Application of Deep Learning methods to analysis of Imaging Atmospheric Cherenkov Telescopes data

Ground based gamma-ray observations with Imaging Atmospheric Cherenkov Telescopes (IACTs) play a significant role in the discovery of very high energy (E > 100 GeV) gamma-ray emitters. The analysis of IACT data demands a highly efficient background rejection technique, as well as methods to accurately determine the energy of the recorded gamma-ray and the position of its source in the sky. We present results for background rejection and signal direction reconstruction from first studies of a novel data analysis scheme for IACT measurements. The new analysis is based on a set of Convolutional Neural Networks (CNNs) applied to images from the four H.E.S.S. phase-I telescopes. As the H.E.S.S. cameras pixels are arranged in a hexagonal array, we demonstrate two ways to use such image data to train CNNs: by resampling the images to a square grid and by applying modified convolution kernels that conserve the hexagonal grid properties. The networks were trained on sets of Monte-Carlo simulated events and tested on both simulations and measured data from the H.E.S.S. array. A comparison between the CNN analysis to current state-of-the-art algorithms reveals a clear improvement in background rejection performance. When applied to H.E.S.S. observation data, the CNN direction reconstruction performs at a similar level as traditional methods. These results serve as a proof-of-concept for the application of CNNs to the analysis of events recorded by IACTs

Use of entropy in the analysis of nominal traits in sheep

In the analysis of dependencies between nominal traits entropy and its function, mutual information seems to be a proper descriptive statistic. This is shown by characterizing the relationships between the prolificacy of dams and selected genetic attributes: the genotype of transferrin, the genotype of hemoglobin, and the type of birth, as well as the environmental attribute, i.e., year of birth. The entropy method may improve the exactitude of investigations concerning the influence of different factors on production trait. The index of relative uniformity, introduced in this study, proved to be an adequate tool for the determination of similarity in the examined flocks. The application of mutual information in the determination of values of the dependence measures in the analyzed experiment was justified

Modelling the Galactic very-high-energy γ\gamma-ray source population

The High Energy Stereoscopic System (H.E.S.S.) Galactic plane survey (HGPS) is to date the most comprehensive census of Galactic $\gamma$-ray sources at very high energies (VHE; $100\,\mathrm{GeV}\leq E\leq 100\,\mathrm{TeV}$). As a consequence of the limited sensitivity of this survey, the 78 detected $\gamma$-ray sources comprise only a small and biased subsample of the overall population. Still, numerical modelling allows us to study the VHE $\gamma$-ray source population in the Milky Way based on this sample. In this work, several azimuth-symmetric and spiral-arm models are compared for spatial source distribution. The luminosity and radius function of the population are derived from the source properties of the HGPS data set and are corrected for the sensitivity bias of the HGPS. Based on these models, VHE source populations are simulated and the subsets of sources detectable according to the HGPS are compared with HGPS sources. The power-law indices of luminosity and radius functions are determined to range between $-1.6$ and $-1.9$ for luminosity and $-1.1$ and $-1.6$ for radius. Azimuth-symmetric distributions and a distribution following a four-arm spiral structure without Galactic bar describe the HGPS data reasonably well. The total number of Galactic VHE sources is predicted to be in the range from 800 to 7000 with a total luminosity and flux of $(1.6-6.3) \cdot 10^{36}$~ph~s$^{-1}$ and $(3-15) \cdot 10^{-10}$~ph~cm$^{-2}$~s$^{-1}$, respectively. Depending on the model, the HGPS sample accounts for $(68-87)\%$ of the emission of the population in the scanned region. This suggests that unresolved sources represent a critical component of the diffuse emission measurable in the HGPS. With the foreseen jump in sensitivity of the Cherenkov Telescope Array, the number of detectable sources is predicted to increase by a factor between 5 - 9.Comment: 11 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

Exploring the population of Galactic very-high-energy γ-ray sources

At very high energies (VHE), the emission of γ rays is dominated by discrete sources. Due to the limited resolution and sensitivity of current-generation instruments, only a small fraction of the total Galactic population of VHE γ-ray sources has been detected significantly. The larger part of the population can be expected to contribute as a diffuse signal alongside emission originating from propagating cosmic rays. Without quantifying the source population, it is not possible to disentangle these two components. Based on the H.E.S.S. Galactic plane survey, a numerical approach has been taken to develop a model of the population of Galactic VHE γ-ray sources, which is shown to account accurately for the observational bias. We present estimates of the absolute number of sources in the Galactic Plane and their contribution to the total VHE γ-ray emission for five different spatial source distributions. Prospects for CTA and its ability to constrain the model are discussed. Finally, first results of an extension of our modelling approach using machine learning to extract more information from the available data set are presented

Probing Galaxy structure with VHE γ\gamma rays

As an observer from within the Milky Way, it is difficult to determine its global structure. Despite extensive observational data from surveys at different wavelengths, we have no conclusive description of the structure of our own Galaxy. For very-high-energy (VHE) $\gamma$ rays, the most comprehensive catalogue of Galactic sources resulting from the H.E.S.S. Galactic Plane Survey (HGPS) shows a striking asymmetry in the distribution of the sources in the latitudinal direction. This could be the result of a local feature in the spatial distribution of the sources or it could be due to the position of the Sun above the Galactic plane. In this contribution, we estimate the position of the Sun based on the latitudinal flux profile of VHE $\gamma$-ray sources, assuming three mirror-symmetric models for the spatial distribution of the sources in three-dimensional space and taking into account the observational bias of the HGPS. We verify our method using simulations and find values for $z_{\odot}$ between $-6\,\mathrm{pc}$ and $94\,\mathrm{pc}$ depending on the considered model. Our results show that the position of the Sun has a significant impact on the observed source distribution and must therefore be taken into account when modelling the population of Galactic VHE $\gamma$ sources. However, it is not conclusive whether the Sun's offset from the Galactic plane is the only factor leading to the asymmetry in the latitudinal profile.Comment: 6 pages, 3 figures, Proceedings of the 7th Heidelberg International Symposium on High-Energy Gamma-Ray Astronomy ($\gamma$-2022), Barcelona, Spai

HexagDLy - Processing hexagonally sampled data with CNNs in PyTorch

HexagDLy is a Python-library extending the PyTorch deep learning framework with convolution and pooling operations on hexagonal grids. It aims to ease the access to convolutional neural networks for applications that rely on hexagonally sampled data as, for example, commonly found in ground-based astroparticle physics experiments

Post-slaughter carcass evaluation in whiteheaded mutton sheep according to the EUROP classification

Analyses were conducted on 120 lambs of the whiteheaded mutton sheep (60 tup lambs and 60 ewe lambs). Lambs were weaned at the age of 60 ± 3 days. Lambs were fattened using pelleted balanced feed. 1 kg of feed contained 860 g dry matter, 147 g crude protein and 6.9 MJ (net energy). On the day of slaughter (100 ± 3 days), tup lambs weighed an average of 33.1 kg and ewe lambs weighed 31.0 kg. After slaughter, a point score conformation and fatness evaluation was performed according to the EUROP classification (E is excellent, U is very good, R is Good, O is fair and P is poor), carcass measurements were taken, and the tissue composition of the half-carcass was determined on the basis of complete dissection. In terms of conformation, the carcasses of tested lambs of both sexes were classified to three grades, that is, E: 14.2%, U: 60.8% and R: 25.0%, respectively. A total of 76.7% carcasses of tup lambs and 73.3% ewe carcasses were classified to two highest grades, that is E and U. In terms of fatness, carcasses were classified to 4 grades, denoting small and medium fatness, that is, 2: 15.0%, 3L: 56.7%, 3H: 20.0% and 4L: 8.3%. A higher number of carcasses with the most desirable degree of fatness (grades 2 and 3L), came from tup lambs (78.3%) than ewe lambs (65.0%). A comparison of the subjective EUROP classification with the results of evaluation based on measurements and complete dissection shows that when evaluating conformation, it was not possible to determine precisely the tissue composition of the carcass. In turn, fatness evaluation may be informative on tissue contents in the carcass.Keywords: Lamb, carcass composition, EUROP classificatio

Seksualny kapitał w wersji publicznej

The main intention of Samuel Nowak—the author of Sexual Capital—is to define “what the mass media are for men labelling themselves as gay, taking into account various, although always treated collectively, contexts: economic, political and medial”(p. 9). The sub-title of the study, which defines the direction of the whole text, is Wyobrażone wspólnotysmaku i medialne tożsamości polskich gejów (“Imagined Communities of Taste and Medial Identities of Polish Gay Persons”). In the Nowak’s study, important is the evaluation from outside (as viewed by science) and from within (as viewed by proponents of LGBT). The critical review of Sexual Capital is compatible with the structure of the original text: originally focuses on scientific theories in order to end with the examples from Polish medial realities

Detection of variable VHE gamma-ray emission from the extra-galactic gamma-ray binary LMC P3

Context. Recently, the high-energy (HE, 0.1-100 GeV) $\gamma$-ray emission from the object LMC P3 in the Large Magellanic Cloud (LMC) has been discovered to be modulated with a 10.3-day period, making it the first extra-galactic $\gamma$-ray binary. Aims. This work aims at the detection of very-high-energy (VHE, >100 GeV) $\gamma$-ray emission and the search for modulation of the VHE signal with the orbital period of the binary system. Methods. LMC P3 has been observed with the High Energy Stereoscopic System (H.E.S.S.); the acceptance-corrected exposure time is 100 h. The data set has been folded with the known orbital period of the system in order to test for variability of the emission. Energy spectra are obtained for the orbit-averaged data set, and for the orbital phase bin around the VHE maximum. Results. VHE $\gamma$-ray emission is detected with a statistical significance of 6.4 $\sigma$. The data clearly show variability which is phase-locked to the orbital period of the system. Periodicity cannot be deduced from the H.E.S.S. data set alone. The orbit-averaged luminosity in the $1-10$ TeV energy range is $(1.4 \pm 0.2) \times 10^{35}$ erg/s. A luminosity of $(5 \pm 1) \times 10^{35}$ erg/s is reached during 20% of the orbit. HE and VHE $\gamma$-ray emissions are anti-correlated. LMC P3 is the most luminous $\gamma$-ray binary known so far.Comment: 5 pages, 3 figures, 1 table, accepted for publication in A&