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The Puzzle of the Strange Galaxy Made of 99.9% Dark Matter Is Solved 13 October 2020
The puzzle of the strange galaxy made of 99.9% dark matter is solved 13 October 2020 The galaxy Dragonfly 44 was discovered in a deep survey of the Coma cluster, a cluster with several thousand galaxies. From the start, the galaxy was considered remarkable by the researchers because the quantity of dark matter they inferred was almost as much as that in the Milky Way, the equivalent of a billion solar masses. However, instead of containing around a hundred thousand million stars, as has the Milky Way, DF44 has only a hundred million stars, a thousand times Image and amplification (in color) of the ultra-diffuse fewer. This means that the amount of dark matter galaxy Dragonfly 44 taken with the Hubble space was ten thousand times greater than that of its telescope. Credit: Teymoor Saifollahi and NASA/HST. stars. If this had been true, it would have been a unique object, with almost 100 times as much dark matter as that expected from the number of its stars. At present, the formation of galaxies is difficult to understand without the presence of a ubiquitous, Nevertheless, by an exhaustive analysis of the but mysterious component, termed dark matter. system of globular cluster around Dragonfly 44, the Astronomers have measure how much dark matter researchers have detected that the total number of there is around galaxies, and have found that it globular clusters is only 20, and that the total varies between 10 and 300 times the quantity of quantity of dark matter is around 300 times that of visible matter. -
Arxiv:2012.09981V1 [Astro-Ph.SR] 17 Dec 2020 2 O
Contrib. Astron. Obs. Skalnat´ePleso XX, 1 { 20, (2020) DOI: to be assigned later Flare stars in nearby Galactic open clusters based on TESS data Olga Maryeva1;2, Kamil Bicz3, Caiyun Xia4, Martina Baratella5, Patrik Cechvalaˇ 6 and Krisztian Vida7 1 Astronomical Institute of the Czech Academy of Sciences 251 65 Ondˇrejov,The Czech Republic(E-mail: [email protected]) 2 Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, 119234, Moscow, Russia 3 Astronomical Institute, University of Wroc law, Kopernika 11, 51-622 Wroc law, Poland 4 Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotl´aˇrsk´a2, 611 37 Brno, Czech Republic 5 Dipartimento di Fisica e Astronomia Galileo Galilei, Vicolo Osservatorio 3, 35122, Padova, Italy, (E-mail: [email protected]) 6 Department of Astronomy, Physics of the Earth and Meteorology, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynsk´adolina F-2, 842 48 Bratislava, Slovakia 7 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, H-1121 Budapest, Konkoly Thege Mikl´os´ut15-17, Hungary Received: September ??, 2020; Accepted: ????????? ??, 2020 Abstract. The study is devoted to search for flare stars among confirmed members of Galactic open clusters using high-cadence photometry from TESS mission. We analyzed 957 high-cadence light curves of members from 136 open clusters. As a result, 56 flare stars were found, among them 8 hot B-A type ob- jects. Of all flares, 63 % were detected in sample of cool stars (Teff < 5000 K), and 29 % { in stars of spectral type G, while 23 % in K-type stars and ap- proximately 34% of all detected flares are in M-type stars. -
A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra
San Jose State University From the SelectedWorks of Aaron J. Romanowsky 2016 A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra-Diffuse Galaxy Dragonfly 44 Pieter van Dokkum, Yale University Roberto Abraham, University of Toronto Jean P. Brodie, University of California Observatories Charlie Conroy, Harvard-Smithsonian Center for Astrophysics Shany Danieli, Yale University, et al. Available at: https://works.bepress.com/aaron_romanowsky/117/ The Astrophysical Journal Letters, 828:L6 (6pp), 2016 September 1 doi:10.3847/2041-8205/828/1/L6 © 2016. The American Astronomical Society. All rights reserved. A HIGH STELLAR VELOCITY DISPERSION AND ∼100 GLOBULAR CLUSTERS FOR THE ULTRA-DIFFUSE GALAXY DRAGONFLY 44 Pieter van Dokkum1, Roberto Abraham2, Jean Brodie3, Charlie Conroy4, Shany Danieli1, Allison Merritt1, Lamiya Mowla1, Aaron Romanowsky3,5, and Jielai Zhang2 1 Astronomy Department, Yale University, New Haven, CT 06511, USA 2 Department of Astronomy & Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada 3 University of California Observatories, 1156 High Street, Santa Cruz, CA 95064, USA 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, USA 5 Department of Physics and Astronomy, San José State University, San Jose, CA 95192, USA Received 2016 June 20; revised 2016 July 14; accepted 2016 July 15; published 2016 August 25 ABSTRACT Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these ultra-diffuse galaxies (UDGs) in a rich cluster suggests that they have very high masses. Here, we present the stellar kinematics of Dragonfly44, one of the largest Coma UDGs, using a 33.5 hr fi +8 -1 integration with DEIMOS on the Keck II telescope. -
Messier Objects
Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun. -
ANNUAL REPORT 2017 THERE NOW ARE 4,256 SATELLITES ORBITING the PLANET, “There Was Nowhere to Go but 179 More Than a Year Ago
ANNUAL REPORT 2017 THERE NOW ARE 4,256 SATELLITES ORBITING THE PLANET, “There was nowhere to go but 179 more than a year ago. Of the current total, 1,419 are operational. everywhere, so just keep on The number of satellites has grown impressively since KSAT had its rolling under the stars.” first satellite contact the night of May 17, 1968. JACK KEROUAC (1922-1969) IN “ON THE ROAD” KSAT has changed over the 15 years success for KSAT depends on its teams, Station in 1967 and the first contact we have been in operation. We’ve and partly because experience suggests in 1968. It’s worth remembering that consistently added to our portfolio of that we should take the best of the past this took place only 10 years after the That first satellite contact from Tromsø, Los Angeles, USA. Lamentably, our activities and sought synergies between with us when we prepare for the future. first satellites were launched. One of Norway triggered an industrial develop- Canadian station in Inuvik, NWT still our business areas. Whenever Satellite Hence, in 2017, we continued to focus the first Norwegian computers was ment that became Kongsberg Satellite awaits Canadian Government licenses Operations supports a new mission, it on customers, unconventional and installed at KSAT and paved the way Services (KSAT), now the world’s largest to attain operational status. The total also creates an opportunity for the flexible solutions, and technological for the digital revolution in Norway. ground station service provider. That number of antennas has grown to 138 Energy, Environment and Security development. -
CONSTELLATION TRIANGULUM, the TRIANGLE Triangulum Is a Small Constellation in the Northern Sky
CONSTELLATION TRIANGULUM, THE TRIANGLE Triangulum is a small constellation in the northern sky. Its name is Latin for "triangle", derived from its three brightest stars, which form a long and narrow triangle. Known to the ancient Babylonians and Greeks, Triangulum was one of the 48 constellations listed by the 2nd century astronomer Ptolemy. The celestial cartographers Johann Bayer and John Flamsteed catalogued the constellation's stars, giving six of them Bayer designations. The white stars Beta and Gamma Trianguli, of apparent magnitudes 3.00 and 4.00, respectively, form the base of the triangle and the yellow-white Alpha Trianguli, of magnitude 3.41, the apex. Iota Trianguli is a notable double star system, and there are three star systems with planets located in Triangulum. The constellation contains several galaxies, the brightest and nearest of which is the Triangulum Galaxy or Messier 33—a member of the Local Group. The first quasar ever observed, 3C 48, also lies within Triangulum's boundaries. HISTORY AND MYTHOLOGY In the Babylonian star catalogues, Triangulum, together with Gamma Andromedae, formed the constellation known as MULAPIN "The Plough". It is notable as the first constellation presented on (and giving its name to) a pair of tablets containing canonical star lists that were compiled around 1000 BC, the MUL.APIN. The Plough was the first constellation of the "Way of Enlil"—that is, the northernmost quarter of the Sun's path, which corresponds to the 45 days on either side of summer solstice. Its first appearance in the pre-dawn sky (heliacal rising) in February marked the time to begin spring ploughing in Mesopotamia. -
Spatially Resolved Stellar Kinematics of the Ultra-Diffuse Galaxy Dragonfly 44
The Astrophysical Journal, 880:91 (26pp), 2019 August 1 https://doi.org/10.3847/1538-4357/ab2914 © 2019. The American Astronomical Society. All rights reserved. Spatially Resolved Stellar Kinematics of the Ultra-diffuse Galaxy Dragonfly 44. I. Observations, Kinematics, and Cold Dark Matter Halo Fits Pieter van Dokkum1 , Asher Wasserman2 , Shany Danieli1 , Roberto Abraham3 , Jean Brodie2 , Charlie Conroy4 , Duncan A. Forbes5, Christopher Martin6, Matt Matuszewski6, Aaron J. Romanowsky2,7 , and Alexa Villaume2 1 Astronomy Department, Yale University, 52 Hillhouse Avenue, New Haven, CT 06511, USA 2 University of California Observatories, 1156 High Street, Santa Cruz, CA 95064, USA 3 Department of Astronomy & Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, USA 5 Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122, Australia 6 Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Mail Code 278-17, Pasadena, CA 91125, USA 7 Department of Physics and Astronomy, San José State University, San Jose, CA 95192, USA Received 2019 March 31; revised 2019 May 25; accepted 2019 June 5; published 2019 July 30 Abstract We present spatially resolved stellar kinematics of the well-studied ultra-diffuse galaxy (UDG) Dragonfly44, as determined from 25.3 hr of observations with the Keck Cosmic Web Imager. The luminosity-weighted dispersion +3 −1 within the half-light radius is s12= 33-3 km s , lower than what we had inferred before from a DEIMOS spectrum in the Hα region. There is no evidence for rotation, with Vmax áñ<s 0.12 (90% confidence) along the major axis, in possible conflict with models where UDGs are the high-spin tail of the normal dwarf galaxy distribution. -
Tetrahedral Hydrocarbon Nanoparticles in Space: X-Ray Spectra
Mon. Not. R. Astron. Soc. 000, 1–7 (2018) Printed 15 October 2018 (MN LATEX style file v2.2) Tetrahedral hydrocarbon nanoparticles in space: X-ray spectra G. Bilalbegovic´1, A. Maksimovic´2, L. A. Valencic3;4 1Department of Physics, Faculty of Science, University of Zagreb, Bijenickaˇ cesta 32, 10000 Zagreb, Croatia 2Center of Excellence for Advanced Materials and Sensing Devices, Rudjer Boskoviˇ c´ Institute, Bijenickaˇ cesta 54, 10000 Zagreb, Croatia 3NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 4The Johns Hopkins University, Department of Physics & Astronomy, 366 Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218, USA 15 October 2018 ABSTRACT It has been proposed, or confirmed, that diamond nanoparticles exist in various environ- ments in space: close to active galactic nuclei, in the vicinity of supernovae and pulsars, in the interior of several planets in the Solar system, in carbon planets and other exoplanets, carbon- rich stars, meteorites, in X-ray active Herbig Ae/Be stars, and in the interstellar medium. Using density functional theory methods we calculate the carbon K-edge X-ray absorption spectrum of two large tetrahedral nanodiamonds: C26H32 and C51H52. We also study and test our methods on the astrophysical molecule CH4, the smallest C-H tetrahedral structure. A possible detection of nanodiamonds from X-ray spectra by future telescopes, such as the project Arcus, is proposed. Simulated spectra of the diffuse interstellar medium using Cyg X-2 as a source show that nanodiamonds studied in this work can be detected by Arcus, a high resolution X-ray spectrometer mission selected by NASA for a Phase A concept study. -
Exoplanet Community Report
JPL Publication 09‐3 Exoplanet Community Report Edited by: P. R. Lawson, W. A. Traub and S. C. Unwin National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California March 2009 The work described in this publication was performed at a number of organizations, including the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Publication was provided by the Jet Propulsion Laboratory. Compiling and publication support was provided by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, or the Jet Propulsion Laboratory, California Institute of Technology. © 2009. All rights reserved. The exoplanet community’s top priority is that a line of probeclass missions for exoplanets be established, leading to a flagship mission at the earliest opportunity. iii Contents 1 EXECUTIVE SUMMARY.................................................................................................................. 1 1.1 INTRODUCTION...............................................................................................................................................1 1.2 EXOPLANET FORUM 2008: THE PROCESS OF CONSENSUS BEGINS.....................................................2 -
Astronomers Discover a Distant Galaxy with a Pulse 16 November 2015
We've got the beat: Astronomers discover a distant galaxy with a pulse 16 November 2015 phase. Until now, no one had considered the effects of these stars on the light coming from more distant galaxies. In distant galaxies the light of each pulsating star is mixed with the light of many more stars that do not vary in brightness. "We realized that these stars are so bright and their pulsations so strong that they are difficult to hide," said Charlie Conroy, an assistant professor at Harvard, who led the research. "We decided to see if the pulsations of these stars could be detected even if we could not separate their light from the Hubble Space Telescope photograph of the galaxy M87, sea of unchanging stars that are their neighbors." which is 50 million light years from Earth. Credit: NASA/ESA Astronomers at Yale and Harvard have found a galaxy with a heartbeat—and they've taken its pulse. It is the first time scientists have measured the effect that pulsating, older red stars have on the light of their surrounding galaxy. The findings are published in the Nov. 16 online edition of the journal Nature. "We tend to think of galaxies as steady beacons in the sky, but they are actually 'shimmering' due to all the giant, pulsating stars in them," said Pieter van Dokkum, the Sol Goldman Professor and chair of astronomy at Yale, and co-author of the study. Later in life, stars like our Sun undergo significant changes. They become very bright and swell up to an enormous size, swallowing any planets within a An image of the pulsating star T Leporis, compared to the radius roughly equivalent to Earth's distance from size of the orbit of the Earth around the Sun. -
Incidental Tables
Sp.-V/AQuan/1999/10/27:16:16 Page 667 Chapter 27 Incidental Tables Alan D. Fiala, William F. Van Altena, Stephen T. Ridgway, and Roger W. Sinnott 27.1 The Julian Date ...................... 667 27.2 Standard Epochs ...................... 668 27.3 Reduction for Precession ................. 669 27.4 Solar Coordinates and Related Quantities ....... 670 27.5 Constellations ....................... 672 27.6 The Messier Objects .................... 674 27.7 Astrometry ......................... 677 27.8 Optical and Infrared Interferometry ........... 687 27.9 The World’s Largest Optical Telescopes ........ 689 27.1 THE JULIAN DATE by A.D. Fiala The Julian Day Number (JD) is a sequential count that begins at Noon 1 Jan. 4713 B.C. Julian Calendar. 27.1.1 Julian Dates of Specific Years Noon 1 Jan. 4713 B.C. = JD 0.0 Noon 1 Jan. 1 B.C. = Noon 1 Jan. 0 A.D. = JD 172 1058.0 Noon 1 Jan. 1 A.D. = JD 172 1424.0 A Modified Julian Day (MJD) is defined as JD − 240 0000.5. Table 27.1 gives the Julian Day of some centennial and decennial dates in the Gregorian Calendar. 667 Sp.-V/AQuan/1999/10/27:16:16 Page 668 668 / 27 INCIDENTAL TABLES Table 27.1. Julian date of selected years in the Gregorian calendar [1, 2]. Julian day at noon (UT) on 0 January, Gregorian calendar Jan. 0.5 JD Jan. 0.5 JD Jan. 0.5 JD Jan. 0.5 JD 1500 226 8923 1910 241 8672 1960 243 6934 2010 245 5197 1600 230 5447 1920 242 2324 1970 244 0587 2020 245 8849 1700 234 1972 1930 242 5977 1980 244 4239 2030 246 2502 1800 237 8496 1940 242 9629 1990 244 7892 2040 246 6154 1900 241 5020 1950 243 3282 2000 245 1544 2050 246 9807 Century years evenly divisible by 400 (e.g., 1600, 2000) are leap years. -
VLT Telescope Control Software Installation and Commissioning (Pdf
VLT Telescope Control Software installation and commissioning. K. Wirenstrand, G. Chiozzi, R. Karban European Southern Observatory Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany e-mail: [email protected], [email protected], [email protected] ABSTRACT Out of the four VLT Unit Telescopes, three have had first light and of those, one is in full scientific operation. So the VLT style Telescope Control Software is in regular operation on three out of four originally foreseen telescopes, and is being installed and tested on the fourth. In fact, it is actually installed and successfully operating on a whole family of ESO telescopes: the NTT, the 3.6m La Silla, the Seeing monitor telescopes on Paranal and La Silla. That means that this software is installed and running on a total of eight telescopes of different kinds, for the moment. The three Auxiliary telescopes of the VLT interferometer and the VLT Survey Telescope, now in the development phase, will join the family. Another member of the family is the Simulation Telescope, called "Control Model", at ESO headquarters in Garching. Although it cannot look at the sky (it is pure electronics and software: no mechanics and no optics) it has been, and still is, of great value. It can be reconfigured to emulate any of the actual telescopes and it is used for off-line testing of new software releases and to analyse and fix problem reports and change requests submitted from observation sites, without disturbing operation. It is also used to test instrumentation software and its interfaces with the TCS before the actual integration at the telescope.