‘Breaking’: the Vera Rubin Observatory has announced its results on transient detection S251112cm. First detected Nov. 12 by humanity’s gravitational-wave array(s), Vera Rubin had then pursued any optical counterpart at that general location:
Rubin imagery begins at Nov. 14. Yes, it’s a bit disappointing that the follow-up took two days. However, this was a target of opportunity (ToO); the Rubin observing schedule had to be sidetracked, after the ToO Committee approved of the pursuit. In other words, the executive decision was made to go after the gravitational-wave event.
Future transient follow-ups will be faster. Once the sky search program is truly underway, there will be 4:1 to 3:1 odds, and maybe 2:1, that Rubin will catch any given point on the sky by pure chance. That’s its revisit cycle: it takes two to four nights (based on weather, downtime, other diversions etc.) for Rubin to cover the full Southern sky. If the ToO Committee can’t rule on a target within four days (preferably less), then what’s the point of it existing- Rubin would have gotten there eventually.
Bonus: Rubin makes Science magazine’s end-of-year lists again:
www.science.org/content/article/science-s-favorite-news-visuals-2025
Beth Rakouskas, 30 Dec 2025 Science’s favorite news visuals of 2025
Not to be too circular, but Science’s infographics and other coverage of Rubin were rather nice.