NOAO News & Reports
October 5, 2009
NOAO Astronomers to Participate in White House Star Party
The White House announced this weekend that President Obama will host a “Star Party” on the White House lawn Wednesday evening. “The event will include 20 telescopes on the White House lawn focused on Jupiter, the Moon and select stars; interactive dome presentations; and hands-on activities including scale models of the Solar System,” the White House said.
Two NOAO astronomers, Dr. Dara Norman and Dr. Stephen Pompea, will be traveling to Washington on Tuesday, having been invited to participate in the White House Star Party. NOAO Press Release 09-03.
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August 26, 2009
NOAO Survey program challenges the universality of the stellar initial mass function
Caption: These two photographs were made by combining data from NASA's Galaxy Evolution Explorer (GALEX) spacecraft and the Cerro Tololo Inter-American Observatory in Chile. GALEX shorter ultraviolet wavelengths are dark blue, while longer ultraviolet wavelengths are lighter blue. R band data are shown in yellow, H-alpha is red. Credit: NASA/JPL-Caltech/JHU
R band and H-alpha data obtained for the "Survey of Ionization in Neutral Gas Galaxies", an NOAO Survey program, was recently combined with GALEX data to examine the premise that the stellar initial mass function (IMF) is universal. The team, which is lead by PI Gerhardt Meurer (JHU), and includes NOAO scientists Patricia Knezek and Chris Smith, found that the extinction-corrected flux ratio F(H-alpha)/f(FUV) from these two tracers of star formation shows strong correlations with surface brightness: low surface brightness (LSB) galaxies have lower ratios compared to high surface brightness galaxies as well as compared to expectations from equilibrium models of constant star formation rate (SFR) using commonly favored IMF parameters. They determined that the F(H-alpha)/f(FUV) correlations cannot be due to residual extinction correction errors, while systematic variations in the star formation history (SFH) cannot explain the trends with both Hα and R surface brightness. They contend that the most plausible explanation for the correlations is systematic variations of the upper mass limit and/or the slope that define the upper end of the IMF driven by the hydrostatic pressure of the interstellar medium.
The results imply that the SFR measured in a galaxy is highly sensitive to the tracer used in the measurement. A nonuniversal IMF would also call into question the interpretation of metal abundance patterns in dwarf galaxies as well as SFHs derived from CMDs. The results were published in the April 10, 2009 issue of the Astrophysical Journal (Vol. 695, p. 765), and a GALEX press release on the results was issued on August 19, 2009. The press release is available at: http://www.galex.caltech.edu/newsroom/glx2009-04r.html
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August 12, 2009
NASA’s Kepler Spies Changing Phases on a Distant World
Caption: Kepler light curve of the exoplanet HAT-P-7b. The planetary occultation is apparent in the top plot and modeled in the bottom zoomed plot window. These observations came from a 10-day commissioning observation just prior to the official start of Kepler science observations in June 2009.
The Kepler space telescope, launched March 6, 2009 by NASA, has detected both the transit of a known gas giant planet (HAT-P-7b) and the occultation of the planet by its host star.
The discovery was published 7 Aug 2009 by the Kepler team in the journal Science (Vol. 325, no. 5941, p. 709).
The find is based on a relatively short 10 days of commissioning data collected before the official start of science operations.
The detection of an occultation in visible light indicates that the exoplanet is likely to be very hot, near 2600K, probably due to a highly absorbing atmosphere. Similar very hot exoplanets have also been found by the CoRot mission.
“Seeing the occultation of HAT7b so clearly in the early Kepler observations shows that we are already operating at levels required to detect Earth-like planets” says NOAO staff scientist Steve B. Howell a member of the Kepler Science Team and co-author of the science paper.
For the full press release, see the NASA Press Release.
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July 24, 2009
Soap Bubble Nebula
Informally known as the “Soap Bubble Nebula”, this planetary nebula (officially known as PN G75.5+1.7) was discovered by amateur astronomer Dave Jurasevich on July 6th, 2008. It was noted and reported by Keith Quattrocchi and Mel Helm on July 17th, 2008. This image was obtained with the Kitt Peak Mayall 4-meter telescope on June 19th, 2009 in the H-alpha (orange) and [OIII] (blue) narrowband filters. In this image, north is to the left and east is down.
Press mentions:
- Pasadena Star-News: Amateur astronomer's nebula discovery officially recognized
- New Scientist: Giant ‘soap bubble’ found floating in space
- Universe Today: Giant Soap Bubble In Space
- The Guardian:Observatory snaps cosmic soap bubble
- Fox News:Amateur Astronomers Discover ‘Soap Bubble’ in Space
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June 1, 2009
DAMIC and MONSOON
Left to right: Kevin Kuk, team leader Juan Estrada, Herman Cease, and Ben Kilminster in their underground lab. The DAMIC (Dark Matter in CCDs) detector is encased in the stack of lead bricks to the right of the group.
Juan Estrada of Fermilab is leading a small group of scientists in a novel experiment to search for low-mass dark matter candidates using CCD detectors designed for the Dark Energy Survey Camera. The team is using the very low noise (2e- rms) of the detectors to measure the nuclear recoil energy that is liberated when a dark matter particle impacts the nucleus of the detectors silicon atoms. This is analogous to measuring the seismic tremble of a mountain after it has been struck by a ping-pong ball. The experiment has pushed the noise threshold of low energy measurement to a new record using the MONSOON image acquisition system designed at NOAO, and the team expects to publish the new result in the coming months.
Coincidently, NOAO has been working to further reducing the read noise of CCD detectors used at the observatories. A group of engineering students at the Harvey Mudd College, working in collaboration with NOAO engineers, have recently concluded a study of a new method to process CCD detector signals to reduce the detector system read noise to below 1e-. The method, called over sampling, will be implemented in the new Torrent detector controller where the performance will be verified. Torrent is the most recent incarnation of the open source MONSOON technology.
More information on the DAMIC experiment from Fermilab’s news pages.
More information on the MONSOON image acquisition systems from the NOAO instrumentation pages.
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April 30, 2009
IYA2009 Boosts GLOBE at Night to Record Number of Dark-Skies Observations | The global citizen-science campaign GLOBE at Night 2009 recorded 80 percent more observations of the world’s dark skies than the program’s previous record—including double the number of digital measurements—thanks in large part to active participation and publicity from the network of 140 countries currently celebrating the International Year of Astronomy 2009 (IYA2009). NOAO Press Release 09-02
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April 12, 2009
Astronomy Picture of the Day | M39: Open Cluster in Cygnus
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March 4, 2009
Elusive Binary Black Hole System Identified | Finding a needle in a haystack might be easy compared to finding two very similar black holes closely orbiting each other in a distant galaxy.
Astronomers from the National Optical Astronomy Observatory (NOAO) in Tucson have found what looks like two massive black holes orbiting each other in the center of one galaxy. It has been postulated that twin black holes might exist, but it took an innovative, systematic search to find such a rare pair. NOAO Press Release 09-01
Selected press mentions:
- Scientific American: Astronomers spot two black holes in an orbital dance
- Science News: These Cosmic Gluttons May Be Tight
- BBC News: Dancing black hole twins spotted
- Nature (subscription required): A candidate sub-parsec supermassive binary black hole system
- Live Science: Black Holes Bound to Join Forces
- Science Centric: Binary black hole system identified
- Discover Magazine (Bad Astronomy Blog): Binary black holes terrorize quasar nucleus
- The Register: Stargazers spy elusive binary black hole system
- More from Google News
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February 8, 2009
Astronomy Picture of the Day | Inside the Eagle Nebula
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