Cosmology and extragalactic astronomy - PowerPoint PPT Presentation

Loading...

PPT – Cosmology and extragalactic astronomy PowerPoint presentation | free to download - id: 714542-MWY2Y



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Cosmology and extragalactic astronomy

Description:

Cosmology and extragalactic astronomy Mat Page Mullard Space Science Lab, UCL 2. Galaxies 1. Galaxies This lecture: Classification of galaxies Spirals Ellipticals ... – PowerPoint PPT presentation

Number of Views:48
Avg rating:3.0/5.0
Slides: 21
Provided by: MatP150
Learn more at: http://www.mssl.ucl.ac.uk
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Cosmology and extragalactic astronomy


1
Cosmology and extragalactic astronomy
Mat Page
Mullard Space Science Lab, UCL
2. Galaxies
2
1. Galaxies
Slide 2
  • This lecture
  • Classification of galaxies
  • Spirals
  • Ellipticals
  • Irregulars
  • Characteristics of the different types

3
Hubbles tuning fork
Slide 3
  • Basic set of galaxy types.

4
3 groups
Slide 4
  • Ellipticals
  • Spirals
  • barred
  • normal
  • Irregulars

5
Ellipticals
Slide 5
  • Classified as E0-E7
  • En
  • n10(1-b/a)

Classified according to view from Earth!
M87 Giant elliptical (E1)
6
Ellipticals
Slide 6
M 110 dwarf elliptical (E6)
  • Most of the galaxies in the local group are
    dwarf ellipticals!

7
Elliptical characteristics
Slide 7
  • Random star motions
  • Little dust, little gas
  • gas is hot, can be X-ray sources
  • no star formation
  • no hot, young bright stars
  • old, red stars
  • no spiral structure
  • Large range of sizes 105-1013 Mo.

8
Spirals
Slide 8
  • Like the Milky Way
  • central bulge
  • flattened disc
  • spiral pattern
  • sometimes a bar
  • Classified as
  • S (for spiral) or
  • SB (barred spiral)
  • plus a,b,c,(d)

XMM-Newton Optical Monitor
Credit Marco Iacobelli (XMM SOC) ESA
NGC 1365 SBbc
9
NGC 2997 Sc
Slide 9
  • This one has no B because it has no bar

10
Spiral classification
Slide 10
  • Sa and SBa have
  • large central bulges
  • Tightly-wound spiral arms
  • Sc and SBc have
  • small central bulges
  • Loosely-wound spiral arms

NGC4321(Sc)
M81(Sab)
11
Slide 11
M81 UV (XMM))
12
Slide 12
M81 21cm
13
Slide 13
M100 (AAT))
14
Slide 14
M51 (HST))
15
Characteristics of spirals
Slide 15
  • Consistent rotational motion in the disc
  • Lots of gas and dust in the disc
  • Star formation in disc, especially in the arms
  • Young, bright blue stars in the arms
  • Spiral structure
  • 109 - 4x1011 Mo

16
Lenticular galaxies
Slide 16
  • Lenticular -- lens-like
  • Like a spiral, but without spiral structure
  • Designated S0 or SB0
  • I think difficult to tell from ellipticals by
    eye.

17
Irregulars
Slide 17
  • No definite structure
  • Everything that doesnt fit on the tuning fork
  • Mostly small, faint
  • May have strong star formation
  • May have lots of gas and dust
  • e.g. LMC and SMC

18
Slide 18
LMC in the UV (Swift UVOT))
19
Back to Hubbles tuning fork
Slide 19
  • Hubble thought that galaxies evolved from
    ellipticals to spirals
  • This is very unlikely!

20
Some key points about galaxies
Slide 20
  • Ellipticals
  • no overall rotation
  • old stars, little gas.
  • Spirals
  • rotating disc
  • old stars in the bulge
  • young stars in the disc and in bulge
  • Lenticulars
  • bulge and disc without spiral structure
  • Irregulars
  • often lots of gas
  • sometimes strong star formation
About PowerShow.com