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26 January 2011: On July 19, 2009 Australian amateur astronomer Anthony Wesley spied a dark scar in the clouds of Jupiter. Wesley alerted professional astronomers and immediately both Gemini telescopes and other large telescopes around the world (and in space) trained their instruments on Jupiter’s new transient feature. Now, after more than a year of studying the unique data a team led by Glenn Orton of NASA’s Jet Propulsion Laboratory and Leigh Fletcher of Oxford University have confirmed that this collision was not like at least one similar past event. The results, published in a recent issue of the journal Icarus (see citations at the end of this feature), indicate that the colliding body was rocky and not an icy comet like the last known collision with Jupiter, the comet Shoemaker-Levy 9 in 1994. These results confirm earlier indications from Hubble Space Telescope data that the collision involved a dense rocky object rather …

20 January 2011: On the night of January 21-22, 2011 the Gemini South 50-watt laser began on-sky engineering testing and commissioning with its successful propagation into the sky over the summit of Cerro Pachón in Chile (see Figures a&b). The laser, an integral part of the Gemini Multi-Conjugate Adaptive Optics System (GeMS), is designed to produce five individual laser guide stars (LGS) that will help provide extremely high angular resolution over a relative wide area of the sky. Adaptive optics systems work by sampling the distortion of starlight by our atmosphere with natural and artificial (laser) guide stars and removing much of the blurring caused by our atmosphere with deformable mirrors. The technical testing and integration of the laser into the GeMS system will continue through this year as the Canopus adaptive optics system and the Gemini South Adaptive Optics Imager are also commissioned and integrated (see geminiann11002c). When complete, this will be …

10 January 2011: Once, the stars of any individual globular cluster were interpreted as a single population, all having formed at the same time. Over the last decade, however, evidence for multiple stellar populations has emerged. New work led by Andrea Dupree (Harvard-Smithsonian Center for Astrophysics) now shows direct evidence for helium abundance variations—a sign of multiple histories—in the bright globular cluster Omega Centauri. The team further finds that helium abundance is correlated with overall metal abundance and especially with enhancement of light elements such as aluminum and sodium, which are produced by high-temperature hydrogen burning within stars (geminiann11001a). Helium enhancement is thus likely a consequence of second-generation stars formed from enriched material processed by the earlier generation of stars. Dupree and collaborators, Jay Strader (Harvard-Smithsonian Center for Astrophysics) and Graeme Smith (University of California Observatories/Lick Observatory), used the Phoenix high-resolution spectrograph on Gemini South to measure the near-infrared helium line at a …

14 December 2010: On December 6-8, 2010 about a dozen representatives from the Association of Universities for Research in Astronomy (AURA) converged at Gemini’s base facility in Hilo, Hawai‘i to discuss a broad range of topics related to diversity in the workforce. Participating institutions included the Space Telescope Science Institute (STScI), the Advanced Technology Solar Telescope (to be built on Haleakala Maui), The National Optical Astronomy Observatory (NOAO), the National Solar Observatory, and Gemini. Representatives from several academic institutions across the United States also participated, providing expert opinion and sharing experiences. This meeting is part of a coordinated effort to match the scientific workforce at the AURA centers, with the demographics of the evolving workforce. The twice-annual meeting brings participants together to review current activities, set future directions and understand issues related to workforce diversity. The agenda ranged from the issue of inspiring a diverse cross-section of youth to pursue careers in science …

23 November 2010: The discovery of an unusual stellar system combined with near-infrared spectroscopy at Gemini North has allowed astronomers to confirm the spectral type of a cool methane dwarf (T dwarf; geminiann10020a) and determine its temperature, mass, and age with confidence. The pair, consisting of a “dead” white dwarf stellar remnant and the cooler T dwarf, provides a unique laboratory in which the age of the system is well-constrained, making the T dwarf a benchmark for testing ultracool atmospheric physics. The near-infrared spectroscopic observations were made using the Near Infrared Imager and spectrograph (NIRI) on the Gemini North telescope on Mauna Kea, Hawai‘i. The team, led by Avril Day-Jones of the Universidad de Chile and including astronomers from the University of Hertfordshire (UK), and the University of Montreal (Canada), are publishing their results in the journal Monthly Notices of the Royal Astronomical Society (preprint here). Ben Burningham (University of Hertfordshire, UK) and …

5 November 2010: Typically, determining the ages of stars is very sensitive to the assumptions or theoretical models astronomers employ. In new work, Phillip Cargile (Vanderbilt University), David James (University of Hawai'i at Hilo and Cerro Tololo Inter-American Observatory), and Rob Jeffries (Keele University, UK) take advantage of the time-dependent destruction of lithium in young stars to measure the age of the open cluster Blanco 1. They conclude that the stars formed 132 +/- 24 million years ago. Trace amounts of lithium were created with the origin of the universe, which stars incorporate as they form. However, as stars develop, the high temperatures at their centers destroy the primordial lithium, and the central temperature depends on the age and mass of the forming star. Considering a cluster of stars that all formed at the same time, the more massive (and more luminous) stars deplete their lithium first. Identifying the mass of stars that …

13 October 2010: pristine new coat of protected silver now glistens on the Gemini South primary mirror (M1) as part of a routine shut-down on Cerro Pachón in Chile (geminiann10018a). The coating, applied in the Gemini South coating chamber on October 8th, 2010 is thought to be one of the “best ever achieved at Gemini” according to Gemini Optics Engineer, Tomislav Vucina. The planned 28-day shut-down (including engineering checks on the sky) which began on September 27th also includes maintenance of the Cassegrain wrap, the acquisition and guiding unit, the adaptive optics fold mirror, and instruments. “A late-spring snowstorm delayed some of our critical preparations but in the last couple weeks we were able to make up that lost time,” said Gemini Systems Engineer, Brian Walls (geminiann10018b). The Gemini coating process uses “sputtering” to lay-down the ultra-thin 4-layer coatings in the giant coating chamber (geminiann10018c) in the basement of the telescope (Gemini has …

20 September 2010: A team of astronomers, led by Phil Lucas of Hertfordshire University in the UK, have discovered what is currently the coldest star-like object. The object, called UGPS J0722-05, is also of particular interest because it is one of our closest neighbors. UGPS J0722-05 is a cold brown dwarf; these small Jupiter-sized objects are hard to find as they are very faint, and they become fainter, and so even harder to find, with decreasing temperature. UGPS J0722-05 was identified as the only possible brown dwarf in a search of over 600 million sources detected in the plane of our Galaxy by the UK Infrared Telescope (UKIRT) as part of the UKIRT Infrared Deep Sky Survey (UKIDSS). Figure 1 shows the UKIDSS discovery image. Using the Near-Infrared Imager and Spectrometer (NIRI) on Gemini North a spectrum of UGPS J0722-05 was obtained in early February of 2010. This spectrum is shown in Figure …

27 August 2010: Laura Churcher and UK colleagues at the Institute of Astronomy, University of Cambridge, and the University of Keele have used the Thermal-Region Camera Spectrograph (T-ReCS) on the Gemini South telescope to obtain the first resolved image of the debris disk around the 12 million year old star HD191089 (geminiann10016a). The value of a resolved image of a debris disk is not only that it shows the radial location of the dust in the system but, as in this case, it can also reveal exciting features such as brightness differences in the disk, which hint at hidden planets. These observations, at a wavelength of 18 microns, show emission from dust that the central starlight has heated. The image of HD191089's debris disk shows that there is dust between 28 and 90 AU (Pluto's orbit is at about 40 AU in the solar system). Inside the inner edge of the disk there …

26 August 2010: Recent observations with the Near-Infrared Imager (NIRI) on the Gemini North telescope have revealed the presence of a large circumstellar disk around the young embedded protostar L1527. The discovery team, led by University of Michigan astronomer John Tobin and including Lee Hartmann also of the University of Michigan and Laurent Loinard of the Centro de Radioastronomía y Astrofísica - Universidad Nacional Autonoma de Mexico, detected the disk in scattered mid-infrared light, as shown in geminiann10015a. The upper layers of the disk appear as two bright bowl-shaped features. The mid-plane of the disk hides the central protostar from direct view, resulting in the dark band between the disk surfaces. The object, located in a star-forming region in the constellation of Taurus, is at a distance of about 450 light-years (140 parsecs) making it one of the nearest and youngest protostars known. Although L1527 is otherwise a fairly typical protostar and will …

24 August 2010: Testing the idea that the powerful radio galaxies (PRGs) are triggered in galaxy interactions, Cristina Ramos Almeida, Clive Tadhunter (University of Sheffield, UK), and collaborators obtained deep imaging data using the Gemini Multi-Object Spectrograph (GMOS) at the Gemini South telescope to study the morphologies of a complete sample of 46 intermediate redshift (0.05<z<0.7) PRGs. In what represents the first systematic imaging study of a major sample of radio galaxies using an 8-meter-class telescope, the team searched for signs of nearby companions in the 2Jy southern radio galaxy sample to look for secondary nuclei, shells, and extended low surface brightness features such as tidal tails and bridges. The observations show that 78-85% of this complete sample of PRGs present peculiar morphologies at relatively high levels of surface brightness (μv = 23.6 mag/arcsec2). This fraction of distorted morphologies is much higher than for radio quiet ellipticals at similar sample brightness level, implying …

23 July 2010: Using the Near-Infrared Coronagraphic Imager (NICI) on the Gemini-South telescope in Chile, an international team led by University of Hawai‘i astronomers Beth Biller and Michael Liu have directly imaged a brown dwarf in a tight orbit around a young Sun-like star. This discovery is a rare find, as the 36 Jupiter-mass brown dwarf companion (dubbed "PZ Tel B" for "PZ Telescopii B") resides only 18 Astronomical Units (AU) from its primary star, similar to the distance of Uranus from the Sun. Most young brown dwarf and planetary companions found by direct imaging are at orbital separations greater than 50 AU – larger than the orbit of Pluto (~40 AU) from the Sun. In the past year, the researchers observed PZ Tel B moving quickly outward from its parent star. However, as recently as 2003 PZ Tel B was undetectable due to its close proximity to its parent star, indicating its …

2 July 2010: The first two accepted papers based on observations with the Near-Infrared Coronagraphic Imager (NICI) at Gemini South illustrate the instrument’s potential diverse uses. The papers include discoveries of several previously unknown companions in binary star systems as well as the study of the age distributions of stars in the outer regions of the galaxy M83. Primarily envisioned as a planet-hunting “machine,” NICI combines an 85-element curvature adaptive optics (AO) system, a Lyot coronagraph, and a dual-channel infrared imager into a single instrument. The high image quality provided by the AO system together with the coronagraph’s light-suppression capability optimize NICI for the detection of extremely faint companions to bright stars. To that end, NICI is currently being used in an extensive campaign to search about 300 nearby stars for planetary-mass companions. However, NICI is also useful for many other applications requiring high-resolution or high-contrast imaging. These first papers present the results …

10 June 2010: A Canadian-U.S. team led by Patrick Dufour (University of Montreal) discovered the most metal-rich white dwarf known to date by examining thousands of stars from the Sloan Digital Sky Survey. Their analysis, based on follow-up observations using the Gemini North telescope and the Multiple-Mirror Telescope (MMT), shows a clear signature of a tidally destroyed dwarf planet that once orbited the parent star. White dwarfs are essentially dead stars that no longer have nuclear reactions in their core. Thus, they slowly cool off by simply radiating the remaining thermal energy left in the core at the end of their lives. They are also very compact objects with surface gravities on the order of 100,000 times larger than that of Earth. As a result, heavy elements sink rapidly toward the center of the star while light elements tend to float at the surface. Consequently, most white dwarfs are found to have nearly …

3 June 2010: Using the Gemini Near-Infrared Imager and spectrometer (NIRI) on the Gemini North telescope, James De Buizer and William Vacca (SOFIA-USRA) obtained spectra that, for the first time, directly identify the origin of “green fuzzy” emission. The Spitzer Space Telescope survey of the central plane of the Milky Way Galaxy revealed an unusual feature of some massive star forming regions in the galaxy: areas of extended emission that appear to have enhanced flux at 4.5 microns (which is usually assigned the color green when constructing three-color images from Spitzer data). These so-called “green fuzzies” (or “extended green objects”) were previously associated with massive young stellar objects (MYSOs) in star forming regions, but the exact origin of the emission could not be determined from the images alone. In one source, known as G19.88-053, the new NIRI data revealed that the enhanced 4.5 micron emission arises from a prominent molecular hydrogen emission line …

27 April 2010: Gemini Observatory aims to be one of the most energy efficient astronomical facilities, with the highest standards of environmental protection. Since it first encouraged, in 2008, staff proposals to reduce its carbon footprint, the organization has formalized its energy planning efforts and developed many initiatives to reduce energy consumption and help the Observatory “tread more lightly on the Earth.” There are many challenges to creating an effective, organization-wide energy-reduction program for two of the world’s largest telescopes, based in two countries, on two continents. Differing energy infrastructures, government systems, cultural norms, and business resources have all required us to remain flexible and creative as we work to reduce, re-use, and recycle wherever possible, but we have already chalked up several successes and a few of the highlights from this program follow: Electricity Chile enjoys relatively low electricity costs, but Hawaii’s are the highest in the United States. In February 2008, …

25 March 2010: A striking new Gemini Observatory image of the Owl Nebula, a prominent object visible in the northern sky, was released today (March 25, 2010) as the culmination of a nationwide student essay contest in Canada. Upon winning the award, high school student Émilie Storer from Collège Charlemagne, in Pierrefonds, Quebec, said, “I definitely want to be an astronomer now!” Émilie was recognized at a celebration held at Collège Charlemagne in Pierrefonds, Quebec, hosted by Canadian Gemini Office Astronomer André-Nicolas Chené, as well as former Gemini Science Fellow Étienne Artigau (now at Université de Montreal). At the event, attended by over 250 students, the scientists explained how the planetary nebula formed and what is known about it from previous studies, as well as what Émilie’s new observations might bring. In addition, a live video-link to the Gemini North control room allowed students to see where the observations were made and talk …

11 March 2010: Galaxies are the building blocks of the universe, so accounting for their formation is an essential problem in astronomy. Most galaxies are either spiral or elliptical, with the latter tending to be larger and more massive. One suggestion that is grounded in fundamental measurements of the universe as a whole is that merging spiral galaxies form elliptical galaxies. A way to test the predictions of this merger hypothesis is to observe examples of galaxy merging in process. Barry Rothberg and Jacqueline Fischer of the Naval Research Laboratory (US) have done that, drawing important conclusions about the objects they observed and the techniques astronomers use to measure them. One critical property of a galaxy is its mass. The motion of stars is sensitive to the gravitational effect of the mass, so measuring the stellar motion can yield a galaxy's mass. Observations of characteristic features in the spectra of stars are sensitive …

11 March 2010: Consequences of galaxy-scale outflows are profound in the early universe, and an international team led by David Alexander at Durham University (UK) provides insight into the process using new observations with the Gemini Near-Infrared Integral Field Spectrometer (NIFS) on Gemini North. The material between galaxies is observed to be enriched in metals (elements more complex than helium) compared with primordial abundances, which requires early generations of star formation to produce the metals. The galactic outflows thought to be responsible for this enrichment must be extremely energetic for the material to escape a galaxy’s strong gravitational pull. Moreover, outflows and superwinds may provide some of the feedback that suppresses further star formation, thus accounting for the sharp decline in the cosmic star-formation rate from its peak at redshifts between z ≈ 2 to 3. Either the stars themselves (through winds and supernovae) or winds and jets that are a result of …

28 February 2010: The staff of Gemini Observatory extends its deepest sympathies to the families of those who suffered losses or are displaced due to the major magnitude 8.8 earthquake that struck southern Chile early Saturday morning, February 27, 2010. Gemini was fortunate that there were no significant structural damages to any of our facilities. The earthquake disrupted observations on early Saturday morning for less than 30 minutes. Subsequent operations have been essentially normal with the exception of Internet connectivity. We are dealing with communications and minor power inconsistencies that should be solved once general Chilean infrastructure issues are resolved. The temblor struck about 700 kilometers south of Gemini South which is on Cerro Pachón. Both of the Gemini telescopes are located in seismically active locations and on October 15, 2006 Gemini North experienced a major (magnitude 6.7) earthquake that inflicted significant damage to the telescope and related systems. In total 26 nights …