Daily Archives: November 15, 2014

Astronomers using NASA's Hubble Space Telescope and Chandra X-ray Observatory have uncovered young, massive and compact galaxies that are dying earlier than expected.

The researchers said that the firestorm of star birth has blasted out most of the remaining gaseous fuel needed to make future generations of stars and are on track to possibly becoming so-called "red and dead galaxies," composed only of aging stars.

Scientists had earlier believed that powerful monster black holes lurking at the centers of the galaxies triggered the gaseous outflows and shut down star birth by blowing out any remaining fuel, but the recent study shows that the stars themselves are turning out the lights on their own star-making party, which happened when the universe was half its current age of 13.7 billion years.

Paul Sell of Texas Tech University in Lubbock, lead author of a science paper, said that the common belief was that stars cannot drive high-velocity outflows in galaxies; only more powerful supermassive black holes can do that, however, it was found that the stars can actually produce the velocities of the outflows alone without needing to invoke the black hole.

Team member Christy Tremonti of the University of Wisconsin-Madison first identified the galaxies from the Sloan Digital Sky Survey as post-starburst objects spouting high-speed gaseous fountains. The sharp visible-light views from Hubble's Wide Field Camera 3 show that the outflows are arising from the most compact galaxies yet found. These galaxies contain as much mass as our Milky Way galaxy, but packed into a much smaller area. The smallest galaxies are about 650 light-years across.

One reason for the stellar shutdown is that the gas rapidly heats up, becoming too hot to contract under gravity to form new stars. Another possibility is that the star-birthing frenzy blasts out most of the star-making gas via powerful stellar winds.

The researchers said that the biggest surprise from Hubble was the realisation that the newly formed stars were born so close together and the extreme physical conditions at the centers of these galaxies explain how they can expel gas at millions of miles per hour.

They found that it was the powerful stellar winds from the most massive and short-lived stars at the end of their lives, combined with their explosive deaths as supernovae. Based on their analysis of the Hubble and Chandra data, team members suggest that the "party begins" when two gas-rich galaxies collide, funneling a torrent of cold gas into the merging galaxies' compact center. The large amount of gas compressed into the small space ignites the birth of numerous stars. The energy from the stellar firestorm then blows out the leftover gas, quenching further star formation.

The study was published in the Royal Astronomical Society.

Read more:
NASA's Hubble telescope finds young galaxies on track to becoming 'red and dead'

The Space Telescope Science Institute (STScI) has appointed Dr. Roeland van der Marel to lead its work on a proposed NASA space telescope that will provide images as sharp as the Hubble Space Telescope, but over a hundred times larger area. The space observatory, called the Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets (WFIRST-AFTA), is being studied for launch in the mid-2020s, pending program approval by NASA.The telescope will be used to probe the distribution of dark matter, which is most of the matter in the universe, and the characteristics of dark energy, a repulsive force that is pushing the universe apart at an ever-faster rate. The telescope will also be used to measure the abundance and characteristics of planets orbiting other stars. As a general-purpose observatory with a large survey program, it will also yield fundamental progress in many other astrophysical subjects.STScI is presently the science operations center for the Hubble Space Telescope and the science and mission operations center for the James Webb Space Telescope, scheduled for launch in 2018.WFIRST-AFTA will produce large-scale maps of the night sky at the highest resolution we have ever had. Our Barbara A. Mikulski Archive for Space Telescopes (MAST) already holds the astronomical data from some 20 astronomy missions. The addition of the enormous WFIRST-AFTA dataset would add considerably to its scientific discovery potential, STScI Director Matt Mountain said.A wide-field infrared survey telescope was the highest-ranked large space mission recommended by the National Academy of Sciences 2010 Astronomy and Astrophysics Decadal Survey. WFIRST-AFTA would fulfill this recommendation. The heart of the proposed telescope is already built. It features a 2.4-meter-diameter mirror (the same size as Hubbles mirror), which was donated to NASA in 2012 by the United States National Reconnaissance Office.WFIRST-AFTA will have a wide-field, near-infrared imaging camera and also a visible-light coronagraph, an instrument specially designed for studying planets orbiting other stars. These instruments share many characteristics with instruments on Hubble and the Webb telescope, with which STScI has extensive experience.We will be extremely excited to help the astronomical community use WFIRST-AFTA to further revolutionize our understanding of the universe, van der Marel said. The Hubble data and analysis tools provided by STScI have already enabled astronomers around the world to make many ground-breaking astronomical discoveries. Building on that experience at STScI will make WFIRST-AFTA a powerful complement to the Webb telescope, and will further expand our knowledge.Van der Marel earned a doctorate in astronomy in 1994 from Leiden University in the Netherlands and joined the STScI staff in 1997. He previously led teams dealing with the scientific operations of Hubbles Advanced Camera for Surveys, and dealing with the structure, optics, and pointing of the Webb telescope. Van der Marel is also an adjunct professor in the Department of Physics and Astronomy at the Johns Hopkins University in Baltimore, Maryland.Van der Marel is an expert on black holes and the structure of galaxies. His research, which includes using the Hubble telescope to study galaxies, has contributed to the discovery that supermassive black holes exist in the centers of most galaxies. In 2005, he won the Pirelli International Award for developing an educational website that explains black holes to students and the public.STScI is collaborating with NASAs Goddard Space Flight Center (Greenbelt, Maryland), NASAs Jet Propulsion Laboratory (La Canada Flintridge, California), the Infrared Processing and Analysis Center (Pasadena, California), and other partners on preparations for the WFIRST-AFTA mission.Contact:Ray VillardSpace Telescope Science Institute, Baltimore, Md.+1 410-338-4514villard@stsci.eduImages and more information about WFIRST:http://hubblesite.org/news/2014/49NASAs WFIRST Portalhttp://wfirst.gsfc.nasa.gov/STScIs Brochure Pushing Astronomys Boundshttp://hubblesite.org/pubinfo/pdf/2014/49/pdf.pdfWFIRST Video Trailer on YouTubehttps://www.youtube.com/watch?v=OtKmBMmpWvwQ&A Session about NASAs WFIRST Mission:http://www.nasa.gov/content/goddard/qa-session-about-nasas-wfirst-mission/

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Lead Appointed on Proposed Wide Field Space Telescope