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Astrophysical Constraints on Fundamental Parameters in Physics and Astronomy

Davis, Adam N.
http://rave.ohiolink.edu/etdc/view?acc_num=case1098973318

Abstract Details

2004, Doctor of Philosophy, Case Western Reserve University, Physics.
Two astrophysical tools are used to constrain parameters in physics and astronomy. Gravitational lensing is used to constrain the velocity dispersion of elliptical galaxies and Big Bang nucleosynthesis (BBN) is used to constrain variations in the fundamental physical parameters Newton's gravitational constant (G) and the fine structure constant (α). Using gravitational lensing two results are obtained depending on assumption of profile for elliptical galaxies. For a SIS density profile I constrain the velocity dispersion to be 156 km/s ≤ σ * ≤ 220 km/s at the 95% confidence level after marginalizing over other parameters. For a generalized NFW density profile I find that the slope of the profile is 1.5 ≤ β ≤ 2.0 after marginalizing over other parameters. Using BBN I find that at the 95% confidence level, 0.84 ≤ G BBN /G 0 ≤ 1.07. If a monotonic power law time dependence (G ∝ t -a ) is assumed, we find a bound of -0.006 ≤ ((dG/dt)/G) today ≤ 0.002 for the rate of change of G. This analysis of the fine structure constant effect's on BBN includes the possible effects a variation on α will have on the cosmic microwave background (CMB) constraints on the baryon to photon ratio (η). And so two limits were examined, when α CMB ≈ α 0 and when α CMB ≈ α BBN . In the former limit I find a combined abundance bound of α BBN /α 0 = 1.09 +0.04 -0.04 . In the latter limit, I found a combined abundance bound of α BBN /α 0 = 1.13 +0.06 -0.05 . This apparent 2σ detection of a time varying fine structure constant is probably not significant. The result depends on the observed 7 Li data which independent tests suggest may suffer from systematic errors. Nonetheless, this analysis is significant step forward for BBN constraints on α in its improvement of the treatment of the α dependence on nuclear reaction rates over previous analyses and the inclusion of a possible CMB influence on η.
Lawrence Krauss (Advisor)
96 p.
Physics, Astronomy and Astrophysics
cosmology; gravitational lensing; fine structure constant; gravitational constant

Recommended Citations

Citations

  • Davis, A. N. (2004). Astrophysical Constraints on Fundamental Parameters in Physics and Astronomy [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1098973318

    APA Style (7th edition)

  • Davis, Adam. Astrophysical Constraints on Fundamental Parameters in Physics and Astronomy. 2004. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1098973318.

    MLA Style (8th edition)

  • Davis, Adam. "Astrophysical Constraints on Fundamental Parameters in Physics and Astronomy." Doctoral dissertation, Case Western Reserve University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1098973318

    Chicago Manual of Style (17th edition)

case1098973318
786
© 2004, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.