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dc.contributor.advisorJog, Chanda J
dc.contributor.authorRahul Nath, R
dc.date.accessioned2016-04-26T09:57:49Z
dc.date.accessioned2018-07-31T06:18:32Z
dc.date.available2016-04-26T09:57:49Z
dc.date.available2018-07-31T06:18:32Z
dc.date.issued2016-04-26
dc.date.submitted2012
dc.identifier.urihttps://etd.iisc.ac.in/handle/2005/2522
dc.identifier.abstracthttp://etd.iisc.ac.in/static/etd/abstracts/3272/G25555-Abs.pdfen_US
dc.description.abstractThe physical explanation for the existence of the galactic warp is one of the major research areas in Astronomy. People have proposed various theories but nobody has yet given a convincing explanation. Most of the spiral galaxies are observed to be warped which reveals that the galactic warp is a stable characteristic. In the theory of kinematic bending wave, warp is considered as a wave that is propagated through the galactic disk with a speed called pattern speed. If the pattern initially had straight line of nodes, according to bending wave theory, the warp would tend to wind up rapidly in the gravitational field of galactic disk. But still we observe warped galaxies in the sky. In the literature, it has been claimed that the winding problem of galactic warp may be solved by incorporating the effect of gravitational field of the dark matter halo in which the galactic disk is embedded. Recently some works on the dynamics of galactic disk claim that the shape of the dark matter halo is pro late spheroid. In this thesis, the effect of the gravitational field of a prolate spheroidal dark matter halo with varying eccentricity to the galactic warp is calculated and discussed. Chapter1 gives the general introduction of the topics discussed in the following chapters. The structure of the spiral galaxy, their classifications, and the disk dynamics are discussed in the first few sections. One of the revolutionary concepts that emerged in the previous century was the existence of the dark matter. Presently tracing the mass distribution and the constituent particles of dark matter is one of the major research areas in theoretical and experimental physics. In this thesis, the effect of a particular type of mass distribution in dark matter halo on the warp is discussed in detail. In the next few sections, the following topics are discussed namely; how the concept of dark matter came into astrophysics, how to measure the total mass inside a given radius and what are the different distributions used for various purposes. A new theory called Modified Newtonian Mechanism was also proposed in the previous century as an alternative to the dark matter concept which is also discussed briefly. Kinematic bending wave theory and the winding problem of the galactic warp is also discussed in detail. In the last section a relation between the pattern speed of the warp and the shape of the dark matter halo is obtained. The calculation of the potential of a prolate spheroidal mass distribution with varying eccentricity is not done in any literature as we know. The calculation of the potential and the patten speed of prolate spheroidal mass distributions and of the galactic disk are described in chapter 2. The calculations of oblate spheroidal mass distribution are also discussed in this chapter but that is out of main theme. In chapter 3 we apply the equations obtained in the Chapter 2 to one simple toy model and to the Galaxy. The rotation curve and the pattern speed of a warp in the gravitational field of prolate spheroidal mass distribution of varying eccentricity are described. Usually the Milky Way disk is treated as an in infinitesimally thin disk but for our calculations the three dimensional but thin disk is used. The usually people use some approximation to calculate the potential due to galactic infinitesimal thin disk. The difference of the work from earlier works done by different people(with the approximation mentioned in above line) is also discussed in this Chapter. Chapter 4 discusses the summary of the entire work.en_US
dc.language.isoen_USen_US
dc.relation.ispartofseriesG25555en_US
dc.subjectGalactic Warpsen_US
dc.subjectDark Matteren_US
dc.subjectSpiral Galaxiesen_US
dc.subjectMilky Wayen_US
dc.subjectDark Matter Halosen_US
dc.subjectSpheroidal Mass Distributionsen_US
dc.subjectMass Distribution Modelsen_US
dc.subjectProlate Spheroidal Mass Distributionen_US
dc.subjectGalactic Disken_US
dc.subjectSpiral Galaxyen_US
dc.subjectOblate Spheroidal Mass Distributionen_US
dc.subject.classificationAstronomyen_US
dc.titleProlate Shaped Dark Matter Halo And The Galactic Warpen_US
dc.typeThesisen_US
dc.degree.nameMSen_US
dc.degree.levelMastersen_US
dc.degree.disciplineFaculty of Scienceen_US


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