Dark matter has a long history, but it was not until modern times that we have a chance of detecting it. This thesis focuses on the velocity distribution and its effect on indirect WIMP detection. Recently a new velocity distribution, based on data from SDSS and GAIA, was proposed. For this reason simulation of capture, annihilation and resulting flux of neutrinos from the Sun and Earth has been made both for the new and Maxwell-Boltzmann velocity distribution. The newly proposed velocity can reduce the annihilation rate in Earth by two thirds. For the Sun the effect depends on the mass of the WIMPs. For 50 GeV WIMPs the newly proposed velocity distribution could increase the annihilation rate by 5%, while for 3 TeV WIMPs it could decrease the annihilation rate by 28%. For Earth and high mass WIMPs the low velocity tail is the important part and the low resolution of this region in the new velocity distribution result in some uncertainties.

No description available.

The recent boom in 21cm astronomy has piqued the interest of many, especially cosmologists realizing its applications in their field. This study aims to determine if 21cm astronomy is a good tool for testing the validity of keV WDM models, as well as creating a code capable of simulating keV WDM models from an existing CDM code. The assumed WDM models vary only in dark matter particle mass and assume a single-species dark matter case as well as totally thermalized particles, such as gravitinos. Small-scale simulations of approximately 183Mpc3, as well as large-scale simulations of approximately 1503Mpc3-1793Mpc3, indicated that the CDM code was successfully modified to simulate WDM through the total dark matter power spectrum and the halo-mass function. Additionally, the large-scale simulations hinted at a positive use of 21cm astronomy for the restriction of keV WDM models, due to the existence of a distinct CDM HI power spectrum as compared to the 0.5keV WDMHI power spectrum. A discernable difference between CDM and keV WDM galactic HI power spectra would provide a step towards a confirmation or falsification of keV WDM models if supplied with a large-scale galactic HI power spectrum study

This licentiate thesis presents contributions to the luminosity measurement from the data recorded by the ATLAS detector in 2017 using a track-counting technique, as well as a search for dark matter in the ATLAS experiment using 139 fb-1 of √s = 13 TeV pp collision data delivered by the LHC from 2015 to 2018. Track-counting luminosity measurements in low-luminosity operations are performed to study the effect of low collision rates on luminosity determination. The luminosity measured in a calibration transfer procedure using the track-counting technique is used to correct the pile-up dependence observed in ATLAS’s main luminosity detector called LUCID. A search in the final state of a lepton, jets and missing transverse energy, where the final state is produced from a pair of top quarks and a spin-0 scalar/pseudoscalar mediator, is presented. A dedicated signal region is designed to target this final state in which the mediator decays into dark matter particles. The signal region covers the search in the mass plane of the mediator and the dark matter particle. Dedicated control regions are designed to estimate the top-quark background events, as well as the events where a Zboson is produced in association with the top quarks. The signal region event counts in the data have not been unblinded yet, but expected exclusion limits at 95% confidence level as a function of mediator mass are presented. Scalar and pseudoscalar mediators are expected to be excluded up to 200 and 250 GeV, respectively, for the dark matter mass of 1 GeV, and the coupling strengths of the mediator to the dark matter and Standard Model particles of 1.

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京都大学 / 新制・課程博士 / 博士(理学) / 甲第23698号 / 理博第4788号 / 新制||理||1685(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 福間 將文, 准教授 吉岡 興一, 教授 萩野 浩一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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<p>We consider the phenomenology of the Magnetic Inelastic Dark Matter model, specifically its capture and subsequent annihilation in the Sun. By using the most recent data from the IceCube and Super- Kamiokande neutrino detection experiments, we are able to put limits on the dipole moment of this WIMP candidate for masses ranging from 100 GeV to 10 TeV with a mass-splitting ranging from 0 to 200 keV. Limits are placed on a 100 GeV WIMP with magnetic dipole interactions as low as 2.6 × 10^−6µN for an inelastic parameter of 100 keV</p> / Master of Science (MSc)

The Cosmic Microwave Background (CMB) serves as a powerful backlight, illuminating thestructures throughout the universe. As the CMB photons travel to our telescopes from the surface of last scattering, their interactions with matter imprint detectable signatures in the CMB spectrum, known as the CMB secondary anisotropies. Among these late-time phenomena, the Sunyaev–Zel’dovich (SZ) effect—caused by scattering of the CMB photons off free electrons—is one of the most powerful, providing a unique window into the pressure and density of the electron gas. As the ionized gas and its feedback on the underlying dark matter distribution via high-energy processes present a significant obstacle to obtain precise cosmological constraints from the matter power spectrum, the SZ effect serves as an invaluable tool to address these challenges. This thesis uses the measurements of the CMB secondary anisotropies, particularly the SZ effect, from the state-of-the-art experiments, the Planck satellite and the ground-based Atacama Cosmology Telescope (ACT), in combination with Large-Scale Structure data to probe the ionized gas in distant galaxies. Chapter 2 presents the second measurement of the kinetic SZ effect in the unWISE galaxies with Planck using the projected-fields estimator. This work concludes that the ionized gas abundance in these galaxies matches the primordial-CMB predictions. Chapter 3 describes the work done to model the galaxy-halo connection of the unWISE catalog with Planck CMB lensing data using the halo model framework. It constrained the halo masses of these samples to ≈ 2 ×10¹³ _⊙/ℎ, and found that they are dominated by central galaxies, rather than satellites. These constraints can be directly used in other cross-correlations of unWISE with, e.g., the tSZ or the kSZ effect in the halo model with the upcoming CMB experiments. Chapter 5 discusses the ongoing work of cross-correlating the Dark Energy Survey Maglim galaxies with the thermal SZ maps from ACT. It measures very extended pressure profiles around Maglim, which suggest strong feedback activity in low mass objects, pushing the ionized gas far outside of the halo. This thesis also presents novel techniques to tackle the key systematics in cosmological cross-correlations. The analysis of Maglim galaxies employs the new Cosmic Infrared Background (CIB) cleaning technique, the moment-deprojection method, which ensures that the measurement is robust to this foreground. Chapter 4 discusses three new methods to remove the CIB and tSZ contamination, using the external Large-Scale Structure data which show a large correlation with both fields (e.g., the unWISE catalog). With the new methods presented, it is possible to remove those contaminants to enhance the measurements of the blackbody component of a CMB map. The results presented in this thesis offer a unique window into the baryons residing in distant galaxies through the SZ effect, confirming there is no missing baryons, and indicating that the feedback is stronger than predicted in simulations. These analyses lay the groundwork for cross-correlations of the upcoming high-resolution, low-noise CMB experiments such as the Simons Observatory, and high density galaxy surveys, including DESI, Euclid, or LSST. The upcoming measurements will yield precise constraints on gas physics, transforming our understanding of galaxy formation, and enabling cosmological constraints from the matter power spectrum, where baryons currently represent the primary uncertainty.

Gravitationslinsen bewirken Ablenkung, Verzögerung und Verzerrung von Signalen im Universum. Jedes Signal wird mindestens schwach durch Gravitationsfelder gelinset, und bei starker Linsenbildung entstehen mehrere Bilder, wenn Quelle und Linse genau ausgerichtet sind. Die Beobachtung von Linsen bei elektromagnetischen Quellen ermöglicht Einblicke in die Materieverteilung von Galaxien bis hin zu Sternen. Linsenbildung ist entscheidend für die Interpretation astronomischer Daten und hat Anwendungen in Astrophysik, Kosmologie und fundamentaler Physik. Mit Fortschritten in der Gravitationswellen-(GW)-Astronomie erlangt GW-Linsenbildung Aufmerksamkeit. Ihre niedrige Frequenz und Phasenkohärenz ergänzen elektromagnetische Beobachtungen und eröffnen neue Phänomene. Diese Arbeit erforscht GW-Linsenbildung in schwachen und starken Regimen und mögliche Anwendungen. In der starken Linsenbildung untersuchen wir kontinuierliche Wellen von rotierenden Neutronensternen (NS), die durch Sgr A*, das zentrale Schwarze Loch der Milchstraße, gelinset werden. Wir zeigen, dass sich Linsenparameter jenseits des Einstein-Radius rekonstruieren lassen. Unter günstigen Annahmen könnten NSs, die von Sgr A* gelinset werden, von künftigen Detektoren beobachtet werden und Einblicke ins galaktische Zentrum bieten. Der zweite Teil untersucht Wellenoptik-Effekte im schwachen Linsenregime, entwickelt Methoden zur Lösung des Beugungsintegrals und wendet diese auf spezifische Linsenmodelle an. Künftige Detektoren wie LISA könnten diese Effekte auch bei großen Linsen-Quellen-Abständen erkennen. Mithilfe realistischer Modelle von dunkler und baryonischer Materie schätzen wir, dass LISA Signaturen von Galaxien, supermassereichen Schwarzen Löchern und dunklen Materiehalos erkennen könnte. Diese Arbeit ebnet den Weg für künftige Entdeckungen in der GW-Linsenbildung und unterstreicht ihr Potenzial, die Astrophysik und Kosmologie zu bereichern. / Gravitational lensing causes deflection, delay, and distortion of signals in the universe. Every signal is at least weakly lensed by gravitational fields, and strong lensing creates multiple images when the source and lens are precisely aligned. Observing lensing from electromagnetic sources provides insights into the distribution of matter, from galaxies to stars. Lensing is crucial for interpreting astronomical data and has applications in astrophysics, cosmology, and fundamental physics. With advances in gravitational wave (GW) astronomy, GW lensing has gained interest. Their low frequency and phase coherence complement electromagnetic observations and reveal new phenomena. This work explores GW lensing in weak and strong regimes and potential applications. In strong lensing, we investigate continuous waves from rotating neutron stars (NS) lensed by Sgr A*, the central black hole of the Milky Way. We show that lensing parameters beyond the Einstein radius can be reconstructed. Under favorable assumptions, NSs lensed by Sgr A* could be observed by future detectors, providing insights into the galactic center. The second part examines wave-optics effects in the weak lensing regime, developing methods to solve the diffraction integral and applying them to specific lens models. Future detectors like LISA could detect these effects even at large lens-source separations. Using realistic models of dark and baryonic matter, we estimate that LISA may detect signatures of galaxies, supermassive black holes, and dark matter halos. This work paves the way for future discoveries in GW lensing and highlights its potential to advance astrophysics and cosmology.