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Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1097 - - PowerPoint PPT Presentation
Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1097 - - PowerPoint PPT Presentation
Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1097 Lien-Hsuan Lin ( ) Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan) Collaborators: Hsiang-Hsu Wang, Pei-Ying Hsieh (ASIAA) Ronald Taam (ASIAA,
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12CO (J=2-1) intensity maps observed by SMA
Hsieh et al. 2008 &2011
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Gas response in different bar models (Athanassoula,1992)
The gaseous disk is placed under an external gravitational potential which consists of three components: a stellar bulge, a Kuzmin/Toomre disk, and a Ferrers ellipsoid.
Stronger bar
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M : fraction of the mass
- f the bar relative to the
spheroidal component R : ratio of the bar semi-major axis to the semi-minor axis Kim et al. 2012
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Comerón et al. 2010
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NGC 1097 1.4/16 NGC 1300 0.84/16 NGC 1512 0.8/9.4
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NGC 4303 0.85/8.5 NGC 4314 0.8/8.3 NGC 6782 2.5/15
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Our Model for Simulations
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(ii) Equation of motion (iii) Equation of state
V P v v t v ∇ − ∇ − = ∇ ⋅ + ∂ ∂ σ ) (
(i) Equation of continuity
Governing Equations
) ( = ⋅ ∇ + ∂ ∂ v t σ σ σ
2
a P =
(isothermal gas)
g
V V V V + + =
1
r r v r r dr dV
2 2
) ( ) ( = Ω = )] ( 2 cos[ ) ( ) , , (
1
t R t R V
p
Ω − Ψ = φ φ
2 2 2 1 2
) ( ) ( R A R R + Ψ − = Ψ
s s
r r R r a A ≡ ≡ ,
1 1
) ( 4
2
z G Vg σδ π = ∇ ) (
2
→ ∝ Ψ R R R
as
∞ → → Ψ
−
R R R
2
) (
as
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(ii) Equation of motion (iii) Equation of state
V P v v t v ∇ − ∇ − = ∇ ⋅ + ∂ ∂ σ ) (
(i) Equation of continuity
Governing Equations
) ( = ⋅ ∇ + ∂ ∂ v t σ σ σ
2
a P =
(isothermal gas)
g
V V V V + + =
1
r r v r r dr dV
2 2
) ( ) ( = Ω = )] ( 2 cos[ ) ( ) , , (
1
t R t R V
p
Ω − Ψ = φ φ
2 2 2 1 2
) ( ) ( R A R R + Ψ − = Ψ
s s
r r R r a A ≡ ≡ ,
1 1
) ( 4
2
z G Vg σδ π = ∇ ) (
2
→ ∝ Ψ R R R
as
∞ → → Ψ
−
R R R
2
) (
as
) ( ) (
1 A B
r r r v r v
−
+ =
(Elmegreen & Elmegreen 1990)
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(ii) Equation of motion (iii) Equation of state
V P v v t v ∇ − ∇ − = ∇ ⋅ + ∂ ∂ σ ) (
(i) Equation of continuity
Governing Equations
) ( = ⋅ ∇ + ∂ ∂ v t σ σ σ
2
a P =
(isothermal gas)
g
V V V V + + =
1
r r v r r dr dV
2 2
) ( ) ( = Ω = )] ( 2 cos[ ) ( ) , , (
1
t R t R V
p
Ω − Ψ = φ φ
2 2 2 1 2
) ( ) ( R A R R + Ψ − = Ψ
s s
r r R r a A ≡ ≡ ,
1 1
) ( 4
2
z G Vg σδ π = ∇ ) (
2
→ ∝ Ψ R R R
as
∞ → → Ψ
−
R R R
2
) (
as
) ( ) (
1 A B
r r r v r v
−
+ =
(Elmegreen & Elmegreen 1990)
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Evolution of the gas disk for NGC 1097
10
- 10
kpc
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Comparison between the simulated density distribution and the optical image for NGC 1097 The bright nuclear starburst ring, dust lanes and the prominent spiral arms in the simulation match well with the observations.
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Comparison between the simulated density distribution and the HI surface density map for NGC 1097
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Comparison between the central part of the simulated density distribution and 12CO(J=2-1) intensity map for NGC 1097
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Toomre Q values
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Comparison between the simulated and observed HI and
12CO(J=2-1) velocity fields for NGC 1097
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Mass inflow rates
Mass in the starburst ring: 11.6 × 108 Mʘ (Sim.) 5.8 +/- 0.6 × 108 Mʘ (Hsieh et al. 2008)
slope = 0.17 Mʘ/yr slope = 0.11Mʘ/yr
Mass in the circumnuclear disk: 9.47 × 107 Mʘ (Sim.) 6.5 × 107 Mʘ (Hsieh et al. 2008)
Average star formation rate : 3.1 Mʘ/yr (Hsieh et al. 2011) Accretion rate for the AGN : 0.017 Mʘ/yr (Nemmen et al. 2011)
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