Astronomy and Astrophysics
نویسنده
چکیده
In this paper I present a new two-dimensional decomposition technique, which models the surface photometry of a galaxy with an exponential light profile for both bulge and disk and, when necessary, with a Freeman bar. The new technique was tested for systematic errors on both artificial and real data and compared with widely used one-dimensional decomposition techniques, where the luminosity profile of the galaxy is used. The comparisons indicate that a decomposition of the two-dimensional image of the galaxy with an exponential light profile for both bulge and disk yields the most reproducible and representative bulge and disk parameters. An extensive error analysis was made to determine the reliability of the model parameters. If the model with an exponential bulge profile is a reasonable description of a galaxy, the maximum errors in the derived model parameters are of order 20%. The uncertainties in the model parameters will increase, if the exponential bulge function is replaced by other often used bulge functions as the de Vaucouleurs law. All decomposition methods were applied to the optical and near-infrared data set presented by de Jong & van der Kruit (1994), which comprises 86 galaxies in six passbands.
منابع مشابه
The Effect of Solar Particles in the Choice of Alloy Shielding in a Satellite
The damages and logical failures in dierent parts of a satellite may occur during a solar event, when a bulk of solar energetic particles approaching the Earth. During solar events, these particles may cause extensive damages which are even permanent (hard errors). A way of damage reduction is designing a proper coating as the fuselage. As protons are the major component of solar particles and ...
متن کاملUnderstanding Activity in Low–Mass Stars
Lucianne M. Walkowicz, Department of Astronomy, University of California Berkeley Andrew A. West, MIT Kavli Institute for Astrophysics and Space Research Gibor Basri, Department of Astronomy, University of California Berkeley Matthew K. Browning, Canadian Institute for Theoretical Astrophysics Adam F. Kowalski, Department of Astronomy, University of Washington Eric Hilton, Department of Astrono...
متن کاملEvolution of Magnetic Fields in High Mass Star Formation: Linking field geometry and collapse for the W51 e2/e8 cores
Evolution of Magnetic Fields in High Mass Star Formation: Linking field geometry and collapse for the W51 e2/e8 cores Ya-Wen Tang Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan & Academia Sinica Institute of Astronomy and Astrophysics, P. B. Box 23-141, Taipei 10617,Taiwan Paul T. P. Ho Academia Sinica Institute of Astronomy and Astrophysi...
متن کاملEvolution of Information and Complexity in an Ever-Expanding Universe
Using the usual definitions of information and entropy in quantum gravity and statistical mechanics and the existing views about the relation between information and complexity, we examine the evolution of complexity in an ever expanding universe.
متن کاملThe Macho Project Large Magellanic Cloud Variable Star Inventory. Xiii. Fourier Parameters for the First Overtone Rr Lyrae Variables and the Lmc Distance
Shapes of RR Lyrae light curves can be described in terms of Fourier coefficients which past research has linked with physical characteristics such as luminosity, mass Department of Physics and Astronomy, University of Pennsylvania, PA 19104 Lawrence Livermore National Laboratory, Livermore, CA 94550 Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, Mailcode 5247, Ne...
متن کامل