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Home , Leo Triplet, NGC 4414, NGC 5866, NGC 7742

Milky Way & 1 Messier Catalog 2 Part 2 (1730-1817) was hunting for comets. People kept reporting the same fuzzy blobs that were NOT comets, so from 1758-1782 he made a catalog of about 100 of these fuzzy things to “ignore”.

In fact, these 110 objects are nebulae, clusters and galaxies, which are the best things to look for in an amateur telescope!

e.g. “M31” is the Andromeda Dr. Bill Pezzaglia Updated: June 5, 2007

Some Galaxies in Messier Catalog 3 4

• 1785 Catalog of 1000 objects • 1788 another 1000 objects • 1802 another 500 objects

Classifies objects into star clusters and nebulae. The “types” were:

1. Bright Nebulae 2. Faint Nebulae 3. Very faint Nebulae 4. Planetary Nebulae 5. Very large Nebulae 6. Very compressed and rich star clusters 7. Compressed clusters of small and large (i.e., faint and bright) 8. Coarsely scattered clusters of stars

Herschel sees more (galaxies) 5 NGC: New Galactic Catalog 6

• 1864 Herschel’s son John publishes the “GC”, Galactic Catalog of 5079 objects. • 1888 J. L. E. Dreyer publishes the “New Galactic Catalog” for use in Lord Rosse’s observatory (the 72” Leviathan Telescope). It will take 45 years for people to realize the “spiral nebulae” seen by Lord Rosse are in fact galaxies.

1 C. Galaxy Structure 7 Edwin Hubble (1889-1953) 8 • 1919 invited to Mount Wilson Observatory • 1925 publishes work that supports idea of existence of galaxies.

• Develops classification scheme for galaxy types 1. Hubble Classification • Elliptical •Spiral • Irregular 2. Active Galaxies

3. Galactic Evolution

C1a. Hubble’s Tuning Fork 9 C1b. Elliptical Galaxies 10

M87 Type E0 Giant Elliptical in Virgo

M87, Elliptical in 11 M87 Giant Elliptical (Virgo) 12 Type: E0, perhaps 3 trillion stars! (largest known)

No spiral arms, so no new !

2 C1c. Spiral Galaxies 13 M74 (NGC 628, Pisces) 14 “Grand Design” spiral

Barred Spirals

Normal Spirals

NGC 4414 () 15 M61 (Virgo) 16

Flocculent (“wooly”) spiral galaxies are opposite of Type Sb “grand design”. The arms are not very distinct.

Andromeda Galaxy (M31) 17 NGC 1300 (Eridanus) 18 Type: Normal Spiral Sb Type: Barred Spiral (Hubble SBc) 21 MPC away (discovered by Herschel 1835) 2.5 million light years away!

3 NGC 7742 19 Galaxies in 20 Spiral with Ring (Black Hole in center?) Two Clusters

M95 & M96 (Leo) 21 M95 (Leo) 22 Two spirals, 34 million light years away Barred Spiral

M66 (Leo) 23 M104: 24 Part of Leo Triplet (M65, M66, NGC 3628) Type: Sa

The spiral structure of M66 is interesting as it shows strong deformations through gravitational interaction with neighboring galaxies, especially M65. This is particularly noticeable in the western spiral arm (top in this image) which appears to be separated and rising above the main galaxy.

4 M104: Sombrero Galaxy 25 C1e. Edge-On Spirals 26

Edge on Spirals show us 1990: motion of stars near center imply a there is a lot of dust/gas billion solar mass black hole! in the galactic planes

NGC 5866 (Type S0 Edge-on) 27 Galaxies in Ursa Major 28 Spindle Galaxy

M81 Bode’s Galaxy 29 M101 Pinwheel (Ursa Major) 30 Grand Design type Sa in Ursa Major Type Sc, “Grand Design” spiral

5 2. Active Galaxies 31 C2a1. Irregular Galaxy M82 32

a) Starburst Galaxies b) Radio Galaxies c) Quasars

CigarType: GalaxyIrr (pec) (M82), LMC and“peculiar” SMC are examples of IrregularStarbust Galaxies. Only 3 % ofGalaxy galaxies are of type Irr

C2a2. Galaxies are Connected 33 C2b1. M87, a Giant E0 (pec) 34

While M81 & M82 seem separate, actually they are The radio jet connected by H gas. coming out of M81’s gravity disrupted M82 M87 is causing a starburst probably due formation to a supermassive black hole

C2b2. 35 C2c1. Quasars (Quasi Stellar Object) 36 Centaurus A • First one discovered was 3C273 • Very big , hence far away, hence VERY an “active” BRIGHT, but mystery was its very small in size • Recent Chandra data shows X-Ray jet of material, radio galaxy consistent with Black Hole • Model: early form of galaxy, with black hole forming.

http://chandra.harvard.edu/photo/2000/0131/

6 C2c2. Quasars/Radio Galaxies same? 37 3. Galaxy Evolution 38

a) Galactic Birth b) Collisions c) Mergers

C3a. Galactic Formation: a mystery! 39 I Zwicky 18: A young galaxy 40 An Irregular galaxy only 45 million light years away, appears To be only 500 million years old!

C3b1. The Antennae 41 C3b3. Galaxy Collisions 42

“Rat Tail” galaxies are probably formed by collisions Generically classified as “Rat Tail Galaxies”

7 C3b2. Ring Galaxies 43 Hoag's Object (Ring Galaxy) 44

AM 0644-741

Probably collision punched out the center of the galaxy

M64 Blackeye Galaxy 45 C3c. M64 46 In Coma Berenices group Type Sb (pec) The dark gas is revolving in the opposite direction as the stars. This is possibly due to the galaxy gobbling up a smaller satellite galaxy 1 billion years ago.

M51 47 References/Notes 48

The blob on the right is a small galaxy that collided •Quasar: http://en.wikipedia.org/wiki/3C_273 •http://www.skyimagelab.com/galaxies.html •http://en.wikipedia.org/wiki/List_of_galaxies

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