snoozing galaxies
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A new map of the heavens took a big step forward last week as scientists and dignitaries, including Chilean President Michelle Bachelet, laid the first stone for the Large Synoptic Survey Telescope on the 8900-foot summit of Cerro Pachón in northern Chile.
Michelle Bachelet, President of Chile, speaking at the first stone ceremony for the LSST. NSF photo
Among those present was UC Davis physicist J. Anthony (Tony) Tyson, who originally conceived the LSST system (which includes a giant camera, novel telescope design and supercomputer) and lead the project from the 1990s to 2013. He now serves as Chief Scientist for the telescope.
Astronomers using NASA’s Hubble Space Telescope have for the first time spotted four images of the same distant exploding star, arranged in an “Einstein’s Cross,” a cross-shape pattern created by the powerful gravity of a foreground galaxy embedded in a massive cluster of galaxies.
Distant supernova split into four images by massive galaxy cluster in the four ground. Because light is taking different paths through the cluster, other images of the supernova may appear later.
First predicted by Albert Einstein, gravitational lensing is similar to a glass lens bending light to magnify and distort the image of an object behind it.
By Kat Kerlin
Recreating the violent conditions of Earth’s formation, scientists are learning more about how iron vaporizes and how this iron rain affected the formation of the Earth and Moon. The study is published March 2 in Nature Geoscience.
“We care about when iron vaporizes because it is critical to learning how Earth’s core grew,” said co-author Sarah Stewart, UC Davis professor of Earth and Planetary Sciences.
Shock and release
By Kat Kerlin
Researchers digging deeper into the origins of the Sutter’s Mill meteorite, which exploded over California’s Gold Country in 2012, have found diamonds and other “treasures” that provide important new insight into the early days of our solar system. They report their results in 13 papers in the November issue of Meteoritics & Planetary Science.
UC Davis scientists Akane Yamakawa and Qing-Zhu Yin in the Department of Earth and Planetary Sciences studied the different forms of the element chromium, called isotopes. They found that at least five different stellar sources composed of mixtures of 54-chromium-rich and -poor materials must have contributed matter to the nascent solar system four and half billion years ago. Some of these materials remained in the Sutter’s Mill meteorite.
About one-fifth of the Earth’s atmosphere is oxygen, pumped out by green plants as a result of photosynthesis and used by most living things on the planet to keep our metabolisms running. But before the first photosynthesizing organisms appeared about 2.4 billion years ago, the atmosphere likely contained mostly carbon dioxide, as is the case today on Mars and Venus.
Over the past 40 years, researchers have thought that there must have been a small amount of oxygen in the early atmosphere. Where did this abiotic (“non-life”) oxygen come from? Oxygen reacts quite aggressively with other compounds, so it would not persist for long without some continuous source.
Full post: Making oxygen before life
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Earlier this year, physicists celebrated results from the BICEP2 experiment which reported evidence of gravitational waves, a signature of cosmic inflation immediately after the Big Bang.
But earlier this week, results from the Planck space telescope cast doubt on the BICEP2 findings. Instead of showing gravitational waves at the beginning of time, BICEP2 might actually have picked up interstellar dust within our own galaxy.
As we blogged last week, the EXES (Echelon-Cross-Echelle Spectrograph) instrument, a collaboration involving UC Davis and NASA Ames scientists and engineers and led by research scientist Matthew J. Richter of the UC Davis Physics Department, successfully carried out its first two flights with the Stratospheric Observatory for Infrared Astronomy (SOFIA) on the nights of April 7 and 9.
The SOFIA flying lab will make its second flight with the EXES experiment on board tonight. The EXES (Echelon-Cross-Echelle-Spectrograph) project is lead by UC Davis phyicist Matt Richter.
The flight plan should have SOFIA, which operates out of Palmdale, Calif., taking off about 7 p.m. Pacific Time and flying over the Sacramento area before heading out over the ocean west of Oregon and Washington for a series of observing legs.
Richter and his team will be aboard and expect to get in about eight hours of observations during the 10-hour flight.
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NASA’s Hubble Space Telescope has weighed the largest known galaxy cluster in the distant universe and found that it definitely lives up to its nickname: El Gordo, Spanish for “the fat one.”
By precisely measuring how much the gravity from the cluster’s mass warps images of far more distant background galaxies, a team of astronomers lead by James Jee of the UC Davis physics department has calculated the cluster’s mass to be as much as 3 million billion times the mass of our Sun. The Hubble data show that the cluster is roughly 43 percent more massive than earlier estimates based on X-ray and dynamical studies of the unusual cluster.