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This breakthrough was announced today in a series of six papers published in a special issue of\u00a0The Astrophysical Journal Letters.\u00a0The image\u00a0reveals the black hole at the centre of Messier 87\u00a0[1], a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5-billion times that of the Sun\u00a0[2].<\/p>\n
The EHT links telescopes around the globe to form an Earth-sized virtual telescope with unprecedented sensitivity and resolution\u00a0[3]. The EHT is the result of years of international collaboration, and offers scientists a new way to study the most extreme objects in the Universe predicted by Einstein\u2019s\u00a0general relativity<\/a>\u00a0during the centennial year of the historic experiment that first confirmed the theory\u00a0[4].<\/p>\n “We have taken the first picture of a black hole,”<\/em> said EHT project director Sheperd S. Doeleman<\/strong> of the Center for Astrophysics | Harvard & Smithsonian. “This is an extraordinary scientific feat accomplished by a team of more than 200 researchers.”<\/em><\/p>\n Black holes are extraordinary cosmic objects with enormous masses but extremely compact sizes. The presence of these objects affects their environment in extreme ways, warping spacetime and super-heating any surrounding material.<\/p>\n “If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow \u2014 something predicted by Einstein\u2019s general relativity that we\u2019ve never seen before,”<\/em> explained chair of the EHT Science Council Heino Falcke<\/strong> of Radboud University, the Netherlands. “This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and allowed us to measure the enormous mass of M87\u2019s black hole.”<\/em><\/p>\n <\/p>\n Multiple calibration and imaging methods have revealed a ring-like structure with a dark central region \u2014 the black hole\u2019s shadow \u2014 that persisted over multiple independent days of observations.<\/p>\n “Once we were sure we had imaged the shadow, we could compare our observations to extensive computer models that include the physics of warped space, superheated matter and strong magnetic fields. Many of the features of the observed image match our theoretical understanding surprisingly well,”<\/em> remarks Paul T.P. Ho<\/strong>, EHT Board member and Director of the East Asian Observatory [5]. “This makes us confident about the interpretation of our observations, including our estimation of the black hole\u2019s mass.”<\/em><\/p>\n Creating the EHT was a formidable challenge which required upgrading and connecting a worldwide network of eight pre-existing telescopes deployed at a variety of challenging high-altitude sites. These locations included volcanoes in Hawai\u02bbi and Mexico, mountains in Arizona and the Spanish Sierra Nevada, the Chilean Atacama Desert, and Antarctica.<\/p>\n The EHT observations use a technique called very-long-baseline interferometry (VLBI) which synchronises telescope facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope observing at a wavelength of 1.3mm. VLBI allows the EHT to achieve an angular resolution of 20 micro-arcseconds \u2014 enough to read a newspaper in New York from a sidewalk caf\u00e9 in Paris\u00a0[6].<\/p>\n The telescopes contributing to this result were\u00a0ALMA<\/a>,\u00a0APEX<\/a>, the\u00a0IRAM 30-meter telescope<\/a>, the\u00a0James Clerk Maxwell Telescope<\/a>, the\u00a0Large Millimeter Telescope Alfonso Serrano<\/a>, the\u00a0Submillimeter Array<\/a>, the\u00a0Submillimeter Telescope<\/a>, and the\u00a0South Pole Telescope<\/a>\u00a0[7]. Petabytes of raw data from the telescopes were combined by highly specialised supercomputers hosted by the\u00a0Max Planck Institute for Radio Astronomy<\/a>\u00a0and\u00a0MIT Haystack Observatory<\/a>.<\/p>\n <\/p>\n The construction of the EHT and the observations announced today represent the culmination of decades of observational, technical, and theoretical work. This example of global teamwork required close collaboration by researchers from around the world. Thirteen partner institutions worked together to create the EHT, using both pre-existing infrastructure and support from a variety of agencies. Key funding was provided by the US National Science Foundation (NSF), the EU’s European Research Council (ERC), and funding agencies in East Asia.<\/p>\n “We have achieved something presumed to be impossible just a generation ago,”<\/em> concluded Doeleman<\/strong>. “Breakthroughs in technology, connections between the world’s best radio observatories, and innovative algorithms all came together to open an entirely new window on black holes and the event horizon.”<\/em><\/p>\n <\/p>\n Notes<\/strong><\/p>\n [1]\u00a0The shadow of a black hole is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole\u2019s boundary \u2014 the event horizon from which the EHT takes its name \u2014 is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across.<\/p>\n [2]\u00a0Supermassive black holes are relatively tiny astronomical objects \u2014 which has made them impossible to directly observe until now. As a black hole\u2019s size is proportional to its mass, the more massive a black hole, the larger the shadow. Thanks to its enormous mass and relative proximity, M87\u2019s black hole was predicted to be one of the largest viewable from Earth \u2014 making it a perfect target for the EHT.<\/p>\n [3]\u00a0Although the telescopes are not physically connected, they are able to synchronize their recorded data with atomic clocks \u2014\u00a0hydrogen masers<\/a>\u00a0\u2014 which precisely time their observations. These observations were collected at a wavelength of 1.3 mm during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data \u2013 roughly 350 terabytes per day \u2013 which was stored on high-performance helium-filled hard drives. These data were flown to highly specialised supercomputers \u2014 known as correlators \u2014 at the\u00a0Max Planck Institute for Radio Astronomy<\/a>\u00a0and\u00a0MIT Haystack Observatory<\/a>\u00a0to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration.<\/p>\n [4]\u00a0100 years ago, two expeditions set out for the island of Pr\u00edncipe off the coast of Africa and Sobra in Brazil to observe the\u00a01919 solar eclipse<\/a>, with the goal of testing general relativity by seeing if starlight would be bent around the limb of the sun, as predicted by Einstein. In an echo of those observations, the EHT has sent team members to some of the world’s highest and isolated radio facilities to once again test our understanding of gravity.<\/p>\n [5]\u00a0The East Asian Observatory (EAO) partner on the EHT project represents the participation of many regions in Asia, including China, Japan, Korea, Taiwan, Vietnam, Thailand, Malaysia, India and Indonesia.<\/p>\n [6]\u00a0Future EHT observations will see substantially increased sensitivity with the participation of the\u00a0IRAM NOEMA Observatory<\/a>, the\u00a0Greenland Telescope<\/a>\u00a0and the\u00a0Kitt Peak Telescope<\/a>.<\/p>\n [7]\u00a0ALMA<\/a> is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences(NINS) of Japan, together with the National Research Council (Canada), the Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. APEX<\/a> is operated by ESO<\/a>, the 30-meter telescope<\/a> is operated by IRAM<\/a> (the IRAM Partner Organizations are MPG (Germany), CNRS (France) and IGN (Spain)), the James Clerk Maxwell Telescope<\/a> is operated by the EAO<\/a>, the Large Millimeter Telescope Alfonso Serrano<\/a> is operated by INAOE<\/a> and UMass<\/a>, the Submillimeter Array<\/a> is operated by SAO<\/a> and ASIAA<\/a> and the Submillimeter Telescope<\/a> is operated by the Arizona Radio Observatory (ARO). The South Pole Telescope<\/a> is operated by the University of Chicago<\/a> with specialized EHT instrumentation provided by the University of Arizona<\/a>.<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA) contribute to paradigm-shifting observations of the gargantuan black hole at the heart of distant galaxy Messier 87 The Event Horizon Telescope (EHT) \u2014 a planet-scale array of eight ground-based radio telescopes forged through international collaboration \u2014 was designed to capture images of a black hole. Today, in […]<\/p>\n","protected":false},"author":1,"featured_media":5353,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[4],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/posts\/5352"}],"collection":[{"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/comments?post=5352"}],"version-history":[{"count":1,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/posts\/5352\/revisions"}],"predecessor-version":[{"id":5354,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/posts\/5352\/revisions\/5354"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/media\/5353"}],"wp:attachment":[{"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/media?parent=5352"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/categories?post=5352"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/newsletter.sinica.edu.tw/en\/wp-json\/wp\/v2\/tags?post=5352"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}