Detecting dark matter

Prof. Pavel Kroupa from Bonn University and Charles University in Prague

@ CCMS/PHYSICS BUILDING R104

Abstract:

 

 

  Neither the standard model of particle physics nor direct detection experiments have yielded any need nor any evidence for the existence of cold or warm dark matter particles. These are only hypothesised to exist if general relativity is extrapolated from the Solar-system scale to galaxies and beyond. Cases in point are the observed non-Keplerian, flat rotation curves of disk galaxies which are the by far dominant population of galaxies and the missing mass phenomenon in galaxy clusters. I will discuss the possibility of confirming the existence of such dark matter particles using Chandrasekhar dynamical friction. Explicit test cases are the satellite galaxies of the Milky Way, the M81 group of galaxies and Hickson compact groups. The observed positions and motion of the galaxies in these systems show that the action of dynamical friction on the speculative dark matter halos is not evident in the data. The systems behave dynamically as if the extended dark matter halos do not exist. Thus, the orbits of the Milky Way satellite galaxies do not seem to be decaying sufficiently with time, nor are the compact galaxy groups merging.  Corroborative evidence comes from the highly symmetric distribution of all non-satellite galaxies in two 1.5Mpc extended, 50kpc-thick planes in the Local Group around the axis joining the Milky-Way and Andromeda galaxies. This symmetric arrangement of matter on Mpc scales remains entirely unexplained by current cosmological and dynamical theory, and is largely ignored by the community, despite being based on the very best extragalactic data at hand (because the involved galaxies are the nearest galaxies to the Milky Way). Further corroborative evidence comes from the five nearest major galaxies having three highly pronounced disk-of-satellite systems, which together falsify the standard dark-matter-based cosmological model with more than five sigma confidence.  The evidence thus gathered consistently and unanimously shows that dark matter particles cannot be present. The observed dynamics therefore cannot be Newtonian, but must, in the classical limit, essentially be Milgromian, and cosmological theory needs a major repositioning. As a consequence, our ability to deduce the physics of galaxy evolution from observation is probably wrong as it is at present based on assuming the standard cosmological model is valid. 

 

 

 

Brief Bio:

 

 

  I was born in southern Bohemia half way between Prague and Vienna and my father fled from the country with me in 1968 on the first night of the invasion by the Warsaw Pact. We lived, each time for five years, in Germany, South Africa, Germany and Australia. I studied physics and mathematics at The University of Western Australia but moved to Cambridge in the UK in 1988 where I obtained my PhD degree in 1992 at Trinity College as an Isaac Newton Scholar. My first post-doctoral position I took up in Heidelberg until 2000 when I moved to Kiel in northern Germany for my first teaching position. After winning a Heisenberg Fellowship there I accepted a professorship offer form the University of Bonn where I am since 2004. In 2017 I was named "professorem hospitem" by the rector of Charles University in Prague, where I now spend much of my time and am also supervising a few PhD students. In terms of prizes and awards I obtained an Isaac Newton Studentship (Trinity College, Cambridge), a Senior Rouse Ball Research Studentship (Trinity College, Cambridge), A Heisenberg Fellowship (Germany), a Swinburne Visiting Professorship (UK), a Leverhulme Trust Visiting Professorship (Australia), an INNOLEC Lectureship in Theoretical Physics (Masaryk University) and have been a Science Visitor at ESO in Garching and Santiago many times. I have also been awarded the Silver Commemorative Medal of the Senate of the Czech Republic and the Crystal Rose by the citizens of my town of birth, Jindrichuv Hradec.

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