Telescopes Indicate Sagittarius A*—The Milky Way’s Black Hole—is Primed for a Cosmic Kick.

 

In a revelation about the supermassive black hole at the heart of our galaxy, Sagittarius A* (Sgr A*), a recent study unveils a cosmic dance. Illustrated here, the findings indicate that Sgr A* is spinning at a remarkable speed, inducing a profound warping of spacetime. This warping effect, as detailed in the latest press release, transforms the structure of spacetime, shaping it more akin to a football than the conventional dimensions of time and space. This artistic portrayal captures the essence of a celestial spectacle where the boundaries between space and time are dynamically altered by the formidable spin of Sagittarius A*.

The groundbreaking insights into the spinning dynamics of Sagittarius A* (Sgr A*) were achieved through the collaborative efforts of NASA’s Chandra X-ray Observatory and the NSF’s Karl G. Jansky Very Large Array (VLA). Employing a novel approach that integrates X-ray and radio data, a dedicated team of researchers measured the rotational speed of Sgr A* by observing the flow of material towards and away from the black hole.

The results unveiled that Sgr A* is spinning at an angular velocity approximately 60% of the maximum possible value, accompanied by an angular momentum reaching around 90% of the maximum possible value. This innovative methodology sheds light on the intricate dynamics of one of the universe’s most enigmatic entities, providing a deeper understanding of the cosmic forces at play in the heart of our galaxy.

Black holes are characterized by two essential attributes: their mass, signifying their weight, and their spin, representing the speed of their rotation. These properties offer profound insights into the nature and behavior of these enigmatic cosmic entities. Previous estimates of the rotation speed of Sagittarius A* (Sgr A*), our galaxy’s supermassive black hole, yielded varying results, ranging from a stationary state to nearly maximum rotation.

The recent study, utilizing data from NASA’s Chandra X-ray Observatory and the NSF’s Karl G. Jansky Very Large Array, suggests a rapid spin for Sgr A*, causing a noticeable squashing of spacetime around it. Illustrated as a cross-section with swirling material in a disk, the depiction highlights the event horizon—a point of no return. Viewed from the side, the spacetime surrounding the spinning black hole takes on a football-like shape, with the degree of flattening corresponding to the speed of rotation. This revelation enhances our understanding of the dynamic interplay between mass, spin, and spacetime in the captivating realm of black holes.

The swirling yellow-orange material flanking Sagittarius A* (Sgr A*) signifies gas in dynamic motion around the supermassive black hole. Inevitably, this material spirals inward, gravitating towards the black hole, crossing the event horizon as it enters the football-shaped spacetime. The region within this shape but outside the event horizon is portrayed as a cavity. Concurrently, blue blobs illustrate jets emanating from the poles of the rapidly spinning black hole. When observed from the top along the jet’s trajectory, spacetime takes on a circular form.

Crucially, a black hole’s spin serves as a potent energy source. Spinning supermassive black holes generate focused outflows, such as jets, when their spin energy is harnessed. This process necessitates the presence of matter in the black hole’s vicinity. While Sagittarius A* has exhibited relative quietness in recent millennia, with relatively weak jets due to limited fuel, the current study suggests a potential shift if the quantity of material surrounding Sgr A* were to increase. This revelation unveils the dynamic interplay between a black hole’s spin, material availability, and the energetic phenomena exhibited in the cosmic theater.

Gas disk covering black hole.

Chandra X-ray image of Sagittarius A* and the surrounding region.

In their quest to unveil the elusive spin of Sagittarius A* (Sgr A*), the authors of this groundbreaking study employed the empirically based “outflow method.” This technique intricately details the connection between the black hole’s spin, its mass, the properties of the surrounding matter, and the characteristics of the outflow. The collimated outflow, responsible for radio waves, and the gas disk enveloping the black hole, contributing to X-ray emission, played pivotal roles in this investigation. By integrating data from NASA’s Chandra X-ray Observatory and the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and incorporating an independent mass estimate from other telescopes, the researchers successfully constrained Sgr A*’s spin.

The detailed findings, spearheaded by Ruth Daly from Penn State University, are outlined in the January 2024 edition of the Monthly Notices of the Royal Astronomical Society and can be accessed online. Collaborators in this significant endeavor include Biny Sebastian from the University of Manitoba, Canada, Megan Donahue from Michigan State University, Christopher O’Dea from the University of Manitoba, Daryl Haggard from McGill University, and Anan Lu from McGill University. NASA’s Marshall Space Flight Center manages the Chandra program, while the Smithsonian Astrophysical Observatory’s Chandra X-ray Center oversees science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Visualizing Sagittarius A*: A Stunning Cross-Section Illustration of the Milky Way’s Supermassive Black Hole.

This artist’s illustration provides a cross-sectional view of Sagittarius A*, the supermassive black hole residing near the center of our Milky Way galaxy. Positioned in the middle of the image, the spinning, circular black hole is depicted in black, while the surrounding spacetime, displayed in shades of dark yellow, appears noticeably squashed, resembling the distinctive shape of an American football.

The swirling gas enveloping Sagittarius A* is portrayed on either side of the black hole within a rectangular-shaped dotted line, indicating the cross-sectional perspective. Against the backdrop, a myriad of faint stars emerges from within brooding, dark red, indistinct clouds, contributing to the cosmic tapestry surrounding this enigmatic celestial entity.