60-second Astro News: Black Holes and Funding Woes

Here’s a quick look at some of the astronomy news that’s come out in December 2024.

Fate of U.S. Megatelescopes Undecided

A new report by a National Science Foundation committee has hedged on how to proceed with the two U.S.-led extremely large telescopes. (We’re talking primary mirrors 25 to 30 meters across.) The Giant Magellan Telescope and Thirty Meter Telescope have vied for funding and support for years, but now astronomers have called for a joint program that incorporates both telescopes, with NSF support.

However, each project needs $1.6 billion from NSF to proceed — an amount once considered enough to construct both telescopes — and even funding one project could “have a significant negative impact on the NSF budget” unless Congress substantially deepens the NSF’s pockets, the report concludes. Without more money, the NSF would not be able to adequately support other telescopes and astronomy research alongside an ELT. The committee did not pick a project to prioritize.

Early Black Holes Grew in Spurts

Astronomers are increasingly finding “overmassive” black holes in the early universe — supermassive leviathans that are easily 100 times larger than expected, given the stellar mass of their host galaxies. There are two explanations: Either black holes start big, or they grow fast.

A new study by Ignas Juodžbalis (University of Cambridge, UK) and others adds another overmassive black hole to the mix: an object as hefty as 400 million Suns some 12.9 billion years ago (in astronomers’ parlance, at a redshift of 6.68). The team spotted the black hole with the James Webb Space Telescope thanks to the glow of its surrounding gas disk.

But the black hole is barely nibbling at the gas around it, accreting at a rate only 2% as high as it theoretically could.

That this object is so big so early, and yet so sluggish, suggests that supermassive black holes are like cosmic hedgehogs: They spend most of their lives sleeping but have brief bouts of ultra-fast growth. The study appears December 18th in Nature.

A larger theoretical analysis, posted the same day to the preprint repository arXiv.org by some of the same authors and their collaborators, suggests that early black holes spent only 1% to 4% of their time gorging.

First Binary Star Found Near Supermassive Black Hole

A family of seemingly young, massive stars clusters around the Milky Way’s central black hole. Astronomers have long been puzzled by their existence: The tidal effects of the black hole’s gravity should preclude stars forming here.

One suggestion is that the stars used to be binaries, but interactions with the black hole forced the stars to merge, resetting their clocks and giving them the stellar equivalent of a face lift.

Now, Florian Peissker (University of Cologne, Germany) and others have spotted a binary star in this cluster for the first time. Using observations from the Very Large Telescope in Chile, the team found that the two stars orbit each other at about the same separation as Mars does the Sun and are likely a couple million years old. The black hole will force the stars to merge in perhaps another million years, the researchers suggest December 17th in Nature Communications.