How to Cite
Downloads
Métricas Alternativas
Dimensions
Abstract
A family of analytical potential-density pairs for flat galaxies with spheroidal halos is presented. The potential are obtained by means of the sum of two independent terms: a potential associated with a thin disc and a potential associated with a spheroidal halo, which are expressed as appropriated superpositions of products of Legendre functions, in such a way that the model implies a linear relationship between the masses of the thin disc and the spheroidal halo. By taking a particular case for the halo potential, we found that the circular velocity obtained can be adjusted very accurately to the observed rotation curves of some specific galaxies, so that the models are stable against radial and vertical perturbations. Two particular models for the galaxies NGC4389 and UGC6969 are obtained by adjusting the circular velocity with data of the observed rotation curve of some galaxies of the Ursa Mayor Cluster, as reported in Verheijen and Sancisi (2001). The values of the halo mass and the disc mass for these two galaxies are computed obtaining a very narrow interval of values for these quantities. Furthermore, the values of obtained masses are in perfect agreement with the expected order of magnitude and with the relative order of magnitude between the halo mass and the disc mass. © 2016. Acad. Colomb. Cienc. Ex. Fis. Nat. All rights reserved.
References
Arfken, G. and Weber, H. (2005). Mathematical Methods for Physicists. 6th ed. Academic Press.
Ashman, K. M. (1990). The origin of mass, disk-to-halo mass ratio and L-V relation of spiral galaxies. Astrophys. J., 359, 15.
Bateman, H. (1944). Partial Differential Equations. Dover. Bevington, P. and Keith, D. (2003). Data Reduction and Error
Analysis for the Physical Sciences. 3rd Ed., Mc Graw Hill. Binney, J. and Merrifield, M. (1998). Galactic Astronomy.Princeton University Press.
Binney, J. and Tremaine, S. (2008). Galactic Dynamics. 2nd ed. Princeton University Press.
Brun, R. and Rademakers, F. (1997). ROOT - An object oriented data analysis framework. Nucl. Instrum. Meth. in Phys. Res. A, 389, 81.
González, G. A., Plata-Plata, S. and Ramos-Caro, J. (2010). Finite thin disk models of four galaxies in the Ursa Major cluster: NGC3877, NGC3917, NGC3949 and NGC4010. MNRAS, 404, 468.
González, G. A. and Reina, J. I. (2006). An infinite family of generalized Kalnajs disks. MNRAS, 371, 1873.
Faber, T. (2006). Galactic halos and gravastars: static spherically symmetric spacetimes in modern general relativity and astrophysics, M. Sc. Thesis in Applied Mathematics, Victoria University of Wellington.
Hunter, C. (1963). The structure and stability of self-gravitating disks. MNRAS, 126, 299.
Kalnajs, A. J. (1972). The equilibria and oscillations of a family of uniformly rotating stellar disks. Astrophys. J., 175, 63.
Lamb, H. (1945). Hydrodynamics. Dover. Morse, P. M. and Fesbach, H. (1953). Methods of Theoretical Physics, Mc Graw Hill.
Pedraza J. F., Ramos-Caro J. and González G. A. (2008). An infinite family of self-consistent models for axisymmetric flat galaxies. MNRAS, 390, 1587.
Pierens, A. and Hure, J. (2004). Rotation curves of galactic disks for arbitrary surface density profiles: a simple and efficient recipe. Astrophys. J., 605, 179.
Ramos-Caro J., López-Suspez F. and González G. A. (2008). Chaotic and Regular Motion Around Generalized Kalnajs disks. MNRAS, 386, 440. Schödel, R. et al. (2002). A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way.Nature, 419, 694.
Verheijen, M. A.W. and Sancisi, R. (2001). The Ursa Major cluster of galaxies. IV. HI synthesis observations. Astron. Astrophys., 370, 765.
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Copyright (c) 2016 Journal of the Colombian Academy of Exact, Physical and Natural Sciences