JWST shows the early Universe is DIFFERENT than we thought (that’s a good thing!)

From Dr. Becky.

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Remember those overmassive galaxies that JWST found that people claimed proved "the big bang never happened?" when in reality it was just that we couldn’t explain how they’d got so big? Well, turns out those galaxies probably aren’t that massive after all. In this video we’re chatting about how new JWST observations have found evidence that galaxies in the early Universe form different types of stars at different rates to in the Milky Way (called the Initial Mass Function of stars). This then has knock on effects on the calculation of the masses of these distant galaxies…

#jwst #astrophysics #bigbang

My previous video on these massive galaxies when they were first found: https://youtu.be/hmkyF1tNFc4
My previous video on changing the IMF in the distant galaxies: https://www.youtube.com/watch?v=W4KH1Jw6HBI

Cameron et al. (2023; top-heavy IMF evidence in early Universe) – https://arxiv.org/pdf/2311.02051.pdf
Steinhardt et al. (2023; idea proposed for bottom-heavy IMF for early universe) -https://arxiv.org/pdf/2208.07879.pdf
Boylan-Kolchin (2023; massive galaxies tension with λ CDM) – https://arxiv.org/pdf/2208.01611.pdf
Labbé et al. (2023; 6 massive galaxies in JWST data) – https://arxiv.org/pdf/2207.12446.pdf
Rana (1987; the initial mass function of stars) – https://articles.adsabs.harvard.edu/pdf/1987A%26A…184..104R

JWST observing schedules: https://www.stsci.edu/jwst/science-execution/observing-schedules
JWST data archive (with public access!): https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html
Twitter bot for JWST current observations: https://twitter.com/JWSTObservation

00:00 – Introduction
01:46 – Ground News AD
03:19 – How we calculate the masses of galaxies & what’s an IMF
07:02 – What’s a top-heavy IMF and why it solves JWST’s "over-massive" galaxy problem
08:48 – Evidence for a top-heavy IMF in the early Universe
12:51 – Some caveats and what’s next…
15:56 – Bloopers

Video filmed on Sony ⍺ 7 IV

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👩🏽‍💻 I’m Dr. Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don’t know. If you’ve ever wondered about something in space and couldn’t find an answer online – you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.