Chung-Pei Ma

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This paper presents a systematic treatment of the linear theory of scalar gravitational perturbations in the synchronous gauge and the conformal Newtonian (or longitudinal) gauge. It differs from others in the literature in that we give, in both gauges, a complete discussion of all particle species that are relevant to any flat cold dark matter (CDM), hot(More)
Several recent observations suggest that gas-poor (dissipationless) mergers of elliptical galaxies build up the massive end of the red sequence. We perform a series of major merger simulations to investigate the spatial and velocity structure of the remnants of such mergers. Regardless of orbital energy or angular momentum, we find that the stellar remnants(More)
We analyze the fundamental plane projections of elliptical galaxies as a function of lumi-nosity, using a sample of ≈ 80, 000 galaxies drawn from Data Release 4 (DR4) of the Sloan Digital Sky Survey (SDSS). We exclude brightest cluster galaxies (BCGs) from our sample because of a problem with the default pipeline sky subtraction for BCGs. The observables we(More)
Observations suggest that the effective radii of high-redshift massive spheroids are as much as a factor ∼ 6 smaller than low-redshift galaxies of comparable mass. Given the apparent absence of low-redshift counterparts, this has often been interpreted as indicating that the high density, compact red galaxies must be " puffed up " by some mechanism. We(More)
We present an analytic model for the fully nonlinear power spectrum P and bis-pectrum Q of the cosmological mass density field. The model is based on physical properties of dark matter halos, with the three main model inputs being analytic halo density profiles, halo mass functions, and halo-halo spatial correlations, each of which has been well studied in(More)
We construct merger trees from the largest database of dark matter haloes to date provided by the Millennium simulation to quantify the merger rates of haloes over a broad range of descendant halo mass (10 12 M 0 10 15 M ⊙), progenitor mass ratio (10 −3 ξ 1), and redshift (0 z 6). We find the mean merger rate per halo, B/n, to have very simple dependence on(More)
Observational work conducted over the past few decades indicates that all massive galaxies have supermassive black holes at their centres. Although the luminosities and brightness fluctuations of quasars in the early Universe suggest that some were powered by black holes with masses greater than 10 billion solar masses, the remnants of these objects have(More)
We perform hydrodynamical simulations of major galaxy mergers using new methods for calculating the growth of massive black holes (BH) in galactic nuclei and their impact on the surrounding galaxy. We model BH growth by including a subgrid model for accretion produced by angular momentum transport on unresolved scales. The impact of the BHs radiation on(More)