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OT 081 is a luminous blazar well known for its variability in many energy bands. The very-high-energy (VHE; E >100 GeV) gamma-ray emission from the source was discovered by MAGIC and H.E.S.S. during flaring activity in July 2016, after a trigger from the Large Area Telescope (LAT) onboard the Fermi satellite. By analysing the multiwavelength light curves andthe broadband spectral energy distribution (SED), we study the activity of the source and investigate four individual states of activity in the window from MJD 57575 to 57602. The intrinsic gamma-ray spectrum can be described by a power law with spectral indices of 3.27 ± 0.44(MAGIC)and 3.39 ± 0.58(H.E.S.S.) over energy ranges 60–300 GeV and 120–500 GeV, respectively. The combined contemporaneous high-energy (HE;E >100 MeV) through VHE SED shows curvatureand can be described by a log-parabola shape. A simple one-zone synchrotron self-Compton (SSC)model is not sufficient to describe the broadband SED. The presence of broad emission lines in the optical spectrum of the source challenges the categorisation of OT 081 as a BL Lac and, together with the emission scenarios tested, points to the possibility that the source is transitional in nature between a BL Lac and a flat-spectrum radio quasar., PoS: Proceedings of Science, 395, ISSN:1824-8039, 37th International Cosmic Ray Conference (ICRC 2021)

Among the many activities organized by the Outreach working group of the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) Collaboration, we would like to present the ongoing project #meetTheMAGICians. Under this hashtag, used on our social media pages (@MAGICtelescopes), we collect live streaming events on astroparticle physics topics, series of social media posts, videos and other contents. In addition to increasing the visibility of the MAGIC collaboration, a central goal of #meetTheMAGICians is to strongly connect the communication of our science to the individual achievements of our researchers. It is a community-wide challenge to increase the individual recognition of early career scientists in large international science collaborations. In this project, we give young members of the MAGIC collaboration the chance to increase their visibility in the astroparticle community by highlighting their individual contributions to our research. At the same time, we aim to communicate to the general public how exciting and diverse astroparticle physics can be, and to stimulate in young students the curiosity towards the extreme Universe. We will present an overview on the present status of the project, and an analysis of both successes and remaining challenges. ISSN:1824-8039

The MAGIC collaboration reports the first detection of very-high-energy (VHE ; E>100 GeV) gamma-ray emission from the flaring blazar TXS1515-273 (RA=15 18 03.610, Dec= -27 31 31.40, J2000.0). The object was observed with the MAGIC telescopes for 1.9 hours on 2019/02/28 under moderate moonlight in the zenith distance range 55 - 60 deg. The preliminary real-time analysis of this data shows a detection of TXS1515-273 with a statistical significance more than 5 standard deviations. The MAGIC observations were triggered by the flaring activity reported by Fermi-LAT from 2019/02/24 to 2019/02/25 (ATel#12532). Few hours before that ATel, a communication from Dave Thompson from the Fermi team alerted the MAGIC collaboration about this source. The redshift of this source is uncertain, with an upper limit z

The MAGIC telescopes performed a rapid follow-up observation of GRB 190114C (Gropp et al., GCN 23688 ; Tyurina et al., GCN 23690, de Ugarte Postigo et al., GCN 23692, Lipunov et al. GCN 23693, Selsing et al. GCN 23695). This observation was triggered by the Swift-BAT alert ; we started observing at about 50s after Swift T0: 20:57:03.19. The MAGIC real-time analysis shows a significance >20 sigma in the first 20 min of observations (starting at T0+50s) for energies >300GeV. The relatively high detection threshold is due to the large zenith angle of observations (>60 degrees) and the presence of partial Moon. Given the brightness of the event, MAGIC will continue the observation of GRB 190114C until it is observable tonight and also in the next days. We strongly encourage follow-up observations by other instruments. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de) and K. Noda (nodak@icrr.u-tokyo.ac.jp). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Observatory Roque de los Muchachos on the Canary island La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

The MAGIC telescopes have observed an increase in the very-high-energy (VHE ; >100 GeV) gamma-ray flux from a position compatible with the blazar BL Lacertae (RA=22h02m43.3s Dec=+42d16m40s, J2000.0, z=0.07). The preliminary analysis of 0.76 hours of MAGIC data taken on 2019/05/03 (MJD 58606.18 to 58606.20) under zenith angle range from 46 to 53 deg and dark time conditions with the atmospheric transmission of 0.85, indicates a flux larger than 0.1 of the flux from the Crab nebula above 200 GeV, and detection significance over 6 sigma. The MAGIC observations were triggered by the flaring activity at HE gamma-rays reported by Fermi-LAT (ATel #12718), and optical observations by Astronomical Observatory of the University of Siena (ATel #12722). MAGIC observations on BL Lacertae will continue during the next days and multiwavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de) and D. Dominis Prester (dijana@phy.uniri.hr) MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

The MAGIC telescopes have observed an unprecedented level of very-high-energy (VHE ; >100 GeV) gamma-ray flux from 1ES 1218+304 (12h21m21.941s, +30d10m37.11s, J2000.0). The preliminary analysis of the data from 2018/12/31 to 2019/01/02 indicates a VHE gamma-ray flux reaching the level of ~25 % of the flux from the Crab nebula above 100 GeV. Compared to the quiescent state reported by VERITAS, this implies an increase by a factor of ~4. The previous record of VHE gamma-ray flux of this source was ~20% of the flux from the Crab nebula above 100 GeV. It was measured by VERITAS on the night of 30 January 2009 (2010ApJ, 709L, 163A). 1ES 1218+304 is a high-synchrotron-peaked BL Lac object located at redshift z=0.182. It was first recognized as a VHE gamma-ray emitter by the MAGIC Collaboration in 2005 (Albert, J., 2006, ApJ, 642L, 119A). The MAGIC observations were triggered by the flaring activity in the optical R-band, measured by the KVA telescope from 2018/12/24 to 2019/01/02. The KVA data showed a flux of 2.35+/-0.05 mJy on 2019/01/02, which is the highest optical flux measurement from this source in a time span of 15 years (http://users.utu.fi/kani/1m/1ES_1218+304_jy.html). MAGIC observations on 1ES 1218+304 will continue during the next weeks and multiwavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de), V. Fallah Ramazani (vafara@utu.fi) and M. Cerruti (matteo.cerruti@icc.ub.edu). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

We report an enhanced emission of VHE gamma-rays from the direction of the blazar TXS 0506+056 (05 09 25.96370, +05 41 35.3279 (J2000), [Lani et al., Astron. J., 139, 1695-1712 (2010)]), located 6 arcmin from the estimated direction of the high energy IceCube neutrino event IceCube-170922A (ATel #10791). On Dec 3rd 2018 the MAGIC telescopes observed this source for about 2 hours under good weather conditions. The source was detected at VHE gamma-rays above 90 GeV with a significance larger than 5 sigma. The preliminary analysis yields an estimate of the VHE gamma-ray flux above 90 GeV of ~10-15% of the flux from the Crab Nebula above the same energy threshold, and a spectral index of ~4. This flux is consistent with the emission level integrated between September 28th 2017 to October 3rd 2017, when the source was discovered at VHE gamma-rays (ATel #10817). The MAGIC telescopes will continue monitoring the VHE gamma-ray emission of TXS 0506+056. Soft-X-rays and ultraviolet ToO observations with the Neil Gehrels Swift Observatory have been approved for the next three nights (PI: Cerruti, on behalf of MAGIC), to occur within the time-window 00:00 to 04:00 UTC. NuSTAR ToO observations have also been approved (PI: Satalecka). Multi-wavelength observations (quasi)-simultaneous with MAGIC in this time-window are strongly encouraged.

The astrophysical journal 863(1), L10 (2018). doi:10.3847/2041-8213/aad083, A neutrino with energy ∼290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS 0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at ∼3σ level. We monitored the object in the very-high-energy (VHE) band with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for ∼41 hr from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons co-accelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of $\sim 10^{45} - 4 \times 10^{46} erg s^{-1}$. The steep spectrum observed by MAGIC is concordant with internal γγ absorption above ∼100 GeV entailed by photohadronic production of a ∼290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton upscattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet comoving frame can be in the range $∼10^{14} – 10^{18}$ eV., Published by IOP, Chicago, Ill. [u.a.]

The -beam asymmetry Sigma in the photoproduction of negative pions on quasi-free neutrons in a deuterium target was measured at the Grenoble Anneau Accelerateur Laser in the energy interval 700-1500 MeV and over a wide angular range, using polarized and tagged photons. Results are compared with recent partial-wave analyses.

The only recent η′ photoproduction data off proton available in literature are the differential and total cross sections published by the CLAS and CB-ELSA-TAPS Collaborations. However, the wide information about reaction cross sections are not sufficient to understand the role of resonances involved in the process. Different theoretical works stressed the importance to measure also polarization observables in order to solve the ambiguities in the choice of the parameters used in their models. We present the analysis of η′ photoproduction off the proton analysis, identifying the investigated meson by the π+π−η, π0π0η, and γγ decay modes by using the GRAAL apparatus; and we show the preliminary GRAAL results on the beam asymmetry Σ at beam energy of 1475 MeV.

This work of thesis aims to study the properties of the recurrent nova RS Ophiuchi, whose latest outburst phase was observed in August 2021. RS Ophiuchi is a binary system composed of a red giant star and a CO white dwarf (WD). These stars are close enough to have the transfer of matter from the red giant to the WD. The accretion of this matter on the surface of the WD gives rise to recurrent releases of energy by a thermonuclear runaway. Simulations of the nova RS Ophiuchi were made with MESA (Modules for Experiments in Stellar Astrophysics) star module as a part of the NuGrid (Nucleosynthesis Grid) collaboration’s collection of software tools for simulations. Two different simulations were made for the WD profile with and without convective boundary mixing. For each WD profile, WD models for different evolutionary paths were made, resulting in WD models with different masses of the accreted shells. For the logarithmic luminosity of the RS Ophiuchi, a value of log10 L L⊙ = 1.867, has been obtained, and comparison with the logarithmic luminosity of models in plots of constant WD Roche lobe radius brought me to the conclusion that RS Ophiuchi has a greater mass of the accreted envelope than most models. Models with logarithmic luminosity close to the one of RS Ophiuchi of both profiles have both pp-chain, and CNO cycles ignited in their accreted envelope, confirming that these models are good models of the nova RS Ophiuchi.

Motivirani s predviđanjem T. Cheng-a i M. Spinratha, testirali smo opisanu metodu detekcije tamne tvari koristeći modificirani Michelsonov interferometar. U prvom dijelu objašnjen je način rada modificiranog Michelsonovog interferometra kojem je jedno zrcalo zamijenjeno sa silicij nitridnom membranom. Opisani su dijelovi eksperimenta, poput rada djelitelja snopa, polarizirajućeg djelitelja snopa, princip rada homodinske detekcije i njenim prednostima poput niskog šuma, brzi Fourierov transformat korišten kao jedna od osnovnih računalnih alata u analizi podataka gdje je još u kratko opisan rad CooleyTukey-ovog algoritma. U drugom dijelu opisan je i eksperimentalni postav te optički put zračenja od izvora do detekcije. Ukratko su opisane fizikalne značajke membrane, opisan je princip rada optičkih fotodetektora,te princip rada akusto-optičkog modulatora. U trećem dijelu opisane su metode prikupljanja, obrade koristeći HPC Buru, i skladištenja podataka za njihovu daljnju obradu. Na kraju je naveden kalibracijski faktor određen korištenjem procedure iz koju je izgradio i opisao M. Vretenar, rezultati preklapanjem, rezultat potrage za anomalnim signalima, te su ti rezultati normirani po amplitudama i broju događaja za određeni udar, da bi na kraju dobili gustoću raspodjele., Motivated with predictions theorised by T. Cheng and M. Spinrath, we have tested the described detection method for dark matter using a modified Michelson interferometer. In the first section a explanation of the modified Michelson interferometer was given. The modification is a replacement of a mirror with a silicon nitrade membrane. Parts of the experiments, such as beamsplitter, polarizing beamsplitter, and the homodyne detection method with it’s advangeges of low noise were discussed. The fast Fourier transform algorithm was used as one of the fundamental computational tools in data analysis, as well as a breif explanation of the Cooley-Tukey algorithm. In the second section an explanation of the experimental setup was given, as well as the optical path from the laser source to the detector. Physical characteristics of the membrane were given, a description of photodetector and acusto-optical modulator was also given. In the third section I describe methods of data collection, analysis using the HPC Bura, and storage for further analysis. In the end I present the calibration factor determined by use of the procedure given and developed by M. Vretenar, results of the data folding method, an attempt to find anomalous signals, and lastly those anomalous signals were normalized by their amplitudes and number of hits per amplitude to get their probabilites.

In this thesis, a method for detecting the displacement of tracking detector modules is developed. The modules are silicon planes mounted on an aluminum frame and used in the MUonE project, which aims at a precision measurement of the scattering angle of elastic muon electron scattering. From the scattering angle, the hadronic contribution to the anomalous magnetic moment of the muon is extracted. To achieve the desired accuracy, the position of the tracking detector planes must be continuously monitored. The allowable relative displacements must be less than 10 µm. To meet the specifications and to monitor as large an area of the detector as possible, a digital holographic interferometer was developed. It is based on a novel lens-less design in off-axis holographic geometry. Light from a fiber-coupled 532-nm laser source is split by a fiber beam splitter, with one output used to illuminate the detector plane and the other for the reference beam. The two beams produce an interference pattern on a CMOS image sensor. To obtain relative displacement information, successive images are superimposed on an initial reference image and reconstructed by solving the Rayleigh-Sommerfeld diffraction integral taking into account the spherical wavefronts of the beams. The interference fringes that appear in the reconstructed holographic image provide a measure of the relative displacement of the detector plane compared to the initial position. The performance of the reconstruction method used was verified with the proposed setup at a real tracking station.

This work of thesis is devoted to the study of Dark Matter (DM) distribution in the globular cluster M15 and will be a basis for a next study of searching for DM signals with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes with M15 as a target. Cherenkov telescopes as MAGIC operate in the VHE γ-ray range, meaning they can detect γ-rays at energies higher than 100GeV. The search of DM with such telescopes is performed as an indirect measurement: what can be observed are γ-rays coming from the annihilation or decay of DM particles. The strength of the signal provided by annihilating (or decaying) DM is represented by the astrophysical J-factor. The J-factor depends on the target distance and its DM distribution. This work is divided in two main parts: first I studied the globular cluster M15 and define its DM profile using existing spectroscopic measurements of the relative velocities of stars in the cluster. After collecting the necessary measurements of the radial velocities of stars in M15 from recent literature, I run a Jeans analysis using the program CLUMPY (https://clumpy.gitlab.io/CLUMPY/), a code for the study of γ-ray signal from DM structures. After this step, I performed a statistical analysis and calculate the astrophysical J-factor. In this way, I obtained a complete and updated description of the Jfactor in M15 which can be used to search for DM annihilation or decay in M15 with MAGIC data.

Blazars are Active Galactic Nuclei (AGNs) whose jet is pointed towards the observer. They are usually divided in two sub-classes, depending on the aspect of their optical spectrum. Blazars which present an optical spectrum which lacks of emission lines are categorised as BL Lacertae objects (BL Lacs), while blazars whose optical spectrum shows strong emission lines are named Flat Spectrum Radio Quasars (FSRQs). The majority of blazars who have been found emitting VHE γ-rays are BL Lacs. MAGIC observed and discovered in the VHE γ-ray band many of them in the past years. Nevertheless some of them remained undetected, meaning the significance of the signal was lower than 5 σ. For my work of thesis, I gathered information and data from such undetected sources and created a catalog of 41 sources, 25 of which are BL Lacs. From them, I selected a sample of 5 sources which were observed in 2020-2022 as a starting point for a more complete upper limits study which is in preparation within the MAGIC collaboration. The sources I analysed in detail are: 4FGLJ0955.1+ 3551, 87GB-225250.5+235403, TXS1700+685, PKS2247-131 and PKS2345-16. From the selected sample of sources I obtained upper limits (ULs) to the light curves (LCs) and spectral energy distributions (SEDs), which can be used in the future to study such sources in a multiwavelength (MWL) context and define a baseline for future studies in case of detection. ULs can in fact, combined with other MWL data, help in understanding the possible emission scenarios of those sources and into defining strategies to detect them., Blazari su Aktivne Galaktičke Jezgre (AGN) čiji je mlaz uperen prema promatračcu. Uobičajeno su podijeljeni u dvije klase ovisno o svojstvima njihova optičkog spektra. Blazari koji imaju optički spektar u kojem nedostaju emisijske linije kategorizirani su kao BL Lacertae objekt (BL Lac), dok se blazari, čiji optički spektar ima jake emisijske linije, nazivaju Flat Spectrum Radio Quasars (FSRQ). Većina blazara koji emitiraju VHE (eng. very high energy) γ-zrake su BL Lac objekti. U proteklim godinama mnogo ih je promatrano i otkriveno sa MAGIC teleskopima. Ipak, neki izvori i dalje ostaju nedetektirani, na što upućuje podatak da je značcajnost manja od 5σ. U svojem radu prikupila sam informacije i podatke upravo od takvih nedetektiranih izvora i stvorila katalog koji sadrži 41 izvor, od kojih su 25 BL Lac objekti. Potom sam izdvojila uzorak od 5 izvora koji su bili promatrani u periodu od 2020. do 2022. godine i to mi je bila početna tocka za detaljniju analizu gornjih granica detekcije koja je u pripremi s kolaboracijom MAGIC. Izvori koje sam detaljnije analizirala su: 4FGL-J0955.1+3551, 87GB-225250.5+235403, TXS1700+685, PKS2247-131 i PKS2345-16. Iz odabranog uzorka uspjela sam odrediti gornje granice detekcije za svjetlosne krivulje i spektralnu distribuciju energije. Ti podatci se u budućnosti mogu upotrijebiti za promatranje sličnih izvora u kontekstu istraživanja u cijelom području elektromagnetskog spektra, i mogu poslužiti kao vodilja u slučaju detekcije. Gornje granice, u kombinaciji sa podatcima u ostalim područjima spektra, mogu pomoći pri razumijevanju moguće emisije za te izvore baš te za određivanje mogućih strategija za detekciju.