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Structure of Our Galaxy (The Milky Way) February 20, 2015
Sankha Karunasekara ( BSc Engineering University of Peradeniya
(ug)
600
.
, Milky way .
, .
.
Sir
WIlliam Herschal 1875
.
,
. .
Figure 1: Herschals' Universe
Note :
.
.
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2 | P a g e
1922 keptayn .
Spheroid ( ) 8.5 * 1.7 kPc . (650,38) Pc
.
harlo shapley
.
.
Sagittarius ( 100kPc)
.
shapley
.
keptayn shapley
( ) .
( Intersteller Extinction) .
1930 Trumpler .
.
8kPc .
:
Shapley
10 0 .
zone of avoidance ,
.
Shapley RR Lyrae
.
Figure 2: Multi wave Length Milkey way
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3 | P a g e
( Interstellter Medium)
.
.
.
3 .
1) Halo ( )
2) Bulge
3) Disk ( )
bulge .
.
.
SBc .
( Spiral arms in Milky way)
200 400
disk .
Halo
,
.
,
.
2 3 kPc arms
.
26000 Orion Arm
.
, , Sagittarius Arm
.
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4 | P a g e
( Our Neighbors)
, andromeda Local group
( ) . 32
( dwarf Galaxies) .
.
sagittarius dwarf LMC (Large Magalanic Cloud) local
group . 30 -40 .
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Figure 4:Leo 01 Figure 3:LMC (Large Magalanic Cloud)
