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17 results on '"Hergt, Lukas"'

1. Planck PR4 (NPIPE) map-space cosmic birefringence

Author

Sullivan, Raelyn Marguerite, Abghari, Arefe, Diego-Palazuelos, Patricia, Hergt, Lukas Tobias, and Scott, Douglas

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Cosmic birefringence is an effect where the plane of polarisation of the cosmic microwave background (CMB) is rotated by an angle $\beta$ through coupling to a hypothetical parity-violating field. We analyse the Planck Public Release 4 (PR4 or NPIPE) data using a map-space analysis method and find $\beta=0.46^\circ\pm 0.04^\circ(\mathrm{stat.})\pm0.28^\circ(\mathrm{syst.})$ for SEVEM CMB maps and $\beta=0.48^\circ\pm 0.04^\circ(\mathrm{stat.})\pm 0.28^\circ(\mathrm{syst.})$ for Commander CMB maps. These values are slightly higher than previously published results, which may be explained by the fact that we have not attempted to remove any potential bias from miscalibration of the Planck polarimeters. The uncertainty in this miscalibration dominates the systematic uncertainty, which also means that our results are consistent with no parity violation. An advantage of the map-space analysis is that it is easy to investigate any variations on the sky, for example caused by foreground contamination. Our results for isotropic birefringence are fairly robust against different spatial data cuts, but there may be hints of a foreground systematic (north versus south hemispheres) or uncontrolled miscalibration effect (T peaks versus E peaks) that should be followed up in future studies. We additionally find no evidence of a cosmic birefringence dipole (anisotropic birefringence)., Comment: 26 pages, 17 figures, 2 tables

Published
2025

2. A glitch in gravity: cosmic Lorentz-violation from fiery Big Bang to glacial heat death

Author

Wen, Robin Y., Hergt, Lukas T., Afshordi, Niayesh, and Scott, Douglas

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology, High Energy Physics - Theory
Abstract

One regime where we might see departures from general relativity is at the largest accessible scales, with a natural choice in cosmology being the cosmological horizon (or Hubble) scale. We investigate a single-parameter extension to the standard cosmological model with a different strength of gravity above and below this scale -- a "cosmic glitch" in gravity. Cosmic microwave background observations, and Baryonic Acoustic Oscillations (including the recent DESI Y1) favour weaker superhorizon gravity, at nearly a percent (or 2$\sigma$ level), easing both the Hubble and clustering tensions with other cosmological data. This compounds evidence for an even stronger glitch during Big Bang nucleosynthesis (from helium abundance observations), suggesting that symmetries of general relativity are maximally violated at the Big Bang, but gradually recovered as we approach the present-day cosmological de Sitter scale, associated with the observed dark energy., Comment: To be published in Astrophysics and Space Science Proceedings: "The Relativistic Universe: From Classical to Quantum, Proceedings of the International Symposium on Recent Developments in Relativistic Astrophysics", Gangtok, December 11-13, 2023: to felicitate Prof. Banibrata Mukhopadhyay on his 50th Birth Anniversary", Editors: S Ghosh & A R Rao, Springer Nature; Reviewing & extending 2311.03028

Published
2024

3. Some Times in Standard Cosmology

Author

Hergt, Lukas Tobias and Scott, Douglas

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The standard cosmological model is sufficiently well constrained that precise estimates can be provided for the redshift of various physically defined times in the chronology of the Universe. For example, it is well known that matter-radiation equality, recombination and reionisation happen at redshifts of around 3000, 1000 and 10, respectively, and these can be specified more precisely by fitting to data. What is less well known are the times in years (and their uncertainties) for these and other epochs in the history of the Universe. Here we provide precise time determinations for six epochs in cosmological history within the standard model, using data from the Planck satellite. Our main results are illustrated in a figure., Comment: 11 pages, 2 figures, 2 tables, data available at https://doi.org/10.5281/zenodo.14054334

Published
2024

4. Methods for CMB map analysis

Author

Sullivan, Raelyn Marguerite, Hergt, Lukas Tobias, and Scott, Douglas

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

This introductory guide aims to provide insight to new researchers in the field of cosmic microwave background (CMB) map analysis on best practices for several common procedures. We will discuss common map-modifying procedures such as masking, downgrading resolution, the effect of the beam and the pixel window function, and adding white noise. We will explore how these modifications affect the final power spectrum measured from a map. This guide aims to describe the best way to perform each of these procedures, when the different steps and measures should be carried out, and the effects of incorrectly performing or applying any of them., Comment: 15 pages, 11 figures, extensive changes from version 1

Published
2024

5. Reassessment of the dipole in the distribution of quasars on the sky

Author

Abghari, Arefe, Bunn, Emory F., Hergt, Lukas T., Li, Boris, Scott, Douglas, Sullivan, Raelyn M., and Wei, Dingchen

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We investigate recent claims by Secrest et al. of an anomalously large amplitude of the dipole in the distribution of CatWISE-selected quasars on the sky. Two main issues indicate that the systematic uncertainties in the derived quasar-density dipole are underestimated. Firstly, the spatial distribution of the quasars is not a pure dipole, possessing low-order multipoles of comparable size to the dipole. These multipoles are unexpected and presumably caused by unknown systematic effects; we cannot be confident that the dipole amplitude is not also affected by the same systematics until the origin of these fluctuations is understood. Secondly, the 50 percent sky cut associated with the quasar catalogue strongly couples the multipoles, meaning that the power estimate at ell=1 contains significant contributions from ell>1. In particular, the dominant quadrupole mode in the Galactic mask strongly couples the dipole with the octupole, leading to a large uncertainty in the dipole amplitude. Together these issues mean that the dipole in the quasar catalogue has an uncertainty large enough that consistency with the cosmic microwave background (CMB) dipole cannot be ruled out. More generally, current data sets are insufficiently clean to robustly measure the quasar dipole and future studies will require samples that are larger (preferably covering more of the sky) and free of systematic effects to make strong claims regarding their consistency with the CMB dipole., Comment: 19 pages, 9 figures

Published
2024
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6. A cosmic glitch in gravity

Author

Wen, Robin Y., Hergt, Lukas T., Afshordi, Niayesh, and Scott, Douglas

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology
Abstract

We investigate a model that modifies general relativity on cosmological scales, specifically by having a `glitch' in the gravitational constant between the cosmological (super-horizon) and Newtonian (sub-horizon) regimes, as motivated e.g. in the Ho\v{r}ava-Lifshitz proposal or in the Einstein-aether framework. This gives a single-parameter extension to the standard $\Lambda$CDM model, which is equivalent to adding a dark energy component, but where the energy density of this component can have either sign. Fitting to data from the Planck satellite, we find that negative contributions are, in fact, preferred. Additionally, we find that roughly one percent weaker superhorizon gravity can somewhat ease the Hubble and clustering tensions in a range of cosmological observations, although at the expense of spoiling fits to the baryonic acoustic oscillation scale in galaxy surveys. Therefore, the extra parametric freedom offered by our model deserves further exploration, and we discuss how future observations may elucidate this potential cosmic glitch in gravity, through a four-fold reduction in statistical uncertainties., Comment: 20 pages, 10 figures, 4 tables. Revised to match version accepted by JCAP

Published
2023
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7. Finite inflation in curved space

Author

Hergt, Lukas T., Agocs, Fruzsina J., Handley, Will J., Hobson, Michael P., and Lasenby, Anthony N.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology
Abstract

We investigate the effects of non-zero spatial curvature on cosmic inflation in the light of cosmic microwave background (CMB) anisotropy measurements from the Planck 2018 legacy release and from the 2015 observing season of BICEP2 and the Keck Array. Even a small percentage of non-zero curvature today would significantly limit the total number of e-folds of the scale factor during inflation, rendering just-enough inflation scenarios with a kinetically dominated or fast-roll stage prior to slow-roll inflation more likely. Finite inflation leads to oscillations and a cutoff towards large scales in the primordial power spectrum and curvature pushes them into the CMB observable window. Using nested sampling, we carry out Bayesian parameter estimations and model comparisons taking into account constraints from reheating and horizon considerations. We confirm the preference of CMB data for closed universes with Bayesian odds of over $100:1$ and with a posterior on the curvature density parameter of $\Omega_{K,0}=-0.051\pm0.017$ for a curvature extension of LCDM and $\Omega_{K,0}=-0.031\pm0.014$ for Starobinsky inflation. Model comparisons of various inflation models give similar results as for flat universes with the Starobinsky model outperforming most other models., Comment: 46 pages, 32 figures, 3 tables, submitted to PRD, from chapter 5 of L. T. Hergt's doctoral thesis at https://www.repository.cam.ac.uk/handle/1810/323129, data available at https://zenodo.org/record/6547872

Published
2022
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8. Constraints on cosmic birefringence using $E$-mode polarisation

Author

Abghari, Arefe, Sullivan, Raelyn M., Hergt, Lukas T., and Scott, Douglas

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

A birefringent universe could show itself through a rotation of the plane of polarisation of the cosmic microwave background photons. This is usually investigated using polarisation $B$ modes, which is degenerate with miscalibration of the orientation of the polarimeters. Here we point out an independent method for extracting the birefringence angle using only temperature and $E$-mode signals. We forecast that, with an ideal cosmic-variance-limited experiment, we could constrain a birefringence angle of $0.3^\circ$ with $3\,\sigma$ statistical significance, which is close to the current constraints using $B$ modes. We explore how this method is affected by the systematic errors introduced by the polarisation efficiency. In the future, this could provide an additional way of checking any claimed $B$-mode derived birefringence signature., Comment: 11 pages

Published
2022
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9. Bayesian evidence for the tensor-to-scalar ratio $r$ and neutrino masses $m_\nu$: Effects of uniform vs logarithmic priors

Author

Hergt, Lukas T., Handley, Will J., Hobson, Michael P., and Lasenby, Anthony N.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We review the effect that the choice of a uniform or logarithmic prior has on the Bayesian evidence and hence on Bayesian model comparisons when data provide only a one-sided bound on a parameter. We investigate two particular examples: the tensor-to-scalar ratio $r$ of primordial perturbations and the mass of individual neutrinos $m_\nu$, using the cosmic microwave background temperature and polarisation data from Planck 2018 and the NuFIT 5.0 data from neutrino oscillation experiments. We argue that the Kullback-Leibler divergence, also called the relative entropy, mathematically quantifies the Occam penalty. We further show how the Bayesian evidence stays invariant upon changing the lower prior bound of an upper constrained parameter. While a uniform prior on the tensor-to-scalar ratio disfavours the $r$-extension compared to the base LCDM model with odds of about 1:20, switching to a logarithmic prior renders both models essentially equally likely. LCDM with a single massive neutrino is favoured over an extension with variable neutrino masses with odds of 20:1 in case of a uniform prior on the lightest neutrino mass, which decreases to roughly 2:1 for a logarithmic prior. For both prior options we get only a very slight preference for the normal over the inverted neutrino hierarchy with Bayesian odds of about 3:2 at most., Comment: 16 pages, 9 figures, 3 tables. Submitted to PRD. Data available at https://doi.org/10.5281/zenodo.4556360

Published
2021
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10. Constraining the kinetically dominated Universe : Bayesian methods and primordial cosmology

Author

Hergt, Lukas, Lasenby, Anthony, Hobson, Mike, and Handley, Will

Subjects
Cosmology, Bayesian Inference, Cosmic Inflation, Spatial curvature of the Universe
Abstract

In this thesis a systematic approach is taken to the study of the generation of primordial perturbations from a nite amount of cosmic in ation. It is demonstrated how a pre-in ationary stage that is kinetically dominated causes features in the primordial power spectrum. These features can be associated with cosmological parameters, which are then constrained using Bayesian methods and CMB data from the Planck satellite. Chapter 1 places this thesis into the context of the current state of cosmology and introduces the needed theoretical background and notation. The remainder of the thesis presents both my published and ongoing work. Chapter 2 starts with an overview of Bayesian methods which are then applied to the question of how a uniform versus logarithmic prior distribution a ect parameter estimations and model comparisons. Two examples of extensions to the current standard model of cosmology are investigated in detail, the tensor-to-scalar ratio of primordial perturbations and three massive neutrinos. Chapter 3 was published in Hergt et al. (2019) [I & chapter 3] and makes a case for a pre-in ationary phase of kinetic dominance. To that end the phase-space trajectories for three representative in ationary potentials are inspected. Comparing di erent priors on the initial conditions of the trajectories, a signi cant fraction of trajectories are found to start out in a kinetically dominated stage. Chapter 4 was published in Hergt et al. (2019) [II & chapter 4]. Assuming a spatially at cosmology, it contrasts the e ects from slow-roll in ation to those from a nite amount of in ation with an earlier kinetically dominated stage. CMB data from the Planck satellite are used to compare these two models and constrain the parameters pertaining to the primordial Universe. There is no clear preference for either model. Any Occam penalty from the higher complexity of a model with a kinetically dominated stage is balanced out by a better t to the large-scale lack of power in the CMB. Chapter 5 extends the previous analysis, allowing for a variable amount of spatial curvature. Even a small amount of present-day curvature signi cantly limits the total amount of in ation, rendering the e ects of kinetic dominance more prominent in the observable window of the CMB. A model comparison of various single- eld in ation models leads to similar results to those of a at cosmology, driven mostly by constraints from the tensor-to-scalar ratio and from reheating. I conclude with potential directions of future research.

Published
2020
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11. Searching for Cosmic Strings in CMB Anisotropy Maps using Wavelets and Curvelets

Author

Hergt, Lukas, Amara, Adam, Brandenberger, Robert, Kacprzak, Tomasz, and Refregier, Alexandre

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology, High Energy Physics - Theory
Abstract

We use wavelet and curvelet transforms to extract signals of cosmic strings from cosmic microwave background (CMB) temperature anisotropy maps, and to study the limits on the cosmic string tension which various ongoing CMB temperature anisotropy experiments will be able to achieve. We construct sky maps with size and angular resolution corresponding to various experiments. These maps contain the signals of a scaling solution of long string segments with a given string tension $G \mu$, the contribution of the dominant Gaussian primordial cosmological fluctuations, and pixel by pixel white noise with an amplitude corresponding to the instrumental noise of the various experiments. In the case that we include white noise, we find that the curvelets are more powerful than wavelets. For maps with Planck specification, we obtain bounds on the string tension comparable to what was obtained by the Planck collaboration. Experiments with better angular resolution such as the South Pole Telescope third generation (SPT-3G) survey will be able to yield stronger limits. For maps with a specification of SPT-3G we find that string signals will be visible down to a string tension of $G \mu = 1.4 \times 10^{-7}$., Comment: 13 pages, 7 figures, 3 tables

Published
2016
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12. The LiteBIRD mission to explore cosmic inflation

Author

Coyle, Laura E., Ghigna, T, Adler, A, Aizawa, K, Akamatsu, H, Akizawa, R, Allys, E, Anand, A, Aumont, J, Austermann, J, Azzoni, S, Baccigalupi, C, Ballardini, M, Banday, A, Barreiro, R, Bartolo, N, Basak, S, Basyrov, A, Beckman, S, Bersanelli, M, Bortolami, M, Bouchet, F, Brinckmann, T, Campeti, P, Carinos, E, Carones, A, Casas, F, Cheung, K, Chinone, Y, Clermont, L, Columbro, F, Coppolecchia, A, Curtis, D, de Bernardis, P, de Haan, T, de la Hoz, E, De Petris, M, Della Torre, S, Delle Monache, G, Di Giorgi, E, Dickinson, C, Diego-Palazuelos, P, Díaz García, J, Dobbs, M, Dotani, T, Eriksen, H, Errard, J, Essinger-Hileman, T, Farias, N, Ferreira, E, Franceschet, C, Fuskeland, U, Galloni, G, Galloway, M, Ganga, K, Gerbino, M, Gervasi, M, Génova-Santos, R, Giardiello, S, Gimeno-Amo, C, Gjerløw, E, González González, R, Grandsire, L, Gruppuso, A, Halverson, N, Hargrave, P, Harper, S, Hazumi, M, Henrot-Versillé, S, Hergt, L, Herranz, D, Hivon, E, Hlozek, R, Hoang, T, Hubmayr, J, Ichiki, K, Ikuma, K, Ishino, H, Jaehnig, G, Jost, B, Kohri, K, Konishi, K, Lamagna, L, Lattanzi, M, Leloup, C, Levrier, F, Lanoppan, A, Luzzi, G, Macias-Perez, J, Maffei, B, Marchitelli, E, Martínez-González, E, Masi, S, Matarrese, S, Matsumura, T, Micheli, S, Migliaccio, M, Monelli, M, Montier, L, Morgante, G, Mousset, L, Nagano, Y, Nagata, R, Natoli, P, Novelli, A, Noviello, F, Obata, I, Occhiuzzi, A, Odagiri, K, Omae, R, Pagano, L, Paiella, A, Paoletti, D, Pascual-Cisneros, G, Patanchon, G, Pavlidou, V, Piacentini, F, Piat, M, Piccirilli, G, Pinchera, M, Pisano, G, Porcelli, L, Raffuzzi, N, Raum, C, Remazeilles, M, Ritacco, A, Rubino-Martin, J, Ruiz-Granda, M, Sakurai, Y, Savini, G, Scott, D, Sekimoto, Y, Shiraishi, M, Signorelli, G, Stever, S, Sullivan, R, Suzuki, A, Takaku, R, Takakura, H, Takakura, S, Takase, Y, Tartari, A, Tassis, K, Thompson, K, Tomasi, M, Tristram, M, Tucker, C, Vacher, L, van Tent, B, Vielva, P, Watanuki, K, Wehus, I, Westbrook, B, Weymann-Despres, G, Winter, B, Wollack, E, Zacchei, A, Zannoni, M, Zhou, Y, Ghigna, Tommaso, Adler, Alexander, Aizawa, Kosuke, Akamatsu, Hiroki, Akizawa, Ryosuke, Allys, Erwan, Anand, Avinash, Aumont, Jonathan, Austermann, Jason, Azzoni, Susanna, Baccigalupi, Carlo, Ballardini, Mario, Banday, Anthony, Barreiro, Rita, Bartolo, Nicola, Basak, Soumen, Basyrov, Artem, Beckman, Shawn, Bersanelli, Marco, Bortolami, Marco, Bouchet, François, Brinckmann, Thejs, Campeti, Paolo, Carinos, Emile, Carones, Alessandro, Casas, Francisco J., Cheung, Kolen, Chinone, Yuji, Clermont, Lionel, Columbro, Fabio, Coppolecchia, Alessandro, Curtis, David, de Bernardis, Paolo, de Haan, Tijmen, de la Hoz, Elena, De Petris, Marco, Della Torre, Stefano, Delle Monache, Giovanni, Di Giorgi, Eugenia, Dickinson, Clive, Diego-Palazuelos, Patricia, Díaz García, Jose, Dobbs, Matt, Dotani, Tadayasu, Eriksen, Hans Kristian, Errard, Josquin, Essinger-Hileman, Thomas, Farias, Nicole, Ferreira, Elisa, Franceschet, Cristian, Fuskeland, Unni, Galloni, Giacomo, Galloway, Mathew, Ganga, Ken, Gerbino, Martina, Gervasi, Massimo, Génova-Santos, Ricardo, Giardiello, Serena, Gimeno-Amo, Christian, Gjerløw, Eirik, González González, Raul, Grandsire, Laurent, Gruppuso, Alessandro, Halverson, Nils, Hargrave, Peter, Harper, Stuart, Hazumi, Masashi, Henrot-Versillé, Sophie, Hergt, Lukas, Herranz, Diego, Hivon, Eric, Hlozek, Renee, Hoang, Thuong, Hubmayr, Johannes, Ichiki, Kiyotomo, Ikuma, Kiyoshi, Ishino, Hirokazu, Jaehnig, Gregory, Jost, Baptiste, Kohri, Kazunori, Konishi, Kuniaki, Lamagna, Luca, Lattanzi, Massimiliano, Leloup, Clement, Levrier, François, Lanoppan, Anto, Luzzi, Gemma, Macias-Perez, Juan, Maffei, Bruno, Marchitelli, Elisabetta, Martínez-González, Enrique, Masi, Silvia, Matarrese, Sabino, Matsumura, Tomotake, Micheli, Silvia, Migliaccio, Marina, Monelli, Marta, Montier, Ludovic, Morgante, Gianluca, Mousset, Louise, Nagano, Yuya, Nagata, Ryo, Natoli, Paolo, Novelli, Alessandro, Noviello, Fabio, Obata, Ippei, Occhiuzzi, Andrea, Odagiri, Kimihide, Omae, Ryuji, Pagano, Luca, Paiella, Alessandro, Paoletti, Daniela, Pascual-Cisneros, Guillermo, Patanchon, Guillaume, Pavlidou, Vasiliki, Piacentini, Francesco, Piat, Michel, Piccirilli, Giulia, Pinchera, Michele, Pisano, Giampaolo, Porcelli, Luca, Raffuzzi, Nicolò Elia, Raum, Christopher, Remazeilles, Mathieu, Ritacco, Alessia, Rubino-Martin, Jose Alberto, Ruiz-Granda, Miguel, Sakurai, Yuki, Savini, Giorgio, Scott, Douglas, Sekimoto, Yutaro, Shiraishi, Maresuke, Signorelli, Giovanni, Stever, Samantha L., Sullivan, Raelyn, Suzuki, Aritoki, Takaku, Ryota, Takakura, Hayato, Takakura, Satoru, Takase, Yusuke, Tartari, Andrea, Tassis, Konstantinos, Thompson, Keith L., Tomasi, Maurizio, Tristram, Matthieu, Tucker, Carole, Vacher, Léo, van Tent, Bartjan, Vielva, Patricio, Watanuki, Kazuya, Wehus, Ingunn Kathrine, Westbrook, Benjamin, Weymann-Despres, Gilles, Winter, Berend, Wollack, Edward J., Zacchei, Andrea, Zannoni, Mario, Zhou, Yu, Coyle, Laura E., Ghigna, T, Adler, A, Aizawa, K, Akamatsu, H, Akizawa, R, Allys, E, Anand, A, Aumont, J, Austermann, J, Azzoni, S, Baccigalupi, C, Ballardini, M, Banday, A, Barreiro, R, Bartolo, N, Basak, S, Basyrov, A, Beckman, S, Bersanelli, M, Bortolami, M, Bouchet, F, Brinckmann, T, Campeti, P, Carinos, E, Carones, A, Casas, F, Cheung, K, Chinone, Y, Clermont, L, Columbro, F, Coppolecchia, A, Curtis, D, de Bernardis, P, de Haan, T, de la Hoz, E, De Petris, M, Della Torre, S, Delle Monache, G, Di Giorgi, E, Dickinson, C, Diego-Palazuelos, P, Díaz García, J, Dobbs, M, Dotani, T, Eriksen, H, Errard, J, Essinger-Hileman, T, Farias, N, Ferreira, E, Franceschet, C, Fuskeland, U, Galloni, G, Galloway, M, Ganga, K, Gerbino, M, Gervasi, M, Génova-Santos, R, Giardiello, S, Gimeno-Amo, C, Gjerløw, E, González González, R, Grandsire, L, Gruppuso, A, Halverson, N, Hargrave, P, Harper, S, Hazumi, M, Henrot-Versillé, S, Hergt, L, Herranz, D, Hivon, E, Hlozek, R, Hoang, T, Hubmayr, J, Ichiki, K, Ikuma, K, Ishino, H, Jaehnig, G, Jost, B, Kohri, K, Konishi, K, Lamagna, L, Lattanzi, M, Leloup, C, Levrier, F, Lanoppan, A, Luzzi, G, Macias-Perez, J, Maffei, B, Marchitelli, E, Martínez-González, E, Masi, S, Matarrese, S, Matsumura, T, Micheli, S, Migliaccio, M, Monelli, M, Montier, L, Morgante, G, Mousset, L, Nagano, Y, Nagata, R, Natoli, P, Novelli, A, Noviello, F, Obata, I, Occhiuzzi, A, Odagiri, K, Omae, R, Pagano, L, Paiella, A, Paoletti, D, Pascual-Cisneros, G, Patanchon, G, Pavlidou, V, Piacentini, F, Piat, M, Piccirilli, G, Pinchera, M, Pisano, G, Porcelli, L, Raffuzzi, N, Raum, C, Remazeilles, M, Ritacco, A, Rubino-Martin, J, Ruiz-Granda, M, Sakurai, Y, Savini, G, Scott, D, Sekimoto, Y, Shiraishi, M, Signorelli, G, Stever, S, Sullivan, R, Suzuki, A, Takaku, R, Takakura, H, Takakura, S, Takase, Y, Tartari, A, Tassis, K, Thompson, K, Tomasi, M, Tristram, M, Tucker, C, Vacher, L, van Tent, B, Vielva, P, Watanuki, K, Wehus, I, Westbrook, B, Weymann-Despres, G, Winter, B, Wollack, E, Zacchei, A, Zannoni, M, Zhou, Y, Ghigna, Tommaso, Adler, Alexander, Aizawa, Kosuke, Akamatsu, Hiroki, Akizawa, Ryosuke, Allys, Erwan, Anand, Avinash, Aumont, Jonathan, Austermann, Jason, Azzoni, Susanna, Baccigalupi, Carlo, Ballardini, Mario, Banday, Anthony, Barreiro, Rita, Bartolo, Nicola, Basak, Soumen, Basyrov, Artem, Beckman, Shawn, Bersanelli, Marco, Bortolami, Marco, Bouchet, François, Brinckmann, Thejs, Campeti, Paolo, Carinos, Emile, Carones, Alessandro, Casas, Francisco J., Cheung, Kolen, Chinone, Yuji, Clermont, Lionel, Columbro, Fabio, Coppolecchia, Alessandro, Curtis, David, de Bernardis, Paolo, de Haan, Tijmen, de la Hoz, Elena, De Petris, Marco, Della Torre, Stefano, Delle Monache, Giovanni, Di Giorgi, Eugenia, Dickinson, Clive, Diego-Palazuelos, Patricia, Díaz García, Jose, Dobbs, Matt, Dotani, Tadayasu, Eriksen, Hans Kristian, Errard, Josquin, Essinger-Hileman, Thomas, Farias, Nicole, Ferreira, Elisa, Franceschet, Cristian, Fuskeland, Unni, Galloni, Giacomo, Galloway, Mathew, Ganga, Ken, Gerbino, Martina, Gervasi, Massimo, Génova-Santos, Ricardo, Giardiello, Serena, Gimeno-Amo, Christian, Gjerløw, Eirik, González González, Raul, Grandsire, Laurent, Gruppuso, Alessandro, Halverson, Nils, Hargrave, Peter, Harper, Stuart, Hazumi, Masashi, Henrot-Versillé, Sophie, Hergt, Lukas, Herranz, Diego, Hivon, Eric, Hlozek, Renee, Hoang, Thuong, Hubmayr, Johannes, Ichiki, Kiyotomo, Ikuma, Kiyoshi, Ishino, Hirokazu, Jaehnig, Gregory, Jost, Baptiste, Kohri, Kazunori, Konishi, Kuniaki, Lamagna, Luca, Lattanzi, Massimiliano, Leloup, Clement, Levrier, François, Lanoppan, Anto, Luzzi, Gemma, Macias-Perez, Juan, Maffei, Bruno, Marchitelli, Elisabetta, Martínez-González, Enrique, Masi, Silvia, Matarrese, Sabino, Matsumura, Tomotake, Micheli, Silvia, Migliaccio, Marina, Monelli, Marta, Montier, Ludovic, Morgante, Gianluca, Mousset, Louise, Nagano, Yuya, Nagata, Ryo, Natoli, Paolo, Novelli, Alessandro, Noviello, Fabio, Obata, Ippei, Occhiuzzi, Andrea, Odagiri, Kimihide, Omae, Ryuji, Pagano, Luca, Paiella, Alessandro, Paoletti, Daniela, Pascual-Cisneros, Guillermo, Patanchon, Guillaume, Pavlidou, Vasiliki, Piacentini, Francesco, Piat, Michel, Piccirilli, Giulia, Pinchera, Michele, Pisano, Giampaolo, Porcelli, Luca, Raffuzzi, Nicolò Elia, Raum, Christopher, Remazeilles, Mathieu, Ritacco, Alessia, Rubino-Martin, Jose Alberto, Ruiz-Granda, Miguel, Sakurai, Yuki, Savini, Giorgio, Scott, Douglas, Sekimoto, Yutaro, Shiraishi, Maresuke, Signorelli, Giovanni, Stever, Samantha L., Sullivan, Raelyn, Suzuki, Aritoki, Takaku, Ryota, Takakura, Hayato, Takakura, Satoru, Takase, Yusuke, Tartari, Andrea, Tassis, Konstantinos, Thompson, Keith L., Tomasi, Maurizio, Tristram, Matthieu, Tucker, Carole, Vacher, Léo, van Tent, Bartjan, Vielva, Patricio, Watanuki, Kazuya, Wehus, Ingunn Kathrine, Westbrook, Benjamin, Weymann-Despres, Gilles, Winter, Berend, Wollack, Edward J., Zacchei, Andrea, Zannoni, Mario, and Zhou, Yu

Published
2024

15. Constraining the kinetically dominated Universe: Bayesian methods and primordial cosmology

Author

Hergt, Lukas

Subjects
Cosmic Inflation, Bayesian Inference, Astrophysics::Cosmology and Extragalactic Astrophysics, Spatial curvature of the Universe, Cosmology
Abstract

In this thesis a systematic approach is taken to the study of the generation of primordial perturbations from a nite amount of cosmic in ation. It is demonstrated how a pre-in ationary stage that is kinetically dominated causes features in the primordial power spectrum. These features can be associated with cosmological parameters, which are then constrained using Bayesian methods and CMB data from the Planck satellite. Chapter 1 places this thesis into the context of the current state of cosmology and introduces the needed theoretical background and notation. The remainder of the thesis presents both my published and ongoing work. Chapter 2 starts with an overview of Bayesian methods which are then applied to the question of how a uniform versus logarithmic prior distribution a ect parameter estimations and model comparisons. Two examples of extensions to the current standard model of cosmology are investigated in detail, the tensor-to-scalar ratio of primordial perturbations and three massive neutrinos. Chapter 3 was published in Hergt et al. (2019) [I & chapter 3] and makes a case for a pre-in ationary phase of kinetic dominance. To that end the phase-space trajectories for three representative in ationary potentials are inspected. Comparing di erent priors on the initial conditions of the trajectories, a signi cant fraction of trajectories are found to start out in a kinetically dominated stage. Chapter 4 was published in Hergt et al. (2019) [II & chapter 4]. Assuming a spatially at cosmology, it contrasts the e ects from slow-roll in ation to those from a nite amount of in ation with an earlier kinetically dominated stage. CMB data from the Planck satellite are used to compare these two models and constrain the parameters pertaining to the primordial Universe. There is no clear preference for either model. Any Occam penalty from the higher complexity of a model with a kinetically dominated stage is balanced out by a better t to the large-scale lack of power in the CMB. Chapter 5 extends the previous analysis, allowing for a variable amount of spatial curvature. Even a small amount of present-day curvature signi cantly limits the total amount of in ation, rendering the e ects of kinetic dominance more prominent in the observable window of the CMB. A model comparison of various single- eld in ation models leads to similar results to those of a at cosmology, driven mostly by constraints from the tensor-to-scalar ratio and from reheating. I conclude with potential directions of future research., Isaac Newton Studentship (maintenance), STFC studentship (fees), Cavendish Laboratory

Published
2021
Full Text
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17. The LiteBIRD mission to explore cosmic inflation

Author

Coyle, Laura E., Matsuura, Shuji, Perrin, Marshall D., Ghigna, Tommaso, Adler, Alexander, Aizawa, Kosuke, Akamatsu, Hiroki, Akizawa, Ryosuke, Allys, Erwan, Anand, Avinash, Aumont, Jonathan, Austermann, Jason, Azzoni, Susanna, Baccigalupi, Carlo, Ballardini, Mario, Banday, Anthony, Barreiro, Rita, Bartolo, Nicola, Basak, Soumen, Basyrov, Artem, Beckman, Shawn, Bersanelli, Marco, Bortolami, Marco, Bouchet, François, Brinckmann, Thejs, Campeti, Paolo, Carinos, Emile, Carones, Alessandro, Casas, Francisco J., Cheung, Kolen, Chinone, Yuji, Clermont, Lionel, Columbro, Fabio, Coppolecchia, Alessandro, Curtis, David, de Bernardis, Paolo, de Haan, Tijmen, de la Hoz, Elena, De Petris, Marco, Della Torre, Stefano, Delle Monache, Giovanni, Di Giorgi, Eugenia, Dickinson, Clive, Diego-Palazuelos, Patricia, Díaz García, Jose, Dobbs, Matt, Dotani, Tadayasu, Eriksen, Hans Kristian, Errard, Josquin, Essinger-Hileman, Thomas, Farias, Nicole, Ferreira, Elisa, Franceschet, Cristian, Fuskeland, Unni, Galloni, Giacomo, Galloway, Mathew, Ganga, Ken, Gerbino, Martina, Gervasi, Massimo, Génova-Santos, Ricardo, Giardiello, Serena, Gimeno-Amo, Christian, Gjerløw, Eirik, González González, Raul, Grandsire, Laurent, Gruppuso, Alessandro, Halverson, Nils, Hargrave, Peter, Harper, Stuart, Hazumi, Masashi, Henrot-Versillé, Sophie, Hergt, Lukas, Herranz, Diego, Hivon, Eric, Hlozek, Renee, Hoang, Thuong, Hubmayr, Johannes, Ichiki, Kiyotomo, Ikuma, Kiyoshi, Ishino, Hirokazu, Jaehnig, Gregory, Jost, Baptiste, Kohri, Kazunori, Konishi, Kuniaki, Lamagna, Luca, Lattanzi, Massimiliano, Leloup, Clement, Levrier, François, Lanoppan, Anto, Luzzi, Gemma, Macias-Perez, Juan, Maffei, Bruno, Marchitelli, Elisabetta, Martínez-González, Enrique, Masi, Silvia, Matarrese, Sabino, Matsumura, Tomotake, Micheli, Silvia, Migliaccio, Marina, Monelli, Marta, Montier, Ludovic, Morgante, Gianluca, Mousset, Louise, Nagano, Yuya, Nagata, Ryo, Natoli, Paolo, Novelli, Alessandro, Noviello, Fabio, Obata, Ippei, Occhiuzzi, Andrea, Odagiri, Kimihide, Omae, Ryuji, Pagano, Luca, Paiella, Alessandro, Paoletti, Daniela, Pascual-Cisneros, Guillermo, Patanchon, Guillaume, Pavlidou, Vasiliki, Piacentini, Francesco, Piat, Michel, Piccirilli, Giulia, Pinchera, Michele, Pisano, Giampaolo, Porcelli, Luca, Raffuzzi, Nicolò Elia, Raum, Christopher, Remazeilles, Mathieu, Ritacco, Alessia, Rubino-Martin, Jose Alberto, Ruiz-Granda, Miguel, Sakurai, Yuki, Savini, Giorgio, Scott, Douglas, Sekimoto, Yutaro, Shiraishi, Maresuke, Signorelli, Giovanni, Stever, Samantha L., Sullivan, Raelyn, Suzuki, Aritoki, Takaku, Ryota, Takakura, Hayato, Takakura, Satoru, Takase, Yusuke, Tartari, Andrea, Tassis, Konstantinos, Thompson, Keith L., Tomasi, Maurizio, Tristram, Matthieu, Tucker, Carole, Vacher, Léo, van Tent, Bartjan, Vielva, Patricio, Watanuki, Kazuya, Wehus, Ingunn Kathrine, Westbrook, Benjamin, Weymann-Despres, Gilles, Winter, Berend, Wollack, Edward J., Zacchei, Andrea, Zannoni, Mario, Zhou, Yu, Coyle, Laura E., Matsuura, Shuji, Perrin, Marshall D., Ghigna, Tommaso, Adler, Alexander, Aizawa, Kosuke, Akamatsu, Hiroki, Akizawa, Ryosuke, Allys, Erwan, Anand, Avinash, Aumont, Jonathan, Austermann, Jason, Azzoni, Susanna, Baccigalupi, Carlo, Ballardini, Mario, Banday, Anthony, Barreiro, Rita, Bartolo, Nicola, Basak, Soumen, Basyrov, Artem, Beckman, Shawn, Bersanelli, Marco, Bortolami, Marco, Bouchet, François, Brinckmann, Thejs, Campeti, Paolo, Carinos, Emile, Carones, Alessandro, Casas, Francisco J., Cheung, Kolen, Chinone, Yuji, Clermont, Lionel, Columbro, Fabio, Coppolecchia, Alessandro, Curtis, David, de Bernardis, Paolo, de Haan, Tijmen, de la Hoz, Elena, De Petris, Marco, Della Torre, Stefano, Delle Monache, Giovanni, Di Giorgi, Eugenia, Dickinson, Clive, Diego-Palazuelos, Patricia, Díaz García, Jose, Dobbs, Matt, Dotani, Tadayasu, Eriksen, Hans Kristian, Errard, Josquin, Essinger-Hileman, Thomas, Farias, Nicole, Ferreira, Elisa, Franceschet, Cristian, Fuskeland, Unni, Galloni, Giacomo, Galloway, Mathew, Ganga, Ken, Gerbino, Martina, Gervasi, Massimo, Génova-Santos, Ricardo, Giardiello, Serena, Gimeno-Amo, Christian, Gjerløw, Eirik, González González, Raul, Grandsire, Laurent, Gruppuso, Alessandro, Halverson, Nils, Hargrave, Peter, Harper, Stuart, Hazumi, Masashi, Henrot-Versillé, Sophie, Hergt, Lukas, Herranz, Diego, Hivon, Eric, Hlozek, Renee, Hoang, Thuong, Hubmayr, Johannes, Ichiki, Kiyotomo, Ikuma, Kiyoshi, Ishino, Hirokazu, Jaehnig, Gregory, Jost, Baptiste, Kohri, Kazunori, Konishi, Kuniaki, Lamagna, Luca, Lattanzi, Massimiliano, Leloup, Clement, Levrier, François, Lanoppan, Anto, Luzzi, Gemma, Macias-Perez, Juan, Maffei, Bruno, Marchitelli, Elisabetta, Martínez-González, Enrique, Masi, Silvia, Matarrese, Sabino, Matsumura, Tomotake, Micheli, Silvia, Migliaccio, Marina, Monelli, Marta, Montier, Ludovic, Morgante, Gianluca, Mousset, Louise, Nagano, Yuya, Nagata, Ryo, Natoli, Paolo, Novelli, Alessandro, Noviello, Fabio, Obata, Ippei, Occhiuzzi, Andrea, Odagiri, Kimihide, Omae, Ryuji, Pagano, Luca, Paiella, Alessandro, Paoletti, Daniela, Pascual-Cisneros, Guillermo, Patanchon, Guillaume, Pavlidou, Vasiliki, Piacentini, Francesco, Piat, Michel, Piccirilli, Giulia, Pinchera, Michele, Pisano, Giampaolo, Porcelli, Luca, Raffuzzi, Nicolò Elia, Raum, Christopher, Remazeilles, Mathieu, Ritacco, Alessia, Rubino-Martin, Jose Alberto, Ruiz-Granda, Miguel, Sakurai, Yuki, Savini, Giorgio, Scott, Douglas, Sekimoto, Yutaro, Shiraishi, Maresuke, Signorelli, Giovanni, Stever, Samantha L., Sullivan, Raelyn, Suzuki, Aritoki, Takaku, Ryota, Takakura, Hayato, Takakura, Satoru, Takase, Yusuke, Tartari, Andrea, Tassis, Konstantinos, Thompson, Keith L., Tomasi, Maurizio, Tristram, Matthieu, Tucker, Carole, Vacher, Léo, van Tent, Bartjan, Vielva, Patricio, Watanuki, Kazuya, Wehus, Ingunn Kathrine, Westbrook, Benjamin, Weymann-Despres, Gilles, Winter, Berend, Wollack, Edward J., Zacchei, Andrea, Zannoni, Mario, and Zhou, Yu

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