Sagittarius A-Star Archives

September 10, 2024September 10, 2024 by Evan Gough

The Milky Way’s Supermassive Black Hole Might Have Formed 9 Billion Years Ago

This is the first image of Sgr A*, the supermassive black hole at the center of our galaxy. A reanalysis of EHT data by NAOJ scientist suggests its accretion disk may be more elongated than shown in this image. Image Credit: EHT

Large galaxies like ours are hosts to Supermassive Black Holes (SMBHs.) They can be so massive that they resist comprehension, with some of them having billions of times more mass than the Sun. Ours, named Sagittarius A* (Sgr A*), is a little more modest at about four million solar masses.

Astrophysicists have studied Sgr A* to learn more about it, including its age. They say it formed about nine billion years ago.

April 5, 2024April 5, 2024 by Evan Gough

The Stellar Demolition Derby in the Centre of the Galaxy

This illustration shows stars orbiting close to the Milky Way's central supermassive black hole. The black hole accelerates stars nearby and sends them crashing into one another. Credit: ESO/L. Calçada/Spaceengine.org

The region near the Milky Way’s centre is dominated by the supermassive black hole that resides there. Sagittarius A*’s overwhelming gravity creates a chaotic region where tightly packed, high-speed stars crash into one another like cars in a demolition derby.

These collisions and glancing blows change the stars forever. Some become strange, stripped-down, low-mass stars, while others gain new life.

January 6, 2020January 6, 2020 by Evan Gough

This is the Core of the Milky Way, Seen in Infrared, Revealing Features Normally Hidden by Gas and Dust

A composite infrared image of the core of the Milky Way galaxy. NASA/SOFIA/JPL-Caltech/ESA/Herschel

The world’s largest airborne telescope, SOFIA, has peered into the core of the Milky Way and captured a crisp image of the region. With its ability to see in the infrared, SOFIA (Stratospheric Observatory For Infrared Astronomy) is able to observe the center of the Milky Way, a region dominated by dense clouds of gas and dust that block visible light. Those dense clouds are the stuff that stars are born from, and this latest image is part of the effort to understand how massive stars form.

April 10, 2019April 10, 2019 by Evan Gough

It’s Finally here. The First Ever Image of a Black Hole

The Event Horizon Telescope (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 and its shadow. The shadow of a black hole seen here 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 during a 2017 global 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. Credit: Event Horizon Telescope Collaboration

“We have taken the first picture of a black hole.”

EHT project director Sheperd S. Doeleman of the Center for Astrophysics | Harvard & Smithsonian.

What was once un-seeable can now be seen. Black holes, those difficult-to-understand singularities that may reside at the center of every galaxy, are becoming seeable. The Event Horizon Telescope (EHT) has revealed the first-ever image of a black hole, and with this image, and all the science behind it, they may help crack open one of the biggest mysteries in the Universe.