California Institute of Technology (Caltech) astronomers using data gathered at the W. M. Keck Observatory have developed a new technique for planetary scientists that could provide insight into how many water planets like Earth exist within our universe. The results have been published on February 24th by The Astrophysical Journal Letters.
Simulated data showing the method used for detecting water vapor features detected around the hot Jupiter tau Boo b. Credit: Alexandra Lockwood (CalTech) background image used with permission from David Aguilar (CFA)Scientists have detected water vapor on other planets in the past, but these detections could only take place under very specific circumstances, according to graduate student Alexandra Lockwood, the first author of the study. “When a planet transits, or passes in orbit, in front of its host star, we can use information from this event to detect water vapor and other atmospheric compounds. Alternatively, if the planet is sufficiently far away from its host star, we can also learn about a planet’s atmosphere by imaging it.”
However, a significant portion of the population of extrasolar planets does not fit either of these criteria and there wasn’t really a way to find information about the atmospheres of these planets. Looking to resolve this problem, Lockwood and her advisor Geoffrey Blake—Caltech professor of cosmochemistry, planetary sciences and chemistry—were inspired by the recent detection of carbon monoxide in the extrasolar planet, tau Boo b and they wondered if they could detect water in a similar manner.
Two hungry young galaxies that collided 11 billion years ago are rapidly forming a massive galaxy about 10 times the size of the Milky Way, according to UC Irvine-led research conducted on the W. M. Keck Observatory and other research facilities around the world. The results will be published today in the journal Nature.
The image at right shows a close-up of the colliding galaxies in red and green. The red data show dust-enshrouded regions of star formation. The green data show gas in the merging galaxies. The blue spots are visible-light observations of galaxies located much closer to us. Credit: JPL-Caltech/UC Irvine/Keck Observatory/STScI/NRAO/SAO/ESA/NASACapturing the creation of this type of large, short-lived star body is extremely rare – the equivalent of discovering a missing link between winged dinosaurs and early birds, said the scientists, who relied primarily on data from Keck Observatory’s NIRC2 fitted with the laser guide star adaptive optics (LGSAO) system. The new mega-galaxy, dubbed HXMM01, is the brightest, most luminous and most gas-rich submillimeter-bright galaxy merger known.
HXMM01 is fading away as fast as it forms, a victim of its own cataclysmic birth. As the two parent galaxies smashed together, they gobbled up huge amounts of hydrogen, emptying that corner of the universe of the star-making gas.
“These galaxies entered a feeding frenzy that would quickly exhaust the food supply in the following hundreds of million years and lead to the new galaxy’s slow starvation for the rest of its life,” said lead author Hai Fu, a UC Irvine postdoctoral scholar.
The discovery solves a riddle in understanding how giant elliptical galaxies developed quickly in the early universe and why they stopped producing stars soon after. Other astronomers have theorized that giant black holes in the heart of the galaxies blew strong winds that expelled the gas. But cosmologist Asantha Cooray, the UC Irvine team’s leader, said that they and colleagues across the globe found definitive proof that cosmic mergers and the resulting highly efficient consumption of gas for stars are causing the quick burnout.
