We performed the first simulations of accretion onto the compact objects in the Reissner-Nordström (RN) space-time. The results could not be more different for the two cases. For a black hole, just as in the familiar Kerr case, matter overflowing the cusp plunges into the black hole horizon. For the naked singularity, the accreting matter forms an inner structure of toroidal topology and...
The significant tensions in constraints on the Hubble constant ($𝐻_0$) and clustering amplitude ( $𝑆_8$) between early- and late-universe observations challenge key assumptions of the LCDM cosmological model. One of these assumptions is the presence of cold dark matter, a yet-to-be-detected non-relativistic particle with minimal interaction with the Standard Model that dominates the mass...
We will discuss interpretation of the nHz stochastic gravitational wave background (SGWB) seen by NANOGrav and other Pulsar Timing Array (PTA) Collaborations in the context of supermassive black hole (SMBH) binaries. The frequency spectrum of this stochastic background is predicted more precisely than its amplitude. We will discuss how Dark Matter friction can suppress the spectrum around nHz...
The detection of gravitational waves (GWs) has led to a deeper understanding of binaries of ordinary astrophysical objects, including neutron stars and black holes. We point out that binary systems may also exist in a dark sector with astrophysical-mass macroscopic dark matter. These “dark binaries”, when coupled to an additional attractive long-range dark force, may generate a stochastic...
We study the thermal freeze-out of two-component dark matter (DM). The freeze-out in a multicomponent dark sector can be more complex and richer than the canonical single-component WIMP DM. This is owing to the relevance of processes of conversions, co-annihilations, co-scatterings, decays and self-scatterings in addition to those of annihilations and elastic scatterings, which can affect the...
The origin and nature of neutrino mass remain one of the most intriguing puzzles in particle physics. To account for the small but nonzero neutrino masses, we propose a hybrid mass-generation mechanism that integrates the canonical seesaw mechanism with radiative neutrino mass generation. This framework is formulated within a non-Abelian discrete flavor symmetry, whose spontaneous breaking not...
Dark matter candidates with masses below 10 GeV/c² hold promise, and a new detector, DarkSide-LowMass, is proposed based on the DarkSide-50 detector and progress towards the DarkSide-20k. DarkSide-LowMass is optimized for low-threshold electron-counting measurements, and sensitivity to light dark matter is explored for various potential energy thresholds and background rates. I will present...
The study and hunt for Dark Matter relies heavily on a proper modelling of the so-called astrophysical (or cosmological) factors. Local density of the prospective DM candidate in the solar vicinity or in the Galactic neighborhood, as well as the distribution of shapes, masses and abundance of the gravitational collapse DM haloes are quantities that are predictions of the the standard...
In the first part of this talk recent results from the joint oscillation analyses using T2K beam neutrinos and atmospheric neutrinos will be discussed, together with the oscillation parameters which are derived from this study.
In the second part of the presentation the studies on the Diffuse Supernova Neutrino Background (DSNB) at the Super-Kamiokande will be covered.
Hyper-Kamiokande is the next generation water Cherenkov neutrino detector,
which construction started in 2020 in Japan, and the experiment is expected to start data taking in 2027. Its fiducial volume, 8 times bigger than Super-Kamiokande, instrumented with new photosensors, combined with the upgraded to 1.3 MW J-PARC neutrino beam produced 295 km away and upgraded a near detector suite, will...
The network of two next-generation underwater Cherenkov neutrino telescopes: ARCA and ORCA is being successively deployed in the Mediterranean Sea by the KM3NeT Collaboration. The focus of ARCA is neutrino astronomy, while ORCA is mainly dedicated to neutrino oscillation studies. Both detectors are already operational in their intermediate states and collect valuable results, including the...
The Giant Radio Array for Neutrino Detection (GRAND) is a next-generation observatory aiming to discover the sources of ultra-high-energy cosmic rays (UHECRs) through the detection of radio signals emitted during the interaction of the UHE particles with the atmosphere. This goal would be achieved by deploying 200,000 radio antennas over 200,000 km2 distributed worldwide, gathering enough UHE...
The success of next-generation neutrino oscillation experiments, such as DUNE and Hyper-Kamiokande, relies heavily on our ability to predict neutrino-nuclei cross sections accurately. In my talk, I will demonstrate how deep learning techniques can enhance the models for neutrino and electron-nuclei scattering cross sections.
I will summarize the status of the Polish participation in the Vera Rubin Observatory and its overlap with other key observatories and instruments. I will highlight the scientific perspectives of the Rubin Observatory and its impact on Particle Astrophysics in Poland, illustrated by some recent scientific results from our team.
The expansion of the Universe at relatively small distances (up to redshifts about 9) can be measured with individual astrophysical sources. I will shortly list those types sources and the used techniques to determine the distance for each individual source. I will present the results of our group based on measurement of the time delays in quasars, and I will discuss the issue of the...
The Astrophysics Centre for Multimessenger studies in Europe is a new Horizon Europe-funded project for the years 2024-2028. It gathers 40 world-class collaborating institutions from 14 countries and brings together the astroparticle and astronomy communities for long-term collaboration.
ACME is a pathfinder to broaden and improve access to the research infrastructures services and data,...
Studies of galaxy clustering show that the relationship between luminous structures and the underlying dark matter distribution is not straightforward. It depends on various, often interrelated, elements, such as the properties of the galaxies or the properties of the environment which in these galaxies reside.
Crucial for these dark-luminous matter relations studies are estimates of the...
Low surface brightness galaxies (LSBs) are estimated to account for 30% to 60% of the total number density of galaxies. In this work, we analyze a dataset of LSBs identified by Thuruthipilly et al. in the Dark Energy Survey (DES) Data Release 1. The aim is to organize these galaxies into categories more detailed than the traditional blue and red classifications.
To achieve this, we apply...
Identifying sources of ultra-high-energy (UHE) particles is one of the key tasks to understand our non-thermal universe in the extreme energy scales. Flares from some astrophysical objects are one of the prominent candidates for producing such UHE particles. The search for sources of UHE neutral particles is easier than for those of UHE charged particles, as the neutrals are not affected by...
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...
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...
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. We...
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...
Low-mass galaxies provide a powerful tool with which to investigate departures from the standard cosmological paradigm in models that suppress the abundance of small dark matter structures. One of the simplest metrics that can be used to compare different models is the abundance of satellite galaxies in the Milky Way. Viable dark matter models must produce enough substructure to host the...
The cosmic web is the largest geometric structure in our universe, consisting of an intricate network of voids, walls, filaments, and dense nodes. $\Lambda$CDM predicts that dark matter halos, which trace this multiscale structure, form hierarchically and host smaller substructures known as subhalos. Understanding how the abundance and internal kinematics of subhalos vary across different...
DarkSide-20k, a direct dark matter search experiment, is located at the Gran Sasso National Laboratory (LNGS), Italy. It is designed to achieve groundbreaking 200-tonne-year exposure, nearly free from instrumental backgrounds. The core of the detector is a dual-phase Time Projection Chamber (TPC) containing 50 tonnes (20 tonnes fiducial) of underground liquid argon (UAr) with low levels of...
Blazars, a subclass of active galactic nuclei, exhibit highly variable
non-thermal emission originating from relativistic jets aligned with the line
of sight to Earth. This variability offers key insights into the physical
processes driving these systems. In this study, we analyzed the X-ray spectra
of a sample of X-ray-bright blazars observed with NICER, fitting three
spectral models: a...
What dominates the quasars Spectral Energy Distribution at IR is dusty torus emission. It is described as the thermal reprocessor of the internal X-ray/UV accretion disc continuum.
Thus, internally, its emission strength should correlate with the strength of illuminating radiation and the amount of captured energy (due to covering factor). In the type 1 AGN, where the torus does not cross 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...
The Hubble constant is a crucial cosmological parameter that is a measure of the rate of change of the cosmic scale factor per unit cosmic scale factor i.e. a_dot / a. There is a considerable discrepancy between the measurements of the Hubble constant from standard candle observations and those from cosmic microwave background (CMB) observations. Data from gravitational wave (GW) events can...
Fast Radio Bursts (FRBs) are bright, millisecond-duration radio transients, a subset of which have been precisely localized to their host galaxies. Due to their high dispersion measures, FRBs offer unique insights into the ionized plasma along their sightlines, enabling their use as cosmological probes. One critical challenge in modern cosmology is the Hubble tension -- a persistent...
Relativistic jets are powerful collimated outflows from accreting compact objects, especially spinning black holes. Jets, as well as their associated mechanisms of energy dissipation and particle acceleration, can be investigated by global or local numerical simulations using methods like general-relativistic magneto-hydro-dynamics (GRMHD), particle-in-cell (PIC), etc. This presentation shall...
An extensive air shower with a particularly large depth of maximum development, Xmax, (~1200 ) 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 discrepancy...
Neutrino Astronomy is proceeding with the development of new neutrino telescopes. The opaqueness of the Universe to the photons at high energies makes the neutrino an excellent probe to study most of the energetic objects of the cosmos. With this aim, the Pacific Ocean Neutrino Telescope (P-ONE) is planned to be deployed at the Cascadian Basin in the Pacific Ocean, off the coast of Vancouver...
Identification of the primary cosmic rays on an event-by-event basis stands as one of the main goals for any cosmic-ray observatory. Several cosmic-ray air-shower experiments use photon tags for gamma/hadron primary particle discrimination. These photon tag variables, for example Ptail or Sb, are easily built from the total signals measured in an array of detectors and are correlated with the...
Hot white dwarfs lose energy mainly in the form of neutrinos through plasmon decay from the inner part of the star. BSM physics can have visible contributions to the cooling of these compact objects. The aim of this study is to show how hot white dwarf cooling could be altered by a dark photon from the $L_\mu - L_\tau$ model and explore these effects from ultra-light to heavy intermediators....
The Large Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND) has been designed to answer one of the highest priority questions in fundamental physics: is the neutrino a Majorana or Dirac particle, is the lepton number conserved, and what is the neutrino mass?
The first phase of the project, the LEGEND-200 detector, is currently running at the Laboratori Nazionali...
Asymmetric dark matter (ADM) explains the present DM abundance by asymmetry between DM particles and anti-particles, like visible matter or standard model (SM) baryons.
ADM is particularly interesting when the visible and dark asymmetries have a common origin, since their abundances are different only by a factor of ~5.
When the asymmetries are equilibrated in the early Universe and thus...
The emerging field of Gravitational Wave Astronomy has already demonstrated its potential to explore the Dynamic Universe. We are just at the beginning of exploring the Universe with gravitational waves. While LIGO-Virgo-KAGRA regularly observes gravitational waves from compact binaries, we do not know what we may discover next. We may observe new source populations, multi-messenger events,...
I will describe the current status of the Einstein Telescope (ET) project and present the Polish participation. I will briefly discuss the highlights of the science case of ET. Finally I will summarize the future steps in the project.
The new German Centre for Astrophysics (DZA) to be founded in 2025 is a bold initiative to advance multi-messenger astrophysics including gravitational wave research. Central to the DZA's mission is the Einstein Telescope, a next-generation gravitational wave observatory that will transform our understanding of cosmic phenomena. Part of the DZA's work is the site investigation for the Einstein...
Over two years ago, we installed an array of microphones to monitor infrasound activity at Sos Enattos mine, located in northeastern Sardinia, one of the candidate sites for the Einstein Telescope, future 3rd generation gravitational waves detector. The setup includes two microphones at a surface station and six additional microphones placed within underground cavities at varying depths. This...
Over the past decade, gravitational wave observations have confirmed more than 80 binary black hole mergers, providing unprecedented insights into the demographics of stellar-mass black holes. These discoveries raise fundamental questions about the astrophysical origins and formation pathways of these enigmatic systems. In this talk, I will delve into the dynamical processes driving the...
Gravitational lensing and gravitational waves - new opportunities to test dark matter
Abstract.
We entered the era when the opening of gravitational wave (GW) window on the universe combined with ongoing (ZTF) and forthcoming (LSST) big real time surveys creates a braekthrough in multi-messenger astrophysics. Most of the astrophysical messengers travel along null geodesics and may undergo...
Although it is conjectured that a phase transition from hadronic to deconfined quark matter is possible in the ultrahigh density environment in Neutron Stars, the nature of such a transition is still unknown. Depending on whether there is a sharp or slow phase transition, one may expect a third family of stable compact stars or “twin stars” to appear, with the same mass but different radii...
Observations of extensive air showers are used to probe hadronic interactions at energies much higher than in any experiments at man-made accelerators. One important observable, that can provide some constraints on the interaction models, is the muon content of air showers. This observable is also crucial in determination of the composition of the primary cosmic rays - it is expected that the...
It is well-known that the composition of the cosmic ray primary particle changes the characteristics of the air shower it induces, most notably the average atmospheric depth of the shower maximum ($X_{max}$). Showers induced by heavy primaries, such as Fe, develop faster and thus higher in the atmosphere than those induced by their lighter counterparts, like protons. This changes the...
There is a statistically solid (on a six sigma level) correlation between the global seismic activity and changes in the intensity of cosmic radiation recorded at the surface of our planet, dubbed the cosmo-seismic effect (https://press.ifj.edu.pl/en/news/2023/06/14/). The relationship which has recently been found in public data by the Cosmic Ray Extremely Distributed Observatory (CREDO)...
The JEM-EUSO (Joint Exploratory Missions for Extreme Universe Space Observatory) collaboration is an international initiative studying ultra-high-energy cosmic rays (UHECRs) and related phenomena. These particles, with energies exceeding 10$^{20}$ eV, provide insights into extreme astrophysical processes but remain challenging to detect due to their low flux.
At the heart of JEM-EUSO's...
The cosmic rays stream reaching Earth is of extragalactic origin, some come from the center of our Galaxy, while the source of cosmic rays of the lowest energies is Sun. A common way to register galactic cosmic ray (GCR) and its variability are measurements made by a global network of ground neutron monitors (NMs), operating continuously since 1951. They measure secondary cosmic rays: the...
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...
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...
The Cherenkov Telescope Array Observatory is the next-generation project for very high-energy gamma-ray astronomy. The project has recently achieved ERIC status. I will briefly review the current status of the project, recent progress, and future plans.
Abstract: The Large-Sized Telescopes (LSTs) with mirror diameters of 23 m are the largest type of telescopes to be used in the future Cherenkov Telescope Array Observatory. Four of such telescopes are planned in the Northern (La Palma, Spain) and two in the Southern (Paranal, Chile) sites. The first telescope, LST-1, has been inaugurated in October 2018 in Observatorio Roque de los Muchachos,...
The High Energy Stereoscopic System (H.E.S.S.), a ground-based gamma-ray observatory, has been instrumental in advancing our understanding of high-energy astrophysical phenomena. This presentation will highlight the most recent scientific results obtained using H.E.S.S., focusing on its contributions to the study of cosmic particle accelerators. I will discuss key discoveries, including...
I will present the most important results of the HAWC Observatory obtained over the last ten year with a focus on the newest discoveries.
The SST-1M telescopes are prototypes of small-size single-mirror Cherenkov telescopes, developed collaboratively by Czech, Polish, and Swiss institutions. Their design is based on the Davies-Cotton concept, featuring a 4-meter mirror and an innovative SiPM-based camera. With a 9.42 m² segmented mirror, a 5.6 m focal length, and a wide 9-degree field of view, the SST-1Ms are optimized for...
Shock waves in cosmic plasma are generally considered as most appropriate candidates for the role of particle accelerators, being the possible sources of relativistic electrons responsible for the non-thermal electromagnetic radiation (radio, X-rays, gamma) as well as cosmic rays (CR). They can be found in numerous astrophysical objects widely varying in scales, from Earth’s bow shock and...
Jets in active galactic nuclei (AGN) are known for their intense X-ray and gamma-ray emission, originating from non-thermal particles. These sources are also linked to high-energy neutrino events and are considered potential sites of ultra-high-energy cosmic ray production. Accelerated particles can be generated in shock waves formed in collisionless AGN plasmas. We report on our recent...
Astrophysical magnetic fields may store significant amounts of energy. The process of magnetic reconnection can release this energy fairly rapidly and transfer it directly to particles. In the relativistic regime, when magnetic energy density dominates the rest-mass plasma density, most of participating particles can achieve relativistic energies. Relativistic reconnection is a complex process...
The applicability of first-order Fermi acceleration in explaining the cosmic ray spectrum has been reexamined using recent results on shock acceleration mechanisms from the Multiscale Magnetospheric mission in Earth's bow shock. It is demonstrated that the Fermi mechanism is a crude approximation of the ballistic surfing acceleration (BSA) mechanism. While both mechanisms yield similar...
Recent progress in understanding the physics of radio pulsars
Radio pulsars, discovered 57 years ago, remain one of the profound puzzles of
the modern astrophysics, as we still lack self-consistent quantitative models of
emission processes in pulsar magnetospheres. However, the advent of powerful
computers and significant improvements in numerical techniques for modeling
relativistic...
