arXiv subjects

M. Barker

Publications and source records attributed to M. Barker.

3 recordsLinked to original sources

arXiv2020

The Four Pillars of Research Software Engineering

Building software that can support the huge growth in data and computation required by modern research needs individuals with increasingly specialist skill sets that take time to develop and maintain. The Research Software Engineering movement, which started in the UK and has been built up over recent years, aims to recognise and support these individuals. Why does research software matter to professional software development practitioners outside the research community? Research software can have great impact on the wider world and recent progress means the area can now be considered as a more realistic option for a professional software development career. In this article we present a structure, along with supporting evidence of real-world activities, that defines four elements that we believe are key to providing comprehensive and sustainable support for Research Software Engineering. We also highlight ways that the wider developer community can learn from, and engage with, these activities.

cs.SE↗

arXiv2011

Comparisons of the MINOS Near and Far Detector Readout Systems at a Test Beam

MINOS is a long baseline neutrino oscillation experiment that uses two detectors separated by 734 km. The readout systems used for the two detectors are different and have to be independently calibrated. To verify and make a direct comparison of the calibrated response of the two readout systems, test beam data were acquired using a smaller calibration detector. This detector was simultaneously instrumented with both readout systems and exposed to the CERN PS T7 test beam. Differences in the calibrated response of the two systems are shown to arise from differences in response non-linearity, photomultiplier crosstalk, and threshold effects at the few percent level. These differences are reproduced by the Monte Carlo (MC) simulation to better than 1% and a scheme that corrects for these differences by calibrating the MC to match the data in each detector separately is presented. The overall difference in calorimetric response between the two readout systems is shown to be consistent with zero to a precision of 1.3% in data and 0.3% in MC with no significant energy dependence.

physics.ins-det↗

arXiv2002

A Limit on the Cosmological Mass Density and Power Spectrum from the Rotation Curves of Low Surface Brightness Galaxies

The concentrations of the cuspy dark matter halos predicted by simulations of cold dark matter are related to the cosmology in which the halos form. Observational constraints on halo concentration therefore map into constraints on cosmological parameters. In order to explain the observed concentrations of dark matter dominated low surface brightness galaxies, we require a cosmology with rather little power on galaxy scales. Formally, we require s_8 G_0.6 < 0.23, where G_0.6 is a modified shape parameter appropriate to this problem. Practically, this means either Omega_m < 0.2 or s_8 < 0.8. These limits apply as long as we insist that the cuspy halos found in simulations must describe the halos of low surface brightness galaxies. A low density cosmology helps with the low observed concentrations, but it offers no explanation of the many cases where the shape of the density profile deviates from the predicted cuspy form. These cases must have suffered very extensive mass redistribution if the current halo formation picture is not to fail outright. It is far from clear whether any of the mass redistribution mechanisms which have been suggested (e.g., feedback) are viable.

astro-ph↗