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Constraining the dark matter density in galaxy clusters
(PoS, 2015)
We illustrate the potential of using stellar velocity dispersion profiles of brightest cluster galaxies
(BCGs), in combination with X-ray and weak-lensing derived cluster mass profiles, to constrain
the matter distribution ...
Modelling the stellar soft-photon energy density of globular clusters
(South African Institute of Physics, 2014)
Recent observations by e.g. Fermi LAT and H.E.S.S. have revealed globular clusters to be sources of high-energy and very-high-energy gamma rays. It has been suggested that the presence of large numbers of millisecond pulsars ...
The anatomy of γ-ray pulsar light curves
(South African Institute of Physics, 2014)
To obtain constraints on the inclination and observer angles, <i>α</i> and <i>ζ</i>, of a <i>γ</i>-ray pulsar from its observed light curve (LC), we make use of geometric models detailing the position and extent of emission ...
Spatial and temporal assessment of atmospheric OC and BC concentrations at South African debits sites
(SASAS, 2014)
The baseline of uncertainty in aerosol radiative forcing is large and depends on aerosol
characteristics (e.g. size and composition), which can vary significantly on a regional scale.
Sources (natural, anthropogenic and ...
Glow-in-the-dark globular clusters: modelling their multiwavelength lanterns
(South African Institute of Physics, 2012)
Globular clusters (GCs) are astronomical tapestries embroidered with an
abundance of exotic stellar-type objects, including ancient metal-poor stars, planetary nebulae,
white dwarfs (WDs), low-mass X-ray binaries (LMXRBs), ...
A search for optical counterparts of the complex Vela X system
(South African Institute of Physics, 2015)
The pulsar wind nebula (PWN) associated with the Vela pulsar is a bright source
in the radio, X-ray and gamma-ray bands, but not in the optical. This source is very near,
lying at a distance of 290 pc, as inferred from ...
The detailed nature of active central cluster galaxies
(South African Institute of Physics, 2014)
We present detailed IFU observations of the central few kiloparsecs of the ionised nebulae surrounding four active central cluster galaxies in cooling flow clusters. All four galaxies have Hα filaments, and existing data ...
Empirical investigation of systems cost estimation models in the Limpopo Province of South Africa: a requirement modelling problem
(CSREA, 2014)
There are many factors believed to be important to systems development cost estimation. However an in-depth analysis demonstrates requirements as central cost drivers. The various transformations requirements go through ...
Spam email classifcation with generalized additive neural networks using ensemble methods
(SATNAC, 2014)
Solutions to minimize the amount
of junk mail we receive are not yet optimal and
thus research towards an improved spam email
classifier is ongoing. Traditional content and listbased
filters are less effective than ...
Investigating brightest cluster galaxies: kinematics with SALT
(South African Institute of Physics, 2014)
We present detailed, high spatial and spectral resolution, longslit observations of
four active central cluster galaxies (CCGs) in cooling flow clusters (Abell 0085, 0133, 0644 and
Ophiuchus). Our sample consists of CCGs ...