Research
My previous research experience has focused on the field of particle physics.
I spent a summer during college as a research assistant at the Stanford Linear
Accelerator Center (SLAC), working on the development of the Gamma-ray Large
Area Space Telescope. I measured leakage currents and other electrical
properties of prototype silicon microstrip detectors, and constructed Monte
Carlo simulations of test beam data.
I spent the following summer at CERN, participating in the Common Muon Proton
Apparatus for Structure and Spectroscopy Experiment by recording and analyzing
data and testing gas electron multiplier detectors and assembling front-end
electronics.
In 2001 I conducted an independent study in astrobiology, developing a
theoretical analysis of bacterial survival rates on incoming meteorites and
considering the implications for theories of panspermia.
I began my graduate work in fall 2005, working with Dr. Chris Churchill.
I am interested in a wide range of research topics, ranging from galaxy
structure and dynamics, and large scale structure, to astronomical instrumentation.
My current project is based on a survey of 92 weak MgII absorbers (those with
Wr(2796) < 0.3 Å) found within 132 HIRES and UVES quasar
spectra. The spectra are 97% complete to Wr(2796) =
0.02 Å over the redshift range 0.15 - 1.45, and have a cumulative
redshift path of roughly 76.
We find pronounced evidence for evolution in the redshift path density, dN/dz,
which decreases monotonically toward higher redshift. Assuming dN/dz is
proportional to (1 + z)g, we estimate g = -1.0 ± 0.5, where
0.5 < g < 1.0 would represent no evolution in the population of absorbers.
Similarly, assuming dN/dz is proportional to (1 + z)2+e /
Wm(1 + z)3 + WL-1/2, we estimate e
= -2.0 ± 1.0, where e = 0 would represent no evolution.
We have also discovered eight MgII absorbing systems with Wr(2796) <
0.02 Å and three with Wr(2796) < 0.01 Å, allowing
us to explore the equivalent width, column density, and Doppler b
parameter distributions down to very small values of Wr(2796).
I am pleased to thank the NMSU Space and Areospace Cluster for a
generous research fellowship. I also thank the NASA's NMSU Space
Grant for a fellowship.
Publications
On the Heterogeneity of Metal-Line and Ly-Alpha Absorption in Galaxy "Halos" at z~0.7
C. W. Churchill, G. G. Kacprzak, C. C. Steidel, & J. L. Evans
2007, ApJ, in press
A Correlation Between Galaxy Morphology and MgII Halo Absorption Strength
Kacprzak, G. G., Churchill, C. W., Steidel, C. C., Murphy, M. T., Sargent, W. L. W., & Rauch, M. 2006, ApJL, in press
Meetings
January 2007: American Astronomical Society meeting, Evidence for Evolution in Weak MgII Absorbers at z < 1.5
J. Evans, C. W. Churchill, M. I. Murphy, & A. M. Widhalm
January 2007: American Astronomical Society meeting, Spatial Probing of MgII Absorption in ``Halo'' Gas through Adaptive Mesh Refinement Simulations of Galaxies
C. W. Churchill, G. Kacprzak, D. Ceverino, J. Evans, & A. Widhalm
