Anuncios

21 Diciembre 2007: The 62nd General Assembly of the United Nations has proclaimed 2009 as the International Year of Astronomy. An initiative of the International Astronomical Union and UNESCO, IYA 2009 is focused completely on public outreach and science education, and includes significant leadership roles for NOAO PAEO staff. For more on the emerging US and international plans, see www.astronomy2009.org

17 Diciembre 2007: On December 8th the first-ever Gemini Staff Family Tour was held at Gemini South. This was followed on December 15th with a Staff Family tour at Gemini North. Over 75 staff and family participated (or led) the tours which gave family members of Gemini’s staff an opportunity to see the Gemini North and South telescope facilities first-hand and see where family members work. At Gemini North, Tony Matulonis (System Support Associate) put the telescope and enclosure through its motions for the group. Tony’s mom (Anna Trope) wrote that this was, “…An absolutely wonderful tour that was an inspiring learning experience!” Gemini’s Human Resources Recruiter Mahshid Albrecht said that it was an experience she will never forget, and that she “…felt like a little kid!” Finally, Dorothy Fukushima made the comment (several times) that everyone else was feeling from the snowy heights of Mauna Kea, “I am sooooo cold!” “This is …

1 Diciembre 2007: Jean-René Roy, Mike Sheehan and Pete McEvoy Gemini Observatory On December 3-4, 2007, more than 70 engineers, technicians, safety officers and coordinators, administrative personnel and astronomers from observatories around the world met in La Serena, Chile for the first Chile Observatory Earthquake Preparedness Workshop. The goal of the workshop was to develop better means to protect our staff and our valued equipment in case of a major earthquake. Chile has one of the highest rates of seismicity in the world and was in fact the location of the most intense earthquake ever recorded; the M9.5 earthquake in 1960, which, combined with its resulting tsunami, caused thousand deaths and devastation in Chile, Hawai‘i, the Philippines, Easter Island and Samoa. Astronomical Observatories in Chile will experience the effects of one or more major earthquakes in their lifetimes and we need to be prepared. About two weeks before the workshop, a magnitude 7.7 …

29 Noviembre 2007: Astronomers have discovered one of the fastest-moving stars ever seen, using a combination of data from NASA’s Chandra X-ray Observatory, the international ROSAT satellite, and the 0.9-meter telescope at Cerro Tololo Inter-American Observatory. A team observed a neutron star known as RX J0822-4300 over a period of about five years. During that span, three Chandra observations clearly show the neutron star moving away from the center of the Puppis A supernova remnant and the stellar debris field created during the same explosion in which the neutron star was formed, about 3,700 years ago. By combining how far the neutron star has moved across the sky with its distance from Earth, astronomers determined the star is moving at more than 3 million miles per hour. NASA Release

16 Noviembre 2007: Statement of The Gemini Observatory Board of Directors The Board of the Gemini Observatory has concluded its meeting of November 14-16, 2007 in La Serena, Chile. In addition to its normal business, it considered the implications of the communication by the Science and Technology Facilities Council of the United Kingdom that it may withdraw as a (23.8%) partner in the Gemini Observatory. The Board deeply regrets the announcement that the UK will likely withdraw as a partner in the Gemini Observatory. The UK astronomical community has made substantial and very valuable contributions to the success of the Gemini partnership from its earliest days. The Board reaffirms its vision for the Observatory and resolves to address any resource problems brought on by the announced UK intentions expeditiously and with minimum impact on the current operation of the Observatory. The Board is confident that the Gemini Observatory will continue to operate efficiently …

15 Noviembre 2007: A team of US-led astronomers used the Gemini North 8-meter telescope to find evidence for the formation of young rocky planets around the star HD 23514 located in the well-known Pleiades (Seven Sisters) star cluster, which is easily visible in the current evening sky. Joseph Rhee (UCLA) and his collaborators used the infrared camera Michelle to measure heat from hot dust surrounding a 100 million year-old star in the bright cluster, one of the very few solar-type stars known to be orbited by warm dust particles. For more, see Gemini Press Release.

5 Noviembre 2007: A fossil group of galaxies is a system of several dozen galaxies with an extended and luminous X-ray halo (Lx > 1042 ergs/sec). Its striking feature is that it is dominated by one single very luminous elliptical galaxy and surrounded by low-luminosity companions. In these systems the difference in brightness between the bright dominant elliptical and the next brightest companion is 2 magnitudes or more (in optical R band). This is as if the bright galaxy had absorbed several of its smaller companions over the history of the group. Compact groups have many members but they have a better balance of bright galaxies. It has been suggested that fossil groups could be the cannibalized remains of compact groups where several of the more massive objects lost energy through tidal friction and merged. In the nearby universe compact groups which are close to the merging phase (and display a wealth of …

5 Noviembre 2007: This image of the freshly expanding cloud of gas and dust around Comet 17P/Holmes was taken at the Kitt Peak Visitor Center observatory on November 2. The comet, which orbits the Sun between Mars and Jupiter, is located in the constellation Perseus and can be seen in the northeast night sky with unaided eyes.

30 Octubre 2007: This image of the freshly expanding cloud of gas and dust around Comet 17P/Holmes was taken with the WIYN 0.9-meter telescope at Kitt Peak National Observatory on the night of October 29, 2007. The image was taken by a group including a teacher and students from the NOAO Astronomy RBSE program. The comet, which orbits the Sun between Mars and Jupiter, is located in the constellation Perseus and can be seen in the northeast night sky with unaided eyes.

17 Octubre 2007: Observations that combine data from the ground-based Gemini North telescope and NASA’s orbiting Chandra X-ray observatory have led to the discovery of the most massive known stellar black hole. Intriguingly, the black hole orbits an exceptionally large companion star, which by an extremely fortunate coincidence also eclipses the black hole from our perspective on Earth. As the only known eclipsing binary black hole/star pair the team was able to determine fundamental parameters of the pair with high precision. The ramifications of this pairing could have a profound effect on our understanding of how the largest stars evolve. The black hole-star pair is located about 3 million light years from Earth in a neighboring galaxy named M33. The combination of X-ray data with Gemini North’s optical images and spectroscopy (see Figure 2) led the international team to conclude that the black hole is 15.7 times the mass of our Sun making …

17 Octubre 2007: Astronomers have located an exceptionally massive black hole in orbit around a huge companion star in the nearby galaxy M33. The mass of the black hole, known as M33 X-7, was determined to be 15.7 times that of the Sun. This result, published in the journal Nature, has intriguing implications for the evolution and ultimate fate of massive stars. Data from NASA’s Chandra X-ray Observatory, Gemini North, and the 2.1-meter and WIYN 3.5-meter telescopes at Kitt Peak were combined to make this discovery, which includes contributions from NOAO astronomer Lucas Macri regarding the precise distance to M33. For more, see Chandra Press Release.

8 Octubre 2007: A Canada-US-UK team led by David Lafrenière and René Doyon of the University of Montreal has released the first results from the Gemini Deep Planet Survey (GDPS), a near-infrared adaptive optics search for giant planets and brown dwarfs around 85 nearby young stars. The observations, made with the ALTAIR/NIRI adaptive optics system at the Gemini North telescope, are aimed at constraining the population of Jupiter-mass planets with orbits that have a semi-major axis in the range of 10-300 astronomical units (AU). This work constitutes a first step toward the detection of the population of “outer” giant planets around other stars. The use of angular differential imaging (see ADI "how-to" box below) in conjunction with NIRI/ALTAIR enabled the team to reach the best sensitivities to date for detecting giant exoplanets with projected separation above ~0.7 arcsecond. The typical detection limits (5 sigma) reached by the survey, in magnitude difference between an …

27 Septiembre 2007: In early September 2007, the 400th Gemini paper was accepted for publication in one of the main refereed astronomical journals. The last time we reported on the Gemini papers statistics was on 4 January 2006, when the 200th Gemini paper appeared. The 400th paper which is titled “SNLS Spectroscopy: Testing for Evolution in Type Ia Supernovae,” 2008, A&A, by T. J. Bronder and 21 co-authors of the Supernova Legacy Survey (SNLS) team. The author team consists of researchers from the United Kingdom, Canada, France, Portugal, and the United States. The article reports on the supernova candidate spectra observed with the Gemini telescopes during the first 34 months of the SNLS, 87 of which have been identified as SNe Ia at a median redshift of z = 0.720. The study shows that there exists a sample at high red fist with properties similar to nearby SNe. Correlations between Type Ia SNE …

24 Septiembre 2007: Chris Willott (University of Ottawa) and a large international research team identified four new quasars at redshift greater than z = 6 from MegaCam imaging at the Canada-France-Hawaii Telescope (CFHT). Follow-up spectroscopy with GMOS at the Gemini South telescope (and the Marcario LRS at the Hobby-Ebbberly Telescope) allowed the team to determine accurate redshifts. The team found what is now the most distant known quasar, CFHQS J2329-0301 at z = 6.43 (Figures 1 and 2). Willott et al. also used the spectra to investigate constraints on the ionization sate of the intergalactic medium at that early age of the universe. Analysis of two of these quasar spectra revealed evidence that the reionization period is considerably longer than predicted by most theoretical models. From the time of recombination, (about 380,000 years after the Big Bang when protons and electrons combined into neutral hydrogen), the universe remained in this state for the …

24 Septiembre 2007: Astronomers have found evidence that stars have been forming in a long tail of gas that extends well outside its parent galaxy, using a combination of images in X-ray light from NASA's Chandra X-ray Observatory and optical light from the Southern Astrophysical Research (SOAR) telescope in Chile. This comet-like tail of newborn stars extends more than 200,000 light years, and suggests that such "orphan" stars may be much more prevalent than previously thought. For more, see Chandra Press Release.

11 Septiembre 2007: An international team of researchers led by Natalia Boris of the University of São Paulo in Brazil has shown that quasar pairs may be excellent beacons for finding clusters of galaxies in the early universe. Quasars are relatively rare astronomical objects. If, as evidence suggests, their spatial distribution follows that of galaxies then the presence of two or more quasars in the same small volume of space might indicate a region that is exceptionally rich in galaxies. Deep multi-color images of four fields around quasar pairs (QP0110-0219, QP1310+0007, QP1355-0032, and QP0114-3140) at redshift z~1 were obtained with the Gemini Multi-Object Spectrograph (GMOS) at both Gemini North and South. The quasar pairs were selected to have redshift differences smaller than 0.01 and projected angular separations less than 300 arcseconds, corresponding to projected physical separations less than 2.5 megaparsecs. Examination of the quasar spectra confirmed that these are bona fide pairs of …

5 Septiembre 2007: At Gemini the night of July 4th, 2005 was filled with fireworks, both earthly and celestial. In support of NASA’s Deep Impact (DI) mission two teams of scientists used the Gemini mid-infrared instruments MICHELLE and T-ReCS to acquire imaging and spectroscopic observations of Comet Tempel 1 throughout the impact event. At Gemini South a team led by David Osip (Carnegie Inst.) and James De Buizer (Gemini) used T-ReCS to image the impact and the resulting dust plume (Figure 1). At Gemini North, David Harker (UCSD) led a team that used MICHELLE to obtain mid-infrared spectra Temple 1 over a three-night observing run. The Harker campaign was conducted in conjunction with a team using the mid-IR instrument COMICS on the Subaru telescope. By observing the comet pre-, and post-impact, the Harker team gathered baseline data sets to compare with data obtained during the moments surrounding impact. The results of the campaign …

3 Septiembre 2007: View the NOAO Showcase: Local Group Galaxies in Google Earth.

29 Agosto 2007: As young stars form and evolve they generate spectacular high-speed jets and outflows consisting of molecular and atomic gas streaming away from the star. It is not completely understood what mechanisms launch these jets. This is partly because most of the action takes place in the inner, difficult to view, regions of the dense gas and dust accretion disk surrounding these forming stars. The best spatial and spectroscopic resolution is needed to dissect this region. A team led by Michihiro Takami (Subaru Telescope, now at ASIAA) and Tracy Beck (Gemini Observatory) have used the adaptive optics fed integral-field spectrograph NIFS on Gemini North to explore the inner structure of the jet in the young star HL Tau, located about 140 parsecs (460 light years) away in the constellation of Taurus. The morphology and kinematics in molecular hydrogen (H2) emission from HL Tau are found to be similar to millimeter wavelength …

28 Agosto 2007: The Milky Way rises above Cerro Tololo Inter-American Observatory and the Blanco 4-meter telescope in this 30-second exposure taken with a Canon 1D Mark IIN digital camera and a 15mm fisheye lens.