NOAO News & Reports
January 26, 2010
Caught in the act: a merging binary QSO
The NOAO i band image of the binary quasar on the right, with the Chandra X-ray image on the left. The X-ray image is contoured and those contours overlaid on the i-band image.
It has been assumed for some time that binary supermassive black holes (SMBH) should be common in the universe, given that galaxies regularly interact and merge and that most, if not all, galaxies contain a SMBH. Such a SMBH will only be detected as a quasar when it is accreting matter. And galaxy merging is a leading proposal to trigger such accretion. Now the first luminous, spatially resolved binary quasar that clearly inhabits an interacting/merging galaxy pair has been reported. ( SDSS J1254+0846: A Binary Quasar Caught in the Act of Merging, Green et. al., Ap. J accepted Jan. 2010 ). The unique properties of this system allow detailed numerical simulations to create plausible scenarios for the histories of both the host galaxies and the SMBH that inhabit them.
The first spectrum confirming this binary QSO was taken by A. Myers at the KPNO Mayall 4-meter using R-C Spectrograph on Feb 12, 2008. Subsequent Chandra/NOAO observations (P. Green, P.I.) with the MOSAIC imager on the Mayall 4m image obtained March 18, 2009 (Barkhouse, Myers observing) revealed the existence of the tidal arms in the host galaxy,seen in the figure above. Additional deeper imaging and spectroscopy with Magellan/IMACS were used by the authors to determine the properties and history of this merger.
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January 6, 2010
Massive Stars: Good Targets for Planet Hunts, Bad Targets for SETI
This artist’s conception shows a Jupiter-sized planet forming from a disk of dust and gas surrounding a young, massive star. The planet’s gravity has cleared a gap in the disk. Of more than 500 stars examined in the W5 star-forming region, 15 show evidence of central clearing that may be due to forming planets.
Credit: David A. Aguilar, CfA
Most searches for planets around other stars, also known as exoplanets, focus on Sun-like stars. Those searches have proven successful, turning up more than 400 alien worlds. However, Sun-like stars aren’t the only potential homes for planets. New research by astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) and the National Optical Astronomy Observatory (NOAO) confirms that planet formation is a natural by-product of star formation, even around stars much heftier than the Sun. CfA Press Release
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January 6, 2010
Beyond IYA2009
Although the International Year of Astronomy 2009 (IYA2009) comes to a formal close this weekend with a ceremony in Padua, Italy, numerous core programs conducted during the year will carry on in 2010 and beyond, many led by educators and outreach professionals in the United States, including NOAO’s Dr. Stephen Pompea (Galileoscope) and Dr. Connie Walker (Dark Skies Awareness). Read more in the Space Daily article.
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January 6, 2010
Ric and Jean Edelman Give 15,000 Galileoscopes to Classrooms in the US
Hundreds of thousands of school children around the country will be a ble to explore the Moon, planets, and our galaxy thanks to a $250,000 donation by Ric and Jean Edelman.
The Edelmans, founders of Edelman Financial Services, one of the country’s leading independent financial advisory firms, have donated $250,000 to the American Astronomical Society to fund the acquisition and distribution of more than 15,000 Galileoscopes to schoolteachers nationwide and train them on adding the telescope kits to their curriculum. The program is operated in partnership with the National Optical Astronomy Observatory. Read more in the Press Release.
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January 5, 2010
Centuries-Old Star Mystery Coming to a Close
Astronomers using NASA’s Spitzer Space telescope have found a likely solution to a centuries-old riddle of the night sky. Every 27 years, a bright star called Epsilon Aurigae fades over period of two years, then brightens back up again. Though amateur and professional astronomers have observed the system extensively, the nature of both the bright star and the companion object that periodically eclipses it have remained unclear. The companion is known to be surrounded by a dusty disk, as illustrated in this artist’s concept.
Image Credit: NASA/JPL-Caltech
For almost two centuries, humans have looked up at a bright star called Epsilon Aurigae and watched with their own eyes as it seemed to disappear into the night sky, slowly fading before coming back to life again. Today, as another dimming of the system is underway, mysteries about the star persist. Though astronomers know that Epsilon Aurigae is eclipsed by a dark companion object every 27 years, the nature of both the star and object has remained unclear.
Now, new observations from NASA’s Spitzer Space Telescope — in combination with archived ultraviolet, visible and other infrared data — point to one of two competing theories, and a likely solution to this age-old puzzle. One theory holds that the bright star is a massive supergiant, periodically eclipsed by two tight-knit stars inside a swirling, dusty disk. The second theory holds that the bright star is in fact a dying star with a lot less mass, periodically eclipsed by just a single star inside a disk. The Spitzer data strongly support the latter scenario. NOAO Astronomer Steve Howell contributed to this discovery. Spitzer Press Release
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January 4, 2010
Runaway anti-matter production makes for a spectacular stellar explosion
The supernova can be seen in the image on the right (labeled “2007”) as the small “dot” in the center of the image. Note that this “dot” is not seen in the image labeled “2002 to 2006”.
University of Notre Dame astronomer Peter Garnavich and a team of collaborators used the NSF’s 4-m Blanco telescope in Cerro Tololo, Chile to discover a distant star that exploded when its center became so hot that matter and anti-matter particle pairs were created. The star, dubbed Y-155, began its life around 200 times the mass of the sun but probably became “pair-unstable” and triggered a runaway thermonuclear reaction that made it visible nearly halfway across the universe.
Garnavich and his collaborators discovered the exploding star during the ESSENCE supernova search, a six-year NOAO Survey Program, that identified more than 200 weaker stellar explosions. University of Notre Dame Press release
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