Tag: zwartgat

After delivering the first images of the event horizon surrounding the Milky Way’s supermassive black hole Sagittarius A* (Sgr A*), the Event Horizon Telescope has taken an even deeper look.

Fresh imagery from the Event Horizon Telescope (EHT) collaboration has uncovered strong and organized magnetic fields spiraling from the edge of the supermassive black hole Sgr A*. Seen in polarized light for the first time, this new view of the monster lurking at the heart of the Milky Way Galaxy has revealed a magnetic field structure strikingly similar to that of the black hole at the center of the M87 galaxy, suggesting that strong magnetic fields may be common to all black holes. This similarity also hints toward a hidden jet in Sgr A*. The results in two studies were published in The Astrophysical Journal Letters. Scientists unveiled the first image of Sgr A*— which is approximately 27,000 light-years away from Earth— in 2022, revealing that while the Milky Way’s supermassive black hole is more than a thousand times smaller and less massive than M87’s, it looks remarkably similar. This made scientists wonder whether the two shared common traits outside of their looks. To find out, the team decided to study Sgr A* in polarized light. Previous studies of light around M87’s black hole revealed that the magnetic fields around the black hole giant allowed it to launch powerful jets of material back into the surrounding environment. Building on this work, the new images have revealed that the same may be true for Sgr A*.

Agenda – Event Horizon Telescope (EHT)

On April 10th 2019, the Event Horizon Telescope (EHT) Collaboration will present its first results in multiple simultaneous press conferences around the world, and many satellite events organized by its stakeholder and affiliated institutions.

Press conferences will be held simultaneously in Brussels (in English), Lyngby (in Danish), Santiago (in Spanish), Shanghai (in Mandarin), Tokyo (in Japanese), Taipei (in Mandarin), and Washington D.C. (in English). The EHT — a planet-scale array of eight ground-based radio telescopes forged through international collaboration — was designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of the supermassive black hole in the centre of Messier 87 (M87*) and its shadow. In this image of M87* taken on 11 April 2017 (a representative example of the images collected in a global 2017 EHT campaign), the shadow of a black hole is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape.

The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across. While this may sound large, this ring is only about 40 microarcseconds across — equivalent to measuring the length of a credit card on the surface of the Moon. Although the telescopes making up the EHT are not physically connected, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected at a wavelength of 1.3 mm in the 2017 campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives.

These data were flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration. This image is the average of three different imaging methods after convolving each with a circular Gaussian kernel to give matched resolutions. The image is shown in units of brightness temperature, , where S is the flux density, λ is the observing wavelength, is the Boltzmann constant, and Ω is the solid angle of the resolution element.

Links:
First Results from the Event Horizon Telescope to be Presented on April 10th

Brussels: European Comission Youtube Channel

Santiago: ALMA website

Taipei: Academia Sinica channel on Youtube

Tokyo: National Astronomical Observatory of Japan channels on Youtube

Washngton: US National Science Foundation Live Stream

Verwacht: eerste foto van een zwart gat

The physics of black holes (TV On-demand)

Famous Black Hole Shows Its Wobbly Past in New Movie

From black holes to quantum computing – with Marika Taylor

First Sagittarius A* Event Horizon Telescope Results VII / VIII – publication

The paper ‘All objects and some questions‘ presents an overview of the thermal history of the Universe and the sequence of objects (e.g., protons, planets, and galaxies) that condensed out of the background as the Universe expanded and cooled.

The authors plot the density and temperature of the Universe as a function of time and the masses and sizes of all objects in the Universe. These comprehensive pedagogical plots draw attention to the triangular regions forbidden by general relativity and quantum uncertainty and help navigate the relationship between gravity and quantum mechanics. How can we interpret their intersection at the smallest possible objects: Planck-mass black holes (“instantons”)? Does their Planck density and Planck temperature make them good candidates for the initial conditions of the Universe? Our plot of all objects also seems to suggest that the Universe is a black hole. The writers explain how this depends on the unlikely assumption that our Universe is surrounded by zero density Minkowski space.