Experiments on the Differential Vlbi Measurements with the Former Russian Deep Space Network
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AAS Worldwide Telescope: Seamless, Cross-Platform Data Visualization Engine for Astronomy Research, Education, and Democratizing Data
AAS WorldWide Telescope: Seamless, Cross-Platform Data Visualization Engine for Astronomy Research, Education, and Democratizing Data The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Rosenfield, Philip, Jonathan Fay, Ronald K Gilchrist, Chenzhou Cui, A. David Weigel, Thomas Robitaille, Oderah Justin Otor, and Alyssa Goodman. 2018. AAS WorldWide Telescope: Seamless, Cross-Platform Data Visualization Engine for Astronomy Research, Education, and Democratizing Data. The Astrophysical Journal: Supplement Series 236, no. 1. Published Version https://iopscience-iop-org.ezp-prod1.hul.harvard.edu/ article/10.3847/1538-4365/aab776 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:41504669 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#OAP Draft version January 30, 2018 Typeset using LATEX twocolumn style in AASTeX62 AAS WorldWide Telescope: Seamless, Cross-Platform Data Visualization Engine for Astronomy Research, Education, and Democratizing Data Philip Rosenfield,1 Jonathan Fay,1 Ronald K Gilchrist,1 Chenzhou Cui,2 A. David Weigel,3 Thomas Robitaille,4 Oderah Justin Otor,1 and Alyssa Goodman5 1American Astronomical Society 1667 K St NW Suite 800 Washington, DC 20006, USA 2National Astronomical Observatories, Chinese Academy of Sciences 20A Datun Road, Chaoyang District Beijing, 100012, China 3Christenberry Planetarium, Samford University 800 Lakeshore Drive Birmingham, AL 35229, USA 4Aperio Software Ltd. Headingley Enterprise and Arts Centre, Bennett Road Leeds, LS6 3HN, United Kingdom 5Harvard Smithsonian Center for Astrophysics 60 Garden St. -
Space Astronomy in the 90S
Space Astronomy in the 90s Jonathan McDowell April 26, 1995 1 Why Space Astronomy? • SHARPER PICTURES (Spatial Resolution) The Earth’s atmosphere messes up the light coming in (stars twinkle, etc). • TECHNICOLOR (X-ray, infrared, etc) The atmosphere also absorbs light of different wavelengths (col- ors) outside the visible range. X-ray astronomy is impossible from the Earth’s surface. 2 What are the differences between satellite instruments? • Focussing optics or bare detectors • Wavelength or energy range - IR, UV, etc. Different technology used for different wavebands. • Spatial Resolution (how sharp a picture?) • Spatial Field of View (how large a piece of sky?) • Spectral Resolution (can it tell photons of different energies apart?) • Spectral Field of View (bandwidth) • Sensitivity • Pointing Accuracy • Lifetime • Orbit (hence operating efficiency, background, etc.) • Scan or Point What are the differences between satellites? • Spinning or 3-axis pointing (older satellites spun around a fixed axis, precession let them eventually see different parts of the sky) • Fixed or movable solar arrays (fixed arrays mean the spacecraft has to point near the plane perpendicular to the solar-satellite vector) 3 • Low or high orbit (low orbit has higher radiation, atmospheric drag, and more Earth occultation; high orbit has slower preces- sion and no refurbishment opportunity) • Propulsion to raise orbit? • Other consumables (proportional counter gas, attitude control gas, liquid helium coolant) 4 What are the differences in operation? • PI mission vs. GO mission PI = Principal Investigator. One of the people responsible for building the satellite. Nowadays often referred to as IPIs (In- strument PIs). GO = Guest Observer. Someone who just want to use the satel- lite. -
Interstellar Extinction in Orion. Variation of the Strength of the UV
MNRAS 000, 1–9 (2017) Preprint 9 July 2018 Compiled using MNRAS LATEX style file v3.0 Interstellar extinction in Orion. Variation of the strength of the UV bump across the complex. Leire Beitia-Antero,1⋆ Ana I. G´omez de Castro,1† 1AEGORA Research Group, Universidad Complutense de Madrid, Facultad de CC. Matem´aticas, Plaza de Ciencias 3, E-28040 Madrid Accepted XXX. Received YYY; in original form ZZZ ABSTRACT There is growing observational evidence of dust coagulation in the dense filaments within molecular clouds. Infrared observations show that the dust grains size distri- bution gets shallower and the relative fraction of small to large dust grains decreases as the local density increases. Ultraviolet (UV) observations show that the strength of the 2175 A˚ feature, the so-called UV bump, also decreases with cloud density. In this work, we apply the technique developed for the Taurus study to the Orion molecular cloud and confirm that the UV bump decreases over the densest cores of the cloud as well as in the heavily UV irradiated λ Orionis shell. The study has been extended to the Rosette cloud with uncertain results given the distance (1.3 kpc). Key words: ISM: dust, extinction 1 INTRODUCTION feature of the extinction curve, the so-called UV bump. The UV bump is, by far, the strongest spectral feature in the ex- The Interstellar Medium (ISM) is a complex ensemble of tinction curve but its source remains uncertain (see e.g. the gas, large molecules and dust coupled through the action of review by Draine (2003)). -
Cassiopeia a January2008
CASSIOPEIA A JANUARY2008 Cassiopeia A is the youngest (about 300 years old) known supernova Su Mo Tu We Th Fr Sa remnant in the Milky Way. Astronomers have used Chandra’s long ob - 01 02 03 04 05 servations of this remnant to make a map of the acceleration of elec - trons in this supernova remnant. The analysis shows that the electrons 06 07 08 09 10 11 12 are being accelerated to almost the maximum theoretical limit in some 13 14 15 16 17 18 19 parts of Cassiopeia A (Cas A) in what can be thought of as a “relativistic pinball machine.” Protons and ions, which make up the bulk of cosmic 20 21 22 23 24 25 26 rays, are expected to be accelerated in a similar way to the electrons. The Cas A observations thus provide strong evidence that supernova 27 28 29 30 31 remnants are key sites for energizing cosmic rays. 3C442A FEBRUARY2008 X -ray data from NASA’s Chandra X -ray Observatory and radio obser - Su Mo Tu We Th Fr Sa vations from the NSF’s Very Large Array show that a role reversal is 01 02 taking place in the middle of 3C442A - a system with two merging gal - 03 04 05 06 07 08 09 axies in the center. Chandra detects hot gas (blue) that has been push - ing aside the radio -bright gas (orange). This is the opposite of what 10 11 12 13 14 15 16 is typically found in these systems when jets from the supermassive black hole in the center create cavities in the hot gas surrounding the 17 18 19 20 21 22 23 galaxy. -
Particle Acceleration in Solar Flares What Is the Link Between Heating and Particle Acceleration?
Energetic Particles in the Solar Atmosphere (X- ray diagnostics) Nicole Vilmer LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot The Sun as a Particle Accelerator: First detection of energetic protons from the Sun(1942) (related to a solar flare) First X-ray observations of solar flares (1970) Chupp et al., 1974 First observations of -ray lines from solar flares (OSO7/Prognoz 1972) Since then many more observations With e.g. RHESSI (2002-2018) And also INTEGRAL, FERMI >120000 X-ray flares observed by RHESSI (NASA/SMEX; 2002-2018) But still a limited number of gamma- ray line flares ~30 Solar flare: Sudden release of magnetic energy Heating Particle acceleration X-rays 6-8 keV 25-80 keV 195 Å 304 Å 21 aug 2002 (extreme ultraviolet) 335 Å 15 fev 2011 HXR/GR diagnostics of energetic electrons and ions SXR emission Hot Plasma (7to 8 MK ) HXR emission Bremsstrahlung from non-thermal electrons Prompt -ray lines : Deexcitation lines(C and 0) (60%) Signature of energetic ions (>2 MeV/nuc) Neutron capture line: p –p ; p-α and p-ions interactions Production of neutrons Collisional slowing down of neutrons Radiative capture on ambient H deuterium + 2.2 MeV. line RHESSI Observations X/ spectrum Thermal components T= 2 10 7 K T= 4 10 7 K Electron bremsstrahlung Ultrarelativistic -ray lines Electron (ions > 3 MeV/nuc) Bremsstrahlung (INTEGRAL) SMM/GRS PHEBUS/GRANAT FERMI/LAT observations RHESSI Pion decay radiation(ions > ~300MeV/nuc) Particle acceleration in solar flares What is the link between heating and particle acceleration? Where are the acceleration sites? What is the transport of particles from acceleration sites to X/ γ ray emission sites? What are the characteristic acceleration times? RHESSI How many energetic particles? Energy spectra? Relative abundances of energetic ions? RHESSI Which acceleration mechanisms in solar flares? Shock acceleration? Stochastic acceleration? (wave-particle interaction) Direct Electric field acceleration. -
Centaurus a at Hard X-Rays and Gamma Rays
Centaurus A at Hard X-Rays and Soft Gamma-Rays Chandra 1-10 keV CGRO-COMPTEL 1 ± 30 MeV Fermi 100 MeV ± 100 GeV Helmut Steinle Max-Planck-Institut für extraterrestrische Physik Garching, Germany ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The Many Faces of Centaurus A ± Sydney, 28 June ± 3 July 2009; H. Steinle, MPE 1 / 35 Centaurus A at Hard X-Rays and Soft Gamma-Rays Contents · Introduction · The Spectral Energy Distribution · Properties of the existing measurements in the hard X-ray / soft Gamma-ray regime · Important satellites for this energy / frequency range · Variability of the X-ray / Gamma-ray emission · Two examples of models for the Cen A Spectral Energy Distribution · Problems (features) to be considered when using the hard X-ray / soft Gamma-ray data ± the ªsoft X-ray transient problemº ± the ªSED problemº · Outlook ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The Many Faces of Centaurus A ± Sydney, 28 June ± 3 July 2009; H. Steinle, MPE 2 / 35 Centaurus A at Hard X-Rays and Soft Gamma-Rays ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Introduction In the introductory (ªsetting the stageº) section of the -
Theoretical Limits of Star Sensor Accuracy †
sensors Article Theoretical Limits of Star Sensor Accuracy † Marcio A. A. Fialho 1,* and Daniele Mortari 2 1 Divisão de Eletrônica Aeroespacial (DIDEA), National Institute for Space Research (INPE), Av. dos Astronautas, 1758, São José dos Campos, SP 12227, Brazil 2 Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA; [email protected] * Correspondence: marcio.fi[email protected]; Tel.: +55-12-3208-6145 † This paper is a revised and extended version of a work previously published as a doctoral thesis chapter. Received: 17 October 2019; Accepted: 25 November 2019; Published: 5 December 2019 Abstract: To achieve mass, power and cost reduction, there is a trend to reduce the volume of many instruments aboard spacecraft, especially for small spacecraft (cubesats or nanosats) with very limited mass, volume and power budgets. With the current trend of miniaturizing spacecraft instruments one could naturally ask if is there a physical limit to this process for star sensors. This paper shows that there is a fundamental limit on star sensor accuracy, which depends on stellar distribution, star sensor dimensions and exposure time. An estimate of this limit is given for our location in the galaxy. Keywords: star sensors; stellar distribution; photometry; astrometry; star catalogs; fundamental limits 1. Introduction Much progress in a variety of fields in science and technology could be accomplished thanks to the miniaturization obtained in microelectronics in the recent decades. One of the most remarkable examples is the prediction by Gordon Moore that the computational power would increase exponentially, an empirical observation that became known as Moore’s law [1–4]. -
The Spitzer Space Telescope and the IR Astronomy Imaging Chain
Spitzer Space Telescope (A.K.A. The Space Infrared Telescope Facility) The Infrared Imaging Chain Fundamentals of Astronomical Imaging – Spitzer Space Telescope – 8 May 2006 1/38 The infrared imaging chain Generally similar to the optical imaging chain... 1) Source (different from optical astronomy sources) 2) Object (usually the same as the source in astronomy) 3) Collector (Spitzer Space Telescope) 4) Sensor (IR detector) 5) Processing 6) Display 7) Analysis 8) Storage ... but steps 3) and 4) are a bit more difficult! Fundamentals of Astronomical Imaging – Spitzer Space Telescope – 8 May 2006 2/38 The infrared imaging chain Longer wavelength – need a bigger telescope to get the same resolution or put up with lower resolution Fundamentals of Astronomical Imaging – Spitzer Space Telescope – 8 May 2006 3/38 Emission of IR radiation Warm objects emit lots of thermal infrared as well as reflecting it Including telescopes, people, and the Earth – so collection of IR radiation with a telescope is more complicated than an optical telescope Optical image of Spitzer Space Telescope launch: brighter regions are those which reflect more light IR image of Spitzer launch: brighter regions are those which emit more heat Infrared wavelength depends on temperature of object Fundamentals of Astronomical Imaging – Spitzer Space Telescope – 8 May 2006 4/38 Atmospheric absorption The atmosphere blocks most infrared radiation Need a telescope in space to view the IR properly Fundamentals of Astronomical Imaging – Spitzer Space Telescope – 8 May 2006 5/38 -
Young Stellar Object Candidates Toward the Orion Region Selected from GALEX (Research Note)
A&A 572, A89 (2014) Astronomy DOI: 10.1051/0004-6361/201424629 & c ESO 2014 Astrophysics Young stellar object candidates toward the Orion region selected from GALEX (Research Note) Nestor Sanchez, Ana Inés Gómez de Castro, Fátima Lopez-Martinez, and Javier López-Santiago S. D. Astronomía y Geodesia, Fac. CC. Matemáticas, Universidad Complutense de Madrid, 28040 Madrid, Spain e-mail: [email protected] Received 18 July 2014 / Accepted 28 October 2014 ABSTRACT We analyze 359 ultraviolet tiles from the All Sky Imaging Survey of the space mission GALEX covering roughly 400 square degrees toward the Orion star-forming region. There are a total of 1 555 174 ultraviolet sources that were cross-matched with other catalogs (2MASS, UCAC4, SDSS, DENIS, CMC15, and WISE) to produce a list of 290 717 reliable sources with a wide range of photometric information. Using different color selection criteria, we identify 111 young stellar object candidates showing both ultraviolet and infrared excesses, of which 81 are new identifications. We discuss the spatial distribution, the spectral energy distributions, and other physical properties of these stars. Their properties are, in general, compatible with those expected for T Tauri stars. This population of TTS candidates is widely dispersed around the Orion molecular cloud. Key words. stars: low-mass – stars: pre-main sequence – stars: variables: T Tauri, Herbig Ae/Be – ultraviolet: stars 1. Introduction and magnetic stellar activity (Edwards et al. 1994; Muzerolle et al. 1998). As spectroscopic observations are time consuming The current paradigm for low-mass star formation catego- and are sometimes restricted to bright objects, a good strategy is rizes young stellar objects (YSOs) into four general classes: to perform spectroscopic follow-ups only for the most reliable Class 0 sources are faint central protostars surrounded by a YSO candidates selected using photometric methods. -
Gao-21-306, Nasa
United States Government Accountability Office Report to Congressional Committees May 2021 NASA Assessments of Major Projects GAO-21-306 May 2021 NASA Assessments of Major Projects Highlights of GAO-21-306, a report to congressional committees Why GAO Did This Study What GAO Found This report provides a snapshot of how The National Aeronautics and Space Administration’s (NASA) portfolio of major well NASA is planning and executing projects in the development stage of the acquisition process continues to its major projects, which are those with experience cost increases and schedule delays. This marks the fifth year in a row costs of over $250 million. NASA plans that cumulative cost and schedule performance deteriorated (see figure). The to invest at least $69 billion in its major cumulative cost growth is currently $9.6 billion, driven by nine projects; however, projects to continue exploring Earth $7.1 billion of this cost growth stems from two projects—the James Webb Space and the solar system. Telescope and the Space Launch System. These two projects account for about Congressional conferees included a half of the cumulative schedule delays. The portfolio also continues to grow, with provision for GAO to prepare status more projects expected to reach development in the next year. reports on selected large-scale NASA programs, projects, and activities. This Cumulative Cost and Schedule Performance for NASA’s Major Projects in Development is GAO’s 13th annual assessment. This report assesses (1) the cost and schedule performance of NASA’s major projects, including the effects of COVID-19; and (2) the development and maturity of technologies and progress in achieving design stability. -
Simulated JWST Data Sets for Multispectral and Hyperspectral Image Fusion Claire Guilloteau, Thomas Oberlin, Olivier Berné, Émilie Habart, Nicolas Dobigeon
Simulated JWST data sets for multispectral and hyperspectral image fusion Claire Guilloteau, Thomas Oberlin, Olivier Berné, Émilie Habart, Nicolas Dobigeon To cite this version: Claire Guilloteau, Thomas Oberlin, Olivier Berné, Émilie Habart, Nicolas Dobigeon. Simulated JWST data sets for multispectral and hyperspectral image fusion. Astronomical Journal, American Astro- nomical Society, 2020, 160 (1), pp.0. 10.3847/1538-3881/ab9301. hal-02886110 HAL Id: hal-02886110 https://hal.archives-ouvertes.fr/hal-02886110 Submitted on 1 Jul 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Open Archive Toulouse Archive Ouverte OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible This is a publisher’s version published in: https://oatao.univ-toulouse.fr/26226 Official URL : https://doi.org/10.3847/1538-3881/ab9301 To cite this version: Guilloteau, Claire and Oberlin, Thomas and Berné, Olivier and Habart, Émilie and Dobigeon, Nicolas Simulated JWST data sets for multispectral and hyperspectral image fusion. (2020) The Astronomical Journal, 160 (1). ISSN 0004-6256. Any correspondence concerning this service should be sent to the repository administrator: [email protected] The Astronomical Journal, 160:28 (13pp), 2020 July https://doi.org/10.3847/1538-3881/ab9301 © 2020. -
Herschel Litho: Orion's Rainbow of Infrared Light
Orion’s Rainbow of Infrared Light www.nasa.gov Orion’s Rainbow of Infrared Light activity in protostars, Herschel’s Photodetector Array Camera and Spectrometer probed long infrared wavelengths of light that trace cold dust particles, while Spitzer gauged the warmer dust emitting shorter infrared wavelengths. In these data, as- tronomers noticed that several of the young stars varied in their brightness by more than 20 percent over just a few weeks. As this twinkling comes from cool material emitting infrared light, the material must be far from the hot center of the young star, likely in the outer disk or surrounding gas envelope. At that distance, it should take years or centuries for material to spiral closer in to the growing starlet, rather than mere weeks. A couple of scenarios under investigation could account for this short span. One possibility is that lumpy filaments of gas funnel from the outer to the central regions of the star, temporarily warming the object as the clumps hit its inner disk. Or, it could be that material occasionally piles up at the inner edge of the disk and casts a shadow on the outer disk. Herschel’s exquisite sensitivity opens up new possibilities for astronomers to study star formation and observe short-term variability in Orion protostars. Follow-up observations with Herschel will help astronomers identify the physical processes Astronomers have spotted young stars in the Orion Nebula responsible for the variability. changing right before their eyes, thanks to the European Space Herschel is a European Space Agency cornerstone mission, Agency’s Herschel Space Observatory and NASA’s Spitzer with science instruments provided by consortia of European Space Telescope.