Milky Way Galaxy

A quarter of a century ago, NASA released the “first light” images from the agency’s Chandra X-ray Observatory. This introduction to the world of Chandra’s high-resolution X-ray imaging capabilities included an unprecedented view of Cassiopeia A, the remains of an exploded star located about 11,000 light-years from Earth. Over the years, Chandra’s views of Cassiopeia A have become some of the telescope’s best-known images.

To mark the anniversary of this milestone, new sonifications of three images — including Cassiopeia A (Cas A) — are being released. Sonification is a process that translates astronomical data into sound, similar to how digital data are more routinely turned into images. This translation process preserves the science of the data from its original digital state but provides an alternative pathway to experiencing the data.

These images show evidence for an exhaust vent attached to a chimney releasing hot gas from a region around the supermassive black hole at the center of the Milky Way, as reported in our latest press release. In the main image of this graphic, X-rays from NASA’s Chandra X-ray Observatory (blue) have been combined with radio data from the MeerKAT telescope (red).

Previously, astronomers had identified a “chimney” of hot gas near the Galactic Center using X-ray data from Chandra and ESA’s XMM-Newton. Radio emission detected by MeerKAT shows the effect of magnetic fields enclosing the gas in the chimney.

The evidence for the exhaust vent is highlighted in the inset, which includes only Chandra data. Several X-ray ridges showing brighter X-rays appear in white, roughly perpendicular to the plane of the Galaxy. Researchers think these are the walls of a tunnel, shaped like a cylinder, which helps funnel hot gas as it moves upwards along the chimney and away from the Galactic Center.

This artist’s illustration depicts the findings of a new study about the supermassive black hole at the center of our galaxy called Sagittarius A* (abbreviated as Sgr A*). As reported in our latest press release, this result found that Sgr A* is spinning so quickly that it is warping spacetime — that is, time and the three dimensions of space — so that it can look more like a football.

These results were made with NASA’s Chandra X-ray Observatory and the NSF’s Karl G. Jansky Very Large Array (VLA). A team of researchers applied a new method that uses X-ray and radio data to determine how quickly Sgr A* is spinning based on how material is flowing towards and away from the black hole. They found Sgr A* is spinning with an angular velocity that is about 60% of the maximum possible value, and with an angular momentum of about 90% of the maximum possible value.

For millennia, musicians have looked to the heavens for inspiration. Now a new collaboration is enabling actual data from NASA telescopes to be used as the basis for original music that can be played by humans.

Since 2020, the “sonification” project at NASA’s Chandra X-ray Center has translated the digital data taken by telescopes into notes and sounds. This process allows the listener to experience the data through the sense of hearing instead of seeing it as images, a more common way to present astronomical data.

A new phase of the sonification project takes the data into different territory. Working with composer Sophie Kastner, the team has developed versions of the data that can be played by musicians.

Sagittarius A* / Galactic Center
Credit: Chandra: NASA/CXC/SAO; IXPE: NASA/MSFC/F. Marin et al;

In a new Nature paper astronomers have reported exciting evidence that the supermassive black hole at the center of our Galaxy, Sagittarius A* (Sgr A* for short), produced an intense flare of X-rays about 200 years ago. Sgr A* is 28,000 light-years from Earth, but even from this considerable distance, if a similar flare occurred today then X-ray telescopes like IXPE and Chandra may be damaged if they looked at Sgr A*.

Currently Sgr A* shows frequent but weak outbursts, and has been referred to as a “sleeping giant” by members of the Event Horizon Telescope Collaboration.

In the new study astronomers learned about Sgr A*’s past outbursts by observing X-rays from clouds of gas around the supermassive black hole. While the primary X-rays from previous outbursts would have reached Earth in the past, X-rays reflected from clouds of gas will take a longer path and can arrive in time to be recorded by telescopes like Chandra and IXPE. This idea goes back decades, with the astronomers referring to a paper published in 1980. In the 1990s, several papers reported evidence for X-ray flares from the center of the Galaxy, including one in 1996 titled “ASCA View of Our Galactic Center: Remains of Past Activities in X-Rays?”.

Sagittarius A* / Galactic Center
Credit: Chandra: NASA/CXC/SAO; IXPE: NASA/MSFC/F. Marin et al; Image Processing: L.Frattare, J.Major & K.Arcand; Sonification: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)

These images show X-ray data of the area around the supermassive black hole at the center of the Milky Way galaxy. New data from NASA’s Imaging X-ray Polarimetry Explorer (IXPE) has provided evidence that this black hole — known as Sagittarius A* (Sgr A*) — had an outburst about 200 years ago after devouring gas and dust within its reach.