1. 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

2. NGC1300 NGC6782 Comparison with observation Gas Flow Conclusion
Outline
NGC1300
NGC6782
Comparison with observation
Gas Flow
Conclusion

3. 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?

4. Lindblad Resonance Profile W OLR : outer Lindblad resonance
OILR : outer-inner Lindblad resonance
IILR : inner-inner Lindblad resonance

5. Location of Lindblad Resonance ( NGC1300)
OILR=8.62kpc
Other effects?

6. 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!

7. NGC1300

9. Comparison with observations

10. NGC6782
4050A
NGC6782 has diamond shape double rings.

11. Location of Lindblad Resonance ( NGC6782)

12. Comparison with observations
Projected with
I.A = 26
P.A. = 177
P.A.disk = 45

13. Comparison with observations

14. Gas Flow
(in rotating frame)

15. Gas Flow
(in rotating frame)

16. 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.

17. Gas Flow
(in rotating frame)

18. Gas Flow
(in rotating frame)

19. 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.