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Gas Flow Induced by a Strong Bar Potential: Straight Dust Lanes Connecting to a Nuclear Starburst Ring. David Yen Department of Mathematics, Fu-Jen Catholic University, Taiwan, R.O.C. Lien-Hsuan Lin Department of Physics, National Taiwan University, Taiwan, R.O.C Chi Yuan - PowerPoint PPT Presentation
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Gas Flow Induced by a Strong Bar Potential: Straight Dust Lanes Connecting to a Nuclear
Starburst Ring
David YenDepartment of Mathematics, Fu-Jen Catholic University, Taiwan,
R.O.C.
Lien-Hsuan Lin Department of Physics, National Taiwan University, Taiwan, R.O.C
Chi YuanInstitute of Astronomy and Astrophysics, Academia Sinica,
Taiwan, R.O.C.
Chao-Chin YangDepartment of Astronomy, UIUC
2006,November 1, KASI, Korea
Outline
•NGC1300
•NGC6782
•Comparison with observation
•Gas Flow
•Conclusion
NGC1300
1. Major bar
2. Central ring
3. Straight dust lane
4. Enhance SF at the end of bar
NGC1300 has a central star formation ring and a pair of straight dust lanes.
How does the straight dust lane form?
How about the location of resonance?
p
OLR : outer Lindblad resonanceOILR : outer-inner Lindblad resonance
IILR : inner-inner Lindblad resonance
Lindblad Resonance
Profile
2
2
OILR=8.62kpckpcskmp /1.4
Location of Lindblad Resonance ( NGC1300)
Other effects?
Grid size : 256X256
Ratio of the bar force :1 : 2 : 3 : 3.75 : 4
Effects of the strength of Bar forces
Size of nucleus ring
Straight dust line
Strong bar for NGC1300? Yes!
NGC1300
Comparison with
observations
NGC6782
4050A
NGC6782 has diamond shape double rings.
(km/s)0.01
223.943r+
r=v
kpc15.3
kpc8.9
kpc2.6
km/s/kpc25
=R
=R
=R
=Ω
OLR
CR
ILR
p
Location of Lindblad Resonance ( NGC6782)
Projected with I.A. = 26P.A. = 177P.A.disk = 45
Comparison with
observations
Comparison with
observations
(in rotating frame)Gas Flow
(in rotating frame)Gas Flow
(in rotating frame)
we can see gas flow suddenly changes its direction upon entering the dust lanes, which are known as shocks, and continues to flow down the dust lanes along the leading edge of the bar.
Gas Flow
(in rotating frame)Gas Flow
(in rotating frame)Gas Flow
Conclusion• Our simulations can reproduce dust lanes, central
starburst rings and outer spirals, exact as seen in the nearby barred galaxies.
• NGC1300 is a major bar galaxy, our simulation produced straight lanes and star formation region located at the end of the bar which match the observations well.
• Our results is in excellent agreement with the diamond-shape which generated by the interaction of OLR and ILR for NGC6782.
• Strong bar potentials may lead to shear instability and develop chaotic sub-structures.
• Gas flow suddenly changes its direction upon entering the dust lanes, which are known as shocks, and continues to flow down the dust lanes along the leading edge of the bar.
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