TY - JOUR

T1 - First M87 Event Horizon Telescope Results. II. Array and Instrumentation

AU - Event Horizon Telescope Collaborat

AU - Akiyama, Kazunori

AU - Alberdi, Antxon

AU - Alef, Walter

AU - Asada, Keiichi

AU - Azulay, Rebecca

AU - Baczko, Anne-Kathrin

AU - Ball, David

AU - Balokovic, Mislav

AU - Barrett, John

AU - Bintley, Dan

AU - Blackburn, Lindy

AU - Boland, Wilfred

AU - Bouman, Katherine L.

AU - Bower, Geoffrey C.

AU - Bremer, Michael

AU - Brinkerink, Christiaan D.

AU - Brissenden, Roger

AU - Britzen, Silke

AU - Broderick, Avery E.

AU - Broguiere, Dominique

AU - Bronzwaer, Thomas

AU - Byun, Do-Young

AU - Carlstrom, John E.

AU - Chael, Andrew

AU - Chan, Chi-Kwan

AU - Chatterjee, Shami

AU - Chatterjee, Koushik

AU - Chen, Ming-Tang

AU - Chen, Yongjun

AU - Cho, Ilje

AU - Christian, Pierre

AU - Conway, John E.

AU - Cordes, James M.

AU - Crew, Geoffrey B.

AU - Cui, Yuzhu

AU - Davelaar, Jordy

AU - De Laurentis, Mariafelicia

AU - Deane, Roger

AU - Dempsey, Jessica

AU - Desvignes, Gregory

AU - Dexter, Jason

AU - Doeleman, Sheperd S.

AU - Eatough, Ralph P.

AU - Falcke, Heino

AU - Fish, Vincent L.

AU - Fomalont, Ed

AU - Fraga-Encinas, Raquel

AU - Friberg, Per

AU - Fromm, Christian M.

AU - Эрштадт, Светлана Георгиевна

AU - Gomez, Jose L.

PY - 2019/4/10

Y1 - 2019/4/10

N2 - The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength of ∼1.3 mm, EHT angular resolution (λ/D) is ∼25 μas, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary. In this Letter we describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance. Meeting the EHT science objectives has required several key developments that have facilitated the robust extension of the VLBI technique to EHT observing wavelengths and the production of instrumentation that can be deployed on a heterogeneous array of existing telescopes and facilities. To meet sensitivity requirements, high-bandwidth digital systems were developed that process data at rates of 64 gigabit s -1 , exceeding those of currently operating cm-wavelength VLBI arrays by more than an order of magnitude. Associated improvements include the development of phasing systems at array facilities, new receiver installation at several sites, and the deployment of hydrogen maser frequency standards to ensure coherent data capture across the array. These efforts led to the coordination and execution of the first Global EHT observations in 2017 April, and to event-horizon-scale imaging of the supermassive black hole candidate in M87.

AB - The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength of ∼1.3 mm, EHT angular resolution (λ/D) is ∼25 μas, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary. In this Letter we describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance. Meeting the EHT science objectives has required several key developments that have facilitated the robust extension of the VLBI technique to EHT observing wavelengths and the production of instrumentation that can be deployed on a heterogeneous array of existing telescopes and facilities. To meet sensitivity requirements, high-bandwidth digital systems were developed that process data at rates of 64 gigabit s -1 , exceeding those of currently operating cm-wavelength VLBI arrays by more than an order of magnitude. Associated improvements include the development of phasing systems at array facilities, new receiver installation at several sites, and the deployment of hydrogen maser frequency standards to ensure coherent data capture across the array. These efforts led to the coordination and execution of the first Global EHT observations in 2017 April, and to event-horizon-scale imaging of the supermassive black hole candidate in M87.

KW - black hole physics

KW - galaxies: individual (M87)

KW - Galaxy: center

KW - gravitational lensing: strong

KW - instrumentation: interferometers

KW - techniques: high angular resolution

KW - SGR-A-ASTERISK

KW - SUPERMASSIVE BLACK-HOLE

KW - MAGNETIC-FIELD STRUCTURE

KW - GHZ VLBI OBSERVATIONS

KW - COHERENCE LIMITS

KW - INTRINSIC SIZE

KW - PICO-VELETA

KW - RADIO

KW - ACCRETION

KW - PARAMETERS

UR - http://www.scopus.com/inward/record.url?scp=85064442259&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/first-m87-event-horizon-telescope-results-ii-array-instrumentation-1

U2 - 10.3847/2041-8213/ab0c96

DO - 10.3847/2041-8213/ab0c96

M3 - статья

VL - 875

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 1

M1 - L2

ER -