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Dark stars at the Galactic Centre: the main sequence
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
2009 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 394, no 1, 82-104 p.Article in journal (Refereed) Published
Abstract [en]

In regions of very high dark matter density such as the Galactic Centre, the capture and annihilation of WIMP dark matter by stars has the potential to significantly alter their evolution. We describe the dark stellar evolution code DarkStars, and present a series of detailed grids of WIMP-influenced stellar models for main-sequence stars. We describe the changes in stellar structure and main-sequence evolution which occur as a function of the rate of energy injection by WIMPs, for masses of 0.3–2.0 M⊙ and metallicities Z= 0.0003–0.02 . We show what rates of energy injection can be obtained using realistic orbital parameters for stars at the Galactic Centre, including detailed consideration of the velocity and density profiles of dark matter. Capture and annihilation rates are strongly boosted when stars follow elliptical rather than circular orbits. If there is a spike of dark matter induced by the supermassive black hole at the Galactic Centre, single solar mass stars following orbits with periods as long as 50 yr and eccentricities as low as 0.9 could be significantly affected. Binary systems with similar periods about the Galactic Centre could be affected on even less eccentric orbits. The most striking observational effect of this scenario would be the existence of a binary consisting of a low-mass protostar and a higher mass evolved star. The observation of low-mass stars and/or binaries on such orbits would either provide a detection of WIMP dark matter, or place stringent limits on the combination of the WIMP mass, spin-dependent nuclear-scattering cross-section, halo density and velocity distribution near the Galactic Centre. In some cases, the derived limits on the WIMP mass and spin-dependent nuclear-scattering cross-section would be of comparable sensitivity to current direct-detection experiments.

Place, publisher, year, edition, pages
2009. Vol. 394, no 1, 82-104 p.
Keyword [en]
elementary particles, stars: evolution, stars: fundamental parameters, stars: interiors, Galaxy: centre, dark matter
URN: urn:nbn:se:su:diva-38215DOI: 10.1111/j.1365-2966.2008.14282.xISI: 000263967700007OAI: diva2:308040
Available from: 2010-04-01 Created: 2010-04-01 Last updated: 2010-04-06Bibliographically approved
In thesis
1. Searches for Particle Dark Matter: Dark stars, dark galaxies, dark halos and global supersymmetric fits
Open this publication in new window or tab >>Searches for Particle Dark Matter: Dark stars, dark galaxies, dark halos and global supersymmetric fits
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The identity of dark matter is one of the key outstanding problems in both particle and astrophysics. In this thesis, I describe a number of complementary searches for particle dark matter. I discuss how the impact of dark matter on stars can constrain its interaction with nuclei, focussing on main sequence stars close to the Galactic Centre, and on the first stars as seen through the upcoming James Webb Space Telescope. The mass and annihilation cross-section of dark matter particles can be probed with searches for gamma rays produced in astronomical targets. Dwarf galaxies and ultracompact, primordially-produced dark matter minihalos turn out to be especially promising in this respect. I illustrate how the results of these searches can be combined with constraints from accelerators and cosmology to produce a single global fit to all available data. Global fits in supersymmetry turn out to be quite technically demanding, even with the simplest predictive models and the addition of complementary data from a bevy of astronomical and terrestrial experiments; I show how genetic algorithms can help in overcoming these challenges.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2010. 84 p.
dark matter, supersymmetry, gamma rays, dwarf galaxies, stellar evolution, cosmological perturbations, phase transitions, statistical techniques
National Category
Subatomic Physics Subatomic Physics Astronomy, Astrophysics and Cosmology Subatomic Physics Other Physics Topics Astronomy, Astrophysics and Cosmology Astronomy, Astrophysics and Cosmology
Research subject
Theoretical Physics
urn:nbn:se:su:diva-38221 (URN)978-91-7447-031-4 (ISBN)
Public defence
2010-05-04, FD5, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 15:15 (English)
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Accepted. Paper 6: Submitted. Available from: 2010-04-12 Created: 2010-04-01 Last updated: 2010-04-07Bibliographically approved

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