Dr. Jessie Christiansen auf Twitter: "In case your local astronomer seems agitated, the big dog gravitational wave detector @LIGO just detected an ‘unknown or unanticipated’ burst of gravitational wav

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Andromeda321 on January 14th, 2020 at 15:43 UTC »

Astronomer here! Here is a quick summary of what is happening!

In short, I had a helluva moment in the middle of TV watching last night when we got this alert and wondered about triggering our telescopes to look for the signal (my group is set up to trigger 8 meter telescopes if it's a valid signal to try and find an electromagnetic counterpart). In short, what LIGO has told us so far is that they have a pipeline that looks for intermediate mass black holes (IMBH)- hundreds to thousands of times the mass of the sun, which have never been observed at this point- and that pipeline did the trigger. The next sentence in the LIGO alert emphasizes this is not a classification of the signal- it could still just be random noise, because LIGO sees some random bursts like that sometimes and they're not yet sure what causes them. But it hasn't been retracted yet, so speculation abounds- for what it's worth, an intermediate mass black hole isn't expected to have an electromagnetic signal, so if it is valid I'm not sure we will be able to do much follow up. And my understanding is this would be a case where the IMBH would have gobbled up a smaller black hole, a few times the mass of the sun, but don't quote me on that.

However, I should emphasize the false alarm rate for this burst is 1/25 years- VERY high for a LIGO signal. I am having fun speculating (we literally ran outside to check Betelgeuse was still there last night because it was between the two potential locations of the signal), but doing that with a dose of skepticism. I should also note that no neutrino detectors reported a burst of neutrinos at the given time, which we expect from a supernova (one releases more neutrinos than the number of atoms in the sun!), so that's also ruled out.

If you want more info on this, I found this thread on Twitter by astrophysicist Chris Barry to be really useful. For a more fun take, this was the official LIGO account's response to my excitement last night. :D

Edit: people are asking if there is an alert to sign up for in case Betelgeuse goes supernova, and I have one better- sign up for SNEWS, the supernova neutrino alert system! As I said, a star that collapses into a supernova will release more neutrinos than the sun has atoms, and the neutrino detectors on Earth will suddenly be swamped when this happens. SNEWS is the alert system for if this happens- note we will see the neutrinos a few hours before the light, as light takes a few hours to get through the mass of the star from its core, and neutrinos don't really interact with matter and escape almost instantly. Always thought that was cool. :)

If you are interested in LIGO alerts, you can follow them on Twitter, or download the app and get real time alerts! This current cycle has a few more months to go until they shut off for upgrades.

Edit 2: for those reading my Twitter bio, I got punched by a wild mountain gorilla in Uganda while trekking out to see them in my pre-astronomer backpacking days. There was a teenage male gorilla whose name was Obia ("Punchy" in the local language), and like teenage males of many species he liked a game of "I punch you and you punch me back," and came forward to me before there was time to react. Luckily it was a "play punch" to my stomach to see if I wanted to play- the guards physically dragging me back to make sure Obia didn't get the wrong idea frankly hurt more!

MisterHibachi on January 14th, 2020 at 15:26 UTC »

How fast do gravitational waves travel? They aren't matter right, just movement/ripples in space-time? Are they constrained by the light-speed speed limit?

Thud on January 14th, 2020 at 14:56 UTC »

Can somebody please check on Betelgeuse and see if it's OK?