Welcome to Hubert L. Bray's
Wave Dark Matter Web Page
``On Dark Matter, Spiral Galaxies, and the Axioms of General Relativity,'' H. Bray, April 22, 2010.
Beginning with a geometric motivation for dark matter going back to the
axioms of general relativity, we show how scalar field dark matter,
which naturally forms dark matter density waves due to its wave nature,
may cause the observed barred spiral pattern density waves in many disk
galaxies and triaxial shapes with plausible brightness profiles in many
elliptical galaxies. If correct, this would provide a unified
explanation for spirals and bars in spiral galaxies and for the
brightness profiles of elliptical galaxies. We compare the results of
preliminary computer simulations with photos of actual galaxies.
for the video of a lecture with a description of the
above paper plus more recent ideas. This talk, entitled "On Dark
Matter, Spiral Galaxies, and the Axioms of General Relativity" was
given at the 41st Barrett Memorial Lectures in Mathematical Relativity
at the University of Tennessee, Knoxville on May 12, 2011. A
similar talk was also given at the 26th Annual Geometry Festival at the
University of Pennsylvania on April 15, 2011. The pdf slide show
for the video of a lecture entitled "Dark Matter in Galaxies" that
Andriy Badin and I gave at Duke University as part of Dark Matter
Awareness Week on December 6, 2010. The last 25 minutes gives an overview of the
Spiral Galaxy Simulation using Matlab:
Elliptical Galaxy Simulation using Matlab:
``On Wave Dark Matter, Shells in Elliptical Galaxies, and the Axioms of General Relativity,'' H. Bray, December 22, 2012.
This paper is a sequel to the paper listed above. We give an
update on where things stand on this ``wave dark matter'' model of dark
matter (aka scalar field dark matter and boson stars), an interesting
alternative to the WIMP model of dark matter, and discuss how it has
the potential to help explain the long-observed interleaved shell
patterns, also known as ripples, in the images of elliptical galaxies.
Shells in Elliptical Galaxies Visualization using Matlab:
``Modeling Wave Dark Matter in Dwarf Spheroidal Galaxies," H. Bray and A. Parry, January 2013.
We compare the mass profiles of spherically symmetric static states of
wave dark matter to the Burkert mass profiles that have been shown by
Salucci et. al. to predict well the velocity dispersion profiles of the
eight classical dwarf spheroidal galaxies. We show that a
reasonable working value for the fundamental constant Upsilon in the
wave dark matter model is 50 years^(-1). We also show that under
precise assumptions the value of Upsilon can be bounded above by 1000
Matlab code used in this paper, zipped with readme.txt file included:
Modeling WDM in Dsph programs.zip
Paper #3 is based in part on:
``Spherically Symmetric Static States of Wave Dark Matter,'' A. Parry, December 2012.
``Wave Dark Matter and the Tully-Fisher Relation,'' H. Bray and A. Goetz, September 2014.
We investigate a theory of dark matter called wave dark matter, also known as
scalar field dark matter (SFDM) and boson star dark matter or Bose-Einstein
condensate (BEC) dark matter, in spherical symmetry and its relation to the
Tully-Fisher relation. We show that fixing the oscillation frequency of wave
dark matter near the edge of dark galactic halos implies a Tully-Fisher-like
relation for those halos. We then describe how this boundary condition, which
is roughly equivalent to fixing the half-length of the exponentially decaying
tail of each galactic halo mass profile, may yield testable predictions for
this theory of dark matter.
Paper #5 pairs naturally with:
``Tully-Fisher Scalings and Boundary Conditions for Wave Dark Matter,'' A. Goetz, February 2015.
We investigate a theory of dark matter called wave dark matter, also
known as scalar field dark matter (SFDM) and boson star dark matter or
Bose-Einstein condensate (BEC) dark matter (also see axion dark
matter), and its relation to the Tully-Fisher relation. We exhibit two
boundary conditions that give rise to Tully-Fisher-like relations for
spherically symmetric static wave dark matter halos: (BC1) Fixing a
length scale at the outer edge of wave dark matter halos gives rise to
a Tully-Fisher-like relation of the form M/(v^4) = constant. (BC2)
Fixing the density of dark matter at the outer edge of wave dark matter
halos gives rise to a Tully-Fisher-like relation of the form
Right click on the above file links to download the files. The .m
files can be run using Matlab. As some of these .m files create many
image files, we suggest creating a new directory for each run and
placing a copy of the .m file in that directory. Then change to
that directory inside Matlab and execute the command line. If you
open the .m files in the Matlab editor, example command lines are
usually listed. There are also example command lines in some of the papers listed
above as well.
Hubert L. Bray
Mathematics and Physics Departments
Duke University, Box 90320
Durham, NC 27708 USA