From Harvard-Smithsonian Center for Astrophysics (US): “Telescopes Unite in Unprecedented Observations of Famous Black Hole”

From Harvard-Smithsonian Center for Astrophysics (US)

04.14.21

Media contacts:
Peter Edmonds
Chandra X-ray Center, Cambridge, Mass.
617-571-7279
pedmonds@cfa.harvard.edu

Molly Porter
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
molly.a.porter@nasa.gov

1
Credit: EHT Collaboration.

In April 2019, scientists released the first image of a black hole in galaxy Messier 87 using the Event Horizon Telescope (EHT).

Event Horizon Telescope Array


Arizona Radio Observatory.

European Southern Observatory(EU)/MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE) ESO’s Atacama Pathfinder Experiment(CL) high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft).


ESO APEX.

Combined Array for Research in Millimeter-wave Astronomy (CARMA Array for Research in Millimeter-wave Astronomy(US)), in the Inyo Mountains to the east of the California Institute of Technology Owens Valley Radio Observatory(US), at a site called Cedar Flat, Altitude 1,222 m (4,009 ft), relocated to Owens Valley Radio Observatory, Altitude 1,222 m (4,009 ft).


CARMA.

National Astronomy Observatory of Japan(JP) Atacama Submillimeter Telescope Experiment (ASTE) deployed to its site on Pampa La Bola, near Cerro Chajnantor and the Llano de Chajnantor, Observatory in northern Chile, Altitude 4,800 m (15,700 ft).


NAOJ Atacama Submillimeter Telescope Experiment (ASTE).

CfA Submillimeter Observatory(US) on MaunaKea, Hawaii, USA, Altitude 4,205 m (13,796 ft).


CfA Submillimeter Observatory.


Greenland Telescope.

Institute of Radio Astronomy [Institut de Radioastronomie Millimétrique](ES) 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada, Altitude 2,850 m (9,350 ft).


(IRAM) 30m.

IRAM-Institut de Radioastronomie Millimetrique (FR) NOEMA Interferometer in the French Alps on the wide and isolated Plateau de Bure at an elevation of 2550 meters, the telescope currently consists of ten antennas, each 15 meters in diameter.interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters.


IRAM NOEMA, France.


James Clerk Maxwell Telescope.

The University of Massachusetts Amherst and Mexico’s Instituto Nacional de Astrofísica, Óptica y Electrónica
LMT – Large Millimeter Telescope Alfonso Serrano(MX), Mexico, at an altitude of 4850 meters on top of the Sierra Negra.


Large Millimeter Telescope Alfonso Serrano.


ESO/NRAO/NAOJ ALMA Array.

South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago; the University of California, Berkeley; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; the University of Colorado, Boulder; McGill(CA) University, The University of Illinois, Urbana-Champaign: University of California, Davis; Ludwig Maximilians Universität München(DE); Argonne National Laboratory; and the National Institute for Standards and Technology. It is funded by the National Science Foundation(US).

Future Array/Telescopes

California Institute of Technology Owens Valley Radio Observatory(US), located near Big Pine, California (US) in Owens Valley, Altitude1,222 m (4,009 ft).


Caltech Owens Valley Radio Observatory.

However, that remarkable achievement was just the beginning of the science story to be told.

Data from 19 observatories released today promise to give unparalleled insight into this black hole and the system it powers, and to improve tests of Einstein’s General Theory of Relativity.

“We knew that the first direct image of a black hole would be groundbreaking,” says Kazuhiro Hada of the National Astronomical Observatory of Japan [国立天文台](JP), a co-author of a new study published in The Astrophysical Journal Letters that describes the large set of data. “But to get the most out of this remarkable image, we need to know everything we can about the black hole’s behavior at that time by observing over the entire electromagnetic spectrum.”

The immense gravitational pull of a supermassive black hole can power jets of particles that travel at almost the speed of light across vast distances. Messier 87*’s jets produce light spanning the entire electromagnetic spectrum, from radio waves to visible light to gamma rays. This pattern is different for each black hole. Identifying this pattern gives crucial insight into a black hole’s properties—for example, its spin and energy output—but is a challenge because the pattern changes with time.

Scientists compensated for this variability by coordinating observations with many of the world’s most powerful telescopes on the ground and in space, collecting light from across the spectrum. These 2017 observations were the largest simultaneous observing campaign ever undertaken on a supermassive black hole with jets.

Three observatories managed by the Center for Astrophysics | Harvard & Smithsonian participated in the landmark campaign: the Submillimeter Array (SMA) in Hilo, Hawaii; the space-based Chandra X-ray Observatory; and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in southern Arizona.

University of Arizona Veritas Four Čerenkov telescopes A novel gamma ray telescope under construction at the CfA Fred Lawrence Whipple Observatory (US), Mount Hopkins, Arizona (US) Altitude 2,606 m 8,550 ft. A large project known as the Čerenkov Telescope Array, composed of hundreds of similar telescopes to be situated at Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) in the Canary Islands and Chile at European Southern Observatory(EU)‘s Cerro Paranal site. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison (US), and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev.

Beginning with the EHT’s now iconic image of Messier 87*, a new video takes viewers on a journey through the data from each telescope. Each consecutive frame shows data across many factors of ten in scale, both of wavelengths of light and physical size.

The sequence begins with the April 2019 image of the black hole. It then moves through images from other radio telescope arrays from around the globe (SMA), moving outward in the field of view during each step. Next, the view changes to telescopes that detect visible light, ultraviolet light, and X-rays (Chandra). The screen splits to show how these images, which cover the same amount of the sky at the same time, compare to one another. The sequence finishes by showing what gamma-ray telescopes on the ground (VERITAS), and Fermi in space, detect from this black hole and its jet.


Each telescope delivers different information about the behavior and impact of the 6.5-billion-solar-mass black hole at the center of Messier 87*, which is located about 55 million light-years from Earth.

“There are multiple groups eager to see if their models are a match for these rich observations, and we’re excited to see the whole community use this public data set to help us better understand the deep links between black holes and their jets,” says co-author Daryl Haggard of McGill University in Montreal, Canada.

The data were collected by a team of 760 scientists and engineers from nearly 200 institutions, spanning 32 countries or regions, and using observatories funded by agencies and institutions around the globe. The observations were concentrated from the end of March to the middle of April 2017.

“This incredible set of observations includes many of the world’s best telescopes,” says co-author Juan Carlos Algaba of the University of Malaya [Universiti Malaya] (MY) in Kuala Lumpur, Malaysia. “This is a wonderful example of astronomers around the world working together in the pursuit of science.”

Additional Information

The Astrophysical Journal Letter describing these results is available here. This paper was led by 33 members of the EHT Multiwavelength Science Working Group, and includes as coauthors members of the following collaborations: the entire Event Horizon Telescope Collaboration; the Fermi Large Area Telescope Collaboration; the H.E.S.S collaboration; the MAGIC collaboration; the VERITAS collaboration and the EAVN collaboration. The coordinators of the EHT Multiwavelength Science Working Group are Sera Markoff, Kazuhiro Hada, and Daryl Haggard, who together with Juan Carlos Algaba and Mislav Baloković, also coordinated work on the paper.

Partner MWL facilities include: European VLBI Network ; National Radio Astronomy Observatory(US) High Sensitivity Array ; VLBI Exploration of Radio Astrometry; Korea Astronomy and Space Science Institute [한국천문연구원] (KR); East Asian VLBI Network/KVN and VERA Array ; NRAO Very Long Baseline Array (US); Global Millimeter VLBI Array ; ESO Very Large Telescope Interferometer GRAVITY Instrument (VLTI/GRAVITY); Neil Gehrels Swift Observatory (Swift); Hubble Space Telescope (HST); Chandra X-ray Observatory (Chandra); Nuclear Spectroscopic Telescope Array (NuSTAR); High Throughput X-ray Spectroscopy Mission and X-ray Multi-Mirror Mission (XMM-Newton); Fermi Large Area Space Telescope (Fermi-LAT) [above]; High Energy Stereoscopic System (H.E.S.S.) [above]; Major Atmospheric Gamma Imaging Cherenkov Telescopes (MAGIC) [above]; Very Energetic Radiation Imaging Telescope Array System (VERITAS) [above].

The 2017 campaign involved a large number of observatories and telescopes [all cited elsewhere in this article dexcept those cited here]. At radio wavelengths it involved: the European Very Long Baseline Interferometry (VLBI) Network (EVN) on May 9, 2017; the High Sensitivity Array (HSA), which includes the Very Large Array (VLA), the MPIFR Effelsberg 100m antenna and the 10 stations of the National Radio Astronomy Observatory (NRAO) Very Long Baseline Array (VLBA) on May 15, 16 and 20; the VLBI Exploration of Radio Astronomy (VERA) over 17 different times in 2017; the Korean VLBI Network (KVN) over seven epochs between March and December; the East Asian VLBI Network (EAVN) and the KVN and VERA Array (KaVA) , over 14 epochs between March and May 2017; the VLBA on May 5, 2017; the Global Millimeter-VLBI-Array (GMVA) on March 30, 2017; the Atacama Large Millimeter/submillimeter Array (ALMA); the Submillimeter Array (SMA) as part of an ongoing monitoring program. At ultraviolet (UV) wavelengths it involved the Neil Gehrels Swift Observatory (Swift) with multiple observations between March 22 and April 20, 2017; and at optical wavelengths: Swift; and the Hubble Space Telescope on April 7, 12, and 17, 2017. (The Hubble data were retrieved from the Hubble archive because it was part of an independent observing program.) At X-ray wavelengths it involved the Chandra X-ray Observatory on April 11 and 14, 2017; the Nuclear Spectroscopic Telescope Array (NuSTAR) on April 11 and 14, 2017; and Swift. At gamma-ray wavelengths it involved Fermi from March 22 to April 20, 2017; the High Energy Stereoscopic System (H.E.S.S); the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes, and the Very Energetic Radiation Imaging Telescope Array System (VERITAS).

The EHT Multi-wavelength (MWL) Working Group is a collective of EHT Collaboration members and external partners working together to ensure broadband MWL coverage during EHT campaigns, to maximize science output. The EHT collaboration involves more than 300 researchers from Africa, Asia, Europe, North and South America. The international collaboration is working to capture the most detailed black hole images ever obtained by creating a virtual Earth-sized telescope. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a fundamentally new instrument with the highest angular resolving power that has yet been achieved.

The individual EHT telescopes [see the full EHT enumeration above] involved are: ALMA, APEX, the IRAM 30-meter Telescope, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope (LMT), the Submillimeter Array (SMA), the Submillimeter Telescope (SMT), and the South Pole Telescope (SPT). The Greenland Telescope, the Kitt Peak Telescope, and NOEMA joined EHT after the 2017 observations.

Partner MWL facilities include: European VLBI Network (EVN); High Sensitivity Array (HSA); VLBI Exploration of Radio Astrometry (VERA); Korea VLBI Network (KVN); East Asian VLBI Network/KVN and VERA Array (EAVN/KaVA); Very Long Baseline Array (VLBA); Global Millimeter VLBI Array (GMVA); Very Large Telescope Interferometer GRAVITY Instrument (VLTI/GRAVITY); Neil Gehrels Swift Observatory (Swift); Hubble Space Telescope (HST); Chandra X-ray Observatory (Chandra); Nuclear Spectroscopic Telescope Array (NuSTAR); High Throughput X-ray Spectroscopy Mission and X-ray Multi-Mirror Mission (XMM-Newton); Fermi Large Area Space Telescope (Fermi-LAT); High Energy Stereoscopic System (H.E.S.S.); Major Atmospheric Gamma Imaging Cherenkov Telescopes (MAGIC); and the Very Energetic Radiation Imaging Telescope Array System (VERITAS).

See the full article here .


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The Harvard-Smithsonian Center for Astrophysics (US) combines the resources and research facilities of the Harvard College Observatory(US) and the Smithsonian Astrophysical Observatory(US) under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory(US) is a bureau of the Smithsonian Institution(US), founded in 1890. The Harvard College Observatory, founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University(US), and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

Founded in 1973 and headquartered in Cambridge, Massachusetts, the CfA leads a broad program of research in astronomy, astrophysics, Earth and space sciences, as well as science education. The CfA either leads or participates in the development and operations of more than fifteen ground- and space-based astronomical research observatories across the electromagnetic spectrum, including the forthcoming Giant Magellan Telescope(CL) and the Chandra X-ray Observatory(US), one of NASA’s Great Observatories.

GMT

Giant Magellan Telescope(CL) 21 meters, to be at the Carnegie Institution for Science’s(US) NOIRLab(US) NOAO(US) Las Campanas Observatory(CL), some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.

Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in the world. Its projects have included Nobel Prize-winning advances in cosmology and high energy astrophysics, the discovery of many exoplanets, and the first image of a black hole. The CfA also serves a major role in the global astrophysics research community: the CfA’s Astrophysics Data System(ADS)(US), for example, has been universally adopted as the world’s online database of astronomy and physics papers. Known for most of its history as the “Harvard-Smithsonian Center for Astrophysics”, the CfA rebranded in 2018 to its current name in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. The CfA’s current Director (since 2004) is Charles R. Alcock, who succeeds Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982).

The Center for Astrophysics | Harvard & Smithsonian is not formally an independent legal organization, but rather an institutional entity operated under a Memorandum of Understanding between Harvard University (US) and the Smithsonian Institution (US). This collaboration was formalized on July 1, 1973, with the goal of coordinating the related research activities of the Harvard College Observatory (US) (HCO) and the Smithsonian Astrophysical Observatory (US) under the leadership of a single Director, and housed within the same complex of buildings on the Harvard campus in Cambridge, Massachusetts. The CfA’s history is therefore also that of the two fully independent organizations that comprise it. With a combined lifetime of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA’s founding.

History of the Smithsonian Astrophysical Observatory (SAO)

Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1,1890. The Astrophysical Observatory’s initial, primary purpose was to “record the amount and character of the Sun’s heat”. Charles Greeley Abbot was named SAO’s first director, and the observatory operated solar telescopes to take daily measurements of the Sun’s intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the Solar constant, as well as to serendipitously discover Solar variability. It is likely that SAO’s early history as a solar observatory was part of the inspiration behind the Smithsonian’s “sunburst” logo, designed in 1965 by Crimilda Pontes.

In 1955, the scientific headquarters of SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). Fred Lawrence Whipple, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO’s move to Harvard’s campus also resulted in a rapid expansion of its research program. Following the launch of Sputnik (the world’s first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the United States Air Force on Project Space Track.

With the creation of National Aeronautics and Space Administration(US) the following year and throughout the space race, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

History of Harvard College Observatory (HCO)

Partly in response to renewed public interest in astronomy following the 1835 return of Halley’s Comet, the Harvard College Observatory was founded in 1839, when the Harvard Corporation appointed William Cranch Bond as an “Astronomical Observer to the University”. For its first four years of operation, the observatory was situated at the Dana-Palmer House (where Bond also resided) near Harvard Yard, and consisted of little more than three small telescopes and an astronomical clock. In his 1840 book recounting the history of the college, then Harvard President Josiah Quincy III noted that “…there is wanted a reflecting telescope equatorially mounted…”. This telescope, the 15-inch “Great Refractor”, opened seven years later (in 1847) at the top of Observatory Hill in Cambridge (where it still exists today, housed in the oldest of the CfA’s complex of buildings). The telescope was the largest in the United States from 1847 until 1867. William Bond and pioneer photographer John Adams Whipple used the Great Refractor to produce the first clear Daguerrotypes of the Moon (winning them an award at the 1851 Great Exhibition in London). Bond and his son, George Phillips Bond (the second Director of HCO), used it to discover Saturn’s 8th moon, Hyperion (which was also independently discovered by William Lassell).

Under the directorship of Edward Charles Pickering from 1877 to 1919, the observatory became the world’s major producer of stellar spectra and magnitudes, established an observing station in Peru, and applied mass-production methods to the analysis of data. It was during this time that HCO became host to a series of major discoveries in astronomical history, powered by the Observatory’s so-called “Computers” (women hired by Pickering as skilled workers to process astronomical data). These “Computers” included Williamina Fleming; Annie Jump Cannon; Henrietta Swan Leavitt; Florence Cushman; and Antonia Maury, all widely recognized today as major figures in scientific history. Henrietta Swan Leavitt, for example, discovered the so-called period-luminosity relation for Classical Cepheid variable stars, establishing the first major “standard candle” with which to measure the distance to galaxies. Now called “Leavitt’s Law”, the discovery is regarded as one of the most foundational and important in the history of astronomy; astronomers like Edwin Hubble, for example, would later use Leavitt’s Law to establish that the Universe is expanding, the primary piece of evidence for the Big Bang model.

Upon Pickering’s retirement in 1921, the Directorship of HCO fell to Harlow Shapley (a major participant in the so-called “Great Debate” of 1920). This era of the observatory was made famous by the work of Cecelia Payne-Gaposchkin, who became the first woman to earn a Ph.D. in astronomy from Radcliffe College (a short walk from the Observatory). Payne-Gapochkin’s 1925 thesis proposed that stars were composed primarily of hydrogen and helium, an idea thought ridiculous at the time. Between Shapley’s tenure and the formation of the CfA, the observatory was directed by Donald H. Menzel and then Leo Goldberg, both of whom maintained widely recognized programs in solar and stellar astrophysics. Menzel played a major role in encouraging the Smithsonian Astrophysical Observatory to move to Cambridge and collaborate more closely with HCO.

Joint history as the Center for Astrophysics (CfA)

The collaborative foundation for what would ultimately give rise to the Center for Astrophysics began with SAO’s move to Cambridge in 1955. Fred Whipple, who was already chair of the Harvard Astronomy Department (housed within HCO since 1931), was named SAO’s new director at the start of this new era; an early test of the model for a unified Directorship across HCO and SAO. The following 18 years would see the two independent entities merge ever closer together, operating effectively (but informally) as one large research center.

This joint relationship was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field, then affiliated with UC Berkeley(US), was appointed as its first Director. That same year, a new astronomical journal, the CfA Preprint Series was created, and a CfA/SAO instrument flying aboard Skylab discovered coronal holes on the Sun. The founding of the CfA also coincided with the birth of X-ray astronomy as a new, major field that was largely dominated by CfA scientists in its early years. Riccardo Giacconi, regarded as the “father of X-ray astronomy”, founded the High Energy Astrophysics Division within the new CfA by moving most of his research group (then at American Sciences and Engineering) to SAO in 1973. That group would later go on to launch the Einstein Observatory (the first imaging X-ray telescope) in 1976, and ultimately lead the proposals and development of what would become the Chandra X-ray Observatory. Chandra, the second of NASA’s Great Observatories and still the most powerful X-ray telescope in history, continues operations today as part of the CfA’s Chandra X-ray Center. Giacconi would later win the 2002 Nobel Prize in Physics for his foundational work in X-ray astronomy.

Shortly after the launch of the Einstein Observatory, the CfA’s Steven Weinberg won the 1979 Nobel Prize in Physics for his work on electroweak unification. The following decade saw the start of the landmark CfA Redshift Survey (the first attempt to map the large scale structure of the Universe), as well as the release of the Field Report, a highly influential Astronomy & Astrophysics Decadal Survey chaired by the outgoing CfA Director George Field. He would be replaced in 1982 by Irwin Shapiro, who during his tenure as Director (1982 to 2004) oversaw the expansion of the CfA’s observing facilities around the world, including the newly named Fred Lawrence Whipple Observatory(US), the Infrared Telescope (IRT) aboard the Space Shuttle, the 6.5-meter Multiple Mirror Telescope(US), the NASA SOHO satellite(US), and the launch of Chandra [above] in 1999.

CfA Fred Lawrence Whipple Observatory(US) , located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

Multi-Mirror Telescope

the 6.5-meter Multiple Mirror Telescope(US) at Arizona Fred Lawrence Whipple Observatory at the summit of Mount Hopkins near Tucson, Arizona, USA, Altitude 2,616 m (8,583 ft) n the Santa Rita Mountains.

CfA-led discoveries throughout this period include canonical work on Supernova 1987A, the “CfA2 Great Wall” (then the largest known coherent structure in the Universe), the best-yet evidence for supermassive black holes, and the first convincing evidence for an extrasolar planet.

The 1990s also saw the CfA unwittingly play a major role in the history of computer science and the internet: in 1990, SAO developed SAOImage, one of the world’s first X11-based applications made publicly available (its successor, DS9, remains the most widely used astronomical FITS image viewer worldwide). During this time, scientists at the CfA also began work on what would become the Astrophysics Data System (ADS), one of the world’s first online databases of research papers. By 1993, the ADS was running the first routine transatlantic queries between databases, a foundational aspect of the internet today.

The CfA Today

Research at the CfA

Charles Alcock, known for a number of major works related to massive compact halo objects, was named the third director of the CfA in 2004. Today Alcock overseas one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $100M. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 Ph.D. students, more than 100 postdoctoral researchers, and roughly 25 undergraduate majors in astronomy and astrophysics from Harvard College. SAO, meanwhile, hosts a long-running and highly rated REU Summer Intern program as well as many visiting graduate students. The CfA estimates that roughly 10% of the professional astrophysics community in the United States spent at least a portion of their career or education there.

The CfA is either a lead or major partner in the operations of the Fred Lawrence Whipple Observatory, the Submillimeter Array, MMT Observatory, the South Pole Telescope, VERITAS, and a number of other smaller ground-based telescopes. The CfA’s 2019-2024 Strategic Plan includes the construction of the Giant Magellan Telescope as a driving priority for the Center.

CfA Submillimeter Array, Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft).

South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago; the University of California, Berkeley; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; the University of Colorado, Boulder; McGill(CA) University, The University of Illinois, Urbana-Champaign: University of California, Davis; Ludwig Maximilians Universität München(DE); Argonne National Laboratory; and the National Institute for Standards and Technology. It is funded by the National Science Foundation(US).

Along with the Chandra X-ray Observatory, the CfA plays a central role in a number of space-based observing facilities, including the recently launched Parker Solar Probe, Kepler Space Telescope, the Solar Dynamics Observatory (SDO), and HINODE. The CfA, via the Smithsonian Astrophysical Observatory, recently played a major role in the Lynx X-ray Observatory, a NASA-Funded Large Mission Concept Study commissioned as part of the 2020 Decadal Survey on Astronomy and Astrophysics (“Astro2020”). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra.

NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker.

NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018.

NASA/Solar Dynamics Observatory.

JAXA/NASA HINODE spacecraft.

SAO is one of the 13 stakeholder institutes for the Event Horizon Telescope Board, and the CfA hosts its Array Operations Center. In 2019, the project revealed the first direct image of a black hole.

Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via JPL/ Event Horizon Telescope Collaboration released on 10 April 2019.

The result is widely regarded as a triumph not only of observational radio astronomy, but of its intersection with theoretical astrophysics. Union of the observational and theoretical subfields of astrophysics has been a major focus of the CfA since its founding.

In 2018, the CfA rebranded, changing its official name to the “Center for Astrophysics | Harvard & Smithsonian” in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. Today, the CfA receives roughly 70% of its funding from NASA, 22% from Smithsonian federal funds, and 4% from the National Science Foundation. The remaining 4% comes from contributors including the United States Department of Energy, the Annenberg Foundation, as well as other gifts and endowments.

The first results show that the intensity of the light produced by material around M87’s supermassive black hole was the lowest that had ever been observed. This produced ideal conditions for viewing the ‘shadow’ of the black hole, as well as being able to isolate the light from regions close to the event horizon from those tens of thousands of light-years away from the black hole.

The combination of data from these telescopes, and current (and future) EHT observations, will allow scientists to conduct important lines of investigation into some of astrophysics’ most significant and challenging fields of study. For example, scientists plan to use these data to improve tests of Einstein’s Theory of General Relativity. Currently, uncertainties about the material rotating around the black hole and being blasted away in jets, in particular the properties that determine the emitted light, represent a major hurdle for these General Relativity tests.

A related question that is addressed by today’s study concerns the origin of energetic particles called “cosmic rays,” which continually bombard the Earth from outer space. Their energies can be a million times higher than what can be produced in the most powerful accelerator on Earth, the Large Hadron Collider. The huge jets launched from black holes, like the ones shown in today’s images, are thought to be the most likely source of the highest energy cosmic rays, but there are many questions about the details, including the precise locations where the particles get accelerated. Because cosmic rays produce light via their collisions, the highest-energy gamma rays can pinpoint this location, and the new study indicates that these gamma-rays are likely not produced near the event horizon—at least not in 2017. A key to settling this debate will be comparison to the observations from 2018, and the new data being collected this week.

“Understanding the particle acceleration is really central to our understanding of both the EHT image as well as the jets, in all their ‘colors’,” says co-author Sera Markoff from the University of Amsterdam. “These jets manage to transport energy released by the black hole out to scales larger than the host galaxy, like a huge power cord. Our results will help us calculate the amount of power carried, and the effect the black hole’s jets have on its environment.”

The release of this new treasure trove of data coincides with the EHT’s 2021 observing run, which leverages a worldwide array of radio dishes, the first since 2018. Last year’s campaign was canceled because of the COVID-19 pandemic, and the previous year was suspended because of unforeseen technical problems. This very week, for six nights, EHT astronomers are targeting several supermassive black holes: the one in M87 again, the one in our Galaxy called Sagittarius A*, and several more distant black holes. Compared to 2017, the array has been improved by adding three more radio telescopes: the Greenland Telescope, the Kitt Peak 12-meter Telescope in Arizona, and the NOrthern Extended Millimeter Array (NOEMA) in France.

“With the release of these data, combined with the resumption of observing and an improved EHT, we know many exciting new results are on the horizon,” says co-author Mislav Baloković of Yale University.

“I’m really excited to see these results come out, along with my fellow colleagues working on the SMA, some of whom were directly involved in collecting some of the data for this spectacular view into M87,” says co-author Garrett Keating, a Submillimeter Array project scientist. “And with the results of Sagittarius A* — the massive black hole at the center of the Milky Way — coming out soon, and the resumption of observing this year, we are looking forward to even more amazing results with the EHT for years to come.”