skip to main content

Title: Making Galaxies: One Star at a Time

In the age of precision cosmology the fundamental parameters of our world model are being measured to unprecedented accuracy. In particular, measurements of the cosmic microwave background radiation dmore »etail the state of the universe only 400,000 years after the big bang. Unfortunately, we have no direct observational evidence about the following few hundred million years, the so called dark ages. However, we do know from the composition of the highest redshift galaxies that it is there where the earliest and first galaxies are being formed. From a physics point of view these earliest times are much easier to understand and model because the chemical composition of the early gas is simpler and the first galaxies are much smaller than the ones found nearby. The absence of strong magnetic fields, cosmic rays, dust grains and UV radiation fields clearly also helps. The first generation of structure formation is as such a problem extremely well suited for direct ab initio calculations using supercomputers. In this colloquium I will discuss the rich physics of the formation of the first objects as computed via ab initio Eulerian cosmological adaptive mesh refinement calculations. We find the first generation of stars to be massive and to form in isolation with mass between 30 and 300 times the mass of the sun. Remarkably the relevant mass scales can all be understood analytically from the microscopic properties of atomic and molecular hydrogen. The UV radiation from these stars photo-evaporates their parent clouds within their lifetimes contributing significantly to cosmological reionization. Their supernovae distribute the first heavy elements over thousands of light years and enrich the intergalactic medium. As we are beginning to illuminate these earliest phases of galaxy formation many new questions arise and become addressable with our novel numerical techniques. How and where are the earliest magnetic fields made? How do the first super-massive black holes form? When and how can the first planets form in the universe? Algorithmic breakthroughs and large supercomputers enable these studies. Hence I will close with discussing how the expanding computing infrastructure at SLAC and scientific visualization at the Schwob Computing and Information Center at the Fred Kavli building allow us to find answers to the fundamental questions about the beginning of structure in the universe.« less
video
Title: Making Galaxies: One Star at a Time
Authors:
Publication Date: 2006-09-18
OSTI Identifier: 1013666
DOE Contract Number: AC02-76SF00515
Other Number(s): TRN: US1105345
Resource Type: Multimedia
Resource Relation: Conference: SLAC Colloquium Series, SLAC National Accelerator Laboratory, Menlo Park, California, presented on September 18, 2006
Research Org: SLAC (SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States))
Sponsoring Org: USDOE Office of Science (SC)
Subject: 43 PARTICLE ACCELERATORS ; 08 HYDROGEN ; ACCURACY ; BLACK HOLES ; CHEMICAL COMPOSITION ; COSMOLOGY ; DUSTS ; FERMILAB ACCELERATOR ; GALAXIES ; HYDROGEN ; MAGNETIC FIELDS ; PHYSICS ; PLANETS ; RADIATIONS ; RELICT RADIATION ; STANFORD LINEAR ACCELERATOR CENTER ; STARS ; SUPERCOMPUTERS ; SUPERNOVAE ; UNIVERSE
Country of Publication: United States
Language: English
Run Time: 1:07:33
System Entry Date: 2016-01-27