List of abstracts
2024

In this contribution, I will discuss with the younger audience how do we build a space mission, in a simplified way but starting from the most basic principle. I will navigate through the long process of establishing science requirements, planning the instrumentation and develop a spacecraft concept. I will illustrate some examples of missions being planned for the future, including (but not limited to) THESEUS. Furthermore, I will describe some of the engineering challenges that we normally have to face while moving to the construction phases of the space instrumentation, summarizing the experience of the shutter unit built in Switzerland for the VIS instrument on-board the Euclid mission.

We investigate the broad-band X-ray continuum of the Be X-ray binary Cepheus X-4 in a quiescent state using 2023 NuSTAR observations. We search for an indication of the spectral transition, which was recently claimed for other Be X-ray binaries in quiescence. Cepheus X-4 hosts a rotating neutron star characterized by a strong magnetic field estimated from a known cyclotron line at around 30 keV. To observe the source at a low luminosity level, we targeted the declining phase of the 2023 outburst. The two performed observations revealed significant dimming of the source by about 70% within about a day, capturing the source at two distinct luminosity states of 10^35 erg/s and 3*10^34 erg/s, respectively. These observations provide broad-band X-ray spectra at the lowest observed luminosity level for this system. By comparing them with previously published data obtained during a previous outburst (with luminosity of a few 10^36 erg/s), we study the spectral transition based on the behaviour of the continuum and the cyclotron line. The cyclotron line is clearly detectable in the first observation with a centroid energy of about 28 keV. For the observation at lowest luminosity, there is no significant detection of the line, which might be attributed to a low signal-to-noise ratio for this case at hard X-rays. However, more careful treatment of the background (which provides a significant contribution above 20 keV) is required to draw further conclusions. We discuss our results in the context of recently proposed theoretical models for quiescent accretion onto strongly magnetized neutron stars.

Particle dark matter (DM) could annihilate into detectable Standard Model particles. Most efforts on the indirect search for DM focus on the high-energy photons directly produced by DM annihilation. However, such prompt signals alone are too weak to be measurable in large astrophysical fore- and backgrounds. Following a multiwavelength approach, the secondary emission from charged annihilation products, including Inverse Compton scattering, bremsstrahlung and synchrotron radiation, should be also taken into account to increase the chances of detecting an unambiguous signal. In our study, we investigate scotogenic DM with a mass around 1 TeV which is consistent with various experimental limits. Scotogenic Weakly Interacting Massive Particles (WIMPs) arise in models where an additional symmetry ensures both the existence of a stable DM candidate and the generation of neutrinos masses through couplings to the dark sector. We present our calculations of the DM photon spectrum in 27 dwarf galaxies of the Milky Way reaching from synchrotron emission in the MHz range to the Inverse Compton peak at MeV energies and to the prompt signature in the GeV up to TeV regime. This unique "triple hump" structure will be easily distinguishable from any other source. We estimate the fore- and background emission from the Milky Way and AGN along the line-of-sight to obtain signal-to-background ratios in different energy bands for each galaxy. We find ratios on the order of 1e-3 between 1 keV and 100 GeV. In the light of upcoming observatories like COSI-SMEX and CTA, the detection of faint DM signals is within reach if a coherent analysis across the MeV to GeV range is applied.

In this review article I will deal, without claiming to be complete, the leading topics of astrophysicswith the aim of making the current knowledge of our Universe easier for the reader."Multifrequency Astrophysics" is a pillar of an interdisciplinary approach to the knowledge ofthe physics of our Universe. Indeed, as clearly demonstrated in the last decades, only with themultifrequency observations of cosmic sources is it possible to get nearly the whole behaviourof a source and then to approach the physics governing the phenomena that originate such abehaviour. I regard a multidisciplinary approach in the study of each kind of phenomenon occurringin each kind of cosmic source as even more powerful than a simple "astrophysical approach".A clear example of a multidisciplinary approach is that of "The Bridge between the Big Bangand Biology". This bridge can be described by using the competencies of astrophysicists, planetaryphysicists, atmospheric physicists, geophysicists, volcanologists, biophysicists, biochemists,and astrobiophysicists. The unification of such fields of expertise can provide the intellectualframework that will better enable an understanding of the physics governing the formation andstructure of cosmic objects, seemingly uncorrelated with one another, but constitutive of the stepsnecessary for the origin of life (e.g. Giovannelli, 2001a). Indeed, a lot of the future research inastrophysics will be focussed on the discovery of exoplanets and on the possibility to detect signalsfor alien life somewhere in the Galaxy. An extension to a multidisciplinary approach comesfrom the use of historical news reported in "old chronicles" that are a fundamental source for thenewborn "archaeoastronomy". There are many problems in performing simultaneous nultifrequency, multisite, multiinstrument,multiplatform measurements due to: (i) objective technological difficulties; (ii) sharing commonscientific objectives; (iii) problems of scheduling and budgets; and (iv) the political managementof science. All these kinds of measurements converge in what is now called MultimessengerAstrophysics, this after the detection of gravitational wave events (GWEs) and the search for theelectromagnetic counterparts of such events.I will provide several examples that marked the continuous evolution on the knowledge of thephysics of our Universe.

In this talk I will present an excursion on the history of the High Energy (HE) space experimentsdesigned for Ultraviolet (UV), Soft and hard X-rays, and Gamma-rays energy ranges, starting fromthe first satellite UHURU until IXPE (Imaging X-ray Polarimetry Explorer). The main resultsobtained will be discussed. Thus it will be possible to follow the advancement of our knowlege ofthe HE-Universe along roughly 50 years with several examples that in my opinion provided thesolution of important steps for understanding the physics governing our Universe. Of course, thisdiscussion do not pretend to be complete because of my limited knowledge and the length of thispaper.

Dwarf galaxies likely serve as the primary origins of the hot intra-cluster medium, which has been the focus of a series of recent X-ray discoveries. Interactions between galaxies could potentially result in elevated rates of star formation within these galaxies, potentially leading to the occurrence of multiple core collapse supernovae and the ejection of hot gas. Numerical simulations are crucial for comprehending the formation and evolution of galaxies. Through these simulations, we can forecast outcomes or contrast results with observations to assess their effectiveness. Galaxy mergers act as the primary driver of galaxy evolution. Recent analyses utilizing JWST data have revealed that minor mergers propel the evolution of massive quiescent galaxies with log(M/MSun) > 10.5 at 0.5 < z < 3. These galaxies are accompanied by companions with mass ratios below 1:10, yet numerous progenitors with a median stellar mass ratio of 1:900 constitute approximately 30% of the collective mass of the incoming material. Using the IllustrisTNG cosmological simulation, we show how the massive quiescent galaxies evolve in cosmic times. We use the merger tree from the TNG300-1 simulation to demonstrate the impact of dwarf galaxies on the mass augmentation of these galaxies during the early Universe. Our analysis involves a comparison of our findings with the observed data from JWST.

Astrophysical black holes grow by accretion and mergers and therefore receive angular momentum. They are surrounded by a plasma-filled corotating region of spacetime, the ergosphere. Gravito-magnetic and ultrarelativistic collisional processes in the ergosphere give rise to a plethora of phenomena which can be studied using the methods of multi-messenger astroparticle physics and numerical simulations. Considerable progress has been achieved in understanding of the formation of Poynting-flux driven jets converting rotational energy of the black holes into relativistic particles and magnetic fields. Next-generation instruments will allow to establish a coherent picture of the role of black holes in the non-thermal Universe.

Positron annihilation results in a gamma-ray line at 511 keV photon energies. Observations of the 511 keV signal in the Galaxy have shown a diffuse nature with the Galactic bulge being as bright as the disk. The origin of these positrons in the Milky Way and how far they propagate before annihilating has been under discussion for five decades with many different sources and mechanisms being used to explain this phenomenon. One such mechanism is found in stellar flares. Previous studies have detected the 511 keV line from high energy Solar flares (1e34 erg) but pico- and nano-flares (1e22 - 1e24 erg) might have an even larger contribution to this line due to their higher frequency. Other stars flare in a similar manner as the Sun with a similar flare frequency energy distribution. We use data from Fermi/GBM and INTEGRAL/SPI to obtain a relation between the 511 keV line luminosity and the flare energy. This yields a quasi-persistent 511 keV flux of the Sun which can be extended to populations of stars, such as in globular clusters. This model applied to the 157 globular clusters of the Milky Way would account for more than 10% of the total Galactic diffuse flux of 3e-3 ph/cm2/s. Our preliminary estimates suggest that the positron production rates in Solar flares obtained from Bisnovatyi-Kogan and Pozanenko (2017) might have been largely overestimated. The expected cumulative flux from all globular clusters is within reach of the upcoming COSI-SMEX mission, slated for launch in 2027 with a planned duration of 2 years.

Specific X-ray reflection features are observed in the spectra of systems with accreting black holes. The main part of X-ray radiation in such systems is produced by a hot corona located near the spin axis of the black hole, while the reflection occurs due to interaction of the emitted photons with the accretion disk surrounding the black hole. The so-called lamp-post model, which assumes a point-like corona on the rotational axis of the black hole, explains such spectra surprisingly well. However, in reality the physical corona will be extended. We present an implementation scheme for incorporating such an extended corona into the RELXILL reflection model, reflection spectra for an extended corona and the first fits of this model to the astrophysical data. With this extended RELXILL model, it will be possible to constrain the size of the corona by relativistic reflection measurements in systems with accreting black holes.

The direct detection of gravitational waves in binary black hole merger has opened a new window in observational astronomy. The first three observing runs of the ground based interferometers LIGO/Virgo have produced a broad range of science results, including the first observations of a binary neutron star merger and of a neutron star-black hole merger. The observations include some exceptional events and have produced the GWTC-2, GWTC-2.1, GWTC-3 catalogs of compact binary mergers, allowing tests of general relativity and studies of black hole and neutron star populations.The presentation will review ground based gravitational wave astronomy, the exceptional mergers, the catalogs. The review will also discuss the multi-messenger observations over the electromagnetic spectrum and with neutrinos and their relevance. Since the spectrum of gravitational waves is extended over a broad range of frequencies, other techniques for gravitational wave detection outside the sensitivity band of ground based interferometers will also be discussed.

We studied the interrelation between the gamma (fluence, 1 sec peak flux, duration) and X-ray (11 hours flux, 24 hours flux, decay index, spectral index, HI column density) data using canonical correlation analysis. Using the canonical variables resulted in the analysis we computed their correlations (canonical loadings) with the original ones. The canonical loadings revealed that the gamma-ray fluence and the early X-ray flux give the strongest contribution to the correlation in contrast to the X-ray decay index and spectral index. An interesting result appears to be a significant contribution of the HI column density to the correlation. Accepting the collapsar model of long GRBs this effect may be interpreted as an indication for the ejection of an HI envelope by the progenitor in course of producing the GRB.

Super-massive black holes exert their gravitational dominance at the heart of nearly all galaxies. While many remain hidden and quiet, there are some where surrounding gas feeds into them, triggering a large variety of dynamic kinematical and radiation processes in the strong-gravity regime. Through astronomical observations spanning various wavelengths, we unveil this spectacle known as Active Galactic Nuclei (AGN), ranging from radio waves to high-energy emissions. In this lecture, I will explore the observational characteristics of AGNs, starting from nearby Seyfert galaxies and extending to the most remote quasars. The main focus will be to unravel the inner workings of the AGN's central engine with the emphasis on understanding the complexities of accretion processes. Additionally, we will draw parallels between AGN accretion mechanisms and those observed in X-ray binaries hosting stellar-mass black holes, providing valuable insights into the broader understanding of cosmic phenomena.

Early phases of star formation may be traced by infrared and sub-mm point sources, while young stellar objects (YSO) also by their optical and X-ray emission. We explore the distribution of X-ray point sources in two nearby molecular clouds with different structures. Heiles Cloud 2 (HCL2) is a ring-like molecular cloud complex in the Taurus region, while L1251 is a cometary shaped cloud in the Cepheus. We pair the X-ray point sources to known YSOs, and to point sources we discovered by our JCMT SCUBA2 sub-mm observations. We also compare the point source distributions to maps of the interstellar medium.

Areas of massive star formation are heavily affected by stellar winds and supernovae, therefore enhanced turbulent flows are expected. DDO 43 is a relatively nearby irregular dwarf galaxy with logSFRD of −2.20 ± 0.04 MSun yr -1 kpc -2, described as having patchy star formation regions in previous studies based on GALEX ultraviolet data. Revisiting the LITTLE THINGS survey, which provides high-quality HI 21 cm VLA observations of the gas content of DDO 43, the line profiles are carefully analyzed in the CLASS radio astronomical data reduction software, and the resulting distribution maps of spectral line properties are investigated together with available GALEX data. Our aim is to provide additional insights into the characteristics of local and global neutral gas flows in massive star-forming regions.

We made an analysis of the spatial distribution of 542 Gamma-Ray Bursts with precisely determined positions. The positional data was splitted according to the origin of the redshift (afterglow or host galaxy), and we investigated some aspects of the observational variations too. The correlation analysis between the GRB redshift and sky position found the Faraway GRB Patch, where nine distant GRBs show deviation from the randomness with an ~1% significance while covering about ~1/60 part of the sky. The results shows that the sky and the radial component of the GRB distribution could be factorized. Using the factorization the spatial distribution was explored with the bootstrap point-radius method. A selected distance range and a cap on the sky was used to determine any deviation from the random distribution. On the northern galactic hemisphere a group of four GRBs between the redshift range (0.59 < z < 0.62) was identified. The group’s direction coincides with the Hercules–Corona Borealis Great Wall (0.9

Gamma-ray bursts (GRBs) more than 50 years after their discovery remain topic of a vivid scientific research, gaining a new momentum with detection of sources of gravitational waves in the last decade, which are closely related to a subclass of GRBs. They are the most violent (and given their short timescale the brightest) cosmic events and for this reason important cosmological probes, visible at very large distances. This review talk will cover specific approaches of their detection (discussing missions from historical to the planned ones) together with importance of followup by ground-based telescopes and alert distributing mechanisms. Observational evidence will be complenented with models of their central engine as well as for the interaction with surrounding material producing the afterglows. Processes during these events include very extreme states of matter and disentangling them can answer many questions of origin in Universe as well as those of fundamental physics.

Gamma-ray bursts (GRBs) are among the most energetic and enigmatic phenomena in the universe. Fitting the observed data from these events is crucial for understanding their physical properties and the underlying mechanisms that power them. However, the complexity of GRB emission processes and the limitations of current observational techniques can make the fitting process challenging and intimidating for researchers. In this talk, we aim to demystify the process of fitting GRB data and provide a comprehensive overview of the key techniques and considerations involved. We will begin by discussing the main observational characteristics of GRBs, including their light curves, spectra, and temporal evolution. Next, we will explore the different approaches to fitting GRB data, including forward modeling, where physical models are used to generate simulated data that can be compared with observations, and inverse modeling, where the observed data is used to constrain the parameters of the physical models. We will discuss the advantages and limitations of each approach and provide practical examples of their application to real GRB data. We will also discuss the potential for future observations, such as those from the upcoming SVOM mission, to provide new insights into GRB physics and to constrain the models further. A practical demonstration will be shown on the case of GRB200131A.

During the examination of optical properties of gamma-ray bursts (GRBs) measured by the Swift satellite, significant discoveries were made. While the satellite measures gamma, X-ray, and optical data simultaneously, in many cases, only an upper limit is established in the optical domain. Hence, survival analysis was necessary, serving as a tool for studying samples where some cases are bounded only from above (or below). We investigated the distribution of optical brightness in relation to gamma-ray properties, finding that the duration, gamma fluence, and peak flux significantly influence the optical brightness distribution, whereas early X-ray flux and gamma photon index do not. The reason for the impact of gamma properties on optical brightness likely lies in the energetics of the jet launched from the central engine of the GRB, triggering afterglow in the surrounding interstellar matter.

We analyzed both the sky and spatial distribution of the precisely located GRBs, i.e. GRBs with redshifts. We analyzed selection effects and using the earlier developed kernel smoothing techniques we determined the GRB's Sky Exposure Function for the full dataset. The Sky Exposure Function were used during the generation of the random catalogs, and calculating the Two-Point Correlation function in the comoving coordinates. The corresponding Two-Point Correlation Function for GRBs was determined by partitioning the data based on the origin of the redshift (afterglow or host galaxy). It seems that there’s no difference between the random dataset's and the real dataset's Two-Point Correlation function.

This project aims to develop a calibration system for SST1M Cherenkov telescopes utilizing DLP projections and a pulsed UV laser. Beginning with laboratory assembly and testing, the system will undergo pixel-by-pixel calibration using calibrated light sensors (a photodiode or SiPM) mounted on XY motorized stages moving in front of the DLP. Once laboratory testing is complete, the system should be mounted on the telescopes for a few campaigns to perform camera calibrations. This will include single pixel illuminations at first, and later projecting more complicated images onto the sensor plane (geometrical shapes corresponding to the trigger logic of the camera, simulated air showers, etc.) and evaluating the results. Ultimately, this calibration system could become part of the Cherenkov Telescope Array (CTA).

The Swift telescope has observed nearly 300 GRBs for which reliable X-ray spectra have been obtained by the Swift XRT instrument, and they have spectroscopically determined redshifts. These redshift measurements are often not very accurate at first, so significant differences may be found compared to the initial data after a few days. Additionally, subsequently released data do not always get incorporated into the automatic processing procedures. Therefore, it is advisable to re-examine the X-ray spectra of GRBs after some time, using the expanded and refined redshift values. In our present work, we performed the re-fitting of X-ray spectra for nearly 300 Swift GRBs and compared the newly obtained results with those available in the catalog.

The polarimetry of the transient sky is a crucial field of investigation in high-energy astrophysics, in particular for Gamma-Ray Bursts (GRBs). The Soft-X and gamma-ray WIde-field Polarimeter (SWIPE) is a new concept mission based on the joint use of photoelectric and Compton polarimeters. At low energies, photoelectric absorption in a gas mixture offers the optimal balance between quantum efficiency and polarization sensitivity. Conversely, Compton scattering proves to be the preferred technique for hard X-rays and gamma-rays. The SWIPE design integrates both approaches to achieve the large collecting area (>1000 cm²) and wide field of view (>1 sr) required by its scientific objectives. The SWIPE Compton polarimeter will be based on an array of plastic and inorganic scintillator bars equipped with Silicon Photomultipliers or Silicon Drift Detectors (SDDs) for readout, at one or both ends of the scintillation bars. This presentation will report also on the ongoing experimental activities for the development of a prototype Compton polarimeter

The evolution of small satellite technologies has unlocked new frontiers in space operations, particularly in the realm of proximity operations. These operations, defined as maneuvers conducted within a 100-meter radius, present unique challenges and opportunities for small satellite missions. Talk presents a comprehensive overview of the VZLUSAT3 mission concept, designed to demonstrate the feasibility of small satellite proximity operations. The mission involves two small satellites: the Proximity spacecraft (VS3-A) and the Target spacecraft (VS3-B), executing a series of proximity maneuvers to achieve various objectives including in-orbit inspection, inter-satellite communication and formation flying. Key to the mission's concept is the operational strategy, divided into three phases: long-range approach (distance over 1000 m), close-range approach (distance below 1000 m), and the execution of proximity operations (distance below 100 m), culminating in the demonstration of critical capabilities like spacecraft inspection by mission specific proximity camera.

The ASTRABAX project ("Aschaffenburg Stratospheric Balloon Experiment"), recently being funded for the years 2024 to 2026, is designed as a multimodal platform to study radiation exposures in the upper atmosphere. Thereby the UV-C radiation at high altitudes is of special interest. Spectral measurements observe this region with two miniature UV-VIS spectrometers. The ASTRABAX platform also contains Geiger counters for the dosimetry of ionizing radiation, a power source for on-board electronics, and common shielding setups for multiple spectral combinations. Furthermore biological cells are exposed simultaneously to radiation with different compositions of particles, X-rays and UV radiation. After the flight, possible changes in the spatial chromatin organization will be examined to study low-dose radiation effects. Material samples intended for the development of satellite components are irradiated also. The first ASTRABAX balloon flight is scheduled for autumn 2024. Investigations under such conditions are realistic and crucial for high altitude flights in the atmosphere, for space flights as well as for comparable exposures on other objects of the solar system, and even for exoplanet habitats to some extent.

The technique of high-resolution detection, wide field-of-view spectral tracking and composition characterization of secondary cosmic rays in the atmosphere is presented. For this purpose, a miniaturized (< 150 g, < 10 cm, room temperature) particle telescope of 2x stacked Timepix3 detectors with Si and CdTe sensors was developed. Penetrating energetic charged particles, such as secondary cosmic ray muons, are detected in sync in both pixel detectors and resolved with high discrimination. Measurements and detailed results of cosmic rays on ground will be presented together with tests and calibrations at particle beam accelerators (protons, electrons). The model and methodology of spectral-sensitive and directional-mapping registration are developed together with detailed post-processing analysis. Development performed for physics research and environmental studies of particle correlations of solar and space radiation in the atmosphere and in the biosphere with UV and ozone depletion. Work performed in frame of project 21GRD02 BIOSPHERE EURAMET with funding from the European Partnership on Metrology, co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States.

Czech Contribution to AHEAD focusses on the design and development of Novel Lobster Eye and Kirkpatrick Baez X ray telescopes. We present Czech contribution to AHEAD with emphasis on the innovative Lobster Eye (LE) and Kirpatrick Baez (KB) modules based on Multi Foil Optics technology (MFO). The LE X- ray optics is a wide field of view (FOV) optics type Lobster Eye (LE) with short focal length (suitable for cubesat application) based on Schmidt design. The 2D LE optics consists of two orthogonal sub-modules of flat smooth reflective foils and each sub-modules focuses in one direction. The advantage of MFO LE is that for off-axis points the angular resolution is preserved throughout the FOV, as demonstrated by simulations and measurements. The detector system includes two detectors - Timepix3 Quad and spectroscope. The benefit of the combined detector system was demonstrated in the real measurement. The KB modules developed and tested include a double test module HORUS as well as a new generation multiple arrays module of 2D X-ray KB optics with long f (nearly 6 meters).

Since launched in March 2021, the 1U-sized CubeSat named GRBAlpha has been provided valuable measurements and detections related to gamma-ray bursts and another types of high-energy transient phenomena. Due to its small size, therefore, GRBAlpha can be coined as the smallest astrophysical space observatory to date. In this presentation I summarize the key steps and milestones related to this otherwise fully-fledged mission: starting from our ideas and initiatives, detector and system design, ground testing and calibration procedure, platform-level and system integration up to the present-day in-orbit operations phase, including commissioning, initial operations, data handling and telemetry, on-board and ground data processing and steps towards properly calibrated scientific data series. In addition, I discuss the status of future plans of this mission include the possibility of further flight software upgrades, aiming to increase the data volume downlink, sampling cadence and to operate our satellite as a discovery engine at the same time.

CubeSats offer excellent opportunities to train students in system engineering skills. It supports a combination of theoretical background with practical hands-on activities. The introduction of CubeSats standards is the basis for hardware realization at different complexity levels. This contribution sketches at the example of the space-ecosystem in Würzburg the pathway from space technology education to innovative research satellites. The achieved technology progress and the intensive research exchanges enabled worldwide CubeSat university cooperation, opening perspectives for interesting scientific and commercial CubeSat applications. Here especially distributed, networked multi-satellite systems offer a broad spectrum of innovative applications in space weather, Earth observation and telecommunications.

Transient High-Energy Sky and Early Universe Surveyor (THESEUS), a multi-instrument space mission concept, is currently one of the three candidates of the European Space Agency (ESA) M7 medium size missions, with strong heritage derived from the M5 Phase-Assessment (Phase-A) study in 2018-2021. Primary goals of this mission include exploring the early universe by identifying and localising Gamma Ray Bursts (GRBs) at high redshifts (potentially up to z = 10 and beyond) and contributing to multimessenger time-domain astrophysics through extensive X/gamma-ray transient universe monitoring. Key to THESEUS success is its comprehensive transient detection and characterization capabilities, enabled by wide and deep sky monitoring across a broad energy band (0.3 keV – 10 MeV) in which the X and Gamma-ray Imaging Spectrometer instrument (XGIS, 2 keV - 10 MeV) plays a key role. Additionally, high positional accuracy (≤ 2 arcmin) and immediate transient identification with highly accurate redshift determination is achieved through the onboard Soft X-ray Imager (SXI, 0.3 - 5 keV) and the InfraRed Telescope (IRT), respectively. This presentation mainly focuses on the design, working principle, and expected performances of the XGIS instrument, illustrating its evolution from the beginning of M5 Phase A to the current M7 Phase A, its unprecedented capabilities and its synergies with the other two instruments onboard THESEUS will also be briefly discussed.

We present the results of the GRBAlpha and VZLUSAT-2 nanosatellites, which carry onboard gamma-ray detectors for monitoring transients. These detectors, with a sensitivity range of 30-900 keV, consist of a 56 cm2 flat CsI(Tl) scintillator read-out by 8 multi-pixel photon counters (SiPMs). GRBAlpha, a 1U CubeSat launched in March 2021, which operates on a 550 km altitude sun-synchronous polar orbit, has, so far, detected 101 gamma-ray transients, such as long and short gamma-ray bursts (GRBs), flashes from the soft-gamma repeater SGR 1935+2154, and solar flares. It detected the extraordinarily bright GRB 221009A, which was the most intense GRB ever recorded in the 55-year history of GRB science. We were able to provide an unsaturated measurement of its peak flux. Three years after the launch, the detector performance is good and we can characterize the degradation of SiPMs in orbit (the biggest issue of these novel photon counters). The same detector system, but double in size, was launched in January 2022 on the VZLUSAT-2 3U CubeSat. So far, it has detected 73 gamma-ray transients, including GRBs, the activity of SGR 1935+2154 and SGR 1806-20, as well as solar flares. Both nanosatellites also detected the second brightest gamma-ray burst GRB 230307A which surprisingly with its long duration is associated with a compact stellar merger. These missions have demonstrated that nanosatellites can be used to monitor gamma-ray transients routinely.

We describe the scientific potential of a Soft X-ray Imager (SXI) onboard the ESA-CAS satellite SMILE to investigate cosmic X-ray sources in the soft X-ray region. For our analysis, we assumed only the cosmic objects located in the planned fields to be observed by SXI. We used the 2-3 keV band flux of MAXI/ISS, covering at least part of the expected band of the SXI/SMILE telescope. We show that compact sources like neutron stars accreting matter from their companions are promising targets for evaluating the possibilities of SXI. We present the typical features of the activity of X-ray binaries. We also discuss how SXI can contribute to this branch.

Originally, the IBWS (INTEGRAL/BART) workshops focused on the work of High energy astrophysics group (at that dime dominated by young research fellows and students) in Astronomical Institute of the Academy of Sciences of the Czech Republic and relevant national and international collaborators from the field, with intensive student participation. During the early years, these activities were focussed on the ESA INTEGRAL satellite and on the related ground-based robotic telescopes, e.g. the small robotic BART telescope at the Ondrejov Observatory. Nowadays, the IBWS workshops promote regional collaboration in galactic and extragalactic high-energy astrophysics, both experimental as well as theoretical, with an emphasis on the interface between satellite projects and ground-based experiments (e.g. robotic telescopes). We continue our emphasis on wide participation and presentations of students and young research fellows. In 2024, there will be an AHEAD summer school within the workshop, with selected lectures for students.

In 2023 the German Federal Ministry of Education and Research (BMBF) and the German organization for science communication “Wissenschaft im Dialog” (German for: Science in dialogue) jointly proclaimed a "Science Year" with the motto “Our Universe”. One of the numerous events that have been supported thereby has been that of the project "Zirkus UNI-versum" (in English: "Circus UNI-verse"), which took place in summer 2023 at Aschaffenburg University of Applied Sciences. Two school classes from the local high school “Kronberg-Gymnasium” first experienced an interactive astronomy lecture including a planetarium star show in a tent. Another highlight was the rocket car race in front of the cafeteria and the exclusive launch of a water rocket on the campus green. After the collective countdown, it reached a height of around eighty meters and thus rose higher than all the trees and buildings on the campus site. For their own exploration of the night sky the pupils obtained small cardboard star maps to assemble themselves as a homework. On the summer evenings of the following school holidays, they certainly observed the sky with a different point of view and, above all, with expert knowledge. The event has given them interesting impressions of Aschaffenburg Technical University as an attractive local education facility. The project "Zirkus UNI-versum" – and other activities for schools – intend to stimulate the interest of pupils in STEM subjects and to attract future engineering students.