Galaxy formation and evaluation presentation.

1. GALAXY FORMATION
AND EVOLUTION
Alexis Chan

2. Objectives
Explain the Basic elements
of Galaxy Formation.
1.
Objectives
2. Compare and Contrast the different
types of galaxies including elliptical,
spiral and irregular galaxies.

3. GALAXY?
A galaxy is a huge collection of gas,
dust, and billions of stars and their
solar systems, all held together by
gravity.
The Milky Way is a barred spiral galaxy
around 13.6 billion years old with large
pivoting arms stretching out across the
cosmos.

4. BASIC ELEMENTS OF GALAXY FORMATION
Fig 1. It illustrates the various
processes of galaxy formation
and evolution.

5. the standard model of
cosmology
-is a branch of astronomy that involves the origin and evolution of the
universe, from the Big Bang to today and on into the future.
cosmological principle
-HOMOGENOUS
-ISOTROPIC
-the universe looks the same everywhere (on the large scale), the same
as it always has and always will.

6. theories in formation of
milky way galaxy
top-down model
-monolithic collapse
model
Eggen, Lynden-Bell & Sandage (1962)
-They suggested that a giant cloud would start
to collapse and would eventually reach
equilibrium

7. theories in formation of
milky way galaxy
bottom-up model
- Hierarchal Clustering
All of the galaxies in the universe, the Milky Way
included, formed and grew through galactic
mergers.
Lambda-Cold Dark Matter Model

8. FORMATION OF MILKY WAY
https://youtu.be/ZatSnkp72-w

9. Formation of Elliptical Galaxies
When two spirals collide, they lose their familiar shape,
morphing into the less-structured elliptical galaxies.

10. Formation of Irregular Galaxies
-typically formed through gravitational interactions and
mergers of other galaxies.
-Some may have been created simply by passing near
another galaxy

11. Fig 2. Evolution of an individual galaxy

12. EVOLUTION OF GALAXY
https://youtu.be/-5AWDQUB_5k

13. SUMMARY
-Galaxies are collections of stars, gas, dust and dark matter held together by gravity.
Their appearance and composition are shaped over billions of years by interactions with
groups of stars and other galaxies. Using supercomputers, scientists can look back in
time and simulate how a galaxy may have formed in the early universe and grown into
what we see today.
-Galaxies are thought to begin as small clouds of stars and dust swirling through space.
As other clouds get close, gravity sends these objects careening into one another and
knits them into larger spinning packs.
-The goal of galaxy evolution is to reconstruct back in time the physical mechanisms that
led to the present-day galaxies and to explain them in terms of the properties of the
matter and of the cosmology.

14. Thank you