NOAO News & Reports
April 16, 2012
The Lives of Stars, or Astronomers as Paparazzi
Left: C. Smith, S. Points, the MCELS Team & NOAO/AURA/NSF. Right: P. Massey & NOAO LGGS Survey
Using NOAO facilities, astronomers from Lowell Observatory have acted as “stellar paparazzi”, managing to identify hundreds of rare yellow supergiants and their more long-lived descendants, the red supergiants, in two neighboring galaxies. These newly identified stellar populations provide an important constraint on the theoretical models which describe how these stars change from blue, to yellow and then to red. The behavior of the models in this phase can influence theoretical predictions, including what types of stars explode as supernova.
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March 15, 2012
Astronomers Using NASA’s Hubble Discover Quasars Acting as Gravitational Lenses
Image Credit: NASA, ESA, and F. Courbin (EPFL, Switzerland)
Astronomers, including NOAO’s Todd Boroson, using NASA’s Hubble Space Telescope have found several examples of galaxies containing quasars, which act as gravitational lenses, amplifying and distorting images of galaxies aligned behind them.
Quasars are among the brightest objects in the universe, far outshining the total starlight of their host galaxies. Quasars are powered by supermassive black holes.
To find these rare cases of galaxy-quasar combinations acting as lenses, a team of astronomers led by Frederic Courbin at the Ecole Polytechnique Federale de Lausanne (EPFL, Switzerland) selected 23,000 quasar spectra in the Sloan Digital Sky Survey (SDSS). They looked for the spectral imprint of galaxies at much greater distances that happened to align with foreground galaxies. Once candidates were identified, Hubble’s sharp view was used to look for gravitational arcs and rings (which are indicated by the arrows in these three Hubble photos) that would be produced by gravitational lensing.
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February 18, 2012
The dark side of the universe
Image Credit: T. Abbott and NOAO/AURA/NSF
AT FIVE tonnes and 520 megapixels, it is the biggest digital camera ever built—which is fitting, because it is designed to tackle the biggest problem in the universe. On February 20th researchers at the Cerro Tololo Inter-American Observatory (pictured), which sits 2,200 metres (7,200 feet) above sea level in the Atacama desert of northern Chile, will begin installing this behemoth on a telescope called Blanco. It is the centrepiece of the Dark Energy Survey (DES), the most ambitious attempt yet to understand a mystery as perplexing as any that faces physics: what is driving the universe to expand at an ever greater rate. Economist Article
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December 19, 2011
NOAO: New Insight into the Bar in the Center of the Milky Way
The BRAVA fields are shown in this image montage. The center of the Milky Way is at coordinates L= 0, B=0. The regions observed are marked with colored circles. This montage shows the southern Milky Way all the way to the horizon, as seen from CTIO. The telescope in silhouette is the Blanco 4-meter, where the observation were made.
Image Credit: D. Talent, K. Don, P. Marenfeld & NOAO/AURA/NSF and the BRAVA Project
It sounds like the start of a bad joke: do you know about the bar in the center of the Milky Way Galaxy? Astronomers first recognized almost 80 years ago that the Milky Way Galaxy, around which the sun and its planets orbit, is a huge spiral galaxy. This isn’t obvious when you look at the band of starlight across the sky, because we are inside the galaxy: it’s as if the sun and solar system is a bug on the spoke of a bicycle wheel. But in recent decades astronomers have suspected that the center of our galaxy has an elongated stellar structure, or bar, that is hidden by dust and gas from easy view. Many spiral galaxies in the universe are known to exhibit such a bar through the center bulge, while other spiral galaxies are simple spirals. And astronomers ask, why? In a recent paper Dr. Andrea Kunder, of Cerro Tololo Inter-American Observatory (CTIO) in northern Chile, and a team of colleagues have presented data that demonstrates how this bar is rotating. NOAO Press Release 11-09
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November 30, 2011
NOAO: New Planet Kepler-21b discovery a partnership of both space and ground-based observations
The Kepler field as seen in the sky over Kitt Peak National Observatory. The approximate position of HD 179070 is indicated by the circle (sky imaged using a diffraction grating to show spectra of brighter stars, credit J. Glaspey; telescopes imaged separately and combined, credit P. Marenfeld)
The NASA Kepler Mission is designed to survey a portion of our region of the Milky Way Galaxy to discover Earth-size planets in or near the “habitable zone,” the region in a planetary system where liquid water can exist, and determine how many of the billions of stars in our galaxy have such planets. It now has another planet to add to its growing list. A research team led by Steve Howell, NASA Ames Research Center, has shown that one of the brightest stars in the Kepler star field has a planet with a radius only 1.6 that of the earth’s radius and a mass no greater that 10 earth masses, circling its parent star with a 2.8 day period. With such a short period, and such a bright star, the team of over 65 astronomers (that included David Silva, Ken Mighell and Mark Everett of NOAO) needed multiple telescopes on the ground to support and confirm their Kepler observations. These included the 4 meter Mayall telescope and the WIYN telescope at Kitt Peak National Observatory. NOAO Press Release 11-08
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