Environmental Engineering Reference
In-Depth Information
ˉ
where
is the angular frequency, computed from the potential
ˉ
=
∂ʦ(
)
R
,
(14)
∂
R
and
ʺ
is the epicyclic frequency defined by
d
dR
2
2
2
ʺ
(
R
)
=
4
ˉ
(
R
)
+
R
ˉ
(
R
)
.
(15)
For an exponential surface density profile, the azimuthal drift velocity is given
approximately by
V
0
V
c
2
2
=
+ σ
R
− σ
ˆ
−
ʱ
.
2
R
(16)
where
V
c
=
R
ˉ
is the azimuthal circular velocity of the disk.
Ta b l e 1
Parameters of the galaxy model
Component
Mass
Number of particles
Cutoff radius
Scale-length
Bulge
0.0025
1
,
024
0.308
0.008
Disc
0.1017
29
,
491
0.5
0.045
760 11.55 0.3
The system of units is such that the unit of mass, length, time, and velocity are: 2
Halo
1.6
245
,
10
11
M
,
.
2
×
40 kpc, 0
.
2558 Gyr, 153km/s, respectively
Ta b l e 2
Geometry of the numerical experiments
ID model Mass proportion
Collision angle (
ⓦ
)
Impact parameter
p
Prograde/retrograde
IC 602
1:1
0.1
30
N/A
IC 60255
”
”
0
Prograde
IC 60266
”
”
0
Retrograde
IC 6027
”
”
45
N/A
IC 6028
”
”
90
N/A
IC 6034
”
0.3
30
N/A
IC 6035
”
”
0
Prograde
IC 6036
”
”
0
Retrograde
IC 6037
”
”
45
N/A
IC 6038
”
”
90
N/A
IC 6039
”
0.6
30
N/A
IC 6040
”
”
0
Prograde
IC 6041
”
”
0
Retrograde
IC 6042
”
”
45
N/A
IC 6043
”
”
90
N/A
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