has event horizon telescope seen a blackhole

Why is the southern part of the ring brighter? As fast-moving material rotates around the black hole, it speeds toward us on one side and away from us on the other. The EHT observations of M87 beautifully confirm this picture! Images of such an encased black hole were predicted to reveal a dark region - the black hole’s “shadow” - surrounded by a ring of emission produced by the distorted paths of light from the surrounding material. While a naked black hole would simply appear dark in an image, an active black hole like M87 is surrounded by dust and gas that forms an accreting disk, as well as funnels at the base of its powerful jets. What they saw was spot-on with predictions: a ring of light spanning ~38–44 µas, with the southern part of the ring appearing brighter than the rest. The images remain consistent over the observations, providing evidence of a stable source. Weather was uniformly good - planet-wide! - during those observations, allowing EHT scientists to combine the data from the eight telescopes and reconstruct images of the black hole.ĮHT observations of M87 taken over 4 days reveal a bright, asymmetric ring north is up and east is left. M87’s black hole was observed on four days in April 2017. Scientists have patiently waited as existing facilities were upgraded and new facilities have been built - and in April 2017, conditions were finally right to obtain the first good look at M87’s event horizon.

It’s been more than a decade since the EHT’s bold imaging plans were first begun. In this way, the EHT is able to achieve unprecedented resolution: it can theoretically resolve down to 25 millionths of an arcsecond at its observing wavelength of 1.3 mm. The EHT works by performing very-long-baseline interferometry by combining different telescopes around the world, the EHT can function like a telescope with an effective size that’s the same as its longest baseline - the distance between component telescopes. For the images of M87 released today, the observations were made by eight ground-based telescopes in Arizona, Hawai’i, Mexico, Chile, Spain, and the South Pole. The EHT is an extensive virtual telescope created by combining simultaneous observations from radio arrays and dishes all around the planet. The eight stations of the EHT 2017 campaign over six geographic locations. So how do we zoom in on this distant object? We need a telescope unlike any other. These factors contribute to making the neighboring behemoth in M87 comparatively accessible for imaging - and, consequently, it’s the first source for which the EHT is presenting images. We’re also peering through much less of the interstellar medium when pointed at M87. M87 may be further away, but its black hole is a thousand times larger than Sgr A*, giving it longer and more manageable variability timescales. This monster’s rapid variability and its position in the galactic plane - where it’s blurred by the interstellar medium - provide additional challenges that must be overcome to accurately capture it. Sgr A*, while the nearest supermassive black hole, suffers from a host of complicating factors for imaging. When astronomers first developed a plan to image a supermassive black hole’s event horizon - the close-in boundary from which not even light can escape - two sources were selected as targets: the black hole at the center of our galaxy, Sgr A* and the gargantuan, jet-producing black hole in the neighboring galaxy M87. Obtaining an up-close view of a black hole is a goal that has long remained out of reach. Hubble image of the elliptical galaxy M87, dominated by the visible jet extending to the northwest of the supermassive black hole at the galaxy’s center (click to enlarge).

Has event horizon telescope seen a blackhole