![]() These measurements provide the first opportunity to image horizon-scale structure in M87. ![]() The M87 data reveal the presence of two nulls in correlated flux density at ~3.4 and ~8.3 giga-lambda and temporal evolution in closure quantities, indicating intrinsic variability of compact structure on a timescale of days, or several light-crossing times for a few billion solar-mass black hole. They are validated through a series of quality assurance tests that show consistency across pipelines and set limits on baseline systematic errors of 2% in amplitude and 1 degree in phase. The final data products include calibrated total intensity amplitude and phase information. In response, we developed three independent pipelines for phase calibration and fringe detection, each tailored to the specific needs of the EHT. ![]() The observations present challenges for existing data processing tools, arising from the rapid atmospheric phase fluctuations, wide recording bandwidth, and highly heterogeneous array. ![]() These global very long baseline interferometric observations include for the first time the highly sensitive Atacama Large Millimeter/submillimeter Array (ALMA) reaching an angular resolution of 25 micro-as, with characteristic sensitivity limits of ~1 mJy on baselines to ALMA and ~10 mJy on other baselines. Data Processing and Calibration, by The Event Horizon Telescope Collaboration Download PDF Abstract:We present the calibration and reduction of Event Horizon Telescope (EHT) 1.3mm radio wavelength observations of the supermassive black hole candidate at the center of the radio galaxy M87 and the quasar 3C 279, taken during the 2017 April 5-11 observing campaign. These efforts led to the coordination and execution of the first Global EHT observations in2017 April, and to event-horizon-scale imaging of the supermassive black hole candidate in M87.Download a PDF of the paper titled First M87 Event Horizon Telescope Results. 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. 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. 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. In this Letterwe describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance. 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. At a nominal operating wavelength of∼1.3 mm, EHT angular resolution(λ/D)is∼25μas, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. en In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a. 18 James Clerk Maxwell Telescope (JCMT), 660 N. Event Horizon Telescope Collaboration, Kazunori Akiyama 1,2,3, Antxon Alberdi 4, Walter Alef 5, Juan Carlos Algaba 6. Imaging of the Galactic Center Supermassive Black Hole. 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. The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation 1, 2. First Sagittarius A Event Horizon Telescope Results.
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