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X-WR-CALNAME:Observing the Big Bang
X-ORIGINAL-URL:https://cosmology.nl
X-WR-CALDESC:Events for Observing the Big Bang
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DTSTART:20190331T010000
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DTSTART:20191027T010000
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DTSTART;TZID=Europe/Amsterdam:20191004T080000
DTEND;TZID=Europe/Amsterdam:20191004T170000
DTSTAMP:20260616T103241
CREATED:20190925T083024Z
LAST-MODIFIED:20191001T210404Z
UID:418-1570176000-1570208400@cosmology.nl
SUMMARY:Grongingen Fall 2019
DESCRIPTION:Groningen\,  October 4th. The meeting will take place in room A8 of the Academy Building\, downtown Groningen (10min walk from the central station\, 4min by bike). Coffee and tea will be available prior to the first talk (at 11.45) and in between both afternoon sessions (at 15.00). \n \n12:00 – 13:00: Talk by Subodh Patil (Bohr Institute) \nTitle:Tensor bounds on the hidden universe (and a 1PI coda on loops in inflation) \nAbstract: \nIn this talk\, we present the observation that primordial gravitational waves\, if ever observed\, can be used to bound\nthe hidden field content of the universe. This is because a large number of hidden fields can resum to potentially observable logarithmic runnings for the graviton two-point function in the context of single field inflation\, courtesy of a `large N’ resummation.  This allows one to translate ever more precise bounds on the tensor to scalar consistency relation into bounds on the hidden field content of the universe\, with potential implications for phenomenological constructions that address naturalness with a large number of species. Along the way\, we need to address certain subtleties regarding loop corrections on cosmological backgrounds\, especially with regards to the correct implementation of dimensional regularization. We find a pleasing confirmation of our understanding by directly reproducing our results from the 1PI effective action (as one must) and present a simplified prescription to calculate loop corrections to certain correlation functions in inflation.   \n13:00 – 14:00: Lunch Break \n14:00 – 14:30: Talk by Alba Kalaja(Groningen University) \nTitle: From Primordial Black Holes Abundance to Primordial Curvature Power Spectrum (and back).\n \nAbstract: \nIn the model where Primordial Black Holes (PBHs) form from large primordial curvature perturbations\, in principle constraints on PBH abundance provide a powerful probe of the early Universe. In this presentation\, I will discuss updated constraints on the primordial curvature power spectrum obtained from the latest limits on PBH abundance taking into account all the steps from gravitational collapse in real space to PBH formation.\nIn particular\, I will show how to combine results from numerical relativity simulations and peak theory to study the conditions for PBH formation including non-linearity terms\, perturbation profile details and a careful treatment of smoothing scales\, and how to translate such conditions into primordial spectrum constraints for a wide range of shapes and abundances.\nOur results show that the correct and accurate modelling of non-linearities\, filtering and typical perturbation profile\, is crucial for deriving meaningful cosmological implications. \n14:30 – 15:00: Talk by Horng Sheng Chia(Amsterdam Univerisity) \nTitle: Gravitational wave signatures of ultralight bosons in binary systems \nAbstract: \nUltralight boson fields exist in various proposed extensions to the Standard Model\, and can form boson clouds around rapidly-rotating black holes through a process called superradiance. In this talk\, I will describe how various properties of these clouds\, such as their shapes and energy spectra\, depend on the masses and intrinsic spins of the boson fields. I will then discuss that how the dynamics of the clouds are greatly enriched when they are in binary black hole systems. Finally\, I will sketch how the dynamical evolution of the clouds backreact on the orbit\, thereby leaving their imprints in the gravitational waves emitted by the binary system. \n  \n15:00 – 15:30: Coffee Break \n15:30 – 16:30: Talk by Elisa Chisari(Utrecht University) \nTitle: Galaxy shapes as a cosmological tool\n \nAbstract: \nTwo phenomena contribute to correlating galaxy shapes across the Universe: the deviation of photons from a straight path due to the spacetime curvature (“gravitational lensing”)\, and tidal interactions (“intrinsic alignments”). Modelling both accurately is crucial to obtaining unbiased constraints on the cosmological model from forthcoming surveys\, particularly in the context of elucidating the origin of accelerated expansion of the Universe. In this talk\, I will cover recent advances in our understanding of the intrinsic alignments of galaxies. While these alignments are typically regarded as a contaminant to weak gravitational lensing\, I will also discuss how they might become a cosmological probe in their own right in the near future. \n 
URL:https://cosmology.nl/event/grongingen-fall-2019/
LOCATION:Academy Building\, Broerstraat 5\, Groningen\, 9712CP
CATEGORIES:THC meeting
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