A presentation for Bsc Physics 6th semester students on their seminar in Astrophysics. Topic: Types of Galaxies

1. Group 1
GalaxyTypes

2. What is a Galaxy?
A galaxy is a system of stars, stellar
remnants, interstellar gas, dust, dark matter,
bound together by gravity

3. <100 million
Dwarfs
100 million
Average
100 trillion
Supergiants

5. 100000000000 (100 thousand million) stars

6. 200 billion galaxies

7. Galaxies
Spiral galaxies
Barred spiral galaxies
Elliptical galaxies
Lenticular galaxies
Irregular galaxies

8. Spiral galaxies
Spiral galaxies appear
as flat white discs with
yellowish bulges at
their centres.
e.g: Milky way

9. Spiral galaxies
Components:
• Stars
• Dust
• Cool gas
• Hot ionised gas

10. Spiral galaxies
Components:
• Stars
• Dust
• Cool gas
• Hot ionised gas

11. Barred spiral galaxy
Galaxies that exhibit a
straight bar of stars
that cuts across the
centre with spiral arms
curling away from the
ends of the bars are
called barred spiral
galaxies.
e.g:Tadpole galaxy

12. Elliptical galaxies
Ellipticalgalaxies are
redder and seem to be
spherical in shape with
a bulge at the centre or
elliptical
e.g: Andromeda galaxy

13. Elliptical galaxies
• Less Cool gas
• More Hot ionised gas

14. Lenticular galaxies
Galaxies that possess
discs but not having
spiral arms
e.g: Cart wheel galaxy

15. Irregular galaxies
Galaxies that appear
neither disc like nor
rounded are called
irregular galaxies.
e.g: Large magellanic
clouds

18. Thanks
Group members: Aaron |Abhinav |Abhiram | Adhithya