Pavel Kroupa

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Pavel Kroupa (born September 24, 1963 in Jindřichův Hradec , Czechoslovakia ) is a Czech - Australian astrophysicist and professor at the Rheinische Friedrich-Wilhelms-Universität Bonn .

Life

Kroupa's family fled the Czech Republic after the failure of the Prague Spring in 1968; as a result, Kroupa grew up in Germany and South Africa. He acquired in 1983 in Göttingen , the High School and then studied physics at the University of Western Australia in Perth . In 1988 he received the Isaac Newton Fellowship from the University of Cambridge and in 1992 a Senior Rouse Ball Research Fellowship from Trinity College (Cambridge) and did his doctorate in England until 1992 on the distribution of low-mass stars in the Milky Way . Afterwards Kroupa worked until 2000 in astronomical research groups of the Ruprecht-Karls-University of Heidelberg and the Max Planck Institute for Astronomy before at the University of Kiel habilitation was and a Heisenberg fellowship awarded. In April 2004 he was appointed to the observatory of the University of Bonn, which is now a department of the Argelander Institute for Astronomy. He was awarded a Swinburne University Visiting Professorship in Melbourne in 2007 and a Leverhulme Trust Visiting Professorship at Sheffield University.

research

Kroupa heads the research group Stellar Populations and Dynamics at the University of Bonn. Kroupa began his research in Australia in 1987 with an investigation of the closest star , Proxima Centauri .

Kroupa is known for his work on the distribution of stellar masses and in Cambridge 1990–1992 derived the canonical IMF ( original mass function ), which is commonly used today, by including binary stars and detailed calculations of the star structure , which describes the distribution of stellar masses at their birth. Together with Carsten Weidner, in 2004 in Kiel, he proposed the existence of a physical maximum stellar mass of around 150 solar masses. In Heidelberg from 1993–1995 he presented the first stellar-dynamic calculations of star clusters in which all stars are born as double stars , thereby solving the problem that field populations have a significantly lower double star rate than star formation regions. He formulated and applied the theory of the pre-main sequence self-evolution of binary stars mathematically, founded the method of dynamic population synthesis and predicted the existence of forbidden binary stars. The idea that brown dwarfs and extrasolar planetary systems arise in circumstellar disks when they are disturbed by flying stars in young star clusters, he proposed in collaboration with Ingo Thies and Christian Theis 2003-2004 in Kiel.

In Kiel he also formulated the concept that the stars in galaxies arise in populations of star clusters. With this he was able to explain the observed heating of the disk of the Milky Way in 2002 and formulate the "IGIMF theory" (integrated galactic initial mass function) with Carsten Weidner . Together with Jan Pflamm-Altenburg, he was able to show in Bonn in 2008 that the IGIMF theory implies that disk galaxies have a radial star formation law, according to which the star formation density is proportional to the radial gas density. The IGIMF theory also implies that the star formation rates of dwarf irregular galaxies are proportional to their gas masses and must be corrected to significantly higher values. The mass- metallicity relation of galaxies follows from this.

Kroupa also carried out the first precise measurement of the spatial movement of two extragalactic systems with Ulrich Bastian in Heidelberg in 1997. In 1997 he also found stellar dynamic solutions for the satellite galaxies of the Milky Way, which do not require any dark matter components. His work implies a possible connection between the satellite galaxies and the bulge of the Milky Way. This connection can be explained by a collision of the early Milky Way with another young galaxy. Since 2010, Kroupa has been increasingly concerned with cosmology. Kroupa is of the opinion that the standard model of cosmology ( lambda CDM model ), which is justified primarily by the analysis of the cosmic microwave background as a relic of the early universe and requires cold dark matter (DM), is made through the observation of galaxies the vicinity of the Milky Way (around 8 MPc distance) has been refuted. In particular, he sees the prediction of two clearly different types of satellite dwarf galaxies that the Standard Model predicts (one DM-containing satellite galaxies that formed in the DM halo of the main galaxy, and one DM-poor Tidal Dwarf Galaxies (TDG) as relics of the collision history of the galaxies), as refuted. He advocates greater funding for research into alternatives (especially MOON and similar theories), but sees obstacles in the sociology of science that lead to the suppression of this research. He does not reject dark matter in principle, but provides for a switch to a hidden sector with ever new theoretical additions (such as dark energy, dark forces that only work between dark matter) similar to the epicycle theory in older astronomy, and thus a systematic switch the fundamental requirement for the falsifiability of a theory.

Publications

  • The distribution of low-mass stars in the disc of the galaxy . University of Cambridge, 1992
  • Binary systems, star clusters and the galactic-field population: applied stellar dynamics . Kiel, 2002
  • The initial mass function of stars: evidence for uniformity in variable systems . Volume 295, Issue 5552 of Science Weekly, American Association for the Advancement of Science, 2002

Essays

  • with RR Burman, DG Blair: "Photometric observations of flares on Proxima Centauri", PASA 8, 119 (1989). bibcode : 1989PASAu ... 8..119K
  • with CA Tout, G. Gilmore: "The distribution of low-mass stars in the Galactic disc", MNRAS 262, 545 (1993). bibcode : 1993MNRAS.262..545K
  • "Inverse dynamical population synthesis and star formation", MNRAS 277, 1491 (1995). bibcode : 1995MNRAS.277.1491K
  • "The dynamical properties of stellar systems in the Galactic disc", MNRAS 277, 1507 (1995). bibcode : 1995MNRAS.277.1507K
  • with U. Bastian, “The HIPPARCOS proper motion of the Magellanic Clouds”, NewA 2, 77 (1997). bibcode : 1997NewA .... 2 ... 77K
  • "Dwarf spheroidal satellite galaxies without dark matter", NewA 2,139 (1997). bibcode : 1997NewA .... 2..139K
  • "On the variation of the initial mass function," Roy Monthly Notices. Astron. Soc., Vol. 322, 2001, p. 231
  • "The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems", Science 295, 82 (2002). bibcode : 2002Sci ... 295 ... 82K
  • "Thickening of galactic discs through clustered star formation", MNRAS 330, 707 (2002). bibcode : 2002MNRAS.330..707K
  • with C. Weidner: "Evidence for a fundamental stellar upper mass limit from clustered star formation", MNRAS 348, 187 (2004). bibcode : 2004MNRAS.348..187W
  • with C. Weidner: “The Variation of Integrated Star Initial Mass Functions among Galaxies”, ApJ 625, 754 (2005). bibcode : 2005ApJ ... 625..754W
  • I. Thies, P. Kroupa, C. Theis, "Induced planet formation in stellar clusters: a parameter study of star-disc encounters", MNRAS 364, 961 (2005). bibcode : 2005MNRAS.364..961T
  • with J. Köppen, C. Weidner: "A possible origin of the mass-metallicity relation of galaxies", MNRAS 375, 673 (2007). bibcode : 2007MNRAS.375..673K
  • with J. Pflamm-Altenburg: “Clustered star formation as a natural explanation for the Hα cut-off in disk galaxies”, Nature 455, 641 (2008). bibcode : 2008Natur.455..641P
  • with J. Pflamm-Altenburg,: "The Fundamental Gas Depletion and Stellar-Mass Buildup Times of Star-Forming Galaxies", ApJ 706, 516 (2009). bibcode : 2009ApJ ... 706..516P
  • with S. Recchi, F. Calura: "The chemical evolution of galaxies within the IGIMF theory: the [α / Fe] ratios and downsizing", A&A 499, 711 (2009). bibcode : 2009A & A ... 499..711R
  • with I. Thies, SP Goodwin u. a .: "Tidally Induced Brown Dwarf and Planet Formation in Circumstellar Disks", ApJ 717, 577 (2010). bibcode : 2010ApJ ... 717..577T
  • with B. Famaey, KS de Boer, J. Dabringhausen, M. Pawlowski, CM Boily, H. Jerjen, D. Forbes, G. Hensler, M. Metz: “Local-Group tests of dark-matter concordance cosmology. Towards a new paradigm for structure formation ", A&A 523, 32 (2010). bibcode : 2010A & A ... 523A..32K
  • "The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology", PASA 29, 395 (2012). bibcode : 2012PASA ... 29..395K
  • with M. Pawlowski, M. Milgrom: "The Failures of the Standard Model of Cosmology Require a New Paradigm", IJMPD 21, 1230003 (2012). bibcode : 2012IJMPD..2130003K
  • "Lessons from the Local Group (and beyond) on dark matter", arXiv1409.6302 (2014). bibcode : 2014arXiv1409.6302K
  • "Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation", CaJPh 93, 169 (2015). bibcode : 2015CaJPh..93..169K

Web links

Individual evidence

  1. ↑ Kroupa: Lessons from the Local Group (and beyond) on dark matter , arxiv : 1409.6302 , in Freeman u. a .: Lessons from the local group
  2. ^ Kroupa: Lessons from the Local Group (and beyond) on dark matter , Publications Astron. Soc. Australia 2012, arxiv : 1409.6302
  3. ↑ Kroupa, Dark matter, cosmology and progress, 2010
personal data
SURNAME Kroupa, Pavel
BRIEF DESCRIPTION Australian astrophysicist and professor at the Rheinische Friedrich-Wilhelms-Universität in Bonn
DATE OF BIRTH September 24, 1963
PLACE OF BIRTH Jindřichův Hradec , Czechoslovakia