With unprecedented angular resolution, EHT (Event Horizon Telescope) scientists have imaged the distant blazar J1924-2914 and uncovered previously unknown details about its structure. The Event Horizon Telescope is a global scientific collaboration that uses various ground-based telescopes and connects them into one planet-sized observatory that enables scientists to explore the cosmos in unprecedented detail.
The EHT is so powerful that scientists were able, for the first time ever, to image the event horizon of a distant black hole at the center of the active elliptical galaxy Messier 87 in 2019.
From Black Holes to Blazars
A Blazar is a powerful active galactic nucleus in which supermassive black holes spew relativistic jets in our direction. We can observe blazars from a distance of billions of light-years using our radio telescopes because they can outshine their entire galaxy.
A helically bent jet emerges from the compact core of the quasar in the images. The EHT, which operates at 230 GHz, the Global Millimeter VLBI Array, which operates at 86 GHz, and the Very Long Baseline Array, which operates at 2.3 and 8.7 GHz, provided nearly simultaneous observations across the radio frequency band to enable a study of the source across different angular scales.
Using the EHT, scientists were able to map the linearly polarized emission of the J1924-2914 quasar.
“Our images constitute the highest angular resolution images of polarized emission from a quasar ever obtained,” says Sara Issaoun, NHFP Einstein Fellow at the Harvard & Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and lead of this study.
“We see interesting details in the strongly polarized innermost core of the source; the morphology of the polarized emission is hinting at the presence of a twisted magnetic field structure,” adds Sara.
Studying the emission in J1924-2914 contributed to the recently published observations of the supermassive black hole at the center of the milky way, Sagittarius A*.
“J1924-2914 is our main calibrator for the Sagittarius A* studies – this means that we needed to understand it really well so that we could use this knowledge to improve the total intensity and polarimetric calibration of the more difficult, time-variable source that is Sagittarius A*” – explained Maciek Wielgus, a scientist at the Max Planck Institute for Radio Astronomy in Bonn, Germany, co-leading this study.
Using the EHT, we can observe active galactic nuclei at the shortest radio wavelengths (about 1.3 mm) with the highest angular resolution ever achieved in astronomy, which is practically like seeing an orange on the Moon from Earth.
The EHT is ideally suited to studying the innermost regions of jets and advancing our understanding of how they form and accelerate. In the future, the EHT will be able to observe many more sources while pushing the boundaries of wavelength and resolution.
Through the use of a virtual telescope, the international collaboration created on April 10, 2019, the first-ever image of a black hole was announced. EHT connects existing telescopes with the most advanced systems, resulting in a new angular-resolving instrument with the highest angular resolution ever.
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Source: Curiosmos