Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-03-18
Astronomy and Astrophysics
Astrophysics
Major revision, A&A in press
Scientific paper
10.1051/0004-6361:20041038
We have investigated the accuracy and reliability of six methods used to determine the length of stellar bars in galaxies or N-body simulations. All these methods use ellipse fitting and Fourier decomposition of the surface brightness. We have applied them to N-body simulations that include stars, gas, star formation, and feedback. Stellar particles were photometrically calibrated to make B and K-band mock images. Dust absorption is also included. We discuss the advantages and drawbacks of each method, the effects of projection and resolution, as well as the uncertainties introduced by the presence of dust. The use of N-body simulations allows us to compare the location of Ultra Harmonic Resonance (UHR or 4/1) and corotation (CR) with measured bar lengths. We show that the minimum of ellipticity located just outside the bulk of the bar is correlated with the corotation, whereas the location of the UHR can be approximated using the phase of the fitted ellipses or the phase of the m=2 Fourier development of the surface brightness. We give evidence that the classification of slow/fast bars, based on the ratio R = Rcr/Rbar could increase from 1 (fast bar) to 1.4 (slow bar) just by a change of method. We thus conclude that one has to select the right bar-length estimator depending on the application, since these various estimators do not define the same physical area.
Michel-Dansac Leo
Wozniak Herve
No associations
LandOfFree
The length of stellar bars in SB galaxies and N-body simulations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The length of stellar bars in SB galaxies and N-body simulations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The length of stellar bars in SB galaxies and N-body simulations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-503038