Search

The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it will offer unique opportunities to address many key astrophysical questions in a completely novel way. The synergy with ground-based and space-born instruments in the electromagnetic domain, by enabling multi-messenger observations, will add further to the discovery potential of LISA. The next decade is crucial to prepare the astrophysical community for LISA's first observations. This review outlines the extensive landscape of astrophysical theory, numerical simulations, and astronomical observations that are instrumental for modeling and interpreting the upcoming LISA datastream. To this aim, the current knowledge in three main source classes for LISA is reviewed; ultra-compact stellar-mass binaries, massive black hole binaries, and extreme or interme-diate mass ratio inspirals. The relevant astrophysical processes and the established modeling techniques are summarized. Likewise, open issues and gaps in our understanding of these sources are highlighted, along with an indication of how LISA could help making progress in the different areas. New research avenues that LISA itself, or its joint exploitation with upcoming studies in the electromagnetic domain, will enable, are also illustrated. Improvements in modeling and analysis approaches, such as the combination of numerical simulations and modern data science techniques, are discussed. This review is intended to be a starting point for using LISA as a new discovery tool for understanding our Universe.

Full list of authors: Amaro-Seoane, Pau; Andrews, Jeff; Sedda, Manuel Arca; Askar, Abbas.; Baghi, Quentin; Balasov, Razvan; Bartos, Imre; Bavera, Simone S.; Bellovary, Jillian; Berry, Christopher P. L.; Berti, Emanuele; Bianchi, Stefano; Blecha, Laura; Blondin, Stephane; Bogdanovic, Tamara; Boissier, Samuel; Bonetti, Matteo; Bonoli, Silvia; Bortolas, Elisa; Breivik, Katelyn; Capelo, Pedro R.; Caramete, Laurentiu; Cattorini, Federico; Charisi, Maria; Chaty, Sylvain; Chen, Xian; Chruslinska, Martyna; Chua, Alvin J. K.; Church, Ross; Colpi, Monica; D'Orazio, Daniel; Danielski, Camilla; Davies, Melvyn B.; Dayal, Pratika; De Rosa, Alessandra; Derdzinski, Andrea; Destounis, Kyriakos; Dotti, Massimo; Dutan, Ioana; Dvorkin, Irina; Fabj, Gaia; Foglizzo, Thierry; Ford, Saavik; Fouvry, Jean-Baptiste; Franchini, Alessia; Fragos, Tassos; Fryer, Chris; Gaspari, Massimo; Gerosa, Davide; Graziani, Luca; Groot, Paul; Habouzit, Melanie; Haggard, Daryl; Haiman, Zoltan; Han, Wen-Biao; Istrate, Alina; Johansson, Peter H.; Khan, Fazeel Mahmood; Kimpson, Tomas; Kokkotas, Kostas; Kong, Albert; Korol, Valeriya; Kremer, Kyle; Kupfer, Thomas; Lamberts, Astrid; Larson, Shane; Lau, Mike; Liu, Dongliang; Lloyd-Ronning, Nicole; Lodato, Giuseppe; Lupi, Alessandro; Ma, Chung-Pei; Maccarone, Tomas; Mandel, Ilya; Mangiagli, Alberto; Mapelli, Michela; Mathis, Stephane; Mayer, Lucio; McGee, Sean; McKernan, Berry; Miller, M. Coleman; Mota, David F.; Mumpower, Matthew; Nasim, Syeda S.; Nelemans, Gijs; Noble, Scott; Pacucci, Fabio; Panessa, Francesca; Paschalidis, Vasileios; Pfister, Hugo; Porquet, Delphine; Quenby, John; Ricarte, Angelo; Roepke, Friedrich K.; Regan, John; Rosswog, Stephan; Ruiter, Ashley; Ruiz, Milton; Runnoe, Jessie; Schneider, Raffaella; Schnittman, Jeremy; Secunda, Amy; Sesana, Alberto; Seto, Naoki; Shao, Lijing; Shapiro, Stuart; Sopuerta, Carlos; Stone, Nicholas C.; Suvorov, Arthur; Tamanini, Nicola; Tamfal, Tomas; Tauris, Thomas; Temmink, Karel; Tomsick, John; Toonen, Silvia; Torres-Orjuela, Alejandro; Toscani, Martina; Tsokaros, Antonios; Unal, Caner; Vazquez-Aceves, Veronica; Valiante, Rosa; van Putten, Maurice; van Roestel, Jan; Vignali, Christian; Volonteri, Marta; Wu, Kinwah; Younsi, Ziri; Yu, Shenghua; Zane, Silvia; Zwick, Lorenz; Antonini, Fabio; Baibhav, Vishal; Barausse, Enrico; Bonilla Rivera, Alexander; Branchesi, Marica; Branduardi-Raymont, Graziella; Burdge, Kevin; Chakraborty, Srija; Cuadra, Jorge; Dage, Kristen; Davis, Benjamin; de Mink, Selma E.; Decarli, Roberto; Doneva, Daniela; Escoffier, Stephanie; Gandhi, Poshak; Haardt, Francesco; Lousto, Carlos O.; Nissanke, Samaya; Nordhaus, Jason; O'Shaughnessy, Richard; Portegies Zwart, Simon; Pound, Adam; Schussler, Fabian; Sergijenko, Olga; Spallicci, Alessandro; Vernieri, Daniele; Vigna-Gomez, Alejandro.-- This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/., The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it will offer unique opportunities to address many key astrophysical questions in a completely novel way. The synergy with ground-based and space-born instruments in the electromagnetic domain, by enabling multi-messenger observations, will add further to the discovery potential of LISA. The next decade is crucial to prepare the astrophysical community for LISA’s first observations. This review outlines the extensive landscape of astrophysical theory, numerical simulations, and astronomical observations that are instrumental for modeling and interpreting the upcoming LISA datastream. To this aim, the current knowledge in three main source classes for LISA is reviewed; ultra-compact stellar-mass binaries, massive black hole binaries, and extreme or interme-diate mass ratio inspirals. The relevant astrophysical processes and the established modeling techniques are summarized. Likewise, open issues and gaps in our understanding of these sources are highlighted, along with an indication of how LISA could help making progress in the different areas. New research avenues that LISA itself, or its joint exploitation with upcoming studies in the electromagnetic domain, will enable, are also illustrated. Improvements in modeling and analysis approaches, such as the combination of numerical simulations and modern data science techniques, are discussed. This review is intended to be a starting point for using LISA as a new discovery tool for understanding our Universe. © The Author(s) 2023, corrected publication 2023., P. Dayal acknowledges support from the European Research council (ERC-717001) and from the Netherlands Research Council NWO (016.VIDI.189.162). P.H. Johansson acknowledges the support from the European Research Council (ERC-818930). S. Toonen acknowledges support from the Netherlands Research Council NWO (VENI 639.041.645 Grants) C. Unal is supported by European Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports (Project CoGraDS - CZ.02.1.01/0.0/0.0/15_003/0000437). S. Chaty acknowledges the LabEx UnivEarthS for the funding of Interface project I10 “From binary evolution towards merging of compact objects”. A. De Rosa acknowledges financial contribution from the agreement ASI-INAF n.2017-14-H.O E. Berti is supported by NSF Grants No. PHY-1912550 and AST-2006538, NASA ATP Grants No. 17-ATP17-0225 and 19-ATP19-0051, NSF-XSEDE Grant No. PHY-090003, and NSF Grant PHY-20043. D. Gerosa is supported by European Union’s H2020 ERC Starting Grant No. 945155–GWmining, Leverhulme Trust Grant No. RPG-2019-350 and Royal Society Grant No. RGS-R2-202004. T. Bogdanovic acknowledges support by the NASA award No. 80NSSC19K0319 and by the NSF award AST-1908042. D. Porquet acknowledges funding support from CNES. C. Danielski acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) B.L. Davis acknowledges support from Tamkeen under the NYU Abu Dhabi Research Institute Grant CAP3. F. Pacucci acknowledges support from a Clay Fellowship by the SAO and from the Black Hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation. A.J. Ruiter acknowledges support from the Australian Research Council Future Fellowship Grant FT170100243. V. Paschalidis is supported by NSF Grant PHY-1912619 and NASA Grant 80NSSC20K1542 to the University of Arizona, and NSF-XSEDE Grant TG-PHY190020. D. Haggard acknowledges support from the NSERC Discovery Grant and Canada Research Chairs programs, and the Bob Wares Science Innovation Prospectors Fund. M. Toscani acknowledges European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 823823 (RISE DUSTBUSTERS project) and COST Action CA16104 - Gravitational waves, black holes and fundamental physics, supported by COST (European Cooperation in Science and Technology). M. Chruslinska, A. Istrate and G. Nelemans acknowledge support from Netherlands Research Council NWO. T. Fragos and S. Bavera acknowledge support from a Swiss National Science Foundation Professorship Grant (project numbers PP00P2_176868 and PP00P2_211006)., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).

Das IceCube Neutrino Observatory, das größte Neutrino-Observatorium der Welt, entdeckte 2013 erstmals einen Fluss hochenergetischer Neutrinos. Diese Neutrinos müssen von astrophysikalischen Beschleunigern erzeugt werden, aber ihr genauer Ursprung ist bisher unbekannt. Vorgeschlagene Neutrinoquellen sind Gezeitenkatastrophen (Tidal Disruption Events, TDEs), Ereignisse bei denen Sterne zerfallen, wenn sie supermassiven Schwarzen Löchern zu nahe kommen. In dieser Doktorarbeit wurde erstmals nach Korrelationen zwischen Neutrinos und TDEs gesucht, wobei eine Zusammenstellung veröffentlichter TDEs und ein IceCube-Datensatz von einer Million Myon-Neutrinos mit GeV-PeV-Energien von verwendet wurde. Es wurde keine signifikante Korrelation gefunden, sodass der Beitrag von TDEs ohne relativistische Jets auf 0-38,0% des gesamten astrophysikalischen Neutrinoflusses begrenzt werden kann. Der Beitrag von TDEs mit relativistischen Jets wurde auf 0-3,0% des Gesamtflusses begrenzt. IceCube veröffentlicht auch hochenergetische (>100 TeV) Myon-Neutrino-Ereignisse in Form von automatischen, öffentlichen Echtzeit-‘Neutrinoalerts’. Im Rahmen dieser Arbeit wurde die Lokalisierung von 22 solcher Neutrinoalerts mit dem optischen Zwicky Transient Facility (ZTF) Teleskop beobachtet, um nach möglichen elektromagnetischen Gegenstücken zu Neutrinos zu suchen. Mit diesem Neutrino-Nachfolgebeobachtungsprogramm wurde die helle TDE AT2019dsg als mutmaßliche Neutrinoquelle identifiziert. Die Wahrscheinlichkeit, solch eine helle TDE zufällig zu finden, beträgt 0,2%. Die Assoziation bedeutet, dass TDEs 3-100% der astrophysikalischen Neutrino-Alerts von IceCube ausmachen. Zusammengenommen deuten diese beiden Ergebnisse darauf hin, dass TDEs einen subdominanten Anteil des astrophysikalischen Neutrinoflusses bei hohen Energien emittieren. Die Assoziation des Neutrinoalerts IC191001A mit AT2019dsg ist erst das zweite Mal, dass ein hochenergetisches Neutrino mit einer mutmaßlichen astrophysikalischen Quelle in Verbindung gebracht werden konnte. The IceCube Neutrino Observatory, the world’s largest neutrino observatory, first discovered a flux of high-energy neutrinos in 2013. These neutrinos must be produced by astrophysical accelerators, but their exact origin remains unknown. One proposed source of neutrinos are Tidal Disruption Events (TDEs), which occur when stars disintegrate after passing sufficiently close to supermassive black holes. In this thesis, the first search for neutrino-TDE correlations was performed, using a compilation of published TDEs and a dataset of one million muon neutrino events of GeV-PeV energies from IceCube. No significant correlation was found, limiting the contribution of TDEs without relativistic jets to 0-38.0% of the total astrophysical neutrino flux. The contribution of TDEs with relativistic jets was limited to 0-3.0% of the total flux. IceCube also publishes high-energy (>100 TeV) probable astrophysical muon neutrino events automatically, in the form of public realtime alerts. As part of this thesis, the location of 22 such neutrino alerts were observed by the Zwicky Transient Facility (ZTF), an optical telescope, in order to search for possible electromagnetic counterparts to neutrinos. With this neutrino follow-up program, the bright TDE AT2019dsg was identified as a probable neutrino source. The probability of finding such a bright TDE by chance is 0.2%. The association implies that TDEs contribute 3-100% of the astrophysical neutrino alerts issued by IceCube. Taken together, these two results suggest that TDEs emit a subdominant fraction of the astrophysical neutrino flux at high energies. The association of neutrino alert IC191001A with AT2019dsg represents only the second time that a high-energy neutrino has been matched to a probable astrophysical source.

Die gemeinsame Beobachtung von Gravitationswellen und Photonen bei der Verschmelzung eines binären Neutronensterns sowie der stichhaltige Hinweis auf einen Blazar als Quelle hochenergetischer Neutrinos im Jahr 2017 trugen wesentlich dazu bei, die Ära der Multi-Messenger-Astronomie einzuläuten. Die Auswirkungen von Echtzeiteffekten der Propagation kosmischer Messenger auf beobachtbare Multi-Messenger-Signaturen werden hergeleitet und mit Hilfe der in dieser Arbeit entwickelten und verbesserten numerischen Tools bestätigt. Darüber hinaus wurde die Plattform Astro-COLIBRI zur Koordinierung von Multi-Messenger-Kampagnen entwickelt, die den Nachweis der am weitesten entfernten aktiven Galaxie mit einem sehr energiereichen Signal im Rahmen dieser Arbeit ermöglichte. Die gewonnenen Erkenntnisse und entwickelte Software tragen zu einer verbesserten Koordination von Multi-Messenger-Kampagnen bei.; The joint observation of gravitational waves and the electromagnetic counterparts of a binary neutron star merger and the compelling evidence for a blazar being a source of high-energy neutrino in 2017 ushered in the era of multi-messenger astronomy. The real-time effects of cosmic-messenger propagation on observable multi-messenger signatures are investigated, whose implications are derived and confirmed by numerical tools developed and improved in this thesis. In addition, the holistic platform Astro-COLIBRI has been developed for coordinating multi-messenger campaigns, which facilitated the detection of the most distant active galaxy with a very-high-energy signal conducted within the thesis. The acquired insights and developed tools contribute to improved coordination of multi-messenger campaigns.; L'observation conjointe des ondes gravitationnelles et des contreparties électromagnétiques de la fusion d'une étoile à neutrons binaire et l'indice qu'un blazar est une source de neutrino de haute énergie en 2017 ont inauguré l'ère de l'astronomie multi-messagers. Les effets en temps réel de la propagation des messagers cosmiques sur les signatures multi-messagers sont étudiés, dont les implications sont dérivées et confirmées par des outils numériques développés et améliorés dans cette thèse. De plus, la plateforme holistique Astro-COLIBRI a été développée pour coordonner les campagnes multi-messagers, ce qui a facilité la détection d'une galaxie active la plus lointaine avec un signal de très haute énergie réalisée dans le cadre de la thèse. Les connaissances acquises et les outils développés contribuent à une meilleure coordination des campagnes multi-messagers.

We describe the use of Multi Order Coverage (MOC) maps as a practical way to manage complex regions of the sky for the planning of multi-messenger observations. MOC maps are a data structure that provides a multi-resolution representation of irregularly shaped and fragmentary regions over the sky based on the HEALPix (Hierarchical Equal Area isoLatitude Pixelization) tessellation. We present a new application of MOC, in combination with the \texttt{astroplan} observation planning package, to enable the efficient computation of sky regions and the visibility of these regions from a specific location on the Earth at a particular time. Using the example of the low-latency gravitational-wave alerts, and a simulated observational campaign with three observatories, we show that the use of MOC maps allows a high level of interoperability to support observing schedule plans. Gravitational-wave detections have an associated credible region localization on the sky. We demonstrate that these localizations can be encoded as MOC maps, and how they can be used in visualisation tools, and processed (filtered, combined) and also their utility for access to Virtual Observatory services which can be queried 'by MOC' for data within the region of interest. The ease of generating the MOC maps and the fast access to data means that the whole system can be very efficient, so that any updates on the gravitational-wave sky localization can be quickly taken into account and the corresponding adjustments to observing schedule plans can be rapidly implemented. We provide example python code as a practical example of these methods. In addition, a video demonstration of the entire workflow is available., To be published in: Astronomy and Computing

Despite their discovery already more than a century ago, Cosmic Rays (CRs) still did not divulge all their properties yet. Theories about the origin of ultra-high energy (UHE, > 10^18 eV) CRs predict accompanying primary photons. The existence of UHE photons can be investigated with the world’s largest ground-based experiment for detection of CR-induced extensive air showers (EAS), the Pierre Auger Observatory, which offers an unprecedented exposure to rare UHE cosmic particles. The discovery of photons in the UHE regime would open a new observational window to the Universe, improve our understanding of the origin of CRs, and potentially uncloak new physics beyond the standard model. The novelty of the presented work is the development of a "real-time" photon candidate event stream to a global network of observatories, the Astrophysical Multimessenger Observatory Network (AMON). The stream classifies CR events observed by the Auger surface detector (SD) array as regards their probability to be photon nominees, by feeding to advanced machine learning (ML) methods observational air shower parameters of individual CR events combined in a multivariate analysis (MVA). The described straightforward classification procedure further increases the Pierre Auger Observatory’s endeavour to contribute to the global effort of multi-messenger (MM) studies of the highest energy astrophysical phenomena, by supplying AMON partner observatories the possibility to follow-up detected UHE events, live or in their archival data.

I hunt very-high-energy (VHE) emission from three classes of transient sources: Gravitational waves (GW), their possible gamma-ray bursts (GRB) counterparts and fast radio bursts (FRB). I tackle three types of challenges: Preobservation, focusing on efficient scheduling, observation planning and fast telescope response; in-observation, focusing on efficient data acquisition on the transients as an expert on call; post-observation, focusing on efficient data analysis in the search for a significant signal. For the GW events, the poor localization requires a special treatment for the follow-up. I work on the optimization of GW follow-up strategies that rely on the maximization of the probability of detecting counterparts to transient GW events either by using solely GW localization maps or by correlating the local distribution of the galaxies in the Universe with GW maps. The tools are combined in a GW scheduler, tested and assessed. Using the developed tools and acquired skills, I develop automatic response schemes to GW alerts for the H.E.S.S. and LST telescopes and a response to UTMOST FRB alerts for H.E.S.S. I also contribute to the update of the GRB program in H.E.S.S. on the technical follow-up front. With the implemented tools, H.E.S.S observed 6 GW events, of which 4 BBH mergers. Other transient sources, for which I am involved in the analysis, are observed also by H.E.S.S.: GRB 190829A, GW170817 (long-term), FRB events and the soft gamma-ray repeater (SGR) SGR 1935+2145. GRB 190829A is the third GRB to be observed at VHE energies on the ground and the second one by H.E.S.S. The VHE data (in addition to the Xray and UV data for FRB 20171019A) is analysed for the other transients. No significant VHE emission was found during the BBH merger follow-up and the GW170817 long-term follow-up observation campaigns. The same non-detection was found for the FRBs and SGR 1935+2154. For those, a search for variability on the minutes to sub-seconds scale did not lead to any significant detection either. Upper limits are derived from the observations of the transients presented above. These results are published and the upper limits permit to constrain the magnetic field in the GW170817 remnant, to constrain the persistent and transient emission from SGR bursts and to derive prospects for the fourth GW observation run, O4.; Je recherche des émissions de très hautes énergies (VHE) à partir de trois types de sources transitoires : les ondes gravitationnelles, les sursauts gamma qui peuvent en émerger et les sursauts radio rapides. Pour les ondes gravitationnelles, la localisation des évènements sur plusieurs dizaines de degrés dans le ciel nécessite un traitement spécial pour le suivi. J'optimise des stratégies de suivi ondes gravitationnelles qui reposent sur la maximisation de la probabilité de détection d'émission électromagnétique homologue, soit en utilisant uniquement des cartes de localisation, soit en utilisant aussi la distribution locale des galaxies dans l'Univers. Les outils développés sont testés et évalués. À l'aide de ces outils et des compétences acquises, je développe un système de réponse automatique aux alertes ondes gravitationnelles pour les télescopes H.E.S.S. et LST et aux alertes UTMOST pour H.E.S.S. Je contribue à la mise à jour du programme de H.E.S.S. de suivi de sursaut gamma. Avec les outils mis en place, H.E.S.S a observé 6 événements ondes gravitationnelles, dont 4 fusions de trous noires. D'autres sources transitoires sont également observées par H.E.S.S., dont le sursaut gamma GRB 190829A, la fusion d'étoile à neutron GW170817 (à long terme aussi), des sursauts radio rapides et la source SGR 1935+2145. GRB 190829A est le troisième sursaut gamma détecté à très hautes énergies au sol. Les données VHE, sont analysées (ainsi que les données X et UV pour FRB 20171019A) pour les autres sources. Aucune émission significative de VHE n'a été trouvée durant les suivis des fusions de trous noirs et durant la campagne d'observation à long terme de GW170817, ainsi que pour les sursauts radio rapide et la source SGR 1935+2154. Je déduis des limites supérieures et publie ces résultats. Les limites déduites permettent de contraindre le champ magnétique dans le vestige de GW170817, de placer des limites supérieures sur l'émission VHE persistante et transitoire provenant des sursauteurs gamma mou, et d'établir des perspectives pour O4.

Der Ursprung der ultrahochenergetischen kosmischen Strahlung (UHECRs) benötigt Modelle der photonuklearen kosmischen Strahlungsinteraktionen. In dieser Arbeit stelle ich Modelle vor, die drei Aspekte der Modellierung der Hochenergie-Astronuklearphysik verbessern: die Photomesonenproduktion durch Kerne der kosmischen Strahlung, die schwerer als Protonen sind, die Gammastrahlenemission von instabilen Kernen, die durch den Photodisintegrationsprozess der kosmischen Strahlung erzeugt werden, und die Simulation der extragalaktischen Ausbreitung von Kernen, die schwerer als Eisen sind (sogenannte superschwere Isotope). Das Photomesonenmodell ist das erste in der Literatur, das über das einfache Prinzip der Nukleonen-Superposition hinausgeht. Es liefert eine detailliertere Beschreibung der inelastischen Wirkungsquerschnitte und des emittierten Spektrums von Sekundärteilchen, einschließlich Isotopen und Pionen, die zu Photonen und Neutrinos führen. Die Auswirkungen des Modells werden in Simulationen von Gammastrahlenausbrüchen und Gezeitenstörungsereignissen gezeigt, und es beeinflusst signifikant die hochenergetische Neutrinoemission, die chemische Zusammensetzung und das Spektrum der emittierten UHECRs. Das zweite Modell beschreibt die Photoproduktion aus den De-Exzitationen und Zerfällen instabiler Kerne, die aus dem Photozerfall der kosmischen Strahlung in Wechselwirkung mit astrophysikalischen Photonen resultieren sollen. Ihre Wirkung wird am Photoemissionsspektrum des Kerns von Centaurus A veranschaulicht und mit ähnlichen Arbeiten verglichen, mit denen es Unstimmigkeiten gibt. Schließlich wird der Photodesintegration von UHECR überschweren Kernen diskutiert. Eine Wechselwirkungstabelle wird unter Verwendung von Querschnitten aus TALYS konstruiert, und die Wechselwirkungsraten werden im Zusammenhang mit der extragalaktischen Ausbreitung berechnet. Überschwere Kerne breiten sich in bestimmten Energiebereichen weiter aus als leichtere Kerne., The origin of the ultra-high-energy cosmic rays (UHECRs) is still unknown. Photonuclear interactions of cosmic rays are key to understanding this problem in a multimessenger context. Nuclear physics insights are crucial in building accurate models to interpret the data that indicates UHECR can be heavier than protons. This thesis presents models that improve three aspects of high-energy astronuclear physics modelling: photomeson production by cosmic-ray nuclei heavier than protons, gamma-ray emission from unstable nuclei created by the photodisintegration of cosmic rays, and the simulation of extragalactic propagation of nuclei heavier than iron (so-called superheavy isotopes). The photomeson model is the first in the literature to go beyond the simple principle of nucleon superposition. It provides a more accurate description of the inelastic cross sections, and the emitted spectrum of secondary particles, including isotopes and pions which lead to photons and neutrinos.The model’s impact is shown in simulations of gamma-ray bursts and tidal disruption events, and it affects significantly the high-energy neutrino emission, the chemical composition and the spectrum of the emitted UHECRs. The second model describes photoproduction from de-excitations and decay of unstable nuclei, which are expected to be produced in photo-disintegration of cosmic rays interacting with astrophysical photons. Its impact is illustrated in the photo-emission from the core of the Centaurus A and compared to similar works with which is in disagreement. This supports the need for sufficiently accurate models. Lastly, the photodisintegration of UHECR superheavy nuclei is discussed. An interaction table is produced with cross sections obtained from TALYS and the interaction rates computed in the context of extragalactic propagation. Superheavy nuclei propagate further than lighter nuclei in certain energy ranges. The models developed are publicly available as open-source software.

Two analyses are detailed in this thesis related to neutrino and multi-messenger astronomy with Cherenkov telescopes in the Mediterranean Sea. The first analysis explores the capabilities of the KM3NeT neutrino telescopes to detect the signal from a Galactic core-collapse supernova (CCSN), as well as the physical constraints that could be extracted from such a detection. Together with the Sun, CCSNe are the only confirmed sources of astrophysical neutrinos. A search method for these astrophysical neutrino sources with KM3NeT has been developed during this thesis, based on the analysis of the first data which has allowed for a good characterisation of the background and the detector performance. The results show that the KM3NeT detector might be sensitive to this MeV neutrino flux, with a coverage at 5σ discovery potential of more than 95% of Galactic CCSN progenitors. Therefore, KM3NeT will contribute to the observation of the next Galactic explosion. The CCSN analysis has been implemented in a real-time trigger, that is active since summer 2019. Moreover, it has yielded the first KM3NeT real-time results with the follow-up of the unmodelled candidate gravitational-wave (GW) events. These results have allowed the KM3NeT experiment to join the SNEWS network, to which all detectors sensitive to CCSN neutrino send their alerts. The second analysis exploits the data of the ANTARES neutrino telescope to search for high-energy neutrinos (TeV-PeV) in time and space coincidence with gravitational-wave sources and very-high energy gamma-ray bursts (GRBs). In fact, compact binary mergers and gamma-ray bursts have long been suggested as potential high-energy neutrino emitters. Typically, these searches look for muon neutrinos coming through the Earth (upgoing tracks). For the first time, all-flavors (including the so-called shower events) were included in this kind of searches. Moreover, these analyses have been applied to sources both below the ANTARES horizon (seen as upgoing events), and above the horizon of the ANTARES telescope (downgoing). This has lead to an improvement of sim15-30% for upgoing events and up to a 200% for searches above the horizon. The analyses carried out during the thesis yielded no neutrino in coincidence with any of the gravitational-wave sources from the first GW catalog, neither with the first GRBs detected at very high energies.; Deux analyses sont détaillées dans cette thèse portant sur l’astronomie à neutrinos et les aspects multi-messanger avec les télescopes de type Cherenkov dans la mer Méditerranée.La première analyse explore les capacités des télescopes à neutrinos KM3NeT pour détecter le signal provenant d’une explosion supernova à effondrement de cœur (CCSN) dans la Galaxie,ainsi que les contraintes physiques qui pourrait être extraites d’une telle détection. A part le Soleil, les explosions supernova sont les seules sources astrophysiques de neutrinos confirmées.Une méthode de recherche des neutrinos émis par ces sources a été développée pendant cette thèse, basée sur l’analyse des premières données de KM3NeT, ce qui a permis de caractériser le bruit de fond et la performance du détecteur. Les résultats obtenus montrent que KM3NeT sera sensible à ce flux de neutrinos aux énergies du MeV, avec une couverture de plus du 95 % des CCSN galactiques à 5 sigma de niveau de confiance. Ceci indique que KM3NeT va contribuer à l’observation de la prochaine explosion supernova Galactique. L’analyse supernova a été implémentée pour des recherches en temps réel et il est actif depuis l’été 2019. En fait, cette analyse a conduit aux premiers résultats de KM3NeT en temps réel avec le suivi des alertes des signaux d’ondes gravitationnelles (GW). Ces résultats ont fait possible l’incorporation de l’expérienceKM3NeT au réseau SNEWS, dont tous les détecteurs sensibles aux neutrinos de supernova font partie.La deuxième analyse utilise les données du télescope à neutrinos ANTARES pour chercher des neutrinos de haute énergie (TeV-PeV) en coïncidence temporelle et spatiale avec des sources d’ondes gravitationnelles et des premiers sursauts gamma (GRBs) détectés à très haute énergie. En fait, les collisions d’objets compacts dans des systèmes binaires et les sursauts gamma ont été suggérés pendant longtemps comme des potentielles sources de neutrinos cosmiques.Typiquement, ces recherches cherchent des neutrinos muoniques qui traversent la Terre, vus comme des longues traces montantes dans le détecteur. Pour la première fois, tous les saveurs de neutrinos, ce qui incluse ce qu’on appelle les événements avec une topologie de type cascade, ont été incorporés dans ce type d’analyse. D’autre part, cette analyse a été faite pour des sources au dessus (événements montants) et en dessous (événements descendant) de l’horizon d’ANTARES.Ceci a mené une amélioration de la sensitivité du télescope du 15-20% pour des analyses montants et jusqu’au 200 % pour des recherches d’événements descendants. Ces analyses ont donné comme résultat aucun neutrino détecté en coïncidence dans les données d'ANTARES avec les sources étudiées.

The Super-Kamiokande detector is a 50-kton water tank instrumented with ∼ 13k photomultipliers, running since 1996. It is sensitive to neutrinos with energies ranging from 4.5 MeV to several TeV. Except for supernova bursts, it is difficult to use Super-Kamiokande as an independent astrophysical trigger as its data are dominated by atmospheric neutrinos in this energy range. However, it can be used to search for neutrino events in time and spatial coincidence with various external triggers. We developed a framework for the follow-up of gravitational wave alerts. We searched for neutrinos in a 1000 seconds time window centered on alert time. Results using LIGO/Virgo O3 datasets will be presented, as well as the plans of future realtime public release for O4 and beyond., on behalf of the Super-Kamiokande collaboration, {"references":["IceCube Collaboration • Raamis Hussain (Wisconsin U., Madison) et al. e-Print: 1908.07706 [astro-ph.HE] DOI: 10.22323/1.358.0918","IceCube Collaboration • M.G. Aartsen (Canterbury U.) et al. e-Print: 2004.02910 [astro-ph.HE] DOI: 10.3847/2041-8213/ab9d24","Super-Kamiokande Collaboration • Y. Fukuda (Tokyo U., ICRR) et al. DOI: 10.1016/S0168-9002(03)00425-X","Bruny Baret (APC, Paris), Imre Bartos (Columbia U.), Boutayeb Bouhou (APC, Paris), Alessandra Corsi (LIGO Lab., Caltech), Irene Di Palma (Hannover, Max Planck Inst. Grav.) et al. e-Print: 1101.4669 [astro-ph.HE] DOI: 10.1016/j.astropartphys.2011.04.001"]}

En el presente manuscrito se expone el trabajo realizado en el seno de la Collaboración ANTARES-KM3NeT sobre la astronomía multi-mensanjero con neutrinos, que se ha enfocado en dos ejes: la detección de neutrinos de supernova a bajas energías (MeV) con los telecopios KM3NeT y la búsqueda de neutrinos de alta energía (TeV-PeV) en ANTARES en coincidencia con fuentes transitorias detectadas en ondas gravitationales o rayos gamma de muy alta energía O(TeV). El primer análisis, explora la capacidad de los telescopios de neutrinos KM3NeT para detectar la señal de una explosión de supernova (CCSN), así como el potencial de explotar dicha detección para aprender sobre la física que hay detrás, en particular la resolución del perfil temporal y el espectro en energía de esta señal. Junto con el Sol, las explosiones de supernova son la única fuente astrofísica de neutrinos que ha sido observada. Durante la tesis se ha desarrollado un método de búsqueda para detectar estos neutrinos astrofísicos de baja energía, que se basa en el análisis de los primeros datos de KM3NeT para caracterizar el ruido de fondo y la respuesta del detector. Los resultados de dicho análisis muestran que los detectores KM3NeT son sensibles a un flujo de neutrinos con energías del MeV, y serán capaces de detectar fuentes supernova en nuestra Galaxia con una probabilidad a 5 sigmas, y por tanto contribuirán a la observación de la próxima explosión Galáctica. Este análisis se ha implementado para búsquedas a tiempo real de forma que nos permita mandar alertas en caso en una detección probable, y está en funcionamiento constante desde 2019. De hecho, este análisis se ha aplicado al seguimiento de las alertas de eventos detectados por ondas gravitacionales como fuentes no modelizadas, que son posibles candidatos a ser supernova, lo que ha llevado a los primeros resultados multi-mensajero de KM3NeT. Además, los resultados de este análisis ha permitido que KM3NeT entre a formar parte de la colaboración SNEWS, que reúne a todos los detectores sensibles a la señal de neutrinos de supernova y recibe sus alertas. El segundo análisis, utiliza los datos del detector ANTARES para buscar neutrinos de alta energía (TeV-PeV) en coincidencia espacial y temporal con la detección de fuentes astrofísicas mediante otros mensajeros. En particular, con señales detectados por ondas gravitacionales (GWs) y con las primeras detecciones de “bursts” de rayos gamma (GRBs) a muy alta energía O(TeV) por telescopios de tipo Cherenkov (IATC’s). De hecho, las colisiones de objetos compactos en sistemas binarios (fuentes de ondas gravitacionales) y las fuentes de rayos gamma energéticos, han sido sugeridos durante mucho tiempo como posibles emisores de neutrinos cósmicos. De normal, las búsquedas de fuentes de neutrinos se centran en neutrinos muónicos que atraviesan la tierra antes de ser detectados en el detector (trazas ascendentes), lo que permite de deshacerse del ruido de fondo de los muones atmosféricos. Por primera vez, todos los sabores de neutrinos (incluyendo los llamados eventos de tipo cascada) han sido considerados en esto tipo de análisis. Además, la búsqueda realizada en el este trabajo, es aplicable a fuentes tanto por encima como por debajo del horizonte de ANTARES (eventos ascendentes y descendentes), lo que permite una cobertura de todo el cielo. Esto es posible gracias a las reducidas ventanas espacial y temporal utilizadas. Los análisis multi-mensajero con ANTARES llevados a cabo durante la tesis han dado resultado que no se han encontrado neutrinos en coincidencia con ninguno de los señales GWs ni GRBs considerados en las búsquedas. Sin embargo, los resultados de este análisis muestran una mejora de la sensibilidad de un 15-30% para fuentes en el horizonte de ANTARES, y hasta un 200% cuando la búsqueda utiliza eventos descendentes, y han llevado a los mejores límites de emisión de neutrinos publicados por ANTARES para este tipo de fuentes. Two analyses are detailed in this thesis related to neutrino and multi-messenger astronomy with Cherenkov telescopes in the Mediterranean Sea. The first analysis explores the capabilities of the KM3NeT neutrino telescopes to detect the signal from a Galactic core-collapse supernova (CCSN), as well as the physical constraints that could be extracted from such a detection. Together with the Sun, CCSNe are the only confirmed sources of astrophysical neutrinos. A search method for these astrophysical neutrino sources with KM3NeT has been developed during this thesis, based on the analysis of the first data which has allowed for a good characterisation of the background and the detector performance. The results show that the KM3NeT detector might be sensitive to this MeV neutrino flux, with a coverage at 5 sigma discovery potential of more than 95% of Galactic CCSN progenitors. Therefore, KM3NeT will contribute to the observation of the next Galactic explosion. The CCSN analysis has been implemented in a real-time trigger, that is active since summer 2019. Moreover, it has yielded the first KM3NeT real-time results with the follow-up of the unmodelled candidate gravitational-wave (GW) events. These results have allowed the KM3NeT experiment to join the SNEWS network, to which all detectors sensitive to CCSN neutrino send their alerts. The second analysis exploits the data of the ANTARES neutrino telescope to search for high-energy neutrinos (TeV-PeV) in time and space coincidence with gravitational-wave sources and very-high energy gamma-ray bursts (GRBs). In fact, compact binary mergers and gamma-ray bursts have long been suggested as potential high-energy neutrino emitters. Typically, these searches look for muon neutrinos coming through the Earth (upgoing tracks). For the first time, all-flavors (including the so-called shower events) were included in this kind of searches. Moreover, these analyses have been applied to sources both below the ANTARES horizon (seen as upgoing events), and above the horizon of the ANTARES telescope (downgoing). This has lead to an improvement of 15-30% for upgoing events and up to a 200% for searches above the horizon. The analyses carried out during the thesis yielded no neutrino in coincidence with any of the gravitational-wave sources from the first GW catalog, neither with the first GRBs detected at very high energies.

Dissertation, RWTH Aachen University, 2019; Aachen 1 Online-Ressource (xvii, 279 Seiten) : Illustrationen (2019). = Dissertation, RWTH Aachen University, 2019, Cosmic rays have been measured for more than a century, however, their sources and their acceleration process are still a major open questions in astroparticle physics. Ideal messenger particles and a smoking gun signal for this hadronic acceleration are neutrinos. With the observation of an high-energy astrophysical neutrino flux in 2013 and the confirmation in the independent detection channel of high-energy through-going muon-neutrinos, the IceCube Neutrino Observatory opened a new window to the non-thermal universe. In this thesis we search for point-like sources of the observed astrophysical high-energy muon-neutrino flux. The search is based on a high statistic and high purity data sample taken by the IceCube Neutrino Observatory and contains data from eight years of livetime. The event selection focus on well-reconstructed, up- and through-going muon neutrino events, which are reconstructed with a median angular resolution of $\sim 1^\circ$ at 1 TeV energy and $\sim 0.3^\circ$ at 1 PeV energy. An unbinned likelihood method is used to test celestial positions for the existence of a point-like source. The likelihood method is optimized to sources showing similar characteristics as the observed astrophysical high-energy muon-neutrino flux. The sensitivity on the muon-neutrino flux of a point-like source with an $E^{-2}$ spectrum is of the order of $E^2\,\mathrm{d}N/\mathrm{d}E = 3 \cdot 10^{-13}\,\mathrm{TeV}\,\mathrm{cm}^{-2}\mathrm{s}^{-1}$ and improves by about $\sim35\%$ compared to previous published analyses. We perform a scan of the full Northern Hemisphere to search for a point-like source any where in the sky. As this test suffers from the large number of tested positions, in addition, sky positions from a pre-defined source list, motivated by gamma-ray observations, are tested to reduce the number of trials. Both test results are non significant and compatible with only background. We also test for neutrino emission from the source position of the blazar TXS 0506+056 for which a gamma-ray flare has been found in spatial and temporal coincidence with a extreme-high-energy neutrino alert by IceCube. This test results in a p-value of 2.93% and thus is still compatible with only background. As no test for a single point-like source shows a significant deviation from background only, we also test for the existence of a population of sub-threshold sources, both using the results from the northern sky scan and the source list. Therefore, we set up a population analysis, which tests for an excess of small but non significant p-values. Also these tests for populations of sources show no significant excess above only background. Thus, exclusion limits are calculated on the flux normalisation for sources following a baseline $E^{-2}$ spectrum and source spectra found in the literature. In addition, also exclusion limits are calculated on populations of neutrino sources in dependence of their effective neutrino luminosity and effective source density. We conclude that rare but strong sources, such as BL Lacs and FSRQs, are challenged by the non observation as a significant excess in the population analysis., Published by Aachen

This thesis presents point-like neutrino source searches using ten years of IceCube data collected between Apr.~6, 2008 to Jul.~10, 2018. These searches evaluate the significance of an astrophysical signal by looking for an excess of clustered neutrino events with energies typically above 1 TeV among a background of atmospheric muons and neutrinos. This involved optimizing the event selection for the final six years of data and applying it to: a full sky scan, a selected source catalog, a catalog population study, and stacked galactic catalog searches. The improved sensitivity of these analyses did not find new evidence for a steady state neutrino source. Upper-limits were placed on the expected flux from sources in the catalogs and an excess was identified as inconsistent with background at the level of 2.9σ at the coordinates of NGC 1068. These results motivate interest in point-like sources given future updates to the detector or a longer lifetime of data.

We summarise the parallel session C7 Multi-Messenger Astronomy of GW Sources in the GR20 Amaldi 10 Conference. The talks in this session covered a wide range of topics in multi-messenger astronomy.

We study the production of cosmogenic neutrinos and photons during the extragalactic propagation of ultra-high-energy cosmic rays (UHECRs). For a wide range of models in cosmological evolution of source luminosity, composition and maximum energy we calculate the expected flux of cosmogenic secondaries by normalizing our cosmic ray output to experimental spectra and comparing the diffuse flux of GeV-TeV gamma-rays to the experimental one measured by the Fermi satellite. Most of these models yield significant neutrino fluxes for current experiments like IceCube or Pierre Auger. Furthermore, we discuss the possibilities of signing the presence of UHE proton sources either within or outside the cosmic ray horizon using neutrinos or photons observations even if the cosmic ray composition becomes heavier at the highest energies. We discuss the possible constraints that could be brought on the UHECR origin from the different messengers and energy ranges., 17 pages, 13 figures, published in Astronomy & Astrophysics