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Full-Text Articles in Physical Sciences and Mathematics
Model-Independent Plotting Of The Cosmological Scale Factor As A Function Of Lookback Time, H. I. Ringermacher, L. R. Mead
Model-Independent Plotting Of The Cosmological Scale Factor As A Function Of Lookback Time, H. I. Ringermacher, L. R. Mead
Faculty Publications
In this work we describe a model-independent method of developing a plot of scale factor a(t) versus lookback time tL from the usual Hubble diagram of modulus data against redshift. This is the first plot of this type. We follow the model-independent methodology of Daly & Djorgovski used for their radio-galaxy data. Once the a(t)data plot is completed, any model can be applied and will display as described in the standard literature. We then compile an extensive data set to z = 1.8 by combining Type Ia supernovae (SNe Ia) data from SNLS3 …
Dynamical Models Of Elliptical Galaxies – I. Simple Methods, A. Angello, N. Evans, Aaron Romanowsky
Dynamical Models Of Elliptical Galaxies – I. Simple Methods, A. Angello, N. Evans, Aaron Romanowsky
Faculty Publications
We study dynamical models for elliptical galaxies, deriving the projected kinematic profiles in a form that is valid for general surface-brightness profiles and (spherical) total mass profiles, without the need for any explicit deprojection. We then show that an almost flat rotation curve, combined with modest velocity anisotropy, is already sufficient to recover the kinematic profiles of nearby ellipticals. As an application, we provide two different sets of mass estimators for elliptical galaxies, based on either the velocity dispersion at a specific location near the effective radius, or the aperture-averaged velocity dispersion. In the large aperture (virial) limit, mass estimators …