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NOAO News Archive: 2009

December 21, 2009

WIYN 3.5-m telescope rounds up “Blue Stragglers”

Figure 1: NGC188 is an open star cluster in the constellation Cepheus

Astronomers have reported new observations of a remarkable binary star population in a well-known star cluster. In a press release (embargoed until Dec 23, 1PM EST), Nature features two interesting studies of a class of atypical stars known as “blue stragglers”. One paper was written by Robert Mathieu and Aaron Geller, University of Wisconsin-Madison, who used the WIYN telescope at Kitt Peak National Observatory for their observations. Mathieu and Geller found that the blue stragglers in NGC188 (Caldwell 1), an open cluster in our galaxy, have a binary fraction of 76%, which is three times the frequency for normal stars of this type. They conclude that possibly all of these stars originate in multiple star systems, and that several formation mechanisms could be operating. Geller, a PhD candidate at the University of Wisconsin-Madison, has been granted long term observing status for this project, which is part of the WIYN Open Cluster Study.

Kitt Peak National Observatory is part of the National Optical Astronomy Observatory (NOAO), which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. The founding members of the WIYN Observatory partnership are the University of Wisconsin-Madison, Indiana University, Yale University, and NOAO.

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November 30, 2009

NEWFIRM Discovery of Warm Molecular Hydrogen in the Wind of M82

New data on M82 from NEWFIRM are compared with published Hα and PAH emission images (left) and H2-to-PAH emission ratio map in the brightest filaments.

Using NEWFIRM on the Mayall 4-meter telescope at Kitt Peak, Veilleux, Rupke and Swaters have reported the discovery of warm H2 gas in the prototypical galactic wind of M82. They report filaments extending above and below the disk, roughly coincident with the location of the galactic wind in this galaxy. The warm H2 material is not found to be a dynamically important component of the outflow: however, a comparison between the H2 emission and the distribution of the CO emission reveals that most of the features seen in CO are detected in H2 but not the converse. Deep H2 2.12 μm observations such as these represent a promising new method to study the elusive but potentially important molecular component of galactic winds. In the accompanying figure the new data are compared with published H-α and PAH emission images (left) and H2-to-PAH emission ratio map in the brightest filaments.

The published results can be found in Veilleux, S., Rupke, D.N.S., & Swaters, R. 2009, ApJ, 700, L149

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November 21, 2009

NGC 253: Dusty Island Universe

The Astronomy Picture of the Day for November 21, 2009 features an image from one of the robotic PROMPT telescopes on CTIO (Cerro Tololo Inter-American Observatory) in Chile.

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October 5, 2009

NOAO Astronomers to Participate in White House Star Party

Dr. Stephen Pompea and Dr. Darra Norman

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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September 17, 2009

Ultraviolet Andromeda

Astronomy Picture of the Day

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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:

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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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August 3, 2009

T Tauri: A Star is Formed

Astronomy Picture of the Day

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July 24, 2009

Soap Bubble Nebula

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:

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June 1, 2009


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

Colliding Galaxies

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:

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February 8, 2009

Astronomy Picture of the Day  |  Inside the Eagle Nebula

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