We derive structural parameters for ∼ 2000 globular clusters in the giant Virgo elliptical M87 using extremely deep Hubble Space Telescope images in F606W (V) and F814W (I) taken with the ACS/WFC. The cluster scale sizes (half-light radii rh) and ellipticities are determined from PSF-convolved Kingmodel profile fitting. We find that the rh distribution closely resembles the inner Milky Way clus...

We present a comprehensive series of simulations to study the secular evolution of disk galaxies expected in a LCDM universe. Our simulations are organized in a hierarchy of increasing complexity, ranging from rigid-halo collisionless simulations to fully live simulations with gas and star formation. Our goal is to examine which structural properties of disk galaxies may result from secular evo...

When considering a graph problem from a parameterized point of view, the parameter chosen is often the size of an optimal solution of this problem (the “standard” parameter). A natural subject for investigation is what happens when we parameterize such a problem by various other parameters, some of which may be the values of optimal solutions to different problems. Such research is known as par...

In this paper we present examples illustrating five important issues involved in the identification of structural information about social processes using the fragmentary data which is usually available for this purpose. These issues are listed below. (i) It is of considerable importance to use continuous-time models to desi;ribe processes for which there is no substant~ve basis for a choice of...

Densest k-Subgraph is the problem to find a vertex subset S of size k such that number edges in subgraph induced by maximized. In this paper, we show fixed parameter tractable when parameterized neighborhood diversity, block deletion number, distance-hereditary and cograph respectively. Furthermore, give 2-approximation \(2^{{{\texttt{tc}}(G)}/2}n^{O(1)}\)-time algorithm where \({{\texttt{tc}}(...