Announcements

14 August 2008: Optical spectroscopy from the Gemini telescopes has revealed a relatively uncommon type of asteroid in the main-belt for the first time. The discovery was made by a joint Brazil and US project led by Thais Mothé-Diniz of the Observatório Nacional in Rio de Janeiro and David Nesvorný of the Southwest Research Institute (Boulder, Colorado). The team used both GMOS North and South to obtain optical spectra of asteroids with estimated ages of < 1 Myr which they then compared to laboratory spectra of meteorites that have fallen to Earth. They found that spectra of asteroids in the newly discovered Datura family have a deep absorption feature near 0.8 microns which classifies them as ‘Q-type’ asteroids. This spectral feature is produced by silicate material, in particular olivine and pyroxene. Most interestingly, the spectra of Q-type objects are well-matched to the most common type of meteorite found on Earth called an ordinary …

14 August 2008: During the second half of July 2008, the Gemini North telescope facility on Mauna Kea underwent a major 20-day scheduled shutdown. The shutdown allowed engineers and technicians to address a number of deferred upgrades and maintenance projects, (see a list of projects here), that are only possible during an extended period of electromechanical work. Included was the successful re-coating of the 8-meter primary mirror with protected silver. "As a scheduled shutdown, we are able to take care of maintenance and upgrades that are not possible when we are on the sky each night," said Brian Walls of Gemini's Systems Engineering team. "And while the new silver coating gets most of the attention, the concurrent work done on the telescope is critical since the entire telescope system needs to function at the same high level..." About four years ago the Gemini North telescope's primary mirror received its first protected silver coating …

31 July 2008: Based on laser guide star adaptive optics (LGS-AO) -fed integral field spectroscopy with the Near-Infrared Spectrograph (NIFS) at Gemini North, Anil C. Seth of the Harvard-Smithsonian Center for Astrophysics and his collaborators demonstrate that the massive nuclear stellar cluster at the core of the spiral galaxy NGC 4244 is strongly rotating. Most late-type spiral galaxies and early-type galaxies have prominent nuclear star clusters (NSCs), i.e. a significant conglomerate of stars about the same size (~ 5 parsecs) as normal globular clusters. Furthermore, the masses of NSCs are coupled to the mass of their host galaxy, following the similar mass vs. velocity dispersion relation known for massive black holes. This suggests that the formation of NSCs and black holes are linked to the formation of their host galaxy. However, unlike that of black holes, the assembly history of NSCs can be inferred from studies of their kinematics and stellar content. NGC …

29 July 2008: The ALTAIR (Access to Large Telescopes for Astronomical Instruction and Research) committee, recently convened by NOAO, seeks to understand the needs of the US community related to ground-based O/IR telescopes in the 6.5- to 10-m aperture range. We ask you to respond to the ALTAIR committee survey regarding your current and future anticipated use of such facilities, including Gemini.

22 July 2008: Astronomer Pierre Martin, director of science operations at the Canada-France-Hawaii Telescope (CFHT), has been selected as the new director of the WIYN Observatory, which operates 3.5-meter and 0.9-meter telescopes on Kitt Peak. Starting September 22, Martin succeeds George Jacoby, who will return to the scientific staff of the National Optical Astronomy Observatory (NOAO).

14 July 2008: Around May 1, 1006 A.D., observers from Africa to Europe to the Far East witnessed and recorded the arrival of light from what is now called SN 1006, a tremendous supernova explosion caused by the final death throes of a white dwarf star. This image of SN1006 is a composite of optical, radio, and X-ray data of the full shell of the supernova remnant. The optical data was obtained at the University of Michigan’s 0.9-meter Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory in Chile. H-alpha, continuum-subtracted data were provided by FrankWinkler (Middlebury College) et al. The object has an angular size of roughly 30 arcminutes (about the size of the full Moon), and a physical size of 60 light-years, based on its distance of nearly 7,000 light-years.

8 July 2008: In mid June 2008, the 500th refereed Gemini paper was accepted for publication in The Astrophysical Journal, one of the main refereed astronomical journals. The last time we reported on Gemini papers statistics was on September 27th 2007 for the 400th Gemini paper. The 500th paper is titled “First Stellar Velocity Dispersion Measurements of a Luminous Quasar Host with Gemini North Laser Guide Star Adaptive Optics”, 2008, The Astrophysical Journal, by Linda C. Watson and 7 co-authors. Linda C. Watson is a Ph.D. student at the Department of Astronomy of the Ohio State University. The authors team consists of researchers from the United States, Canada and Germany. The paper presents new results on the kinematics of stars orbiting at the heart of the quasar host galaxy PG 1426+015 (z = 0.086). The velocities were derived from high spatial resolution near infrared spectra obtained with the integral field unit spectrograph NIFS. …

5 July 2008: The Supernova Legacy Survey (SNLS) had ambitious goals from the start - to produce a definitive sample of distant supernovae for cosmology. The aim was not only to find an order-of-magnitude more distant supernovae than previous surveys, but study them with higher precision. Such a dataset has the potential to distinguish between theories for the mysterious Dark Energy that appears to be causing the expansion of the Universe to accelerate. The 5-year survey began in 2003 and the final supernova spectrum was recently taken at Gemini North (Fig. 1). The survey has been a great success, generating over 400 spectroscopically confirmed Type Ia supernovae. This has been achieved by the international SNLS team using a combination of survey images from CFHT, (obtained from the "Deep" part of the CFHT Legacy Survey), and spectroscopic follow-up using the worlds largest ground-based telescopes including Gemini North and South, VLT, Keck and Magellan. The …

3 July 2008: n what appears to be a masterful illusion, astronomers at Gemini Observatory have imaged two nearly identical spiral galaxies in Virgo, 90 million light years distant, in the early stages of a gentle gravitational embrace. The new image was obtained at the Gemini South telescope in Chile using GMOS, the Gemini Multi-Object Spectrograph. Like two skaters grabbing hands while passing, NGC 5427 (the nearly open-faced spiral galaxy at lower left) and its southern twin NGC 5426 (the more oblique galaxy at upper right), are in the throes of a slow but disturbing interaction-one that could take a hundred million years to complete.

1 July 2008: Probing the Host Galaxy of a Luminous Quasar with Gemini Laser Adaptive Optics A team led by Linda C. Watson, Ph. D. student at the Department of Astronomy, Ohio State University, has made the first bulge stellar velocity dispersion measurement of a luminous quasar host with the Gemini North Laser Guide Star adaptive optics system. The target quasar was PG1426+015, about 1.36 billion light-years away (Figure 1). This result is also the basis for the 500th refereed paper based on Gemini observations. They employed the spectro-imaging spectrograph NIFS fed by the Gemini facility adaptive optics system Altair to obtain high signal-to-noise ratio measurements of near-infrared Si I and Mg I lines and also several CO bandheads in the quasar host galaxy spectrum of PG 1426+15 (Figure 2). Using these measurements, the team found a stellar velocity dispersion of 217 +/- 15 kilometers/second in the region of the galaxy between 0.1'' …

25 June 2008: UK astronomers have reached a milestone in the construction of one of the largest-ever cameras designed to detect the mysterious component of the Universe known as Dark Energy. The pieces of glass for the five unique lenses in the Dark Energy Camera have been shipped from the US to France to be shaped and polished into their final form. The largest of the five is one meter in diameter, making it one of the largest lenses in the world. The camera will be placed on NSF’s Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile to conduct a project called the Dark Energy Survey (DES), as well as other observations for the astronomical community. DES observations will start in 2011 and continue until 2016.

19 June 2008: Call it the case of the missing dwarf. A team of stellar astronomers is engaged in an interstellar crime scene investigation. They have two suspects, traces of assault and battery, but no corpse. The southern planetary nebula SuWt 2 (seen in this color image taken with the 1.5-meter telescope at Cerro Tololo Inter-American Observatory in Chile) is the scene of the crime, some 6,500 light-years from Earth in the direction of the constellation Centaurus.

2 June 2008: The June 2008 NOAO/NSO Newsletter includes articles on the new ALTAIR committee on large telescopes, a science highlight and operational report from the NEWFIRM infrared imager at Kitt Peak, and the results from a survey of the community on their use of the Gemini Observatory.

19 May 2008: Read about the results of our Gemini Opportunity survey of the community, which showed great interest in increased US participation in Gemini. This issue of Currents also explains the need for active involvement by the community in the Giant Segmented Mirror Telescope project, as we move toward public-private GSMT partnerships.

16 May 2008: A team of astronomers has used infrared spectral images of Saturn’s moon, Titan, acquired with the Gemini North Frederick C. Gillett Telescope, to dispute an earlier claimed detection of widespread morning methane drizzle. Titan, the second largest moon in the solar system, has long fascinated astronomers because it is the only moon in the solar system with a thick atmosphere. Adding to the fascination, its cold atmosphere (94 K or -180º C near the surface) has a number of interesting similarities to our Earth’s atmosphere. For example, its complex temperature profile (temperature vs. altitude) has the same overall structure as Earth’s and the atmospheric surface pressures are nearly the same. Also like the earth’s atmosphere, nitrogen is the dominant chemical species. After nitrogen, methane is the most abundant chemical species in Titan’s atmosphere. It has sometimes been said that methane plays the same role in Titan’s atmosphere as water does …

6 May 2008: Taking advantage of the spatial resolution and sensitivity offered by T-ReCS on Gemini South, an international team led by Tanio Diaz-Santos (CSIC, Spain) has completed a survey of nearby Luminous Infrared Galaxies (LIRGs) at 8-microns. The survey showed that to first order the star-formation-rate (SFR) of a galaxy can be determined from its 8-micron emission. This is particularly important for these sources since LIRGs produce the majority of their extended IR luminosity in deeply obscured star-forming regions. This makes traditional star-formation rate (SFR) indicators, for example the UV continuum or the H-alpha line emission, unsuitable for use with LIRGs due to the heavy extinction caused by the dust associated with the star formation sites. However, at longer wavelengths the extinction due to the dust begins to decrease and features like the Paschen-alpha line or even the mid-infrared (MIR) dust continuum emission itself serve as reliable tracers of the star-formation rate …

5 May 2008: The international star-hunting activity known as GLOBE at Night, led by the NOAO educational outreach group, inspired 6,838 measurements of night-sky brightness by citizen scientists around the world, including 660 digital measurements using handheld sky-quality meters. The third edition of GLOBE at Night was held from February 25-March 8. Just over 4,800 of the measurements came from the United States (with 48 states and the District of Columbia reporting at least one measurement). Observers in Hungary submitted the most measurements (380) from outside the U.S., followed by Romania, the Czech Republic, Costa Rica, and Spain, all with over 100 observations.

24 April 2008: The Association of Universities for Research in Astronomy (AURA) has selected Dr. David Silva as the new director of NOAO. Silva brings a wide variety of experience to this appointment, from his current duties as Observatory Scientist for the Thirty Meter Telescope project to past responsibilities for data management and user support at the European Southern Observatory (ESO) in Germany. During a prior tenure at NOAO from 1991 to 1996, Silva served as project manager during the commissioning of the WIYN 3.5-meter telescope on Kitt Peak, and as a staff astronomer in the U.S. office of the Gemini Observatory. Silva is scheduled to formally start work as director on July 7.

14 April 2008: An international team led by Brazilian astronomer Cássio L. Barbosa (UNIVAP, Sao José dos Campos) employed the Gemini North Laser Guide Star (LGS) adaptive optics system Altair to probe deep into the core of star forming region W51. This is one of the most luminous complexes of massive star forming regions in our Galaxy. W51 has two bright infrared sources: IRS1 and IRS2 which are coincident with known radio sources. The team used the Near-Infrared Integral Field Spectrograph (NIFS) to spectro-image three fields in IRS 2, which contains three ultra-compact HII regions: W51d, d1 and d2 (Figure 1). The spectral data cube they constructed allowed the researchers to reconstruct spectral maps at various wavelengths, providing key diagnostics on the composition and velocities of the stellar and gas components in this obscure but active region. The high angular resolution achieved by NIFS and Altair/LGS made possible the separation of the strong …

10 April 2008: Near-infrared observations taken at Gemini North have detected ammonia in the spectra of the coolest brown dwarf ever discovered. This is the first time such a finding has been made in near-infrared spectra of a sub-stellar object other than a planet. The brown dwarf (an object with a mass between that of a star and planet) is known as CFBDS J005910.83-011401.3 (shortened as CFBDS0059) and has an oven-like temperature of only about 350º C and a mass between 15-30 times that of Jupiter. The object is about 40 light-years from us and is located in the constellation Cetus near the boundary with Pisces. It is an unusual isolated object not orbiting another star, but if it were, it would be more difficult to study due to the competing light of the companion star. CFBDS0059 might be a prototype of a new proposed class of brown dwarfs called Y dwarfs that …