More Mystery Objects Found Near Milky Way’s Supermassive Black Hole

Astronomers first discovered G-objects at the Milky Way’s monster black hole more than a decade ago.  (Image: via   wikimedia  /  CC0 1.0)
Astronomers first discovered G-objects at the Milky Way’s monster black hole more than a decade ago. (Image: via wikimedia / CC0 1.0)

Astronomers have discovered several bizarre objects at the Galactic Center that are concealing their true identity behind a smokescreen of dust; they look like gas clouds, but behave like stars.

At the American Astronomical Society Meeting in Denver, a team of researchers, led by UCLA Postdoctoral Scholar Anna Ciurlo, announced the results they obtained using 12 years of data taken from the W. M. Keck Observatory on Maunakea, Hawaii, saying:

The researchers made their discovery by obtaining spectroscopic measurements of the Galactic Center’s gas dynamics using Keck Observatory’s OH-Suppressing Infrared Imaging Spectrograph (OSIRIS). Randy Campbell, science operations lead at Keck Observatory, said:

Astronomers first discovered G-objects at the Milky Way’s monster black hole more than a decade ago; G1 was first seen in 2004, and G2 was discovered in 2012. Both were thought to be gas clouds until they made their closest approach to the supermassive black hole. G1 and G2 somehow managed to survive the black hole’s gravitational pull, which can shred gas clouds apart.

This 3-D spectro-imaging data cube was produced using software called OsrsVol, short for OSIRIS-Volume Display. W. M. Keck Observatory Science Operations Lead Randy Campbell developed this custom volume rendering tool to separate G3, G4, and G5 from the background emission. Once the 3-D analysis was performed, the team could clearly distinguish the G-objects, which allowed them to follow their movement and see how they behave around the supermassive black hole. (Image: W. M. Keck Observatory)

This 3-D spectro-imaging data cube was produced using software called OsrsVol, short for OSIRIS-Volume Display. W. M. Keck Observatory Science Operations Lead Randy Campbell developed this custom volume rendering tool to separate G3, G4, and G5 from the background emission. Once the 3-D analysis was performed, the team could clearly distinguish the G-objects, which allowed them to follow their movement and see how they behave around the supermassive black hole. (Image: W. M. Keck Observatory)

UCLA Astronomy Professor Mark Morris, a co-principal investigator and fellow member of UCLA’s Galactic Center Orbits Initiative (GCOI), said:

It appears that a lot of energy was dumped into the G-objects, causing them to swell up and grow larger than typical stars. GCOI thinks that these G-objects are the result of stellar mergers — where two stars orbiting each other, known as binaries, crash into each other due to the gravitational influence of the giant black hole.

Over a long period of time, the black hole’s gravity alters the binary stars’ orbits until the duo collides. The combined object that results from this violent merger could explain where the excess energy came from. Morris said:

Andrea Ghez, founder and director of GCOI, said:

What makes G-objects unusual is their “puffiness.” It is rare for a star to be cloaked by a layer of dust and gas so thick that astronomers do not see the star directly. They only see the glowing envelope of dust. To see the objects through their hazy environment, Campbell explained how he developed a tool called OSIRIS-Volume Display (OsrsVol):

Ciurlo added:

These newly discovered infrared sources could potentially be G-objects — G3, G4, and G5 — because they share the physical characteristics of G1 and G2. The team will continue to follow the size and shape of the G-objects’ orbits, which could provide important clues as to how they formed.

The astronomers will especially be paying close attention when these dusty stellar compact objects make their closest approach to the supermassive black hole. This will allow them to further observe their behavior and see whether the objects remain intact just as G1 and G2 did, or become a snack for the supermassive black hole. Only then will they give away their true nature. Morris said:

Ciurlo added:

Provided by: W. M. Keck Observatory [Note: Materials may be edited for content and length.]

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