THE GRAVITATIONAL POTENTIAL OF THE BAR IN NGC-4314

Citation
Ac. Quillen et al., THE GRAVITATIONAL POTENTIAL OF THE BAR IN NGC-4314, The Astrophysical journal, 437(1), 1994, pp. 162-172
Citations number
55
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
437
Issue
1
Year of publication
1994
Part
1
Pages
162 - 172
Database
ISI
SICI code
0004-637X(1994)437:1<162:TGPOTB>2.0.ZU;2-S
Abstract
We present near-infrared images of NGC 4314 in the J, H, and K bands. Colors in these bands are constant across the bar of NGC 4314, indicat ing that the mass-to-light ratio is constant over much of the galaxy. We have developed an efficient procedure for mapping the gravitational potential of a nonaxisymmetric galaxy based on its appearance in the near-infrared using a Fourier transform method. We account for the thi ckness of the galaxy's stellar disk by convolving its K image with a f unction that depends upon the vertical stellar scale height. We apply this procedure to NGC 4314 and find that prograde orbits integrated in the potential are consistent with the shape of the bar for a disk ver tical scale height of h = 350 +/- 100 pc and a corotation radius of r = 3.5 +/- 0.5 kpc. We find that the inner m = 4 Lindblad resonance is approximately at the location of knoblike features seen near the end o f the bar. The shape of nearly closed orbits at this radius are lozeng e or diamond shaped and have low speeds along the major axis of the ba r. The low speeds imply an increase in density along the major axis of the bar. The angle of the major axis of the m = 4 component of the su rface density begins to twist at the location of its resonance, and th e angle of the m = 2 component begins to twist at a larger radius near the corotation radius.