Hubble Space Telescope Observer’S Guide Spring 2021
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Arxiv:1504.01453V1 [Astro-Ph.GA] 7 Apr 2015 Ences
Draft version August 9, 2018 A Preprint typeset using LTEX style emulateapj v. 03/07/07 THE WEAK CARBON MONOXIDE EMISSION IN AN EXTREMELY METAL POOR GALAXY, SEXTANS A ∗ Yong Shi1,2, 3, Junzhi Wang4,5, Zhi-Yu Zhang6, Yu Gao7,5,3, Lee Armus8, George Helou8, Qiusheng Gu1,2, 3, Sabrina Stierwalt9 Draft version August 9, 2018 ABSTRACT Carbon monoxide (CO) is one of the primary coolants of gas and an easily accessible tracer of molecular gas in spiral galaxies but it is unclear if CO plays a similar role in metal poor dwarfs. We carried out a deep observation with IRAM 30 m to search for CO emission by targeting the brightest far-IR peak in a nearby extremely metal poor galaxy, Sextans A, with 7% Solar metallicity. A weak CO J=1-0 emission is seen, which is already faint enough to place a strong constraint on the conversion factor (αCO) from the CO luminosity to the molecular gas mass that is derived from the spatially resolved dust mass map. The αCO is at least seven hundred times the Milky Way value. This indicates that CO emission is exceedingly weak in extremely metal poor galaxies, challenging its role as a coolant in these galaxies. Subject headings: galaxies: dwarf – submillimeter: ISM – galaxies: ISM 1. INTRODUCTION 2013) in low metallicity environments. Probing CO emis- Stars form out of molecular clouds (Kennicutt 1998; sion at lower metallicities establishes if CO emission can Gao & Solomon 2004). The efficient cooling of molec- be an efficient gas coolant and effective tracer of molec- ular gas is the prerequisite for gas collapse and star ular gas in metal poor galaxies both locally and in early formation. -
Hubble Space Telescope Observer’S Guide Winter 2021
HUBBLE SPACE TELESCOPE OBSERVER’S GUIDE WINTER 2021 In 2021, the Hubble Space Telescope will celebrate 31 years in operation as a powerful observatory probing the astrophysics of the cosmos from Solar system studies to the high-redshift universe. The high-resolution imaging capability of HST spanning the IR, optical, and UV, coupled with spectroscopic capability will remain invaluable through the middle of the upcoming decade. HST coupled with JWST will enable new innovative science and be will be key for multi-messenger investigations. Key Science Threads • Properties of the huge variety of exo-planetary systems: compositions and inventories, compositions and characteristics of their planets • Probing the stellar and galactic evolution across the universe: pushing closer to the beginning of galaxy formation and preparing for coordinated JWST observations • Exploring clues as to the nature of dark energy ACS SBC absolute re-calibration (Cycle 27) reveals 30% greater • Probing the effect of dark matter on the evolution sensitivity than previously understood. More information at of galaxies http://www.stsci.edu/contents/news/acs-stans/acs-stan- • Quantifying the types and astrophysics of black holes october-2019 of over 7 orders of magnitude in size WFC3 offers high resolution imaging in many bands ranging from • Tracing the distribution of chemicals of life in 2000 to 17000 Angstroms, as well as spectroscopic capability in the universe the near ultraviolet and infrared. Many different modes are available for high precision photometry, astrometry, spectroscopy, mapping • Investigating phenomena and possible sites for and more. robotic and human exploration within our Solar System COS COS2025 initiative retains full science capability of COS/FUV out to 2025 (http://www.stsci.edu/hst/cos/cos2025). -
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). -
Precollimator for X-Ray Telescope (Stray-Light Baffle) Mindrum Precision, Inc Kurt Ponsor Mirror Tech/SBIR Workshop Wednesday, Nov 2017
Mindrum.com Precollimator for X-Ray Telescope (stray-light baffle) Mindrum Precision, Inc Kurt Ponsor Mirror Tech/SBIR Workshop Wednesday, Nov 2017 1 Overview Mindrum.com Precollimator •Past •Present •Future 2 Past Mindrum.com • Space X-Ray Telescopes (XRT) • Basic Structure • Effectiveness • Past Construction 3 Space X-Ray Telescopes Mindrum.com • XMM-Newton 1999 • Chandra 1999 • HETE-2 2000-07 • INTEGRAL 2002 4 ESA/NASA Space X-Ray Telescopes Mindrum.com • Swift 2004 • Suzaku 2005-2015 • AGILE 2007 • NuSTAR 2012 5 NASA/JPL/ASI/JAXA Space X-Ray Telescopes Mindrum.com • Astrosat 2015 • Hitomi (ASTRO-H) 2016-2016 • NICER (ISS) 2017 • HXMT/Insight 慧眼 2017 6 NASA/JPL/CNSA Space X-Ray Telescopes Mindrum.com NASA/JPL-Caltech Harrison, F.A. et al. (2013; ApJ, 770, 103) 7 doi:10.1088/0004-637X/770/2/103 Basic Structure XRT Mindrum.com Grazing Incidence 8 NASA/JPL-Caltech Basic Structure: NuSTAR Mirrors Mindrum.com 9 NASA/JPL-Caltech Basic Structure XRT Mindrum.com • XMM Newton XRT 10 ESA Basic Structure XRT Mindrum.com • XMM-Newton mirrors D. de Chambure, XMM Project (ESTEC)/ESA 11 Basic Structure XRT Mindrum.com • Thermal Precollimator on ROSAT 12 http://www.xray.mpe.mpg.de/ Basic Structure XRT Mindrum.com • AGILE Precollimator 13 http://agile.asdc.asi.it Basic Structure Mindrum.com • Spektr-RG 2018 14 MPE Basic Structure: Stray X-Rays Mindrum.com 15 NASA/JPL-Caltech Basic Structure: Grazing Mindrum.com 16 NASA X-Ray Effectiveness: Straylight Mindrum.com • Correct Reflection • Secondary Only • Backside Reflection • Primary Only 17 X-Ray Effectiveness Mindrum.com • The Crab Nebula by: ROSAT (1990) Chandra 18 S. -
• 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 .................. -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
The Search for Living Worlds and the Connection to Our Cosmic Origins
The Search for Living Worlds and the Connection to Our Cosmic Origins Contact person: Prof Martin Barstow Address: Department of Physics & Astronomy, University of Leicester, UK Email: [email protected] Telephone: +44 116 252 3492 Imaging Earth 2.0. Simulation of the inner solar system viewed at visible wavelengths from a distance of 13 parsec with a LUVOIR telescope. The enormous glare from the central star has been suppressed with a coronagraph so the faint planets can be seen. The atmosphere of each planet can be probed with spectra to reveal its composition. Credit: L. Pueyo, M M. N’Diaye (STScI)/A. Roberge (NASA GSFC). The Search for Living Worlds – ESA Voyage 2050 White Paper Executive summary One of the most exciting scientific challenges is to detect Earth-like planets in the habitable zones of other stars in the galaxy and search for evidence of life. During the past 20 years the detection of exoplanets, orbiting stars beyond our own has moved from science fiction to science fact. From the first handful of gas giants, found through radial velocity studies, detection techniques have increased in sensitivity, finding smaller planets and diverse multi-planet systems. Through enhanced ground-based spectroscopic observations, transit detection techniques and the enormous productivity of the Kepler space mission, the number of confirmed planets has increased to more than 2000. There are several space missions, such as TESS (NASA), now operational, and PLATO (ESA), which will extend the parameter space for exoplanet discovery towards the regime of rocky earth- like planets and take the census of such bodies in the neighbourhood of the Solar System. -
The Making of the Chandra X-Ray Observatory: the Project Scientist’S Perspective
SPECIAL FEATURE: PERSPECTIVE The making of the Chandra X-Ray Observatory: The project scientist’s perspective Martin C. Weisskopf1 National Aeronautics and Space Administration/Marshall Space Flight Center, Huntsville, AL 35805 Edited by Harvey D. Tananbaum, Smithsonian Astrophysical Observatory, Cambridge, MA, and approved January 22, 2010 (received for review December 16, 2009) The history of the development of the Chandra X-Ray Observatory is reviewed from a personal perspective. This review is necessarily biased and limited by space because it attempts to cover a time span approaching five decades. historical perspective | x-ray astronomy t is sobering for me to realize that there arescientistswhoareworkingwithdata Ifrom this truly great observatory who were not even born when the founda- tion for what is now the Chandra X-Ray Observatory was laid. Thus, it may surprise many to know that the beginning was suc- cinctly and accurately outlined in a research proposal that Riccardo Giacconi and col- leagues wrote in 1963, a mere 9 months after he and his team’s discovery of the first ex- trasolar x-ray source Scorpius X-1. As im- portant, the data from this rocket flight also indicated the presence of the “diffuse x-ray background.” Fig. 1 illustrates the showpiece of this insightful proposal. It shows a ≈1-m diameter, 10-m focal length, grazing-incidence x-ray telescope. The telescope was of sufficient area and angular resolution to determine the nature of the unresolved x-ray background. We all owe Riccardo an enormous debt of gratitude for his insight, leadership, and, in my case (and I suspect for many others), inspiration. -
On the Detection of Exoplanets Via Radial Velocity Doppler Spectroscopy
The Downtown Review Volume 1 Issue 1 Article 6 January 2015 On the Detection of Exoplanets via Radial Velocity Doppler Spectroscopy Joseph P. Glaser Cleveland State University Follow this and additional works at: https://engagedscholarship.csuohio.edu/tdr Part of the Astrophysics and Astronomy Commons How does access to this work benefit ou?y Let us know! Recommended Citation Glaser, Joseph P.. "On the Detection of Exoplanets via Radial Velocity Doppler Spectroscopy." The Downtown Review. Vol. 1. Iss. 1 (2015) . Available at: https://engagedscholarship.csuohio.edu/tdr/vol1/iss1/6 This Article is brought to you for free and open access by the Student Scholarship at EngagedScholarship@CSU. It has been accepted for inclusion in The Downtown Review by an authorized editor of EngagedScholarship@CSU. For more information, please contact [email protected]. Glaser: Detection of Exoplanets 1 Introduction to Exoplanets For centuries, some of humanity’s greatest minds have pondered over the possibility of other worlds orbiting the uncountable number of stars that exist in the visible universe. The seeds for eventual scientific speculation on the possibility of these "exoplanets" began with the works of a 16th century philosopher, Giordano Bruno. In his modernly celebrated work, On the Infinite Universe & Worlds, Bruno states: "This space we declare to be infinite (...) In it are an infinity of worlds of the same kind as our own." By the time of the European Scientific Revolution, Isaac Newton grew fond of the idea and wrote in his Principia: "If the fixed stars are the centers of similar systems [when compared to the solar system], they will all be constructed according to a similar design and subject to the dominion of One." Due to limitations on observational equipment, the field of exoplanetary systems existed primarily in theory until the late 1980s. -
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 ).