Announcements

12 April 2005: Recent spectroscopic studies of infrared light reflected from the surface of Sedna reveal that it is probably unlike Pluto and Charon since Sedna's surface does not display evidence for a large amount of either water or methane ice. Due to Sedna’s extreme distance from the Sun, the frigid surface has probably been untouched for millions of years by anything except cosmic rays and solar ultraviolet radiation. Gemini Observatory astronomer Chad Trujillo led an effort by the same California Institute of Technology research team responsible for Sedna's original discovery to obtain spectra of this distant planetoid using the Near Infrared Imager (NIRI) on Gemini North. Their aim was to better understand the surface of this distant world and how it has evolved since its formation. “It is likely that Sedna has experienced an extremely isolated life in the outskirts of our solar system,” said Trujillo. “Out there beyond what we used …

5 April 2005: The winter rains were plentiful in 2004-2005, giving rise to a beautiful display of wildflowers along the road to Kitt Peak. A number of telescopes are visible in the background of this image from March 2005, including the Mayall 4-meter telescope at the peak of the mountain.

28 March 2005: Can galaxies observed at very high redshifts (at a time when the universe was a fraction of its current age) evolve to look like today's nearby galaxies simply by growing older? The answer is no according to an international team of scientists led by Inger Jørgenson (Gemini Observatory) who used GMOS on Gemini North, combined with HST imaging data to survey distant galaxies and chart their evolution. The team's results demonstrate that cluster galaxies closer to us are not aged versions of the kinds of early galaxies seen in distant clusters that existed when the universe was half its current age, about seven billion years ago. To evolve into galaxies like those we see in nearby clusters, these galaxies require more than just a single episode of star formation as current theories suggest — the distant early "progenitors" have to undergo a set of profound transformations that most likely include …

25 March 2005: This open star cluster in the constellation Scorpius is set against the dramatic backdrop of the Milky Way. At 800-1000 light years away, M7's 80-odd stars are spread over some 20-25 light-years and are in excess of 200 million years old. This image of M7 was taken during the Advanced Observing Program.

11 March 2005: How do massive stars form? The time scale for massive star formation is much shorter than for low-mass stars. During the birth process, a massive core will form first and begin evolving (converting hydrogen to helium) while the larger protostar is still accreting material. Like their lower-mass cousins, massive stellar objects are obscured by overlying envelopes of gas and dust during their formation which makes this stage of massive star formation a challenge to observe. Despite the difficulty of discerning the massive cores as they form, progress is being made on both theoretical and observational fronts. New, large-aperture ground-based telescopes (like Gemini) are providing capabilities which allow astronomers to look much farther away to study more of these rare massive stars in their formative stages and evolve in their birth environments. An international team including Robert Blum (CTIO), Peter Conti (JILA), Augusto Damineli, Elysandra Figuerêdo, and Cássio Barbosa (University of …

10 March 2005: The March 2005 NOAO-NSO Newsletter contains articles on the pending NSF Senior Review, observing opportunities in Semester 2005B, the Gemini WFMOS instrument concept, and the WIYN One-Degree Imager.

1 March 2005: How do you hide something as big and bright as a galaxy? You smother it in cosmic dust. Researchers used data from NASA's Spitzer Space Telescope and the NOAO Deep Wide-Field Survey to uncover a hidden population of monstrously bright galaxies approximately 11 billion light-years away.

23 February 2005: About 500 million years ago a spheroidal galaxy captured a small gas-rich galaxy in a merger that led to a burst of star formation. Using the integral field unit (IFU) on GMOS-South, Mark Swinbank (University of Durham, UK), led an international research team to explore this merging system that is still in the process of digesting the gas and stellar components of the two original galaxies. The galaxy SDSS J101345.39+011613.06, known simply as “E+A” (geminiann05002a), has a redshift of 0.1055, corresponding to a distance of roughly 490 Mpc (or 1.6 billion light-years). This hybrid galaxy has a disturbed morphology and shows signatures of both old low-mass stars (spectral type K) and massive but short-lived stars (spectral type A) distributed throughout. However, the youngest and most massive ones—the OB-type stars—are missing, which indicates that the last star-forming event in E+A took place a few hundred million years ago. Recent spectroscopy conducted …

10 February 2005: Visible light images from NOAO telescopes (left) have been used by scientists from the Spitzer Science Center to help them better understand dozens of massive embryonic stars in the Trifid Nebula (M20), which were discovered in images from two instruments aboard the Spitzer Space Telescope (right).

31 January 2005: NOAO Astronomer Steve Ridgway is part of a team that used the CHARA array on Mount Wilson to make detailed measurements of the physical properties of Regulus, the brightest star in Leo. They found that Regulus’ frenetic spin gives the star a grossly bulging mid-section; its equatorial diameter is one-third larger than its north-south diameter. The star’s axis of rotation happens to point in the same direction as its motion through the galaxy—meaning Regulus zips along like an enormous, spinning bullet.

27 January 2005: A long-standing problem in understanding the evolution of stars has been determining the nature of the stellar progenitors for white dwarf stars. In particular, astronomers want to know how a rather massive star (up to seven times the mass of the Sun) can lose enough mass to become a white dwarf. Key questions include: Which main-sequence stars eventually end their life as white dwarfs? How much mass do they lose in late evolutionary stages? What process allows this to occur? Some answers can be found in the 100th published paper based upon Gemini data. A Canadian, U.S., and Australian team led by Ph. D. student Jason Singh Kalirai of the University of British Columbia selected 24 individual white dwarfs[1] in the field of the rich open star cluster NGC 2099 (M37). This initial identification was made from analysis of deep wide-field imaging using the Canada-France-Hawaii Telescope. By following up on …

11 January 2005: A current rendering of the 8.4-meter Large Synoptic Survey Telescope (LSST) which will use a special three-mirror design, creating an exceptionally wide field of view. The LSST Corporation has awarded a $2.3 million contract to the University of Arizona Steward Observatory Mirror Lab to purchase the glass and begin engineering work for the 8.4-meter diameter main mirror that will enable the LSST to survey the visible sky in only three nights. LSST press release

2 January 2005: Like the annual New Year’s fireworks display, astronomers at Gemini Observatory are ushering in 2005 with a striking image that dazzles the eye with stellar pyrotechnics. In this new image, the face-on spiral galaxy NGC 6946 is ablaze with colorful outbursts fueled by the births and deaths of multitudes of brilliant, massive stars.

24 December 2004: The staff of the National Optical Astronomy Observatory wishes you all the best this holiday season.

20 December 2004: Using adaptive optics on the Gemini North and Keck II telescopes on Mauna Kea, Hawai’i, a U.S. team has discovered a new phenomenon in the atmosphere of Saturn’s largest moon Titan. Unlike previous observations showing storms at the south pole, these new images reveal atmospheric disturbances at Titan’s temperate mid latitudes—about halfway between the equator and the poles. Read the Gemini Press Release.

13 December 2004: Discovered just this past summer, Comet Machholz continues to brighten toward being visible with the unaided eye in both the northern and southern hemispheres. This image was taken at the Kitt Peak Visitor Center Observatory on December 11, 2004.

7 December 2004: Gemini staff have successfully repeated the coating of a 8-meter primary mirror with protected silver during a 9-day shutdown period. This is the second successful silver coating of a Gemini primary mirror and was applied on Thanksgiving Day in a 7-hour process interrupted by an intense hail storm at midday. This is the second time a Gemini primary mirror has been coated with protected silver (Gemini South was coated in May 2004) and now all key optical surfaces (primary, secondary and science fold mirrors) are coated. This is a milestone in front surface mirror coating technology. The result is a dramatic reduction in the thermal emissivity of the telescope systems—down to an unprecedented level of about 2% or lower. Following the successful coating, team members cheered as reflectivity values were announced and they realized that the coating was successful. The application of protected silver coatings on both Gemini telescopes is …

2 December 2004: This image of the massive N11 complex is featured on the cover of the December 2004 NOAO Newsletter. Numerous star forming regions and shells blown out by supernovae and strong stellar winds can be seen. The data used to create the image were taken with the University of Michigan Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory near La Serena, Chile, as part of the Magellanic Clouds Emission Line Survey (MCELS).

30 November 2004: Kevin Luhman (Harvard-Smithsonian Center for Astrophysics), Dawn Peterson (University of Rochester) and S. T. Megeath (also CfA) used the newly commissioned Gemini Near Infrared Spectrograph (GNIRS) on Gemini South to determine the nature of the low-mass object OTS 44. The observations of the faint infrared object confirmed that it is a very low-mass, newborn brown dwarf and the lowest mass brown dwarf found to date in the Chamaeleon I cloud complex. The Chamaeleon I cloud complex is a nearby star-forming region located about 170 parsecs (554 light-years) away from us toward the constellation of Chamaeleon. From the strength of the water vapor (steam) absorption band around 1.5 and 2 microns, and in comparison to other low-mass stellar objects, the team determined OTS 44 to be of very late spectral type M9.5 (geminiann04018a). They estimate its effective temperature at 2300 K. Using the flux in the H band and the object’s …

4 November 2004: Using archived science verification data from the Hokupa'a/QUIRC Adaptive Optics system on Gemini North, a French/US team of astronomers led by Jean-Pierre Maillard of the Institut d’Astrophysique de Paris has confirmed the physical association of a cluster of massive stars in the infrared source IRS 13 near the center of the Milky Way galaxy. The team also used data from Hubble Space Telescope, the Chandra X-Ray Observatory, the Canada-France-Hawai’i Telescope (CFHT), and the Very Large Array to complement the Gemini data. The Gemini observations consisted of deconvolved H and Kp band images that identified the existence of two formerly undetected sources within the eastern component of IRS 13 (called IRS 13E). When the Gemini data were used in conjunction with longer and shorter wavelength observations, it was possible to conclude that these sources were massive stars comparable to the stars of the same type which are exceptionally concentrated in the …