Conveners
PhD short talks
- Bogumiła Świeżewska (Uniwersytet Warszawski)
- Andrzej Hryczuk (National Centre for Nuclear Research (NCBJ))
Terminal velocity reached by bubble walls in cosmological first-order phase transitions is an important parameter determining both primordial gravitational wave spectrum and the production of baryon asymmetry in models of electroweak baryogenesis. We developed a numerical code to study the real-time evolution of expanding bubbles and investigate how their walls reach stationary states. In...
Secluded sectors containing self-interacting Dark Matter offer a compelling framework for explaining dark matter production through interactions confined within the dark sector. Introducing a feeble coupling between the dark and visible sectors via a Higgs portal not only opens up new avenues for detection and enriches thermal production dynamics, but also provides a potential explanation for...
In my talk, I will discuss transitions in a maximally symmetric composite Higgs model with next-to-minimal coset, where a pseudoscalar singlet emerges alongside the Higgs doublet. I will focus on the scenario involving an explicit source of CP violation in the strong sector, which induces a $\mathbb{Z}_2$ asymmetric scalar potential, and consequently leads to nonzero vacuum expectation value...
Gravitational Waves have proven to be an excellent tool for understanding populations of binaries. For the upcoming LISA detector, Binary White Dwarfs are one of the most promising sources. In this work, we focus on modelling the Gravitational Wave background from White Dwarf Binaries in the LISA sensitivity range and building a model of their population in the Milky Way.
The COMPAS binary...
Gravitational-wave (GW) astronomy is an established field that is rapidly expanding with increasing detections from merging compact binary systems. The next generation of GW detectors promises a tenfold increase in sensitivity, leading to a thousandfold increase in the observable volume of the Universe and a corresponding rise in detection rates. This growing dataset provides a unique...
Slow first-order phase transitions generate large inhomogeneities that can lead to the formation of primordial black holes (PBHs). We show that the gravitational wave (GW) spectrum then consists of a primary component sourced by bubble collisions and a secondary one induced by large perturbations. The latter gives the dominant peak if $\beta/H_0 <12$, impacting, in particular, the...
Residual eccentricity in gravitational waveforms can be a unique tool to identify binary systems formed in dynamical environments. In general relativity, eccentricity is not defined uniquely. Different waveform models rely on gauge-dependent definitions of eccentricity, which leads to incompatibility between them. We remove this ambiguity by employing a gauge-invariant eccentricity definition...
Detecting gravitational waves (GW) has given us new possibilities to probe the Universe. In this talk, I will focus on the prospects of GW detection coming from cosmological supercooled phase transition (PT) with the future generation of detectors, i.e. LISA/ET. Observation of such an event will give us information about the physics of the early Universe.
In the standard model (SM), there is...
Atmospheric neutrino events observed at the Super-Kamiokande detector are divided into classes based on their topology. In the case of partially-contained events, neutrino interacts within the inner part of the detector, but some of the charged particles produced in this interaction leave the inner region and enter into the outer part of the detector, as opposed to the fully-contained events,...
In my talk, I will present the motivation that stands for the joint oscillation analysis using both: atmospheric neutrino data collected by the Super-Kamiokande detector and T2K beam neutrino data. T2K is a long-baseline neutrino experiment designed to study neutrino oscillations, particularly the appearance of electron neutrinos in a muon neutrino beam and the disappearance of muon neutrinos,...
High energy neutrinos are unique particles with tiny masses, interacting via weak and gravitational forces. Their astrophysical origins, detection techniques, and determining their production mechanisms are challenging. Tidally disrupted events (TDE) are potential candidates for very-high- and ultra-high-energy neutrinos. The p-p and p-gamma are two interactions, which can produce such...
The DarkSide experiment has been designed to search for direct interactions of the cold dark matter particles. Due to the expected very low signal, different techniques have been implemented to minimize the background. Currently the DarkSide-20k (DS-20k) detector is under construction in the underground laboratory at Gran Sasso (LNGS) in Italy.
One of the material which is going to be...
The LSST survey, with its first observations anticipated in May 2025, presents not only extraordinary opportunities but also significant challenges. A particularly compelling question is whether it will be possible to estimate or at least constrain the physical properties of dust, despite the survey’s focus solely on the optical range. Dust plays a crucial role in the processes governing...
Unveiling the routes galaxies take to quiescence is one of the most open challenges in galaxy evolution. While the most of the studies focused on characterizing quiescent galaxies (QG) across cosmic time through their stellar properties using optical/near-infrared (NIR) data, the mid-infrared regime was only recently examined thanks to the advent of JWST. The need to understand the MIR...
In the era of high precision Cosmic Microwave Background (CMB) measurements, polarisation based internal lensing reconstruction methods will have the highest signal-to-noise ratio. Diffused contamination from polarised galactic emission is a main concern for such experiments that aims to do reconstruction of lensing potential at small scales. We investigate the impact of galactic foregrounds...
CREDO collaboration studies cosmic-ray related phenomena on a large scale, searching for so called Cosmic-Ray Ensembles (CRE) or other unusual correlations and anomalies of non local nature. Such studies require data on Extensive Air Showers (EAS) and flux of secondary cosmic-ray particles that covers large areas. To perform such measurements, a large network of inexpensive detectors working...
Neutron star mergers, known to be the progenitors of short gamma-ray bursts, may also produce luminous transients called kilonova. These transients are powered by the radioactive decay of heavy elements synthesised in neutron-rich ejecta. Kilonova emission arises from two major sources: the dynamical ejecta expelled during the merger and the winds from the accretion disk. The accretion onto...
An extensive air shower with a particularly large depth of maximum development, Xmax, (~1200 $g/cm^{2}$) was observed at the Pierre Auger Observatory. With the help of the Top-Down Reconstruction chain, we aim at further studying this air shower. The Top-Down chain is a Monte Carlo simulation scheme which focuses on reconstructing the observed air shower while accounting for the well-known...
Blazars are a unique subclass of active galactic nuclei (AGN) characterised by their relativistic jets oriented towards Earth. This study focuses on the blazar PKS 2155-304, a high synchrotron-peaked BL Lac object located at a redshift of z=0.116. We utilised multiwavelength observations, ranging from optical to gamma-ray, primarily from the Fermi Large Area Telescope (LAT) and the Swift...
Accretion disks around compact objects, such as black holes (BHs) or neutron stars (NSs), exhibit various types of spectral variability. These include long-term variabilities driven by thermoviscous instabilities in the accretion disks of low-mass X-ray binaries (LMXBs) and short-term variabilities, which are often attributed to thermal instabilities caused by radiation pressure from the...
