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Wu Jun = 中子星的極性w-模振盪 / 吳俊. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 100-102). / Text in English; abstracts in English and Chinese. / Wu Jun = Zhong zi xing de ji xing w-mo zhen dang / Wu Jun. / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background introduction and historical review --- p.1 / Chapter 1.2 --- Outline of the thesis --- p.3 / Chapter 1.3 --- Notations and conventions --- p.4 / Chapter 2 --- Equilibrium and oscillations of Relativistic stars --- p.5 / Chapter 2.1 --- Relativistic stars --- p.5 / Chapter 2.1.1 --- Equilibrium configuration --- p.6 / Chapter 2.1.2 --- Equation of state --- p.7 / Chapter 2.2 --- Oscillations of relativistic stars --- p.9 / Chapter 2.2.1 --- Families of fluid modes --- p.10 / Chapter 2.2.2 --- Families of spacetime modes (w-mode) --- p.11 / Chapter 3 --- Polar oscillations of neutron stars --- p.14 / Chapter 3.1 --- Axial oscillations of neutron stars --- p.14 / Chapter 3.2 --- LD formulation --- p.16 / Chapter 3.2.1 --- Equations inside star --- p.17 / Chapter 3.2.2 --- Boundary conditions at r = 0 and r = R --- p.19 / Chapter 3.2.3 --- Perturbations outside star --- p.21 / Chapter 3.3 --- AAKS formulation --- p.22 / Chapter 3.3.1 --- Equations inside the star --- p.23 / Chapter 3.3.2 --- Behavior at the center and the stellar surface --- p.25 / Chapter 3.3.3 --- Evolution outside star --- p.28 / Chapter 3.3.4 --- Connection formula --- p.29 / Chapter 4 --- QNMs of polar oscillations --- p.31 / Chapter 4.1 --- Solution outside star --- p.31 / Chapter 4.2 --- LD approach --- p.32 / Chapter 4.3 --- Hamiltonian constraint --- p.33 / Chapter 4.4 --- Boundary conditions a.t r = R --- p.37 / Chapter 4.5 --- Direct integration scheme (DIS) --- p.42 / Chapter 4.6 --- Two-way integration scheme (TIS) --- p.43 / Chapter 4.7 --- Connect the interior and exterior solutions --- p.45 / Chapter 4.8 --- Numerical results --- p.46 / Chapter 5 --- Polar oscillations without fluid motions --- p.50 / Chapter 5.1 --- Zero pressure variation approximation (ZPVA) --- p.51 / Chapter 5.1.1 --- Evolution formulas --- p.51 / Chapter 5.1.2 --- Boundary conditions --- p.53 / Chapter 5.1.3 --- Approximate QNMs --- p.55 / Chapter 5.2 --- Zero density variation approximation (ZDVA) --- p.55 / Chapter 5.2.1 --- Single equation formulas --- p.58 / Chapter 5.2.2 --- Numerical results --- p.61 / Chapter 5.2.3 --- Summary --- p.62 / Chapter 5.3 --- Application of ZDVA --- p.65 / Chapter 5.3.1 --- Relation between axial and polar w-modes --- p.65 / Chapter 5.3.2 --- Analysis --- p.66 / Chapter 6 --- Universal behavior of polar QNMs --- p.69 / Chapter 6.1 --- Universal behavior of polar w-modes --- p.70 / Chapter 6.2 --- Ordinary CQM of neutron stars --- p.71 / Chapter 6.2.1 --- TOV parameters of a CQM star --- p.71 / Chapter 6.2.2 --- Stability problem of CQM --- p.73 / Chapter 6.2.3 --- EOS near the surface --- p.75 / Chapter 6.3 --- Scaling behavior of polar oscillations --- p.78 / Chapter 6.3.1 --- Scaling behavior of fluid motions --- p.79 / Chapter 6.3.2 --- Scaled wave equations --- p.80 / Chapter 6.4 --- Scaled Cubic-Quintic Model (SCQM) --- p.82 / Chapter 7 --- Conclusion --- p.85 / Chapter 7.1 --- Summary of Our Work --- p.85 / Chapter 7.2 --- Outlook --- p.86 / Chapter A --- Expansion of Hamiltonian constraint around the center --- p.88 / Chapter B --- Factorization integration scheme (FIS) --- p.92 / Chapter C --- Equivalence of two definitions of the Zerilli function --- p.96

My research has focused on locating and measuring star formation and AGN activity in different environments with interferometric and single-dish radio observations. As my first PhD project, I studied the complex interaction between an intermediate redshift (z 0.3) starburst galaxy and a nearby ( 7 kpc separation) QSO using sub-arcsecond VLA observations. I found new evidence for jet-induced star formation activity in the companion galaxy, making the system a strong candidate for this rare, and potentially important process in the early Universe. In my second paper, I investigated the infrared-radio correlation (IRRC) of spheroid- and disc-dominated galaxies in the COSMOS field out to z 1.5. With 1.4 GHz data and Herschel photometry I found that the redshift evolution reported in recent works is due to an increasing radio excess emission associated with spheroid-dominated galaxies, compared to disc-dominated ones, i.e. the ‘purest' star-forming systems in our sample. I theorize that the extra radio power in spheroid-dominated systems is due to low-level AGN activity, even though these sources were not identified by most commonly-used diagnostics as AGN hosts. This finding will significantly increase the accuracy of future high-redshift radio surveys measuring star formation. In my third project I assembled and analysed the largest-to-date low-z IRRC sample of galaxies. I demonstrated the importance of selection effects influencing IRRC statistics, and carried out an improved IRRC analysis that yielded more accurate measures of the correlation's properties. With rich ancillary data it will provide insight into the physical processes that give rise to the IRRC. Finally, I adopted an MCMC-based model optimization to fit a radiative transfer model to ammonia line spectra of a binary molecular cloud core. I determined the physical structures and the masses of the cores and found they are gravitationally unbound.

Over the last three decades, the far-infrared emission from distant galaxies has been revealed to us. This far-infrared light is emitted by dust clouds heated by UV radiation from young stars. This reveals to us some of the most remarkable and highly star-forming galaxies in the Universe. The Herschel space observatory was able to capture this light. With this thesis I have attempted to get a better understanding of the underlying galaxy population. I have done this by observing the most extreme forms of star formation in the early Universe seen in maps obtained by the SPIRE instrument and using prior information from deep high resolution surveys. In particular I have examined the dependencies of dusty galaxy properties on their environment. I have confirmed that star formation is primarily dependent on both galaxy mass and whether a galaxy lies in the "blue cloud". Environment is the primary influence on the fraction of galaxies lying in the blue cloud and has a minor, but significant, affect on the average star formation rate of star forming galaxies. The highest redshift galaxies directly detected in the Herschel SPIRE maps are very rare, but due to the large area of the HerMES surveys we are able to find a statistical significant sample. With the addition of longer wavelength SCUBA-2 data I further confine the redshift of the dusty galaxies and find that the star formation rates of those sources are extremely high and exceed 1000 M_ a year. The observed number counts of these extremely bright sources have been a problem for galaxy evolution models. I am able to explain the observed number count of red SPIRE sources by adding correlated confusion noise and Gaussian instrumental noise to simulated galaxy catalogues. My results emphasise that it is crucial to correct for noise and selection effects for comparison with simulations. I exploit a novel way of fitting the full SPIRE maps using prior information from deep high resolution surveys, obtained from wavelengths ranging from optical to radio. In doing so I obtain the most accurate values of the cosmic infrared background (CIB) at the SPIRE wavelengths. With these results we have a better indication of which sources are producing the CIB, and therefore the bulk of star formation. My results indicate that future large area surveys like LSST are likely to resolve a substantial fraction of the population responsible for the CIB at 250 μm ≤ λ ≤ 500 μm.

Our understanding of the magnetic fields of stars is nearly monopolized by knowledge of our own sun. Very-long baseline radio interferometry (VLBI) provides a means of directly imaging the radio coronae of other stars at a high enough resolution to discern discrete features, something not possible with other observational methods. It also allows the highest positional accuracy of any observational method available. This thesis details the VLBI study of two nearby radio-loud stars in close binary systems. Both systems were observed at numerous epochs spaced over a range of several months with the global-scale radio interferometer array the VLBA-HSA. These observations were combined with archival data from the National Radioastronomy Observatory (NRAO) Archive. The resulting positions, as well as previously published positions, were used to calculate a least-squares solution for all the orbital and astrometric parameters of both systems. This made it possible to determine the position of the physical star with respect to the radio emission in each image. The images of both stars were found to conform to theoretical emission produced by a model dipolar magnetosphere with a filled or partially-filled coronal loop.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 116-120). Also available on the Internet.