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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
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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 Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan, R.O.C. Chao-Chin Yang Department of Astronomy, UIUC 2006,November 1, KASI, Korea
Outline NGC1300 NGC6782 Comparison with observation Gas Flow Conclusion
NGC1300 • Major bar • 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?
W p Lindblad Resonance Profile OLR : outer Lindblad resonance OILR : outer-inner Lindblad resonance IILR : inner-inner Lindblad resonance
Location of Lindblad Resonance ( NGC1300) OILR=8.62kpc Other effects?
Effects of the strength of Bar forces Grid size : 256X256 Ratio of the bar force : 1 : 2 : 3 : 3.75 : 4 Size of nucleus ring Straight dust line Strong bar for NGC1300? Yes!
NGC6782 4050A NGC6782 has diamond shape double rings.
Comparison with observations Projected with I.A. = 26 P.A.= 177 P.A.disk = 45
Gas Flow (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)
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.