Hubble Space Telescope Observer’S Guide Winter 2021
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The ARAUCARIA Project – First Observations of Blue Supergiants in NGC 3109
Reports from Observers The ARAUCARIA Project – First Observations of Blue Supergiants in NGC 3109 Chris Evans1 Fabio Bresolin Miguel Urbaneja Grzegorz Pietrzyn´ski 3,4 Wolfgang Gieren 3 Rolf-Peter Kudritzki 1 United Kingdom Astronomy Technology Centre, Edinburgh, United Kingdom Institute for Astronomy, University of Hawaii, USA 3 Universidad de Concepción, Chile 4 Warsaw University Observatory, Poland NGC 3109 is an irregular galaxy at the edge of the Local Group at a distance of 1.3 Mpc. Here we present new VLT observations of its young, massive star population, which have allowed us to probe stellar abundances and kinemat- ics for the first time. The mean oxygen abundance obtained from early B-type supergiants confirms suggestions that NGC 3109 is a large Magellanic Irregular Figure 1: Part of the V-band FORS pre-image of our NGC 3109 is very metal poor. In this at 1.3 Mpc, which puts it at the outer edge most western field, with the targets encircled. NGC 3109 is approximately edge-on and the FORS context we advocate studies of the stel- of the Local Group. Using FORS in the targets are well sampled along both the major lar population of NGC 3109 as a com- configurable MOS (multi-object spectros- and minor axes. pelling target for future Extremely Large copy) mode, we have observed 91 stars Telescopes (ELTs). in NGC 3109. These were observed in Example spectra are shown in Figure . 4 MOS configurations, using the 600 B Of our 91 targets, 1 are late O-type stars, grism (giving a common wavelength cov- ranging from O8 to O9.5 – such high- The ARAUCARIA Project is an ESO Large erage of l3900 to l4750 Å). -
• Context. Young Exoplanetary Systems with Ages 600 Ma (I.E. Hyades-Like Or Younger) Can Provide Constraints on the Time Scal
• Context. Young exoplanetary systems with ages 600 Ma (i.e. Hyades-like or younger) can provide constraints on the time scale and mechanism of planet formation, and on the planet evolution (orbital migration, late heavy bombardment...). Apart from the very young “planet” candidates found by direct imaging (around e.g. HR 8799, 2M1207-39 or AB Pic), some young planet candidates have been found with the radial velocity method, such as HD 70573b (Setiawan et al. 2007) in the Hercules-Lyra subgroup of the Local Association or the controversial TW Hya b (Setiawan et al. 2008). [left, top: histogram of planet ages, from Joergens (2009, ASTROCAM school)] • Aims. We search for bright Hipparcos stars with radial-velocity planets that are member candidates in young moving groups (Montes et al. 2001), such as the Hyades, IC 2391, Ursa Majoris and Castor superclusters and the Local Association ( = 100-600 Ma), and very young moving groups like Pictoris or TW Hydrae ( < 100 Ma). Generally, these stars are discarded from accurate radial-velocity searches based on activity indicators, but there might be young stars that passed the rejection filter (e.g. HD 81040, ~ 700 Ma; Sozzetti et al. 2006). • Methods. On 2009 Sep 1, the Extrasolar Planets Encyclopaedia (exoplanet.eu) tabulated 346 planet candidates in 295 planetary systems detected by radial velocity (35 multiple planet systems). Of them, 228 have Hipparcos stars as host stars. We have computed Galactocentric space velocities UVW derived from star coordinates, proper motions, and parallactic distances (from van Leeuwen 2007), and systemic radial velocities, Vr (), from a number of works, including Nordström et al. -
3. Extrasolar Planets How Planets Were Discovered in the Solar System
3. Extrasolar Planets How planets were discovered in the solar system Many are bright enough to see with the naked eye! More distant planets are fainter (scattered light flux - 4 ∝ apl ) and were discovered by imaging the sky at different times and looking for fast-moving things which must be relatively nearby (Kuiper belt objects and asteroids etc are still discovered in this way) but People are still some (e.g., Neptune) were predicted based on searching for planet X perturbations to the orbit of known planets in the solar system (e.g., Gaudi & Bloom Problem for detecting planets is that there is a lot of 2005 say Gaia will area of sky the planets could be hiding in, so narrow detect 1M out to searches to ecliptic planet (although tenth planet J 2000AU) has i=450) and use knowledge of dynamics to predict planet locations Can we do the same thing in extra-solar systems? Extra-solar planet Not quite so easily! The geometry of the problem is SS planet different, which means that: Earth • you don’t get a continuous motion across the sky • although we have narrowed down the region where the planet can be • but the planet is very far away and so it is faint, scattered light flux -2 -2 ∝ d* apl where d* is measured in pc (1pc=206,265AU) • which is compounded by the fact that it is close to a very bright star So how do we detect extrasolar planets? Mostly using indirect detection techniques: Effect on motion of parent star • Astrometric wobble • Timing shifts • Doppler wobble method Effect on flux we detect from parent star • Planetary transits -
Chapter 8.Pdf
CHAeTER 8 INFLUENCE OF PULSARS ON SUPERNOVAE In recent years there has been a great deal of effort to understand in detail the observed light curves of type I1 supernovae. In the standard approach, the observed light curve is to be understood in terms of an initial deposition of thermal energy by the blast wave; and a more gradual input of thermal energy due to radioactive decay of iron-peak elements is invoked to explain the behaviour at later times. The consensus is that the light curves produced by these models are in satisfactory agreement with those observed. In this chapter we discuss the characteristics of the expected light curve, if in addition to the abovementioned sources of energy, there is a continued energy input from an active central pulsar. We argue that in those rare cases when the energy loss rate of the pulsar is comparable to the luminosity of the supernova near light maximum, the light curve will be characterized by an extended plateau phase. The essential reason for this is that the pulsar luminosity is expected to decline over timescales which are much longer than the timescale of, say, radioactive decay. The light curve of the recent supernova in the Large Magellanic Cloud is suggestive of continued energy input from an active pulsar. A detection of strong W,X -ray and 1-ray plerion after the ejecta becomes optically thin will be a clear evidence of the pulsar having powered the light curve. CONTENTS CHAPTER 8 INFLUENCE OF PULSARS ON SUPERNOVAE 8.1 INTRODUCTION ................... 8-1 8.2 EARLIER WORK .................. -
The Distance to the Large Magellanic Cloud
Proceedings Astronomy from 4 perspectives 1. Cosmology The distance to the large magellanic cloud Stefan V¨olker (Jena) In the era of modern cosmology it is necessary to determine the Hubble constant as precise as possible. Therefore it is important to know the distance to the Large Mag- ellanic Cloud (LMC), because this distance forms the fundament of the cosmological distance ladder. The determination of the LMC's distance is an suitable project for highschool students and will be presented in what follows. Calculating the distance to the LMC using the supernova SN 1987 A [1, 2] By combining the angular size α of an object with its absolute size R, one can calculate the distance d (at least for our cosmological neighborhood) using the equation R R d = ≈ (1) tan α α and the approximation d R. In the case of the SN 1987 A students can measure the angular size of the circumstellar ring on the Hubble Space Telescope (HST) image (Figure 1). The absolute size of the ring can be derived from the delay time due to light-travel effects seen in the emission light curve (also Figure 1). Once the supernova exploded, the UV-flash started 1,00 0,75 0,50 intensity (normalized) 0,25 0 0 500 1000 time t/d ESA/Hubble tP1' tP2' Figure 1: left: HST picture of the SN 1987 A; right: emission light curve of the circumstellar [2, 3] propagating and reached the whole ring at the same time, which started emitting immediately. The additional distance x is linked to the delay time by the equation x = c · ∆t = c · (t 0 − t 0 ). -
And Ecclesiastical Cosmology
GSJ: VOLUME 6, ISSUE 3, MARCH 2018 101 GSJ: Volume 6, Issue 3, March 2018, Online: ISSN 2320-9186 www.globalscientificjournal.com DEMOLITION HUBBLE'S LAW, BIG BANG THE BASIS OF "MODERN" AND ECCLESIASTICAL COSMOLOGY Author: Weitter Duckss (Slavko Sedic) Zadar Croatia Pусскй Croatian „If two objects are represented by ball bearings and space-time by the stretching of a rubber sheet, the Doppler effect is caused by the rolling of ball bearings over the rubber sheet in order to achieve a particular motion. A cosmological red shift occurs when ball bearings get stuck on the sheet, which is stretched.“ Wikipedia OK, let's check that on our local group of galaxies (the table from my article „Where did the blue spectral shift inside the universe come from?“) galaxies, local groups Redshift km/s Blueshift km/s Sextans B (4.44 ± 0.23 Mly) 300 ± 0 Sextans A 324 ± 2 NGC 3109 403 ± 1 Tucana Dwarf 130 ± ? Leo I 285 ± 2 NGC 6822 -57 ± 2 Andromeda Galaxy -301 ± 1 Leo II (about 690,000 ly) 79 ± 1 Phoenix Dwarf 60 ± 30 SagDIG -79 ± 1 Aquarius Dwarf -141 ± 2 Wolf–Lundmark–Melotte -122 ± 2 Pisces Dwarf -287 ± 0 Antlia Dwarf 362 ± 0 Leo A 0.000067 (z) Pegasus Dwarf Spheroidal -354 ± 3 IC 10 -348 ± 1 NGC 185 -202 ± 3 Canes Venatici I ~ 31 GSJ© 2018 www.globalscientificjournal.com GSJ: VOLUME 6, ISSUE 3, MARCH 2018 102 Andromeda III -351 ± 9 Andromeda II -188 ± 3 Triangulum Galaxy -179 ± 3 Messier 110 -241 ± 3 NGC 147 (2.53 ± 0.11 Mly) -193 ± 3 Small Magellanic Cloud 0.000527 Large Magellanic Cloud - - M32 -200 ± 6 NGC 205 -241 ± 3 IC 1613 -234 ± 1 Carina Dwarf 230 ± 60 Sextans Dwarf 224 ± 2 Ursa Minor Dwarf (200 ± 30 kly) -247 ± 1 Draco Dwarf -292 ± 21 Cassiopeia Dwarf -307 ± 2 Ursa Major II Dwarf - 116 Leo IV 130 Leo V ( 585 kly) 173 Leo T -60 Bootes II -120 Pegasus Dwarf -183 ± 0 Sculptor Dwarf 110 ± 1 Etc. -
Phd Thesis: Search for Planets Around Young Stars with the Radial Velocity Technique
Dissertation submitted to the Combined Faculties for the Natural Sciences and for Mathematics of the Ruperto-Carola University of Heidelberg, Germany for the degree of Doctor of Natural Sciences Put forward by: Diplom-Physiker Patrick Weise Born in Bremen Oral examination: October 13, 2010 Search for planets around young stars with the radial velocity technique Referees: Prof. Dr. Thomas Henning Prof. Dr. Immo Appenzeller Suche nach Planeten um junge Sterne mit der Radialgeschwindigkeitsmethode Zusammenfassung Riesenplaneten entstehen in zirkumstellaren Scheiben um junge Sterne. Es existieren zwei verschiedene theroretische Beschreibungen, wonach Riesenplaneten durch grav- itative Instabilität oder Kern-Akkretion entstehen. Beide Modelle können auch zusam- men unter bestimmten Bedingungen zutreffen, aber die Kern-Akkretion scheint der dominante Prozess zu sein. Bisher wurde jedoch die Planetenentstehung noch nicht direkt beobachtet. Aus diesem Grund soll in dieser Arbeit nach sub-stellaren Be- gleitern um junge Sterne (1–100 Mjahre) gesucht werden, da die Eigenschaften junger Planeten wichtige Hinweise auf die Prozesse der Planetenentstehung geben können. In dieser Arbeit wurden echelle Spectren von 100 jungen Sternen aufgenommen und deren Eigenschaften charakterisiert. Thie Radialgeschwindigkeit wurde durch Kreuz- Korrelation der Spektren mit Vorlagen in MACS gewonnen. Weiterhin wurde die stel- lare Aktivität durch die Analyse des Linien Bisektors und anderer Indikatoren, charak- terisiert. FÃijr 12 der untersuchten Sterne ist die Variation der Radialgeschwindigkeit durch die Modulation der stellaren Aktivität mit der Rotationsperiode gegeben. Weit- erhin wurden sechs Riesenplaneten und ein Brauner Zwerg im Orbit um junge Sterne (2–90 Myr) gefunden. Dennoch ist die Anzahl der gefundenen sub-stellaren Begleiter zu wenig und das Alter der Sterne zu ungenau um Aussagen zu der Entstehung von Planeten zu treffen. -
Messenger-No117.Pdf
ESO WELCOMES FINLANDINLAND AS ELEVENTH MEMBER STAATE CATHERINE CESARSKY, ESO DIRECTOR GENERAL n early July, Finland joined ESO as Education and Science, and exchanged which started in June 2002, and were con- the eleventh member state, following preliminary information. I was then invit- ducted satisfactorily through 2003, mak- II the completion of the formal acces- ed to Helsinki and, with Massimo ing possible a visit to Garching on 9 sion procedure. Before this event, howev- Tarenghi, we presented ESO and its scien- February 2004 by the Finnish Minister of er, Finland and ESO had been in contact tific and technological programmes and Education and Science, Ms. Tuula for a long time. Under an agreement with had a meeting with Finnish authorities, Haatainen, to sign the membership agree- Sweden, Finnish astronomers had for setting up the process towards formal ment together with myself. quite a while enjoyed access to the SEST membership. In March 2000, an interna- Before that, in early November 2003, at La Silla. Finland had also been a very tional evaluation panel, established by the ESO participated in the Helsinki Space active participant in ESO’s educational Academy of Finland, recommended Exhibition at the Kaapelitehdas Cultural activities since they began in 1993. It Finland to join ESO “anticipating further Centre with approx. 24,000 visitors. became clear, that science and technology, increase in the world-standing of ESO warmly welcomes the new mem- as well as education, were priority areas Astronomy in Finland”. In February 2002, ber country and its scientific community for the Finnish government. we were invited to hold an information that is renowned for its expertise in many Meanwhile, the optical astronomers in seminar on ESO in Helsinki as a prelude frontline areas. -
TSP 2004 Telescope Observing Program
THE TEXAS STAR PARTY 2004 TELESCOPE OBSERVING CLUB BY JOHN WAGONER TEXAS ASTRONOMICAL SOCIETY OF DALLAS RULES AND REGULATIONS Welcome to the Texas Star Party's Telescope Observing Club. The purpose of this club is not to test your observing skills by throwing the toughest objects at you that are hard to see under any conditions, but to give you an opportunity to observe 25 showcase objects under the ideal conditions of these pristine West Texas skies, thus displaying them to their best advantage. This year we have planned a program called “Starlight, Starbright”. The rules are simple. Just observe the 25 objects listed. That's it. Any size telescope can be used. All observations must be made at the Texas Star Party to qualify. All objects are within range of small (6”) to medium sized (10”) telescopes, and are available for observation between 10:00PM and 3:00AM any time during the TSP. Each person completing this list will receive an official Texas Star Party Telescope Observing Club lapel pin. These pins are not sold at the TSP and can only be acquired by completing the program, so wear them proudly. To receive your pin, turn in your observations to John Wagoner - TSP Observing Chairman any time during the Texas Star Party. I will be at the outside door leading into the TSP Meeting Hall each day between 1:00 PM and 2:30 PM. If you finish the list the last night of TSP, or I am not available to give you your pin, just mail your observations to me at 1409 Sequoia Dr., Plano, Tx. -
Dwarf Galaxies
Europeon South.rn Ob.ervotory• ESO ML.2B~/~1 ~~t.· MAIN LIBRAKY ESO Libraries ,::;,q'-:;' ..-",("• .:: 114 ML l •I ~ -." "." I_I The First ESO/ESA Workshop on the Need for Coordinated Space and Ground-based Observations - DWARF GALAXIES Geneva, 12-13 May 1980 Report Edited by M. Tarenghi and K. Kjar - iii - INTRODUCTION The Space Telescope as a joint undertaking between NASA and ESA will provide the European community of astronomers with the opportunity to be active partners in a venture that, properly planned and performed, will mean a great leap forward in the science of astronomy and cosmology in our understanding of the universe. The European share, however,.of at least 15% of the observing time with this instrumentation, if spread over all the European astrono mers, does not give a large amount of observing time to each individual scientist. Also, only well-planned co ordinated ground-based observations can guarantee success in interpreting the data and, indeed, in obtaining observ ing time on the Space Telescope. For these reasons, care ful planning and cooperation between different European groups in preparing Space Telescope observing proposals would be very essential. For these reasons, ESO and ESA have initiated a series of workshops on "The Need for Coordinated Space and Ground based Observations", each of which will be centred on a specific subject. The present workshop is the first in this series and the subject we have chosen is "Dwarf Galaxies". It was our belief that the dwarf galaxies would be objects eminently suited for exploration with the Space Telescope, and I think this is amply confirmed in these proceedings of the workshop. -
Chapter 1 a Theoretical and Observational Overview of Brown
Chapter 1 A theoretical and observational overview of brown dwarfs Stars are large spheres of gas composed of 73 % of hydrogen in mass, 25 % of helium, and about 2 % of metals, elements with atomic number larger than two like oxygen, nitrogen, carbon or iron. The core temperature and pressure are high enough to convert hydrogen into helium by the proton-proton cycle of nuclear reaction yielding sufficient energy to prevent the star from gravitational collapse. The increased number of helium atoms yields a decrease of the central pressure and temperature. The inner region is thus compressed under the gravitational pressure which dominates the nuclear pressure. This increase in density generates higher temperatures, making nuclear reactions more efficient. The consequence of this feedback cycle is that a star such as the Sun spend most of its lifetime on the main-sequence. The most important parameter of a star is its mass because it determines its luminosity, ef- fective temperature, radius, and lifetime. The distribution of stars with mass, known as the Initial Mass Function (hereafter IMF), is therefore of prime importance to understand star formation pro- cesses, including the conversion of interstellar matter into stars and back again. A major issue regarding the IMF concerns its universality, i.e. whether the IMF is constant in time, place, and metallicity. When a solar-metallicity star reaches a mass below 0.072 M ¡ (Baraffe et al. 1998), the core temperature and pressure are too low to burn hydrogen stably. Objects below this mass were originally termed “black dwarfs” because the low-luminosity would hamper their detection (Ku- mar 1963). -
Large Magellanic Cloud, One of Our Busy Galactic Neighbors
The Large Magellanic Cloud, One of Our Busy Galactic Neighbors www.nasa.gov Our Busy Galactic Neighbors also contain fewer metals or elements heavier than hydrogen and helium. Such an environment is thought to slow the growth The cold dust that builds blazing stars is revealed in this image of stars. Star formation in the universe peaked around 10 billion that combines infrared observations from the European Space years ago, even though galaxies contained lesser abundances Agency’s Herschel Space Observatory and NASA’s Spitzer of metallic dust. Previously, astronomers only had a general Space Telescope. The image maps the dust in the galaxy known sense of the rate of star formation in the Magellanic Clouds, as the Large Magellanic Cloud, which, with the Small Magellanic but the new images enable them to study the process in more Cloud, are the two closest sizable neighbors to our own Milky detail. Way Galaxy. Herschel is a European The Large Magellanic Cloud looks like a fiery, circular explosion Space Agency in the combined Herschel–Spitzer infrared data. Ribbons of dust cornerstone mission, ripple through the galaxy, with significant fields of star formation with science instruments noticeable in the center, center-left and top right. The brightest provided by consortia center-left region is called 30 Doradus, or the Tarantula Nebula, of European institutes for its appearance in visible light. and with important participation by NASA. NASA’s Herschel Project Office is based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for two of Herschel’s three science instruments.