Thread by @BethanyEWindsor

.@grahamsleight kicking off the Hay Lecture today at @reclamation2022 #Eastercon with my very own @rclivermore!

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Today’s lecture is “Witnessing the Dawn of Galaxies”, focusing on the early universe and asking all of the important “whys” about #JWST #Eastercon

The Hubble ultra deep field could be covered up by the Queen’s eye on an arms length 1p piece-it’s a tiny piece of sky! #Eastercon

If we look at the furthest galaxies we can see with Hubble, the galaxies were formed when the universe was less than a billion years old #Eastercon

Just under a billion years after the Big Bang, we hit the limit as to what Hubble can do..what do galaxies look like after that limit? That’s where #JWST comes in! #Eastercon

A potted history of the universe from @rclivermore, getting all of the important points on the timeline, hey, @reclamation2022?! #Eastercon

We want to see the first galaxies and understand reionisation-for this, we need #JWST. What kind of a telescope is this? #Eastercon

It’s a big one! Telescopes are light buckets, so to look at faint things, we need a big bucket! #JWST has a huge mirror at 6.6m, slightly taller than a 🦒! #Eastercon

Bad screen capture, but TL;DR: Big mirror. #Eastercon

There are five layers of the #JWST sun shield and it’s like a crisp packet-@rclivermore said you could (but shouldn’t…) stab it with a Biro 😝 #Eastercon

What light is the telescope going to pick up? We’re revising the electromagnetic spectrum and doing an experiment here at @reclamation2022! #Eastercon

With infrared, you can see the stars inside the nebula #Eastercon

The universe expanding can be likened to galaxies drawn on a balloon-as it inflates, other galaxies move further away. It’s not the galaxies, it’s the space in between getting larger #Eastercon

Where should #JWST go? In space, so light isn’t coming through the atmosphere. Temperature affects infrared-we feel it as heat. It needs to be cool, so far from the Sun and Earth, and shielded from both. BUT! Close to Earth for comms is needed #Eastercon

L2 is the chosen location for #JWST-the Sun and the Earth’s gravity aligns so JWST always stays behind the Earth from the point of view of the Sun, blocking heat of both with a shield #Eastercon

(@davecl42 is watching along and can call me out on any things I’m not live Tweeting well…sorry, scientists, you’ve got a logistician in the driving seat…!) #Eastercon #WishingYouWereHereDave

How does #JWST do spectroscopy? Point the camera at a big field and split up the light is one, that NIRCAM and NIRISS will take care of #Eastercon

You can see lots of galaxies this way, but they are all overlapping, so that’s best for bright things. NIRISS can also do single objects, along with NIRI #Eastercon

MIRI also does slitted, but this only allows one thing at once. Multi-object is similar, but allows for viewing lots of objects with no overlap. NIRSpec, which also does slitted, can make slit masks on the fly to allow for multi-object viewing! #Eastercon

You can see each of the little shutters (some of which have been stuck open, unfortunately) and what the results are! #Eastercon

Integral field units provide a cube of data for one galaxy at a time (and one that is far away). It has to be a really special galaxy to make it worth the time! NIRSpec and MIRI provide this #Eastercon

Imaging can give lots of information for the most distant and faintest things. A filter is used to get certain wavelengths and then a black and white photo is taken to know how far away the galaxy is #Eastercon

If an image is only seen in one of them, the red, is it a galaxy? Is it an artefact? This is the limit of Hubble #Eastercon

#JWST provides clarity that it is a galaxy and provides dates #Eastercon

Gravitational lending allows us to use general relativity to…see some stuff…and, by “us”, I mean @rclivermore and colleagues, I can rarely find my keys… 😝 #Eastercon

This is, as far as I’m concerned, @rclivermore’s galaxy and it should be called the Windsor Cluster (not because I’m self-important, but because she’ll be a Windsor IN THREE MONTHS TODAY!) #Eastercon

#JWST is currently cooling down-MIRI needs to be the coolest and has reached its operating temperature! Science is IMMINENT! #Eastercon

And now it’s over to Q&A! Thank you to everyone that attended the Hay Lecture and come and find @rclivermore in the bar, or on Discord, throughout @reclamation2022 to talk more 🌌!