Papers - OKUMURA Akira

Joint Observation of the Galactic Center with MAGIC and CTA-LST-1

Abe S., Berti A., Di Pierro F., López-Coto R., Moralejo A., Ohtani Y., Sitarek J., Strzys M., Suda Y., Vovk I., 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., de Menezes R., Del Peral L., Deleglise G., Delfino M., Delgado C., Delgado Mengual J., della Volpe D., Dellaiera M.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes (IACTs), designed to detect very-high-energy gamma rays, and is operating in stereoscopic mode since 2009 at the Observatorio del Roque de Los Muchachos in La Palma, Spain. In 2018, the prototype IACT of the Large-Sized Telescope (LST-1) for the Cherenkov Telescope Array, a next-generation ground-based gamma-ray observatory, was inaugurated at the same site, at a distance of approximately 100 meters from the MAGIC telescopes. Using joint observations between MAGIC and LST-1, we developed a dedicated analysis pipeline and established the threefold telescope system via software, achieving the highest sensitivity in the northern hemisphere. Based on this enhanced performance, MAGIC and LST-1 have been jointly and regularly observing the Galactic Center, a region of paramount importance and complexity for IACTs. In particular, the gamma-ray emission from the dynamical center of the Milky Way is under debate. Although previous measurements suggested that a supermassive black hole Sagittarius A* plays a primary role, its radiation mechanism remains unclear, mainly due to limited angular resolution and sensitivity. The enhanced sensitivity in our novel approach is thus expected to provide new insights into the question. We here present the current status of the data analysis for the Galactic Center joint MAGIC and LST-1 observations.

Scopus

Interpolation of Instrument Response Functions for the Cherenkov Telescope Array in the Context of pyirf

Dominik R.M., Linhoff M., Sitarek J., 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., Contreras J.L., Cossou C., Costa A.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

The Cherenkov Telescope Array (CTA) will be the next generation ground-based very-high-energy gamma-ray observatory, constituted by tens of Imaging Atmospheric Cherenkov Telescopes at two sites once its construction and commissioning are finished. Like its predecessors, CTA relies on Instrument Response Functions (IRFs) to relate the observed and reconstructed properties to the true ones of the primary gamma-ray photons. IRFs are needed for the proper reconstruction of spectral and spatial information of the observed sources and are thus among the data products issued to the observatory users. They are derived from Monte Carlo simulations, depend on observation conditions like the telescope pointing direction or the atmospheric transparency and can evolve with time as hardware ages or is replaced. Producing a complete set of IRFs from simulations for every observation taken is a time-consuming task and not feasible when releasing data products on short timescales. Consequently, interpolation techniques on simulated IRFs are investigated to quickly estimate IRFs for specific observation conditions. However, as some of the IRFs constituents are given as probability distributions, specialized methods are needed. This contribution summarizes and compares the feasibility of multiple approaches to interpolate IRF components in the context of the pyirf python software package and IRFs simulated for the LargeSized Telescope prototype (LST-1). We will also give an overview of the current functionalities implemented in pyirf.

Scopus

Improvement of the follow-up observations of IceCube neutrinos by CTA LST

Noda K., Artero M., Fiasson A., Abe K., Abe S., Aguasca-Cabot A., Agudo I., Alvarez Crespo N., Antonelli L.A., Aramo C., Arbet-Engels A., Arcaro C., 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., Foffano L., Freixas Coromina L., Fröse S., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Gasbarra C., Gasparrini D., Geyer D., Giesbrecht Paiva J., Giglietto N.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

A decade has passed since high-energy astrophysical neutrinos have been discovered by IceCube, however the corresponding sources have not been fully identified yet. The reported coincidence of the high-energy IceCube-170922A with the gamma-ray blazar TXS 0506+056 is not enough to claim that blazars are the dominant high-energy neutrino emitters in the Universe. In fact, recently IceCube announced a second correlation with NGC 1068, a nearby Seyfert galaxy, which is significantly different from a gamma-emitting blazars. The hunt for counterparts of the IceCube neutrinos using gamma-ray telescopes started in 2012. Nonetheless, these efforts will continue with the next-generation gamma-ray telescopes, such as the CTA Large Size Telescopes (LSTs) and other telescopes, by means of an improved and revised observation strategy. These new observations will allow us to detect enough sources in order to elucidate the mystery of the neutrino emitters. In this contribution, we introduces the efforts made thus far in the search for gamma-ray counterpart of high-energy IceCube events using the current generation IACTs, focusing on alerts made of multiple neutrinos events, and present an idea to improve in the observational strategies with the CTA LSTs that will become operational in the coming decade. We will discuss how to reduce the bias to gamma-ray emitters in order to search for possible neutrino counterparts.

Scopus

Imaging Atmospheric Cherenkov Telescopes pointing determination using the trajectories of the stars in the field of view.

Dalchenko M., Heller M., 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., 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., Giesbrecht Paiva J., Giglietto N., Giordano F.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

We present a new approach to the pointing determination of Imaging Atmospheric Cherenkov Telescopes (IACTs). This method is universal and can be applied to any IACT with minor modifications. It uses the trajectories of the stars in the field of view of the IACT’s main camera and requires neither dedicated auxiliary hardware nor a specific data taking mode. The method consists of two parts: firstly, we reconstruct individual star positions as a function of time, taking into account the point spread function of the telescope; secondly, we perform a simultaneous fit of all reconstructed star trajectories using the orthogonal distance regression method. The method does not assume any particular star trajectories, does not require a long integration time, and can be applied to any IACT observation mode. The performance of the method is assessed with commissioning data of the Large-Sized Telescope prototype (LST-1), showing the method’s stability and remarkable pointing performance of the LST-1 telescope.

Scopus

Highlights of Galactic Science with the MAGIC telescopes

Strzys M.C., 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., Ishio K., Jiménez Martínez I., Jormanainen J.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

There are several types of Galactic sources that can potentially accelerate charged particles up to GeV and TeV energies. These accelerated particles can produce Very High Energy (E>100 GeV) gamma-ray emission through different non-thermal processes such as inverse Compton scattering of ambient photon fields by accelerated electrons or pion decay after proton-proton collisions. Here we present highlight results of observations with the MAGIC telescopes on Galactic sources: millisecond pulsars, supernova remnants (SNRs), pulsar wind nebulae (PWNe), novae and binary systems. In particular, we present the promising PeVatron candidate SNR G106.3+2.7 containing an energetic PWN named Boomerang. Also, in the ongoing search for new source classes we looked for very-high-energy emission from the millisecond pulsar PSR J0218+4232 that has long been considered as one of the best candidates. Furthermore, we present the observations during an exceptionally bright X-ray outburst from the low mass X-ray binary MAXI J1820+070. Finally, we highlight the MAGIC results of the first nova detected at VHEs: RS Ophiuchi, a recurrent symbiotic nova located in the Milky Way. The detection with the MAGIC telescopes proves a hadronic origin of the the gamma-ray emission, and helps in understanding the contribution of novae to the cosmic-ray budget.

Scopus

Gamma-ray Spectral Line emission search from Dark Matter Annihilation up to 100 TeV towards the Galactic Centre with MAGIC

Inada T., Kerszberg D., Hütten M., Rico J., Teshima M., Kohri K., Hiroshima N., 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.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

The detection of line-like TeV gamma-ray features configures as a smoking gun for the discovery of TeV-scale particle dark matter. We report the first search for dark matter spectral lines in the Galactic Centre region up to gamma-ray energies of 100 TeV with the MAGIC telescopes (La Palma, Canary Islands). The Galactic Centre region is expected to host the closest dark matter halo of considerable size and is therefore well suited for this kind of searches. Observations at large zenith angles improve sensitivity for gamma rays in the TeV regime due to the increased telescope collection area. We present the results obtained with more than 200 hours of large-zenith angle observations of the Galactic Centre region, which allow us to obtain competitive limits to the dark matter annihilation cross-section at high particle masses (< 5 × 10−28 cm3 s−1 at 1 TeV and < 1 × 10−25 cm3 s−1 at 100 TeV), improving the best current constraints above 20 TeV. In addition, we also study the impact of an inner cored dark matter halo on probing the annihilation cross-section. Finally, we use the derived limits to constrain super-symmetric wino models.

Scopus

Galactic Center Studies with CTA-LST-1

Abe S., Ohtani Y., Strzys M., Teshima M., Vovk I., 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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

The Galactic Center region is known to host a wide variety of very-high-energy gamma-ray sources. In 2018 the prototype of the Large-Sized Telescope (LST-1) for CTA was inaugurated, and has been regularly observing the Galactic Center since 2021. To observe the Galactic Center in the southern sky, LST-1, located in the Northern hemisphere, requires an observation mode at a low telescope elevation. In this study, we assessed the performance of LST-1 at the large zenith angle, based both on simulations and observational data for the standard candle Crab Nebula. Analyzing LST-1 data from the Galactic Center observations, we obtained the spectral energy distributions of Sagittarius A* and G0.9+0.1, which were comparable with the results from the current imaging atmospheric Cherenkov telescopes, with a broad energy coverage owing to the large-zenith-angle observation and the low energy threshold of LST-1.

Scopus

First Science Results from CTA LST-1 Telescope and status of LST-2-4

Mazin D., 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., Giesbrecht Paiva J., Giglietto N., Giordano F., Gliwny P.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

The prototype Large-Sized Telescope (LST-1) of the Cherenkov Telescope Array (CTA) was inaugurated on La Palma, Canary Islands, in 2018. Since then, the telescope is in the commissioning phase and takes regular gamma-ray data on astrophysical sources while waiting for other CTA telescopes in La Palma to be constructed. Here we present the status of the commissioning, lessons learned, the telescope performance, and scientific highlights achieved in the last couple of years. The science results include the detection of active galactic nuclei flares, studies of pulsar wind nebulae and pulsars, the detection of a Nova, and searches for gamma-ray emission from gamma-ray bursts. We also present the status of the construction of the three further LST telescopes (LST-2-4) in La Palma and plans for their commissioning.

Scopus

First results of pulsar observations with the LST-1

Mas-Aguilar Á., Brunelli G., Ceribella G., López-Moya M., López-Coto R., 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., 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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

After the discovery of Crab, Vela, and Geminga pulsars at Very High Energies, the search for new pulsars at tens of GeV has been gaining huge importance. However, their steep spectra along with the sensitivity of the current generation of Imaging Atmospheric Cherenkov telescopes (IACTs) are limiting the capability to detect more pulsars. The LST-1 is the first prototype of the Large-Sized Telescope of the forthcoming CTA observatory with enhanced sensitivity at tens of GeV. The LST-1 started its commissioning phase in 2018, and since then it has observed the Crab pulsar regularly. Here, we show the first results of the analysis of the Crab and other pulsars taken with the LST-1. The two characteristic emission peaks of the Crab pulsar, P1, and P2, are detected with high significance showing a clear improvement in sensitivity over the previous generation of IACTs. The spectrum is reconstructed up to 450 GeV for P1 and up to 700 GeV for P2. The low energy threshold of LST-1 also allows us to measure the spectrum of the Crab pulsar in the overlapping region with the Fermi-LAT and cross-calibrate both instruments. The results obtained with the first pulsar observations with the LST-1 confirm the excellent potential of LST telescopes to study and discover new pulsars in the near future.

Scopus

Expected exclusion limits to TeV dark matter from the Perseus Cluster with the Cherenkov Telescope Array

Adam R., Hernández-Cadena S., Hütten M., Pérez-Romero J., Sánchez-Conde M.A., Abe K., Abe S., Acharyya A., 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., Chudoba J., Coimbra Araujo C.H., Conforti V., Conte F., Contreras J.L.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

Clusters of galaxies are the largest gravitationally-bound structures in the Universe. They are composed of galaxies and gas (approximately 15% of the total mass) mostly dark matter (DM, accounts up to 85% of the total mass). If the DM is composed of Weakly Interacting Massive Particles (WIMPs), galaxy clusters represent one of the best targets to search for gamma-ray signals induced by the decay of WIMPs, with masses around the TeV scale. Due to its sensitivity and energy range of operation (from 20 GeV to 300 TeV), the Cherenkov Telescope Array (CTA) Observatory has a unique opportunity to test WIMPs with masses close to the unitarity limit. This will complement the searches for DM from other gamma-ray observatories as well as direct and collider experiments. The CTA Observatory is planning to search for gamma-ray emission, either its origin may be cosmic-ray (CR) or DM related, in the Perseus galaxy cluster during the first years of operation. In this poster, we will present the software created to perform the analysis using the ctools software and the corresponding results.

Scopus

Evidence of hadronic origin of the gamma-ray emission from the nova RS Oph by the MAGIC telescopes

Green D.M., Ramazani V.F., Leone F., López-Coto R., López-Oramas A., Sitarek J., 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., Fallah Ramazani V., 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.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

RS Ophiuchi (RS Oph) is a symbiotic recurrent nova that shows eruptive events roughly every 15 years. On August 8th, 2021, RS Oph erupted with its latest outburst. This event was detected by a wide range of multi-wavelength (MWL) instruments from radio up to very-high-energy (VHE) gamma rays. The MAGIC telescopes followed up on optical and high-energy triggers and initiated an observation campaign from August 9th till September 1st. RS Oph is the first nova detected in the VHE gamma-ray energy range. We report on the detection of VHE gamma rays at a significant level of 13.2σ during the first 4 days of RS Oph with the MAGIC telescopes. We combine the VHE emission detected by MAGIC with optical and high energy observations and conclude RS Oph accelerated hadrons during its eruption. We will present the MWL modeling revealing this hadronic emission, and its further implications for Galactic cosmic-rays.

Scopus

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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：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.

Scopus

Development of a blue-mirror multilayer coating on light concentrators for future SiPM cameras

Okumura A., Haga J., Inoue C., Nishimoto K., Furuta K., Tajima H.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

Silicon photomultipliers (SiPMs) have a few advantages over conventional photomultiplier tubes (PMTs) used in imaging atmospheric Cherenkov telescopes. The first notable characteristic is their higher photon detection efficiency (PDE) of up to about 60%, which is roughly 1.2–1.5 times better than that of PMTs in the 300–450 nm range, enabling us to lower the energy threshold of gamma-ray observations and increase the photon statistics. The second advantage is that SiPMs are chemically stable after exposure to long and bright illumination, while PMTs can cause gain and quantum efficiency degradation after the same exposure. Therefore, the use of SiPMs under bright or full moon conditions may extend the total observation time in the highest energy coverage region of individual telescopes. However, the SiPM PDE is too high in wavelengths longer than 500 nm; hence, the signal-to-noise ratio (S/N) of the Cherenkov signal over the night-sky background (NSB) is not necessarily superb. This is because the Cherenkov signal is dominant over the wavelength of 300–500 nm, while the NSB is brighter in the region of 550 nm or longer. To improve the S/N with minimal and cost-effective additional hardware, we have developed multilayer coating designs with only 8 layers and applied them to the specular surfaces of light concentrators. The layers were designed to reflect more photons in the 300–500 nm range but fewer in 550–800 nm. Using a prototype light concentrator fabricated with the novel multilayer design, we demonstrated that a SiPM array exhibits ∼50% better photon collection efficiency at 403 nm than that obtained with PMTs, agreeing with the result of a ray-tracing simulation. The efficiency measured at 830 nm was also successfully reduced by 30–50%.

Scopus

Detection of the 2021 Outburst of RS Ophiuchi with the LST-1

Kobayashi Y., Aguasca-Cabot A., Bernardos Martín M.I., Green D., López-Coto R., Abe K., Abe S., 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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

Novae are luminous explosions in close binaries which host a white dwarf and a companion donor star. They are triggered by a thermonuclear runaway when the white dwarf accretes a critical amount of matter from the secondary. Though novae are established as high-energy gamma-ray emitters through observations by the Fermi Large Area Telescope (LAT), the origin of the gamma-ray emission, whether it is hadronic or leptonic, had been under intense debate until very recently. RS Ophiuchi (RS Oph) is a well-known recurrent symbiotic nova with a recurrence time scale of 15 years. The most recent outburst of RS Oph in 2021 brought the first detection of very-high-energy (VHE) gamma rays from a nova ever. The first Large-Sized Telescope prototype (LST-1) of the Cherenkov Telescope Array observed this historic event along with H.E.S.S. and MAGIC. The LST-1 observations in the first days after the burst onset show a clear VHE gamma-ray signal from RS Oph. The low energy threshold of LST-1 allows us to reconstruct the RS Oph gamma-ray spectrum down to ∼30 GeV, providing the best connection of the VHE gamma-ray data to the Fermi LAT energy range. The results from the analysis of the LST-1 observations are consistent with those obtained with H.E.S.S. and MAGIC, and also support a hadronic origin for the observed gamma-ray fluxes. In this contribution, we will present the analysis results of the LST-1 observations of the 2021 outburst of RS Oph.

Scopus

Detecting and characterizing pulsar halos with the Cherenkov Telescope Array Observatory

Eckner C., 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., Chudoba J., Coimbra Araujo C.H., Conforti V., Conte F., Contreras J.L., Cossou C., Costa A., Costantini H., Cristofari P.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

The recently identified source class of pulsar halos may be populated and bright enough at TeV energies to constitute a large fraction of the sources that will be observed with the Cherenkov Telescope Array (CTA), especially in the context of the planned Galactic Plane Survey (GPS). In this study, we examine the prospects offered by CTA for the detection and characterization of such objects. CTA will cover energies from 20 GeV to 300 TeV, bridging the ranges already probed with the Fermi Large Area Telescope and High Altitude Water Cherenkov Observatory, and will also have a better angular resolution than the latter instruments, thus providing a complementary look at the phenomenon. From simple models for individual pulsar halos and their population in the Milky Way, we examine under which conditions such sources can be detected and studied from the GPS observations. In the framework of a full spatial-spectral likelihood analysis, using the most recent estimates for the instrument response function and prototypes for the science tools, we derive the spectral and morphological sensitivity of the CTA GPS to the specific intensity distribution of pulsar halos. From these, we quantify the physical parameters for which pulsar halos can be detected, identified, and characterized, and what fraction of the Galactic population could be accessible. We also discuss the effect of interstellar emission and data analysis systematics on these prospects.

Scopus

Defining the data legacy of the MAGIC telescopes: adopting a standardised data format and open-source analysis tools

Nigro C., 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., Ishio K., Jiménez Martínez I., Jormanainen J.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

Very-high-energy (VHE, E > 100 GeV) gamma-ray telescopes have traditionally conducted science with proprietary data and software. After two decades of operations, they have accumulated thousands of hours of observations whose full scientific exploitation cannot be accomplished by the restricted group of scientists operating these instruments. The advent of a new generation of open gamma-ray observatories and, at the same time, the forthcoming end of their scientific operations, call for the realisation of public archives of their observations. With the objective to facilitate the exchange and dissemination of data from current- and next-generation gamma-ray instruments, the "Data formats for gamma-ray astronomy" (GADF) initiative was formed to provide an open and standardised format for gamma-ray astronomical data. In this contribution, we present the effort to produce data of the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes in this standardised format. A total of 150 hours of observations of different sources were converted to the GADF format and then validated by analysing them with the open-source software Gammapy and comparing the results obtained against those produced with the MAGIC proprietary software, MARS. The effort to standardise and validate the MAGIC data in an open and shared format constitute the first fundamental milestone towards the realisation of its public data legacy.

Scopus

Dark matter searches in dwarf spheroidal galaxies with the Cherenkov Telescope Array

Saturni F.G., Doro M., Morselli A., Rodríguez-Fernández G., 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., Chudoba J., Coimbra Araujo C.H., Conforti V., Conte F., Contreras J.L., Cossou C.

Proceedings of Science   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

Dark matter (DM) is one of the major components in the Universe. However, at present its existence is still only inferred through indirect astronomical observations. DM particles can annihilate or decay, producing final-state Standard Model pairs that subsequently annihilate into high-energy γrays. The dwarf spheroidal galaxies (dSphs) in the Milky Way DM halo have long been considered optimal targets to search for annihilating DM signatures in GeV-to-TeV γ-ray spectra due to their high DM densities (hence high astrophysical factors), as well as the expected absence of intrinsic γ-ray emission of astrophysical origin. For such targets, it is important to compute the amount of DM in their halos in a consistent way to optimize the γ-ray data analysis. Such estimates directly affect the observability of DM signals in dSphs, as well as the DM constraints that can be derived in case of null detection. In this contribution, we present the results on the sensitivity of the Cherenkov Telescope Array (CTA) for DM annihilation and decay searches using planned observations of the Milky Way dSphs. We select the most promising targets among all presently known dwarf satellites, providing new determinations of their expected DM signal. This study shows an improvement of approximately an order of magnitude in sensitivity compared to current searches in similar targets. We also discuss the results in terms of cuspy and cored DM models, and investigate the sensitivity obtained by the combination of observations from different dSphs. Finally, we explore the optimal strategies for CTA observations of dSphs.

Scopus

Ctapipe - Prototype Open Event Reconstruction Pipeline for the Cherenkov Telescope Array

Linhoff M., Beiske L., Biederbeck N., Fröse S., Kosack K., Nickel L., 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., Belardinelli D., Benbow W., Bernardini E., Bernete Medrano J., Bernlöhr K., Berti A., Beshley V., Bhattacharjee P., Bhattacharyya S., Bi B., 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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of Science  

The Cherenkov Telescope Array Observatory (CTAO) is the next-generation ground-based gamma-ray observatory currently under construction. It will improve over the current generation of imaging atmospheric Cherenkov telescopes (IACTs) by a factor of five to ten in sensitivity and it will be able to observe the whole sky from a combination of two sites: a northern site in La Palma, Spain, and a southern one in Paranal, Chile. CTAO will also be the first open ground-based gamma-ray observatory. Accordingly, the CTAO data processing pipeline is developed as open-source software and ctapipe will be a core package therein. The event reconstruction pipeline accepts raw data of the telescopes and processes it to produce suitable input for the higher-level science tools. Its primary tasks include reconstructing the physical properties of each recorded air shower and providing the corresponding instrument response functions. ctapipe is a python framework providing algorithms and command-line tools to facilitate raw data calibration, image extraction, image parametrization and event reconstruction. Its current main focus is the analysis of simulated data but it has also been successfully applied for the analysis of data obtained with the CTA prototype telescopes, and first science results have now been obtained by the LST-1 collaboration using ctapipe. A plugin system also allows the processing of nonCTA data. Recent updates, including event reconstruction using machine learning and a new plugin system as well as the roadmap towards a 1.0 release will be presented.

Scopus

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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：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.

Scopus

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   Vol. 444   2024.9

　More details

Language：English   Publishing type：Research paper (scientific journal)   Publisher：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.

Scopus