The Central Velocity Field in NGC 253 : Possible Indication of a Bar

Details The Central Velocity Field in NGC 253 : Possible Indication of a Bar The Central Velocity Field in NGC 253 : Possible Indication of a Bar

2000-10-12

arxiv.org/abs/astro-ph/0010252v1

Astronomy and Astrophysics

Astrophysics

26 latex pages, 7 figures, accepted in Astrophysical Journal

Scientific paper

10.1086/319430

We have investigated whether motion of gas in a bar-like potential can account for the peculiar but systematic velocity field observed in the nuclear region of the starburst galaxy NGC 253. This unusual velocity field with gradients along both major and minor axes was revealed in a high resolution ($1.8^{\arcsec}\times 1.0^{\arcsec}$) H92$\alpha$ recombination line observation by Anantharamiah and Goss (1996). A simple logarithmic potential is used to model the bar. Assuming that the bulk of the gas flows along closed and non-intersecting x1 (bar) and x2 (anti-bar) orbits of the bar potential, we have computed the expected velocity field and position-velocity diagrams and compared them with the observations. A comparison of the integrated CO intensity maps with the spatial distribution of the x1 and x2 orbits in the model indicates that the nuclear molecular gas in NGC 253 lies mainly on the x2 orbits. We also find that the velocity field observed in the central 100 pc region in the H92$\alpha$ recombination line is well accounted for by the bar model if most of the ionized gas resides in the inner x2 orbits. However, the model is unable to explain the velocity field on a larger scale of $\sim 500$ pc observed using the OVRO interferometer with a resolution of $5^{\arcsec}\times 3^{\arcsec}$. The direction of the observed CO velocity field appears twisted compared to the model. We suggest that this perturbation in the velocity field may be due to an accretion event that could have occurred $10^7$ years ago.

Affiliated with

Also associated with

No associations

Rating

The Central Velocity Field in NGC 253 : Possible Indication of a Bar 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 Central Velocity Field in NGC 253 : Possible Indication of a Bar, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Central Velocity Field in NGC 253 : Possible Indication of a Bar will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-83590