研究者詳細 - 奥村　曉

論文 - 奥村　曉

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Constraints on axion-like particles with the Perseus Galaxy Cluster with MAGIC

D’Amico G., Batković I., Doro M., Manganaro M., Abe H., Abe S., Abhir J., Acciari V.A., Agudo I., Aniello T., Ansoldi S., Antonelli L.A., Arbet Engels A., Arcaro C., Artero M., Asano K., Baack D., Babić A., Baquero A., Barres de Almeida U., Barrio J.A., Baxter J., Becerra González J., Bednarek W., Bernardini E., Bernardos M., Bernete J., Berti A., Besenrieder J., Bigongiari C., Biland A., Blanch O., Bonnoli G., Bošnjak , Burelli I., Busetto G., Campoy-Ordaz A., Carosi A., Carosi R., Carretero-Castrillo M., Castro-Tirado A.J., Ceribella G., Chai Y., Chilingarian A., Cifuentes A., Cikota S., Colombo E., Contreras J.L., Cortina J., Covino S., D’Elia V., Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Delgado Mendez C., Depaoli D., Di Pierro F., Di Venere L., Dominis Prester D., Donini A., Dorner D., Elsaesser D., Emery G., Escudero J., Fariña L., Fattorini A., Foffano L., Font L., Fröse S., Fukami S., Fukazawa Y., García López R.J., Garczarczyk M., Gasparyan S., Gaug M., Giesbrecht Paiva J.G., Giglietto N., Giordano F., Gliwny P., Godinović N., Grau R., Green D., Green J.G., Hadasch D., Hahn A., Hassan T., Heckmann L., Herrera J., Hrupec D., Hütten M., Imazawa R., Inada T., Iotov R., Ishio K., Jiménez Martínez I., Jormanainen J.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Axion-like particles (ALPs) are pseudo-Nambu-Goldston bosons that appear in theories beyond the standard model and are capable of converting to photons in the presence of magnetic fields. Such interaction can have an observable effect on the gamma-ray spectrum of astrophysical targets. We have examined about 40 hours of observations made with the ground-based MAGIC Cherenkov telescopes in the direction of the Perseus Galaxy Cluster. The sources of VHE gamma rays present in the cluster and object of the study are the radiogalaxy NGC1275 and the HBL object IC310. These sources are bright in gamma rays and embedded in the cluster’s high magnetic field, making them very good targets for this kind of study. Having not found statistical evidence for ALPs, we exclude ALPs models with masses in the sub-eV range in line with previous results. Last, we address the potential for gamma-ray-based instruments, both current and future, to identify ALP signals using this analysis technique, finding that the search for wiggles in TeV gamma-ray spectra is very unlikely to be sensitive enough for observations with IACTs.

Chasing Gravitational Waves with the Cherenkov Telescope Array Open Access

Green J.G., Carosi A., Nava L., Patricellix B., Schüssler F., Seglar-Arroyo M., Stamerra A., Abe K., Abe S., Acharyya A., Adam R., Aguasca-Cabot A., Agudo I., Alfaro J., Alvarez-Crespo N., Alves Batista R., Amans J.P., Amato E., Ambrosino F., Angüner E.O., Antonelli L.A., Aramo C., Arcaro C., Arrabito L., Asano K., Aschersleben J., Ashkar H., Augusto Stuani L., Baack D., Backes M., Balazs C., Balbo M., Baquero Larriva A., Barbosa Martins V., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Batzofin R., Baxter J., Beck G., Becker Tjus J., Beiske L., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., Biederbeck N., Biland A., Bissaldi E., Blanch O., Blazek J., Boisson C., Bolmont J., Bonnoli G., Bordas P., Bosnjak Z., Bradascio F., Braiding C., Bronzini E., Brose R., Brown A.M., Brun F., Brunelli G., Bulgarelli A., Burelli I., Burmistrov L., Burton M., Bylund T., Calisse P.G., Campoy-Ordaz A., Cantlay B.K., Capalbi M., Caproni A., Capuzzo-Dolcetta R., Carlile C., Caroff S., Carosi R., Carrasco M.S., Cascone E., Cassol F., Castrejon N., Catalani F., Cerasole D., Cerruti M., Chaty S., Chen A.W., Chernyakova M., Chiavassa A., Chudoba J., Coimbra Araujo C.H., Conforti V.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The detection of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this GW event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a GW signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. Achieving such a feat will require a comprehensive real-time strategy capable of coordinating searches over potentially very large regions of the sky. This work will evaluate and provide estimations on the number of GW-CTA events determined from simulated BNS systems and short GRBs, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA.

DOI： 10.22323/1.444.1534

Characterization of SiPM and development of test bench modules for the next-generation cameras for Large-Sized Telescopes for Cherenkov Telescope Array

Saito T., Hashiyama K., Iwasaki H., Kubo H., Mizote M., Okumura A., Tajima H., Yamamoto T.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The recent improvements in the performance of the silicon photomultipliers (SiPMs) made them attractive options as photo sensors of imaging atmospheric Cherenkov telescopes (IACTs). In fact, they are already adopted in some IACTs such as FACT and the Small-Sized Telescopes of the Cherenkov Telescope Array (CTA). However, the application to the Large-Sized Telescopes (LSTs) of CTA requires additional studies. As the pixel size of LSTs is larger than the nominal size of SiPMs, the signal from multiple sensors must be summed up. Also, the high detection efficiency of the night sky background (NSB) photons may degrade the telescope performance. To overcome this, the pulse width must be as small as 3 ns and the detection efficiency for NSB photons must be suppressed as much as possible. Heat generation and gain stabilization are also issues. We studied different types of SiPMs from Hamamatsu photonics and characterized them for the LST application, addressing the previous points. Also, to prove the SiPM performance in LST, we are developing a SiPM module which can be installed in the exisiting LST camera. Here we present the results of this evaluation and the status of the test bench module development.

Bright blazar flares with CTA

Cerruti M., Finke J., Grolleron G., Lenain J.P., Hovatta T., Joshi M., Lindfors E., Morris P., Petropoulou M., Romano P., Vercelloneh S., Zacharias M., Abe K., Abe S., Acharyya A., Adam R., Aguasca-Cabot A., Agudo I., Alfaro J., Alvarez-Crespo N., Alves Batista R., Amans J.P., Amato E., Ambrosino F., Angüner E.O., Antonelli L.A., Aramo C., Arcaro C., Arrabito L., Asano K., Aschersleben J., Ashkar H., Augusto Stuani L., Baack D., Backes M., Balazs C., Balbo M., Baquero Larriva A., Barbosa Martins V., de Almeida U.B., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Batzofin R., Baxter J., Beck G., Becker Tjus J., Beiske L., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., Biederbeck N., Biland A., Bissaldi E., Blanch O., Blazek J., Boisson C., Bolmont J., Bonnoli G., Bordas P., Bosnjak Z., Bradascio F., Braiding C., Bronzini E., Brose R., Brown A.M., Brun F., Brunelli G., Bulgarelli A., Burelli I., Burmistrov L., Burton M., Bylund T., Calisse P.G., Campoy-Ordaz A., Cantlay B.K., Capalbi M., Caproni A., Capuzzo-Dolcetta R., Carlile C., Caroff S., Carosi A., Carosi R., Carrasco M.S., Cascone E., Cassol F., Castrejon N., Catalani F., Cerasole D., Chaty S., Chen A.W., Chernyakova M.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The TeV extragalactic sky is dominated by blazars, radio-loud active galactic nuclei with a relativistic jet pointing towards the Earth. Blazars show variability that can be quite exceptional both in terms of flux (orders of magnitude of brightening) and time (down to the minute timescale). This bright flaring activity contains key information on the physics of particle acceleration and photon production in the emitting region, as well as the structure and physical properties of the jet itself. The TeV band is accessed from the ground by Cherenkov telescopes that image the pair cascade triggered by the interaction of the gamma ray with the Earth's atmosphere. The Cherenkov Telescope Array (CTA) represents the upcoming generation of imaging atmospheric Cherenkov telescopes, with a significantly higher sensitivity and larger energy coverage with respect to current instruments. It will thus provide us with unprecedented statistics on blazar light-curves and spectra. In this contribution we present the results from realistic simulations of CTA observations of bright blazar flares, taking as input state-of-the-art numerical simulations of blazar emission models and including all relevant observational constraints.

Evaluation of the effective mirror area of CTA Small-Sized Telescopes for camera design and Monte Carlo simulation

Okumura A., Ross D., Saturni F.G., Sironi G., White R.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The effective mirror area of an imaging atmospheric Cherenkov telescope is a crucial key parameter for trigger threshold determination and energy calibration. It is usually calculated by 3D ray-tracing simulation using a simplified telescope model, and the result is used in Monte Carlo simulations. However, simplified telescope and camera models are not adequate for the Schwarzschild–Couder configuration to be used in Small-Sized Telescopes (SSTs) of the Cherenkov Telescope Array. This is because the complex 3D structure of the secondary mirror, telescope masts, and camera body block a significant fraction of Cherenkov and night-sky photons. To evaluate the effective mirror area of an SST and to finalize its camera body design with minimal shadowing, a complex 3D model was built and simulated using the ROBAST ray-tracing library. A camera body size of 570 mm and a window size of 430 mm were selected for the final camera design based on the evaluation of shadowing by simulation. A non-axisymmetric effective area distribution was determined via the modeling of the complex telescope structure, while meeting the SST effective area requirement.

Update on the performance of the MAGIC Intensity Interferometer

Martínez I.J., Acciari V.A., Cifuentes A., Colombo E., Cortina J., Delgado C., Díaz C., Fiori M., Fink D., Guberman D., Hassan T., Lyard E., Mariotti M., Martínez G., Mirzoyan R., Naletto G., Njoh Ekoume T., Polo M., Produit N., Rodríguez-Vázquez J.J., Saha P., Schweizer T., Walter R., Wunderlich C.W., Zampieri L., Abe H., Abe S., Abhir J., Agudo I., Aniello T., Ansoldi S., Antonelli L.A., Arbet Engels A., Arcaro C., Artero M., Asano K., Baack D., Babić A., Baquero A., Barres de Almeida U., Barrio J.A., Batković I., Baxter J., Be-Cerra González J., Bednarek W., Bernardini E., Bernardos M., Bernete J., Berti A., Besenrieder J., Bigongiari C., Biland A., Blanch O., Bonnoli G., Bošnjak , Burelli I., Busetto G., Campoy-Ordaz A., Carosi A., Carosi R., Carretero-Castrillo M., Castro-Tirado A.J., Ceribella G., Chai Y., Chilingarian A., Cikota S., Contreras J.L., Covino S., D’Amico G., D’Elia V., Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Delgado Mendez C., Depaoli D., Di Pierro F., Di Venere L., Dominis Prester D., Donini A., Dorner D., Doro M., Elsaesser D., Emery G., Escudero J., Fariña L., Fattorini A., Foffano L., Font L., Fröse S., Fukami S., Fukazawa Y., García López R.J.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

In recent years, the MAGIC telescopes have been equipped with a setup that allows its Imaging Atmospheric Cherenkov Telescopes (IACTs) to function as an Intensity Interferometer. The deadtime-free setup includes a 4-channel GPU-based real-time correlator together with optical filters in the 350-450 nm wavelength range and specialized Active Mirror Control (AMC) configurations. This implementation allows MAGIC to perform measurements of the spatial coherence (visibility) of the intensity fluctuations of an object’s starlight over several separations (baselines) and construct a model of said object. The accessible baseline range for MAGIC is 40-90 m which translates into an angular resolution of 0.5-1 mas. Additionally, thanks to the AMC it can access even smaller baselines, of less than 17 m (which is the diameter of each of both dishes) to measure objects of greater angular size (>1 mas) and even measure the zero-baseline correlation, which is key to calibrate the system. We present the latest measurements that allow us to understand the performance and systematics of our setup and validate our analysis.

The Real Time Analysis framework of the Cherenkov Telescope Array’s Large-Sized Telescope

Caroff S., Aubert P., Garcia E., Maurin G., Pollet V., Vuillaume T., Abe K., Abe S., Aguasca-Cabot A., Agudo I., Alvarez Crespo N., Antonelli L.A., Aramo C., Arbet-Engels A., Arcaro C., Artero M., Asano K., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Baxter J., Becerra González J., Bernardini E., Bernardos M.I., Bernete Medrano J., Berti A., Bhattacharjee P., Biederbeck N., Bigongiari C., Bissaldi E., Blanch O., Bonnoli G., Bordas P., Bulgarelli A., Burelli I., Burmistrov L., Buscemi M., Cardillo M., Carosi A., Carrasco M.S., Cassol F., Cauz D., Cerasole D., Ceribella G., Chai Y., Cheng K., Chiavassa A., Chikawa M., Chytka L., Cifuentes A., Contreras J.L., Cortina J., Costantini H., Dalchenko M., Dazzi F., De Angelis A., de Bony de Lavergne M., De Lotto B., De Lucia M., de Menezes R., Del Peral L., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Dellaiera M., Di Piano A., Di Pierro F., Di Pilato A., Di Tria R., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Eisenberger L., Elsässer D., Emery G., Escudero J., Fallah Ramazani V., Ferrara G., Ferrarotto F., Fiasson A., Foffano L., Freixas Coromina L., Fröse S., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Gasbarra C., Gasparrini D.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The Large-Sized Telescopes (LSTs) of the Cherenkov Telescope Array Observatory (CTAO) will play a crucial role in the study of transient gamma-ray sources, such as gamma-ray bursts and flaring active galactic nuclei. The low energy threshold of LSTs makes them particularly well suited for the detection of these phenomena. The ability to detect and analyze gamma-ray transients in real-time is essential for quickly identifying and studying these rare and fleeting events. In this conference, we will present recent advances in the real-time analysis of data from the LST-1, the first prototype of LST located in the Canary island of La Palma. We will discuss in particular the development of new algorithms for event reconstruction and background rejection. These advances will enable rapid identification and follow-up observation of transient gamma-ray sources, making the LST-1 a powerful tool for the study of the dynamic universe. The implementation of this framework in the future Array Control and Data Acquisition System (ACADA) of CTAO will be discussed as well, based on the experience with LST.

The rapporteur report on the diversity session at the ICRC2023 Open Access

Takahashi S., Ishihara A., Okumura A., Itow Y.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The Diversity Session at ICRC2023 marked a significant step towards enhancing inclusivity within the astroparticle community. This report not only documents the lively discussions of the session but also highlights a cornerstone of our efforts: the outcomes of the pre-conference diversity survey. Professor Hiromi Yokoyama’s thought-provoking presentation illuminated a pivotal aspect: the factors affecting the attrition of female students, particularly in the field of physics.

DOI： 10.22323/1.444.0038

The next generation cameras for the Large-Sized Telescopes of the Cherenkov Telescope Array Observatory

Heller M., Altet J., Aragones X., Barrio J.A., Bellato M., Bernasconi E., Biland A., Blanch O., Burmistrov L., Charbon E., Dalchenko M., Di Pierro F., Giangrande L., Gascon D., Gòmez S., Hoffmann D., Martinez G., Mariotti M., Matteo D., Montaruli T., Okumura A., Aguilera A.P., Manera R., Rando R., Saito T., Sanuy A., Tejedor L.A., Uzun Y.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The latest generation of silicon photomultipliers (SiPM) offers twice as much sensitivity to Cherenkov light observed at ground level when compared to photomultipliers. Their use for imaging atmospheric Cherenkov telescopes is increasing, from the FACT telescope, the pioneer, to the small-sized telescopes of the Cherenkov Telescope Array (CTA) or the LHAASO WFCTA camera. The robustness of the SiPMs represents a unique opportunity to ensure long-term operation with low maintenance. In this work, we present the latest developments and performance of a SiPM camera aiming at upgrading the large-sized telescopes (LST) cameras of CTA. The SiPM camera, equipped with 0.05 deg pixels, provides images of improved resolution for better feature extraction. The increase in the number of pixels has driven the development of low-power front-end electronics whose design is presented in this work. We also present the fully digital readout architecture of the proposed camera, which will enable the implementation of novel triggering algorithms based on artificial intelligence.

The Cosmic-ray Electron and Positron Spectrum Measured with MAGIC

Chai Y., Ishio K., Kerszberg D., Mangano S., Abe H., Abe S., Abhir J., Acciari V.A., Agudo I., Aniello T., Ansoldi S., Antonelli L.A., Arbet Engels A., Arcaro C., Artero M., Asano K., Baack D., Babić A., Baquero A., Barres de Almeida U., Barrio J.A., Batković I., Baxter J., Becerra González J., Bednarek W., Bernardini E., Bernardos M., Bernete J., Berti A., Besenrieder J., Bigongiari C., Biland A., Blanch O., Bonnoli G., Bošnjak , Burelli I., Busetto G., Campoy-Ordaz A., Carosi A., Carosi R., Carretero-Castrillo M., Castro-Tirado A.J., Ceribella G., Chai Y., Chilingarian A., Cifuentes A., Cikota S., Colombo E., Contreras J.L., Cortina J., Covino S., D’Amico G., D’Elia V., Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Delgado Mendez C., Depaoli D., Di Pierro F., Di Venere L., Dominis Prester D., Donini A., Dorner D., Doro M., Elsaesser D., Emery G., Escudero J., Fariña L., Fattorini A., Foffano L., Font L., Fröse S., Fukami S., Fukazawa Y., García López R.J., Garczarczyk M., Gasparyan S., Gaug M., Giesbrecht Paiva J.G., Giglietto N., Giordano F., Gliwny P., Godinović N., Grau R., Green D., Green J.G., Hadasch D., Hahn A., Hassan T., Heckmann L., Herrera J., Hrupec D., Hütten M., Imazawa R., Inada T., Iotov R.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Cosmic-ray electrons and positrons (CREs) of TeV energies suffer severe energy loss during propagation due to inverse Compton scattering and synchrotron radiation process, they are therefore very useful to constrain the local cosmic-ray sources in the Galaxy. The ability to measure CREs by ground-based imaging atmospheric Cherenkov telescopes (IACTs) has been demonstrated in the past. In this proceeding, we will present two methods – a template fit method and a tight cut method based on a two-steps-trained Random Forest (RF) – optimized for the detection and study of CREs and will report on the measurement of the CREs energy spectrum from 300 GeV to 6 TeV with the MAGIC telescopes.

Study on the gain and photon detection efficiency drops of silicon photomultipliers under bright background conditions

Okumura A., Wakazono K., Furuta K., Tajima H.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The use of silicon photomultipliers (SiPMs) in imaging atmospheric Cherenkov telescopes is expected to extend the observation times of very-high-energy gamma-ray sources, particularly within the highest energy domain of 50–300 TeV, where the Cherenkov signal from celestial gamma rays is adequate even under bright moonlight background conditions. Unlike conventional photomultiplier tubes, SiPMs do not exhibit quantum efficiency or gain degradation, which can be observed after long exposures to bright illumination. However, under bright conditions, the photon detection efficiency of a SiPM can be undergo temporary degradation because a fraction of its avalanche photodiode cells can saturate owing to photons from the night-sky background (NSB). In addition, the large current generated by the high NSB rate can increase the temperature of the silicon substrate, resulting in shifts in the SiPM breakdown voltages and consequent gain changes. Moreover, this large current changes the effective bias voltage because it causes a voltage drop across the protection resistor of 100–1000 Ω. Hence, these three factors, namely the avalanche photodiode (APD) saturation, Si temperature, and voltage drop must be carefully compensated for and/or considered in the energy calibration of Cherenkov telescopes with SiPM cameras. In this study, we measured the signal output charge of a SiPM and its variation as a function of different NSB-like background conditions up to 1 GHz/pixel. The results verify that the product of the SiPM gain and photon detection efficiency is well characterized by these three factors.

Sensitivity of the Cherenkov Telescope Array to the gamma-ray emission from neutrino sources detected by IceCube

Sergijenko O., Brown A.M., Fiorillo D., de León A.R., Satalecka K., Tung C.F., Taboada I., Abe K., Abe S., Acharyya A., Adam R., Aguasca-Cabot A., Agudo I., Alfaro J., Alvarez-Crespo N., Alves Batista R., Amans J.P., Amato E., Ambrosino F., Angüner E.O., Antonelli L.A., Aramo C., Arcaro C., Arrabito L., Asano K., Aschersleben J., Ashkar H., Augusto Stuani L., Baack D., Backes M., Balazs C., Balbo M., Baquero Larriva A., Barbosa Martins V., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Batzofin R., Baxter J., Beck G., Becker Tjus J., Beiske L., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., Biederbeck N., Biland A., Bissaldi E., Blanch O., Blazek J., Boisson C., Bolmont J., Bonnoli G., Bordas P., Bosnjak Z., Bradascio F., Braiding C., Bronzini E., Brose R., Brun F., Brunelli G., Bulgarelli A., Burelli I., Burmistrov L., Burton M., Bylund T., Calisse P.G., Campoy-Ordaz A., Cantlay B.K., Capalbi M., Caproni A., Capuzzo-Dolcetta R., Carlile C., Caroff S., Carosi A., Carosi R., Carrasco M.S., Cascone E., Cassol F., Castrejon N., Catalani F., Cerasole D., Cerruti M., Chaty S., Chen A.W., Chernyakova M., Chiavassa A., Chudoba J., Coimbra Araujo C.H., Conforti V.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Gamma-ray observations of the astrophysical neutrino sources are fundamentally important for understanding the underlying neutrino production mechanism. We investigate the Cherenkov Telescope Array (CTA) ability to detect the very-high-energy (VHE) gamma-ray counterparts to the neutrino-emitting Active Galaxies. The CTA performance under different configurations and array layouts is computed based on the neutrino and gamma-ray simulations of steady and transient types of sources, assuming that the neutrino events are detected with the IceCube neutrino telescope. The CTA detection probability is calculated for both CTA sites taking into account the visibility constraints. We find that, under optimal observing conditions, CTA could observe the VHE gamma-ray emission from at least 3 neutrino events per year.

Pybkgmodel - a background modelling toolbox for the CTA

Strzys M.C., Abe S., de Bony de Lavergne M., Hütten M., Mender S., Vovk I., Abe K., Abe S., Acharyya A., Adam R., Aguasca-Cabot A., Agudo I., Alfaro J., Alvarez-Crespo N., Alves Batista R., Amans J.P., Amato E., Ambrosino F., Angüner E.O., Antonelli L.A., Aramo C., Arcaro C., Arrabito L., Asano K., Aschersleben J., Ashkar H., Augusto Stuani L., Baack D., Backes M., Balazs C., Balbo M., Baquero Larriva A., Barbosa Martins V., de Almeida U.B., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Batzofin R., Baxter J., Beck G., Becker Tjus J., Beiske L., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., Biederbeck N., Biland A., Bissaldi E., Blanch O., Blazek J., Boisson C., Bolmont J., Bonnoli G., Bordas P., Bosnjak Z., Bradascio F., Braiding C., Bronzini E., Brose R., Brown A.M., Brun F., Brunelli G., Bulgarelli A., Burelli I., Burmistrov L., Burton M., Bylund T., Calisse P.G., Campoy-Ordaz A., Cantlay B.K., Capalbi M., Caproni A., Capuzzo-Dolcetta R., Carlile C., Caroff S., Carosi A., Carosi R., Carrasco M.S., Cascone E., Cassol F., Castrejon N., Catalani F., Cerasole D., Cerruti M., Chaty S., Chen A.W., Chernyakova M., Chiavassa A., Chudoba J., Coimbra Araujo C.H., Conforti V., Conte F.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Despite the advancement in background rejection techniques, observation of the very-high-energy gamma-ray sky by imaging atmospheric Cherenkov telescopes (IACTs) are subject to an irreducible background from gamma-like hadron- or electron-induced air showers. The determination of this residual background is crucial for accurate spectral and spatial measurements. The Cherenkov Telescope Array (CTA) will become the next generation of IACTs. To unveil its full potential, the improved reconstruction performance of CTA needs to be coupled with a reliable background estimate across the entire field of view. This may become especially important in the case of the planned surveys of large areas of the sky. In this contribution we will present pybkgmodel, an open-source python software package developed for CTA. It aims at providing in a consistent way the various background modelling methods, based on the experience from current IACTs such as H.E.S.S, MAGIC, and VERITAS. It is designed as a toolbox allowing a user to easily choose the optimal reconstruction approach for various target regions or a combination of several algorithms. We will introduce the design of the package as well as demonstrate its functionality using data for the CTA Large-Sized Telescope prototype (LST-1).

Potential of the Cherenkov Telescope Array for studying the young nearby supernova remnants

Prokhorov D.A., Lee S.H., Nagataki S., Vink J., Ellison D.C., Ferrand G., Patnaude D.J., Roepke F.K., Seitenzahl I.R., Slane P.O., Abe K., Abe S., Acharyya A., Adam R., Aguasca-Cabot A., Agudo I., Alfaro J., Alvarez-Crespo N., Alves Batista R., Amans J.P., Amato E., Ambrosino F., Angüner E.O., Antonelli L.A., Aramo C., Arcaro C., Arrabito L., Asano K., Aschersleben J., Ashkar H., Augusto Stuani L., Baack D., Backes M., Balazs C., Balbo M., Baquero Larriva A., Barbosa Martins V., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Batzofin R., Baxter J., Beck G., Becker Tjus J., Beiske L., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., Biederbeck N., Biland A., Bissaldi E., Blanch O., Blazek J., Boisson C., Bolmont J., Bonnoli G., Bordas P., Bosnjak Z., Bradascio F., Braiding C., Bronzini E., Brose R., Brown A.M., Brun F., Brunelli G., Bulgarelli A., Burelli I., Burmistrov L., Burton M., Bylund T., Calisse P.G., Campoy-Ordaz A., Cantlay B.K., Capalbi M., Caproni A., Capuzzo-Dolcetta R., Carlile C., Caroff S., Carosi A., Carosi R., Carrasco M.S., Cascone E., Cassol F., Castrejon N., Catalani F., Cerasole D., Cerruti M., Chaty S., Chen A.W., Chernyakova M., Chiavassa A.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Modern imaging atmospheric Cherenkov telescopes have extensively observed young nearby supernova remnants (SNRs), with ages of about 1000 years or less, in the very-high-energy (VHE) gamma-ray band. These efforts resulted in the detection of VHE emission from three young SNRs – Cassiopeia A, Tycho, and SN 1006 – and provided significant evidence for emission from the more distant Kepler’s SNR. However, many questions on the production of VHE gamma rays in these remnants remain unanswered. Using detailed physical models for Tycho’s SNR based on the CR-hydro-NEI code and physically motivated models for the other young nearby remnants, we simulated observations with the Cherenkov Telescope Array (CTA) of these gamma-ray sources. We highlight properties of these remnants accessible for investigation with future CTA observations and discuss which questions are expected to be answered.

Performance update of an event-type based analysis for the Cherenkov Telescope Array

Bernete J., Gueta O., Hassan T., Linhoff M., Maier G., Sinha A., Abe K., Abe S., Acharyya A., Adam R., Aguasca-Cabot A., Agudo I., Alfaro J., Alvarez-Crespo N., Alves Batista R., Amans J.P., Amato E., Ambrosino F., Angüner E.O., Antonelli L.A., Aramo C., Arcaro C., Arrabito L., Asano K., Aschersleben J., Ashkar H., Augusto Stuani L., Baack D., Backes M., Balazs C., Balbo M., Baquero Larriva A., Barbosa Martins V., de Almeida U.B., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Batzofin R., Baxter J., Beck G., Becker Tjus J., Beiske L., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., Biederbeck N., Biland A., Bissaldi E., Blanch O., Blazek J., Boisson C., Bolmont J., Bonnoli G., Bordas P., Bosnjak Z., Bradascio F., Braiding C., Bronzini E., Brose R., Brown A.M., Brun F., Brunelli G., Bulgarelli A., Burelli I., Burmistrov L., Burton M., Bylund T., Calisse P.G., Campoy-Ordaz A., Cantlay B.K., Capalbi M., Caproni A., Capuzzo-Dolcetta R., Carlile C., Caroff S., Carosi A., Carosi R., Carrasco M.S., Cascone E., Cassol F., Castrejon N., Catalani F., Cerasole D., Cerruti M., Chaty S., Chen A.W., Chernyakova M., Chiavassa A., Chudoba J., Coimbra Araujo C.H., Conforti V., Conte F.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The Cherenkov Telescope Array (CTA) will be the next-generation observatory in the field of very-high-energy (20 GeV to 300 TeV) gamma-ray astroparticle physics. The traditional approach to data analysis in this field is to apply quality cuts, optimized using Monte Carlo simulations, on the data acquired to maximize sensitivity. Subsequent steps of the analysis typically use the surviving events to calculate one set of instrument response functions (IRFs) to physically interpret the results. However, an alternative approach is the use of event types, as implemented in experiments such as the Fermi-LAT. This approach divides events into sub-samples based on their reconstruction quality, and a set of IRFs is calculated for each sub-sample. The sub-samples are then combined in a joint analysis, treating them as independent observations. In previous works we demonstrated that event types, classified using Machine Learning methods according to their expected angular reconstruction quality, have the potential to significantly improve the CTA angular and energy resolution of a point-like source analysis. Now, we validated the production of event-type wise full-enclosure IRFs, ready to be used with science tools (such as Gammapy and ctools). We will report on the impact of using such an event-type classification on CTA high-level performance, compared to the traditional procedure.

Performance of the Large-Sized Telescope prototype of the Cherenkov Telescope Array

Morcuende D., López-Coto R., Moralejo A., Nozaki S., Vuillaume T., Abe K., Abe S., Aguasca-Cabot A., Agudo I., Alvarez Crespo N., Antonelli L.A., Aramo C., Arbet-Engels A., Arcaro C., Artero M., Asano K., Aubert P., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Baxter J., Becerra González J., Bernardini E., Bernardos M.I., Bernete Medrano J., Berti A., Bhattacharjee P., Biederbeck N., Bigongiari C., Bissaldi E., Blanch O., Bonnoli G., Bordas P., Bulgarelli A., Burelli I., Burmistrov L., Buscemi M., Cardillo M., Caroff S., Carosi A., Carrasco M.S., Cassol F., Cauz D., Cerasole D., Ceribella G., Chai Y., Cheng K., Chiavassa A., Chikawa M., Chytka L., Cifuentes A., Contreras J.L., Cortina J., Costantini H., Dalchenko M., Dazzi F., De Angelis A., de Bony de Lavergne M., De Lotto B., De Lucia M., de Menezes R., Del Peral L., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Dellaiera M., Di Piano A., Di Pierro F., Di Pilato A., Di Tria R., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Eisenberger L., Elsässer D., Emery G., Escudero J., Fallah Ramazani V., Ferrara G., Ferrarotto F., Fiasson A., Foffano L., Freixas Coromina L., Fröse S., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Gasbarra C., Gasparrini D., Geyer D.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The next-generation ground-based gamma-ray Cherenkov Telescope Array Observatory (CTAO) will consist of imaging atmospheric Cherenkov telescopes (IACTs) of three different sizes distributed in two sites. The Large-Sized Telescopes will cover the low-energy end of the CTA energy range, starting at about 20 GeV. After its first years of operation at the CTA northern site, the Large-Sized Telescope prototype (LST-1) is in the final stage of its commissioning phase, having collected a significant amount of scientific data to date. In this contribution, we present the physics performance of the telescope using low-zenith Crab Nebula observations and Monte Carlo simulations fine-tuned accordingly. We show performance figures of merit such as the energy threshold, effective area, energy and angular resolution, and sensitivity based on the standard Hillas-parameters approach and following the source-independent and dependent analysis methods. The analysis threshold is estimated at 30 GeV. The energy resolution is around 30%, and the angular resolution is 0.3 degrees at 100 GeV. The best integral sensitivity of LST-1 is about 1.1% of the Crab Nebula flux above 250 GeV for 50 hours of observations. We also show the spectral energy distribution and light curve from Crab Nebula observations, which agree with results from other IACTs and link smoothly with Fermi-LAT when considering statistical and systematic uncertainties near the energy threshold.

Performance of joint gamma-ray observations with MAGIC and LST-1 telescopes

Di Pierro F., Berti A., de Menezes R., Jobst E., Ohtani Y., Sitarek J., Suda Y., Visentin E., Abe H., Abe K., Abe S., Abhir J., Acciari V.A., Aguasca-Cabot A., Agudo I., Alvarez Crespo N., Aniello T., Ansoldi S., Antonelli L.A., Aramo C., Arbet-Engels A., Cornelia A., Artero M., Asano K., Aubert P., Baack D., Babić A., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Baxter J., Becerra González J., Bednarek W., Bernardini E., Bernardos M.I., Bernete Medrano J., Besenrieder J., Bhattacharjee P., Biederbeck N., Bigongiari C., Biland A., Bissaldi E., Blanch O., Bonnoli G., Bordas P., Bošnjak , Bulgarelli A., Burelli I., Burmistrov L., Buscemi M., Busetto G., Campoy-Ordaz A., Cardillo M., Caroff S., Carosi A., Carosi R., Carrasco M.S., Carretero-Castrillo M., Cassol F., Castro-Tirado A.J., Cauz D., Cerasole D., Ceribella G., Chai Y., Cheng K., Chiavassa A., Chikawa M., Chilingarian A., Chytka L., Cifuentes A., Cikota S., Colombo E., Contreras J.L., Cortina J., Costantini H., Covino S., D’Amico G., Dalchenko M., D’Elia V., Da Vela P., Dazzi F., De Angelis A., de Bony de Lavergne M., De Lotto B., De Lucia M., Del Peral L., Deleglise G., Delfino M., Delgado C., Delgado Mengual J., della Volpe D., Dellaiera M., Del Popolo A., Depaoli D., Di Piano A.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

The prototype Large-Sized Telescope (LST-1) of the Cherenkov Telescope Array Observatory (CTAO) is in commissioning phase at the Observatorio del Roque de Los Muchachos at 2200 m a.s.l. in La Palma (Canary Islands, Spain). LST-1 is a 23-m diameter telescope and is the first of four that will compose the LST part of the CTAO Northern array. The LST subarray is optimized to provide the best sensitivity for gamma rays in the 20 GeV - 200 GeV energy range. The MAGIC telescopes, which are located approximately 100 m from the LST-1, is operating as a two 17-m telescope stereoscopic system for more than 14 years. LST-1 and MAGIC routinely perform joint observations of gamma-ray sources to exploit the potential of the three-telescope system. This contribution describes the analysis pipeline and evaluates the performance of the system using Monte Carlo simulations and data on the Crab Nebula. The sensitivity achieved during joint observations with MAGIC and LST-1 is about 30% higher than that of MAGIC alone.

Observation of Active Galactic Nuclei with the Large-Sized Telescope prototype of the Cherenkov Telescope Array

Takeishi R., Álvarez Crespo N., Arbet-Engels A., Baquero Larriva A., Baxter J., Biederbeck N., Caroff S., Di Marco G., Fallah Ramazani V., Green D., Heckmann L., Láinez M., Nickel L., Nievas Rosillo M., Pons E., Priyadarshi C., Sanchez D.A., Vázquez Acosta M., Abe K., Abe S., Aguasca-Cabot A., Agudo I., Antonelli L.A., Aramo C., Arcaro C., Artero M., Asano K., Aubert P., Baktash A., Bamba A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Becerra González J., Bernardini E., Bernardos M.I., Bernete Medrano J., Berti A., Bhattacharjee P., Bigongiari C., Bissaldi E., Blanch O., Bonnoli G., Bordas P., Bulgarelli A., Burelli I., Burmistrov L., Buscemi M., Cardillo M., Carosi A., Carrasco M.S., Cassol F., Cauz D., Cerasole D., Ceribella G., Chai Y., Cheng K., Chiavassa A., Chikawa M., Chytka L., Cifuentes A., Contreras J.L., Cortina J., Costantini H., Dalchenko M., Dazzi F., De Angelis A., de Bony de Lavergne M., De Lotto B., De Lucia M., de Menezes R., Del Peral L., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Dellaiera M., Di Piano A., Di Pierro F., Di Pilato A., Di Tria R., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Eisenberger L., Elsässer D., Emery G., Escudero J., Ferrara G., Ferrarotto F., Fiasson A., Foffano L., Freixas Coromina L., Fröse S.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory. It will consist of three different sizes of telescopes, with a collective improvement of about an order of magnitude in sensitivity, compared with the current generation gamma-ray telescopes. LargeSized Telescopes (LSTs) will be the most sensitive at energies from tens of GeV up to a few TeVs, and will be the best suited to observe gamma-ray sources such as Active Galactic Nuclei (AGN). The first Large-Sized Telescope prototype (LST-1), inaugurated in 2018 and currently in commissioning phase, has accumulated more than one thousand hours of data to date. From 2020 to 2022, we have detected various gamma-ray sources, and prominent among them are several well-known AGN, like Mrk 421, Mrk 501, 1ES 1959+650, 1ES 0647+250, PG 1553+113, etc. We report on light curves and energy spectra reconstructed out of these observations down to energies of tens of GeV, which is very close to the energy threshold of LST-1.

New constraints on Lorentz invariance violation using the extraordinary flare of Mrk 421 in 2014

D’Amico G., Strišković J., Terzić T., Abe H., Abe S., Abhir J., Acciari V.A., Agudo I., Aniello T., Ansoldi S., Antonelli L.A., Arbet Engels A., Arcaro C., Artero M., Asano K., Baack D., Babić A., Baquero A., Barres de Almeida U., Barrio J.A., Batković I., Baxter J., Becerra González J., Bednarek W., Bernardini E., Bernardos M., Bernete J., Berti A., Besenrieder J., Bigongiari C., Biland A., Blanch O., Bonnoli G., Bošnjak , Burelli I., Busetto G., Campoy-Ordaz A., Carosi A., Carosi R., Carretero-Castrillo M., Castro-Tirado A.J., Ceribella G., Chai Y., Chilingarian A., Cifuentes A., Cikota S., Colombo E., Contreras J.L., Cortina J., Covino S., D’Elia V., Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Delgado Mendez C., Depaoli D., Di Pierro F., Di Venere L., Dominis Prester D., Donini A., Dorner D., Doro M., Elsaesser D., Emery G., Escudero J., Fariña L., Fattorini A., Foffano L., Font L., Fröse S., Fukami S., Fukazawa Y., García López R.J., Garczarczyk M., Gasparyan S., Gaug M., Giesbrecht Paiva J.G., Giglietto N., Giordano F., Gliwny P., Godinović N., Grau R., Green D., Green J.G., Hadasch D., Hahn A., Hassan T., Heckmann L., Herrera J., Hrupec D., Hütten M., Imazawa R., Inada T., Iotov R., Ishio K.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

An extraordinary flare from blazar Mrk 421 was recorded on the night of April 24, 2014, by the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes at very high energy (VHE) from 100 GeV up to 10 TeV. Several quantum-gravity models indicate that the photon group velocity in vacuum may be energy dependent, known as in-vacuum dispersion. Violation of Lorentz Invariance (LIV) of this kind can lead to an observable effect on the time of flight of VHE photons from cosmic origin. Observations of fast and distant phenomena, such as the flare from Mrk 421, are excellent testing grounds for this hypothesis. Using an innovative binned likelihood analysis, for the first time from this source we were able to search for arrival-time delays scaling linearly or quadratically with the energy of the photon. The non-detection of energy-dependent time delays led us to set constraints on the parameter space of quantum-gravity predictions.

Multiwavelength study of GRB 201216C using the sub-TeV emission detected by MAGIC

Fukami S., Berti A., Loporchio S., Nava L., Suda Y., Noda K., Asano K., Bošnjak Ž., Longo F., Jordana-Mitjans N., Melandri A., Mundell C., Shrestha M., Steele I., Abe H., Abe S., Abhir J., Acciari V.A., Agudo I., Aniello T., Ansoldi S., Antonelli L.A., Arbet Engels A., Arcaro C., Artero M., Asano K., Baack D., Babić A., Baquero A., Barres de Almeida U., Barrio J.A., Batković I., Baxter J., Becerra González J., Bednarek W., Bernardini E., Bernardos M., Bernete J., Besenrieder J., Bigongiari C., Biland A., Blanch O., Bonnoli G., Burelli I., Busetto G., Campoy-Ordaz A., Carosi A., Carosi R., Carretero-Castrillo M., Castro-Tirado A.J., Ceribella G., Chai Y., Chilingarian A., Cifuentes A., Cikota S., Colombo E., Contreras J.L., Cortina J., Covino S., D’Amico G., D’Elia V., Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Delgado Mendez C., Depaoli D., Di Pierro F., Di Venere L., Dominis Prester D., Donini A., Dorner D., Doro M., Elsaesser D., Emery G., Escudero J., Fariña L., Fattorini A., Foffano L., Font L., Fröse S., Fukazawa Y., García López R.J., Garczarczyk M., Gasparyan S., Gaug M., Giesbrecht Paiva J.G., Giglietto N., Giordano F., Gliwny P., Godinović N., Grau R., Green D., Green J.G.

Proceedings of Science 444 巻 2024年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of Science

Recently, several gamma-ray bursts (GRBs) have been detected in the very-high-energy (VHE) gamma-ray energy range by ground-based gamma-ray experiments such as MAGIC, H.E.S.S., and LHASSO. For some GRBs, the VHE emission is consistent with synchrotron self-Compton (SSC) emission from high-energy electrons accelerated in the forward shock of the relativistic jet. However, more statistics are needed to further constrain the emission models. GRB 201216C is a long bright GRB detected in a broad energy range from radio to VHE. The redshift is estimated to be 1.1, making the GRB the most distant source detected in the VHE energy range. MAGIC started the observation 56 seconds after the GRB was triggered by the Swift-BAT telescope. We performed a detailed analysis and detected the signal with about 6 sigma in the first 20 minutes. MAGIC continued the observation for 2.2 hours on the same night and 4 hours on the next night. No signal was detected later than 40 minutes after the GRB trigger. We have performed modelling of the multi-wavelength emission using the MAGIC data. We analysed simultaneous optical data from Liverpool Telescope with MAGIC and included the results in the modelling. The sub-TeV emission is consistent with the single-zone SSC model in the forward shock. In this presentation, we show the final results of the MAGIC data analysis of GRB 201216C and discuss the emission mechanism of the multi-wavelength data.

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