AstroPhysics Group Research


The AstroPhysics Group at Shepherd is involved in several areas of research, and has published and presented multiple works in the following areas.

-- Cosmology -- -- Observational Astronomy -- -- Historical Astronomy/Astronomy Education -- -- Virtual Reality --





Cosmology


RESEARCH SYNOPSIS: The Group's research attempts to address two fundamental problems in cosmology:

  1. On the largest scales, the Universe is believed to be everywhere homogeneous and isotropic: this is the Copernican cosmological principle. It is evidentially verified by such observations as the isotropy of the cosmic microwave background, the x-ray background, and the number counts of radio sources. However, on smaller scales, the universe is certainly not homogeneous: galaxies are observed to be distributed not at random, but clustered with respect to each other. Any theory of structure formation must take this disparity on multiple scales into account.
  2. For some time it has been known that the morphological fractions of ellipticals, lenticulars, and spirals are related to the density of the environment. The fraction of ellipticals ranges from less than 10% in the lowest density environments to more than 50% in the centers of galaxy clusters. It is still not apparent whether this is a result of conditions conducive to formation of a particular morphological type (nature) or to an evolutionary process (nurture).

The particular behavior of astronomical clustering on multiple scales suggests that the concepts of fractal geometry may apply. The modern motivation for fractal geometry may best be summed up by this quote of Benoit Mandelbrot: ``Mountains are not cones, clouds are not spheres, coastlines are not circles, and bark is not smooth, nor does lightning travel in a straight line''. Fractals are, in simplest terms, objects which are (approximately) self-similar on all scales.

The research focuses on the use of the pointwise dimension (which is based on fractal geometry) to understand both the large-scale structure of the universe and the connection between galaxy morphology and environment.




SELECTED PUBLICATION:

An Examination of the Large-Scale Clustering of the Las Campanas Redshift Survey (Astrophysical Journal)




Observational Astronomy


RESEARCH SYNOPSIS: Our expanded facilities allow us to provide research opportunities for students in a number of observational fields. A collection of images can be found at the Shepherd University Observatory's dedicated website.



FOR MORE INFORMATION:

Shepherd University Observatory




Historical Astronomy/Astronomy Education


RESEARCH SYNOPSIS: Keeping an eye to the past allows us to better understand the developments leading to the present state of the astronomical sciences, and gives us a more confident position from which to direct future efforts in astronomy. The Group is currently working on a long-term study and critique of historical developments in astronomical thought in the 16th and 17th centuries, and the applications in modern astronomical education.




SELECTED PUBLICATION:

Copernicus's Neglected Successor (Mercury)




Virtual Reality


RESEARCH SYNOPSIS: Three-dimensional simulations and visualizations of astronomical data are invaluable to the astronomer. Seeing astronomical objects in three dimensions (as opposed to the two dimensions our sky limits us to) allows visual evaluations and facilitates clearer and deeper understandings of the physical situations underlying the results of mathematical analyses. We use an SGI O2 workstation on-site on which we develop our models. We also have remote access to ImmersaDesk and CAVE (CAVE Automatic Virtual Environment) hardware and software.




SELECTED PUBLICATION:

A Java 3D visualization application for research use in astronomy (Journal of Computing Sciences in Colleges)