@caroline for legal reasons I have to say that it’s not worth it even if the burrito has an extra scoop of guac
Posts
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I just want to get out in front of any wild rumors and say that I am vehemently opposed to ritual child sacrifice in all its forms -
I just want to get out in front of any wild rumors and say that I am vehemently opposed to ritual child sacrifice in all its formsI just want to get out in front of any wild rumors and say that I am vehemently opposed to ritual child sacrifice in all its forms
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a himalayan salt lamp except the salt is actually just an exceptionally large melatonin crystal and you take two licks before bed for a good nights sleep@LockEx ooh, two licks for a good night's sleep, one chomp for an upset tummy
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a himalayan salt lamp except the salt is actually just an exceptionally large melatonin crystal and you take two licks before bed for a good nights sleepa himalayan salt lamp except the salt is actually just an exceptionally large melatonin crystal and you take two licks before bed for a good nights sleep
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okay, so my robovac has apparently knocked my copy of lucretius off my shelf and its been tearing off a page or two each time it runs.okay, so my robovac has apparently knocked my copy of lucretius off my shelf and its been tearing off a page or two each time it runs.
i'm not prepared to deal with a robot that's into epicureanism so like idk what to do here
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New-ish paper alert!@OftOverthinking That's a great question!
So when astrophysicists talk about black holes, we often refer to a thing called the 'metric', which describes the shape and curvature of spacetime.
Black holes are really cool because they actually have really simple metrics associated with them which only depend on their mass and rotation.
If the black hole isn't rotating it's described by the Schwarzschild metric, which is actually spherically symmetric with an event horizon described by a sphere.
When you start spinning it, it's better described by the Kerr metric which looks like a sphere for slight rotations and becomes increasingly squashed as the speed of rotation grows.
It's really difficult to measure the spin of black holes, so typically we just talk about the size of the event horizon for non-rotating BHs (the Schwarzschild radius) since it's not too different when things start spinning.
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New-ish paper alert!This paper (along with a companion paper which more rigorously deals with some of the statistics but which is currently paper #5 on the todo list...) is a really important vindication of the technique of triaxial Schwarzschild modeling. This technique is cutting-edge and has only been used for a handful of galaxies because of its high computational cost, but this work shows that it's probably quite good at producing unbiased descriptions of the structure of the biggest galaxies in our universe! 5/5
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New-ish paper alert!This paper takes on the task by by building a suite of fake galaxies that look similar to one we observed (and published a BH mass measurement for!) a few years back. Each of these fake galaxies has a known black hole mass, stellar mass, dark matter halo, and intrinic three-dimensional shape and orientation on the sky. For each of these fake galaxies we went through our procedure from toots 2 and 3 to see what values for those parameters we'd find.
All in all, we found that our modelling and parameter inference actually does really well, with the true values landing in our 68% credible region about 68% of the time without obvious biases!
We also tried doing some corrections for variable generalized degrees of freedom which have been proposed, but those corrections actually led to more significant biases than if we did nothing. 4/5
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New-ish paper alert!Finally, we take those quarter million orbits and figure out how to give each of them a mass such that the stellar mass distribution we assumed in the previous toot is reproduced and that we reproduce a set of measured stellar motions as best as possible. We then do this whole process tens of thousands of times for different proposed galaxy mass distributions, eventually finding the galaxy which matches the data best.
But how do we know that galaxy that's chosen actually looks like the real galaxy in the sky? What if some proposed galaxies just have more *flexibility* to fit the data, so they can fit it better than something that matches the physical galaxy in the sky.
Its a bit like fitting noisy data with a line vs a parabola -- in most cases, the parabola will be able to fit better because it has more degrees of freedom in its fit. But that doesn't mean that the underlying data came from a parabola. 3/5
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New-ish paper alert!Most of the work I do centers around looking for the largest supermassive black holes in our corner of the universe through measurements of the bulk motions of stars near the centers of the most masssive galaxies. The trickiest part of this process is building models which replicate the structure and dynamical behaviors of these galaxies.
The best* (my opinion and a major component of my phd) technique for doing this is Schwarzschild modelling. In this technique, you first propose a galaxy- the shape and mass distribution of the stellar component, the distribution of the dark matter halo, and the black hole. For these choices, we try to think of every single stellar orbit which can exist in that trial galaxy -- every initial condition; energy; angular momentum, then we calculate the motion of that star over roughly the age of the universe. We do this for something like a quarter million stellar orbits in total, which is enough to pretty well mimic a real galaxy. 2/5
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New-ish paper alert!New-ish paper alert!
https://iopscience.iop.org/article/10.3847/1538-4357/ad3935 or https://emilyliepold.com/publication/2024-03-14-mocks
This is a fun short paper where we looked at our method for performing triaxial Schwarzschild modeling to see if there are obvious inherent biases in our results. Here's a short #science and #astronomy thread! 1/5
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Technically I graduated last summer but I’ve found that you get sooooo many compliments walking around wearing doctoral regaliaTechnically I graduated last summer but I’ve found that you get sooooo many compliments walking around wearing doctoral regalia
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Was just told I have the personality of a trombone player by someone I love and idk if I’ve ever felt so insultedWas just told I have the personality of a trombone player by someone I love and idk if I’ve ever felt so insulted
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i’m not supposed to share this with anyone but my one time passcode is 357176i’m not supposed to share this with anyone but my one time passcode is 357176
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Literally every apple music station I've listened to this week has wound up at Sufjan Stevens within four songs, whether or not the starting point was related, and yes I am a grief-stricken excatholic queer, but sometimes I'd prefer happy musicLiterally every apple music station I've listened to this week has wound up at Sufjan Stevens within four songs, whether or not the starting point was related, and yes I am a grief-stricken excatholic queer, but sometimes I'd prefer happy music
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acab includes scruff mcguffacab includes scruff mcgruff
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The best part of family visiting is getting uncontrollably anxious that someone’s going to judge you for the cleanliness of your microwave@anguinea oh no the folks who are visiting are too short to see the top of the fridge; I just have an anxiety disorder lol
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The best part of family visiting is getting uncontrollably anxious that someone’s going to judge you for the cleanliness of your microwave@connie but what if someone sees it
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The best part of family visiting is getting uncontrollably anxious that someone’s going to judge you for the cleanliness of your microwaveIt looks great now btw
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The best part of family visiting is getting uncontrollably anxious that someone’s going to judge you for the cleanliness of your microwaveDon’t mind me, just scrubbing down the top of my fridge