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Open Access Publications from the University of California

Scholarly Works (4 results)

  • Thesis
  • Peer Reviewed
UC Santa Cruz Electronic Theses and Dissertations (2012)

Gamma-ray bursts (GRBs), thought to be produced by the core-collapse of massive stars or merging compact objects, are the most luminous events observed since the Big Bang. GRBs are intrinsically interesting as laboratories to study physical processes at energies much higher than can be produced in the largest particle accelerators on Earth. A better understanding of GRBs may also allow for their use as cosmological tools - backlights for the study of the evolution of the Universe back to the era of the first gravitationally-bound structures. In this work, results from observations of satellite-detected GRBs with the Milagro and VERITAS very high energy (VHE, >100 GeV) gamma-ray telescopes are presented. No significant flux of VHE gamma rays associated with any of the 144 GRBs observed was detected. The limits on VHE gamma-ray emission during the GRB early afterglow phase obtained from the VERITAS observations are among the most constraining to date and the interpretation of these non-detections in the context of GRB emission models is discussed. Results from observation of the "naked-eye burst" GRB 080319B with Milagro are shown to rule out the popular synchrotron self-Compton model of emission over a broad range of energy space. Finally, the prospects for GRB observations with both current and future-generation VHE observatories are examined.

    Cover page: Observations of Gamma-Ray Bursts at Extreme Energies
    • Thesis
    • Peer Reviewed
    UC Santa Cruz Electronic Theses and Dissertations (2025)

    New tools are presented to generate simulated catalogs of microlensing events in theMilky Way from populations of primordial black holes tracing the dark matter halo. These Monte Carlo methods are orders of magnitude faster than the state-of-the-art simulations, and reduce the computational requirements from a large computer cluster to a laptop for full-sky surveys. A new statistic and method is demonstrated for highly efficient detection of microlensing events in multi-color star surveys. The background filtering is sufficiently strong to reject all lightcurves in a subset of NOIRLab Source Catalog data, while maintaining high efficiency on simulated events injected on the same data. These insights are combined to predict the exclusions on PBH dark matter the Legacy Survey of Space and Time will create over the ten-year survey.

      Cover page: Prospects for Finding Primordial Black Holes with the Rubin ObservatoryCreative Commons 'BY-NC' version 4.0 license
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2019)
      Astrophysical and cosmological observations currently provide the only robust, empirical measurements of dark matter. Future observations with Large Synoptic Survey Telescope (LSST) will provide necessary guidance for the experimental dark matter program. This white paper represents a community effort to summarize the science case for studying the fundamental physics of dark matter with LSST. We discuss how LSST will inform our understanding of the fundamental properties of dark matter, such as particle mass, self-interaction strength, non-gravitational couplings to the Standard Model, and compact object abundances. Additionally, we discuss the ways that LSST will complement other experiments to strengthen our understanding of the fundamental characteristics of dark matter. More information on the LSST dark matter effort can be found at https://lsstdarkmatter.github.io/ .
        Cover page: Probing the Fundamental Nature of Dark Matter with the Large Synoptic Survey Telescope
        • Article
        • Peer Reviewed
        UC Irvine Previously Published Works (2019)
        Astrophysical observations currently provide the only robust, empirical measurements of dark matter. In the coming decade, astrophysical observations will guide other experimental efforts, while simultaneously probing unique regions of dark matter parameter space. This white paper summarizes astrophysical observations that can constrain the fundamental physics of dark matter in the era of LSST. We describe how astrophysical observations will inform our understanding of the fundamental properties of dark matter, such as particle mass, self-interaction strength, non-gravitational interactions with the Standard Model, and compact object abundances. Additionally, we highlight theoretical work and experimental/observational facilities that will complement LSST to strengthen our understanding of the fundamental characteristics of dark matter.
          Cover page: Dark Matter Science in the Era of LSSTCreative Commons 'BY' version 4.0 license
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