Announcements 2005

23 Febrero 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 Febrero 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 Enero 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 Enero 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 Enero 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 Enero 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.