Event Horizon Telescope

Kort over teleskopnetværket EHT.

Event Horizon Telescope (EHT) er et stort radioteleskopnet bestående af et globalt netværk af radioteleskoper og som kombinerer data fra adskillige very-long-baseline interferometri (VLBI) stationer rundt omkring på Jorden. Målet med EHT-projektet er at observere miljøet lige udenfor de supermassive sorte hullers begivenhedshorisont (på engelsk Event Horizon), med en vinkelopløsning høj nok til at kunne betragte strukturer med en størrelse af det sorte huls begivenhedshorisont. Blandt projektets observationelle mål er de to sorte huller med den tilsyneladende største vinkelstørrelse: M87* i centrum af den enorme elliptiske galakse i stjernebilledet Jomfruen; Messier 87 - og Sagittarius A* der er i Mælkevejens galaksekerne.[1][2]

Det først billede af det supermassive sorte hul i centrum af galaksen Messier 87, blev offentliggjort af EHT-samarbejdet den 10. april 2019.[3] Det sorte hul fik øgenavnet Pōwehi, der betyder "embellished dark source of unending creation" på Hawaiiansk.[4][5] Radioteleskopnet gjorde denne observation via en bølgelængde på 1,3mm og med den teoretiske diffraktion-begrænsede opløsning på 25 mikro-arcsekunder. Fremtidige planer omfatter forbedring af radioteleskopnettets opløsning ved at tilføje flere radioteleskoper og ved at anvende radiobølger med kortere bølgelængde.[6][1]

Messier 87*

Den 10. april 2019 blev det annonceret på en pressekonference i Bruxelles af Event Horizon Telescope-samabejdet, at man for første gang i historien havde taget et billede af et sort hul. Det supermassive sorte hul i centrum af M87, der benævnes M87*,[4][7] er optaget ved hjælp af radio-interferometri. Man har selvfølgelig ikke lavet et billede af det sorte hul, men man har lavet billeder i falske farver fra otte radioteleskopers modtagne radiobølger med en bølgelængde på 1,3 mm (EHF; millimeterbølger) udenfor, men tæt på, det supermassive sorte huls begivenhedshorisont i centrum af galaksen M87. Via Event Horizon Telescope samarbejdet har man estimeret M87* til at have en masse på (6,5 ± 0,2stat ± 0,7sys ) × 109 solmasser.[8] Det er en af de højeste kendte masser for sådan et objekt.

Samarbejde

(c) ALMA, CC BY 4.0
En skematisk diagram af EHT VLBI mekanismen. Hver radioantenne, spredt over et stort geografisk område, har et ekstremt præcist atomur. Analoge signaler samlet af antennen bliver konverteret til digitale signaler og gemt på harddiske sammen med tidssignaler fra atomuret. Harddiskkene med data bliver herefter sendt til en central lokation for at blive synkroniseret. En astronomisk observationsbillede dannes ved databehandling samlet fra flere lokationer.

Institutioner affillieret med EHT omfatter:[9]

  • Aalto University
  • Boston University
  • Brandeis University
  • California Institute of Technology
  • Canadian Institute for Advanced Research
  • Canadian Institute for Theoretical Astrophysics
  • Chalmers University of Technology, Onsala Space Observatory
  • Chinese Academy of Sciences
  • Consejo Nacional de Ciencia y Tecnología
  • Cornell University, Center for Astrophysics and Planetary Science
  • European Research Council
  • Google Research
  • The Graduate University for Advanced Studies (SOKENDAI), Department of Statistical Science / Department of Astronomical Science
  • Hiroshima University, Hiroshima Astrophysical Science Center
  • Huazhong University of Science and Technology, School of Physics
  • Institute of Statistical Mathematics
  • Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas
  • Instituto Geográfico Nacional
  • Instituto Nacional de Astrofísica, Óptica y Electrónica
  • Istituto Nazionale di Astrofisica (INAF) – Istituto di Radioastronomia, Italian ALMA Regional Centre
  • Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
  • Joint Institute for VLBI in Europe
  • Kogakuin University of Technology Engineering
  • Korea Astronomy and Space Science Institute
  • Leiden University, Leiden Observatory
  • Los Alamos National Laboratory
  • Max-Planck-Institut für extraterrestrische Physik
  • Nanjing University, Key Laboratory of Modern Astronomy and Astrophysics / School of Astronomy and Space Science
  • National Optical Astronomy Observatory
  • National Radio Astronomy Observatory
  • National Sun Yat-Sen University, Physics Depatment
  • National Taiwan University, Department of Physics
  • Netherlands Organisation for Scientific Research
  • Peking Universitet, Department of Astronomy, School of Physics / Kavli Institute for Astronomy and Astrophysics
  • Rhodes University, Centre for Radio Astronomy Techniques and Technologies, Department of Physics and Electronics
  • Seoul National University, Department of Physics and Astronomy
  • Tohoku University, Astronomy Institute / Frontier Research Institute for Interdisciplinary Sciences
  • Universidad de Concepción, Astronomy Department
  • Universidad Nacional Autónoma de México, Instituto de Astronomía / Instituto de Radioastronomía y Astrofísica
  • Universitat de València, Departament d'Astronomia i Astrofísica / Observatori Astronòmic
  • University College London, Mullard Space Science Laboratory
  • University of Amsterdam, Anton Pannekoek Institute & GRAPPA
  • University of Arizona
  • University of California Berkeley
  • University of California Santa Barbara
  • University of Chinese Academy of Sciences, School of Astronomy and Space Sciences
  • University of Illinois, Department of Astronomy / Department of Physics
  • University of Massachusetts Amherst, Department of Astronomy
  • University of Pretoria, Department of Physics
  • University of Science and Technology
  • University of Science and Technology of China, Astronomy Department
  • University of St. Petersburg, Astronomy Institute
  • University of Tokyo, Graduate School of Science, Department of Astronomy / Kavli Institute for Physics & Mathematics of the Universe
  • University of Toronto, Dunlap Institute for Astronomy and Astrophysics
  • University of Waterloo, Waterloo Center for Astrophysics / Department of Physics and Astronomy
  • Yonsei University, Department of Astronomy

Kilder/referencer

  1. ^ a b The Event Horizon Telescope Collaboration (10. april 2019). "First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole". The Astrophysical Journal Letters. 87 (1): L1. doi:10.3847/2041-8213/ab0ec7.
  2. ^
  3. ^
  4. ^ a b Lu, Donna (12. april 2019). "How do you name a black hole? It is actually pretty complicated". New Scientist. London. Hentet 12. april 2019. “For the case of M87*, which is the designation of this black hole, a (very nice) name has been proposed, but it has not received an official IAU approval,” says Christensen.
  5. ^ Chan, Tracy (10. april 2019). "Hawaii Telescopes Helped Capture the First Image of a Black Hole – and It Has a Hawaiian Name". Hawaii Magazine. Hentet 11. april 2019.
  6. ^ Susanna Kohler (10. april 2019). "First Images of a Black Hole from the Event Horizon Telescope". AAS Nova. Hentet 10. april 2019.
  7. ^ Many authors (10. april 2019). "First M87 Event Horizon Telescope Results". The Astrophysical Journal Letters – IOPscience. See vol. 875, No. 1 for links to papers open access-publikation - kan frit læses
  8. ^ The Event Horizon Telescope Collaboration (10. april 2019). "First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole". The Astrophysical Journal. 875 (1). doi:10.3847/2041-8213/ab1141.
  9. ^ "Affiliated Institutes". eventhorizontelescope.org (engelsk). Arkiveret fra originalen 20. april 2019. Hentet 2019-04-10.

Eksterne henvisninger

  • v
  • d
  • r
Begreber
  • Astronomisk interferometri
  • Very Long Baseline Interferometri (VLBI)
  • Radioteleskop (Radiovindue)
  • Astronomisk radiokilde
  • Enheder (watt og jansky)
Radioteleskoper
Individuelle teleskoper
  • RATAN-600 radioteleskop (Rusland)
  • 500 m Aperture Spherical Telescope (FAST, Kina)
  • Arecibo Observatory (Puerto Rico, US)
  • Caltech Submillimeter Observatory (CSO, US)
  • Effelsberg-teleskop (Tyskland)
  • Large Millimeter teleskop (Mexico)
  • Yevpatoria RT-70 (Rusland)
  • Galenki RT-70 (Rusland)
  • Suffa RT-70 (Uzbekistan)
  • Green Bank telescope (West Virginia, US)
  • Lovell telescope (UK)
  • Ooty telescope (Indien)
  • UTR-2 decameter radioteleskop (Ukraine)
  • Sardinia radioteleskop (Italien)
  • Usuda telescope (Japan)
  • Qitai radioteleskop (Kina)
Sydlige halvkugle
HartRAO (Sydafrika)
Parkes Observatory (Australien)
Warkworth Radio Astronomical Observatory (NZ)
Interferometri
  • Allen Telescope Array (ATA, California, US)
  • Atacama Large Millimeter Array (ALMA, Chile)
  • Australia Telescope Compact Array (ATCA, Australien)
  • Australian Square Kilometre Array Pathfinder (ASKAP, Australien)
  • Canadian Hydrogen Intensity Mapping Experiment (CHIME, Canada)
  • Combined Array for Research in Millimeter-wave Astronomy (CARMA, California, US)
  • European VLBI Network (Europa)
  • Event Horizon Telescope (EHT)
  • Green Bank Interferometer (GBI, West Virginia, US)
  • Giant Metrewave Radio Telescope (GMRT, Indien)
  • Korean VLBI Network (KVN, Sydkorea)
  • Low-Frequency Array (LOFAR, Holland)
  • MeerKAT (South Africa)
  • Large Latin American Millimeter Array (LLAMA, Argentina/Brasilien)
  • Murchison Widefield Array (MWA, Australien)
  • Multi-Element Radio Linked Interferometer Network (MERLIN, UK)
  • Molonglo Observatory Synthesis Telescope (MOST, Australien)
  • Northern Cross Radio Telescope (Italien)
  • Northern Extended Millimeter Array (Frankrig)
  • One-Mile Telescope (UK)
  • Primeval Structure Telescope (PaST, Kina)
  • Square Kilometre Array (SKA, Australia, Sydafrika)
  • Submillimeter Array (SMA, US)
  • Very Large Array (VLA, New Mexico, US)
  • Very Long Baseline Array (VLBA, US)
  • Westerbork Synthesis Radio Telescope (WSRT, Holland)
Rumbaserede
Observatorier
  • Algonquin Radio Observatory (Canada)
  • Haystack Observatory (US)
  • Jodrell Bank Observatory (UK)
  • Mullard Radio Astronomy Observatory (UK)
  • National Radio Astronomy Observatory (US)
  • Onsala Space Observatory (Sweden)
  • Special Astrophysical Observatory of the Russian Academy of Science (SAORAS, Rusland)
  • Warkworth Radio Astronomical Observatory
  • Pushchino Radio Astronomy Observatory (PRAO ASC LPI, Rusland)
Flerbrug
  • PARL (Canada)
  • DRAO (Canada)
  • ESA New Norcia (Australien)
Mennesker
Relaterede artikler
Optisk astronomi Submillimeter astronomi Infrarød astronomi Højenergi astronomi Gravitationel-bølge astronomi

Eksterne henvisninger

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The Event Horizon Telescope and Global mm-VLBI Array on the Earth.jpg
Forfatter/Opretter: ESO/O. Furtak, Licens: CC BY 4.0
This infographic details the locations of the participating telescopes of the Event Horizon Telescope (EHT) and the Global mm-VLBI Array (GMVA). Their goal is to image, for the very first time, the shadow of the event horizon of the supermassive black hole at the centre of the Milky Way, as well as to study the properties of the accretion and outflow around the Galactic Centre.
Open Access logo PLoS transparent.svg
Forfatter/Opretter: art designer at PLoS, modified by Wikipedia users Nina, Beao, and JakobVoss, Licens: CC0
Open Access logo, converted into svg, designed by PLoS. This version with transparent background.
EHT-infography.jpg
(c) ALMA, CC BY 4.0
A schematic diagram of the VLBI mechanism of EHT. Each antenna, spread out over vast distances, has an extremely precise atomic clock. Analogue signals collected by the antenna are converted to digital signals and stored on hard drives together with the time signals provided by the atomic clock. The hard drives are then shipped to a central location to be synchronised. An astronomical observation image is obtained by processing the data gathered from multiple locations.