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Abstract: In this talk, I start with a pedagogical overview of the cosmological principle and its role in constructing inflationary models of the universe. I then discuss slow-roll inflation as a concrete framework, before introducing a Higgs model non-minimally coupled to gravity. I show how a non-Riemannian geometric structure allows the Higgs energy scale to generate a viable inflationary scale consistent with observations.
- 02.06. Montserrat Armas Padilla (Instituto de Astrofisica de Canarias): UltracompCAT and the Hunt for New Ultra-Compact X-ray Binaries
Abstract: The ultra-compact family of low-mass X-ray binaries (LMXBs) consists of systems with orbital periods shorter than 80 minutes. Such short periods imply small Roche lobes, into which only degenerate (hydrogen-poor) donor stars can fit. They are unique laboratories for studying accretion processes in hydrogen-deficient environments, as well as key stages of binary evolution. They are also expected to be primary sources for low-frequency gravitational-wave studies with the upcoming LISA mission.
I will present UltraCompCAT, a catalogue of ultra-compact and short orbital period X-ray binaries compiling the available multi-wavelength information for the currently known population of these objects. This homogeneous framework allows us to study, for the first time, this tantalising family of X-ray binaries as a population. I will review the current state of the field, discuss some of the main global properties of the population, and present ongoing efforts aimed at identifying new ultra-compact X-ray binaries.
- 19.08. Alisha Roberts (University of Wisconsin-Madison): A Multimessenger Analysis of the High-Energy Milky Way: Source Populations Contribute Significantly to IceCube's Galactic Neutrino Flux
Abstract: In this talk, I discuss recent results from a joint analysis of the high-energy neutrino emission observed from the Galactic Plane by IceCube and the diffuse ultra-high-energy gamma-ray emission measured by LHAASO. We compare this data to models that include diffuse emission from cosmic-ray interactions in the interstellar medium, unresolved TeV halos, and unresolved Galactic neutrino sources. We find that the gamma-ray emission can be explained by a combination of diffuse processes and unresolved TeV halos. The observed neutrino emission cannot be generated by cosmic-ray interactions in the interstellar medium alone, but requires contributions from one or more unresolved source populations. Across a wide range of assumptions about Galactic cosmic-ray transport, we find that Galactic neutrino sources contribute significantly to the neutrino flux observed from the Galactic Plane and are likely responsible for most of this emission.