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SUMMARY:Dwarf galaxy archaeology: Answering big questions with tiny galaxi
 es - Anna Frebel (MIT)
DTSTART:20210603T150000Z
DTEND:20210603T160000Z
UID:TALK159898@talks.cam.ac.uk
CONTACT:Clare Worley
DESCRIPTION:The first stars and first galaxies formed a few hundred millio
 n years after the Big Bang. Their emergence transformed the universe: the 
 first heavy elements changed the gas physics and high energy photons reion
 ized their surroundings. Hence\, understanding this early era is\nat the f
 rontier of modern astrophysics and cosmology. It can be well probed with a
 ncient ultra-faint dwarf galaxies that orbit the Milky Way today. Two ultr
 a-faint dwarf galaxies have been particularly interesting in this regard. 
 Reticulum II is the first known "r-process galaxy". A prolific nucleosynth
 esis event must have gone off in this system very early on so that subsequ
 ent stars formed from gas enriched in large amounts of the very heaviest e
 lements. This has helped solving a 60 year old puzzle about the astrophysi
 cal site of the rapid (r-) process. Tucana II is a spatially extended meta
 l-poor galaxy with member stars found out to nine half light radii. Other 
 systems also show indications of distant member stars\, suggesting that su
 ch extended "halos" may not be uncommon among the tiniest dwarf galaxies\,
  possibly\nbeing a signature of the very first mergers between galaxies at
  the earliest times.
LOCATION:ONLINE - Details will be sent by email
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