Searching for very-high-energy electromagnetic counterparts to gravitational-wave events with the Cherenkov Telescope Array

Proceedings of Science 395 (2022)

Authors:

B Patricelli, A Carosi, L Nava, M Seglar-Arroyo, F Schüssler, A Stamerra, A Adelfio, H Ashkar, A Bulgarelli, T Di Girolamo, A Di Piano, T Gasparetto, J Green, F Longo, I Agudo, A Berti, E Bissaldi, G Cella, A Circiello, S Covino, G Ghirlanda, B Humensky, S Inoue, J Lefaucheur, M Filipovic, M Razzano, D Ribeiro, O Sergijenko, G Stratta, S Vergani, H Abdalla, H Abe, S Abe, A Abusleme, F Acero, A Acharyya, V Acín Portella, K Ackley, R Adam, C Adams, SS Adhikari, I Aguado-Ruesga, R Aguilera, A Aguirre-Santaella, F Aharonian, A Alberdi, R Alfaro, J Alfaro, C Alispach, R Aloisio, R Alves Batista, JP Amans, L Amati, E Amato, L Ambrogi, G Ambrosi, M Ambrosio, R Ammendola, J Anderson, M Anduze, EO Angüner, LA Antonelli, V Antonuccio, P Antoranz, R Anutarawiramkul, J Aragunde Gutierrez, C Aramo, A Araudo, M Araya, A Arbet-Engels, C Arcaro, V Arendt, C Armand, T Armstrong, F Arqueros, L Arrabito, B Arsioli, M Artero, K Asano, Y Ascasíbar, J Aschersleben, M Ashley, P Attinà, P Aubert, CB Singh, D Baack, A Babic, M Backes, V Baena, S Bajtlik, A Baktash, C Balazs, M Balbo, O Ballester, J Ballet, B Balmaverde, A Bamba, R Bandiera, A Baquero Larriva, P Barai

Abstract:

The detection of electromagnetic (EM) emission following the gravitational wave (GW) event GW170817 opened the era of multi-messenger astronomy with GWs and provided the first direct evidence that at least a fraction of binary neutron star (BNS) mergers are progenitors of short Gamma-Ray Bursts (GRBs). GRBs are also expected to emit very-high energy (VHE, > 100 GeV) photons, as proven by the recent MAGIC and H.E.S.S. observations. One of the challenges for future multi-messenger observations will be the detection of such VHE emission from GRBs in association with GWs. In the next years, the Cherenkov Telescope Array (CTA) will be a key instrument for the EM follow-up of GW events in the VHE range, owing to its unprecedented sensitivity, rapid response, and capability to monitor a large sky area via scan-mode operation. We present the CTA GW follow-up program, with a focus on the searches for short GRBs possibly associated with BNS mergers. We investigate the possible observational strategies and we outline the prospects for the detection of VHE EM counterparts to transient GW events.

Sensitivity of CTA to gamma-ray emission from the Perseus galaxy cluster

Proceedings of Science 395 (2022)

Authors:

H Abdalla, H Abe, S Abe, A Abusleme, F Acero, A Acharyya, V Acín Portella, K Ackley, R Adam, C Adams, SS Adhikari, I Aguado-Ruesga, I Agudo, R Aguilera, A Aguirre-Santaella, F Aharonian, A Alberdi, R Alfaro, J Alfaro, C Alispach, R Aloisio, R Alves Batista, JP Amans, L Amati, E Amato, L Ambrogi, G Ambrosi, M Ambrosio, R Ammendola, J Anderson, M Anduze, EO Angüner, LA Antonelli, V Antonuccio, P Antoranz, R Anutarawiramkul, J Aragunde Gutierrez, C Aramo, A Araudo, M Araya, A Arbet-Engels, C Arcaro, V Arendt, C Armand, T Armstrong, F Arqueros, L Arrabito, B Arsioli, M Artero, K Asano, Y Ascasíbar, J Aschersleben, M Ashley, P Attinà, P Aubert, CB Singh, D Baack, A Babic, M Backes, V Baena, S Bajtlik, A Baktash, C Balazs, M Balbo, O Ballester, J Ballet, B Balmaverde, A Bamba, R Bandiera, A Baquero Larriva, P Barai, C Barbier, V Barbosa Martins, M Barcelo, M Barkov, M Barnard, L Baroncelli, U Barres de Almeida, JA Barrio, D Bastieri, PI Batista, I Batkovic, C Bauer, R Bautista-González, J Baxter, U Becciani, J Becerra González, Y Becherini, G Beck, J Becker Tjus, W Bednarek, A Belfiore, L Bellizzi, R Belmont, W Benbow, D Berge, E Bernardini, MI Bernardos, K Bernlöhr, A Berti

Abstract:

In these proceedings we summarize the current status of the study of the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse gamma-ray emission from the Perseus galaxy cluster. Gamma-ray emission is expected in galaxy clusters both from interactions of cosmic rays (CR) with the intra-cluster medium, or as a product of annihilation or decay of dark matter (DM) particles in case they are weakly interactive massive particles (WIMPs). The observation of Perseus constitutes one of the Key Science Projects to be carried out by the CTA Consortium. In this contribution, we focus on the DM-induced component of the flux. Our DM modelling includes the substructures we expect in the main halo which will boost the annihilation signal significantly. We adopt an ON/OFF observation strategy and simulate the expected gamma-ray signals. Finally we compute the expected CTA sensitivity using a likelihood maximization analysis including the most recent CTA instrument response functions. In absence of signal, we show that CTA will allow us to provide stringent and competitive constraints on TeV DM, especially for the case of DM decay.

Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre

Proceedings of Science 395 (2022)

Authors:

H Abdalla, H Abe, S Abe, A Abusleme, F Acero, A Acharyya, V Acín Portella, K Ackley, R Adam, C Adams, SS Adhikari, I Aguado-Ruesga, I Agudo, R Aguilera, A Aguirre-Santaella, F Aharonian, A Alberdi, R Alfaro, J Alfaro, C Alispach, R Aloisio, R Alves Batista, JP Amans, L Amati, E Amato, L Ambrogi, G Ambrosi, M Ambrosio, R Ammendola, J Anderson, M Anduze, EO Angüner, LA Antonelli, V Antonuccio, P Antoranz, R Anutarawiramkul, J Aragunde Gutierrez, C Aramo, A Araudo, M Araya, A Arbet-Engels, C Arcaro, V Arendt, C Armand, T Armstrong, F Arqueros, L Arrabito, B Arsioli, M Artero, K Asano, Y Ascasíbar, J Aschersleben, M Ashley, P Attinà, P Aubert, CB Singh, D Baack, A Babic, M Backes, V Baena, S Bajtlik, A Baktash, C Balazs, M Balbo, O Ballester, J Ballet, B Balmaverde, A Bamba, R Bandiera, A Baquero Larriva, P Barai, C Barbier, V Barbosa Martins, M Barcelo, M Barkov, M Barnard, L Baroncelli, U Barres de Almeida, JA Barrio, D Bastieri, PI Batista, I Batkovic, C Bauer, R Bautista-González, J Baxter, U Becciani, J Becerra González, Y Becherini, G Beck, J Becker Tjus, W Bednarek, A Belfiore, L Bellizzi, R Belmont, W Benbow, D Berge, E Bernardini, MI Bernardos, K Bernlöhr, A Berti

Abstract:

High-energy gamma rays are promising tools to constrain or reveal the nature of dark matter, in particular Weakly Interacting Massive Particles. Being well into its pre-construction phase, the Cherenkov Telescope Array (CTA) will soon probe the sky in the 20 GeV - 300 TeV energy range. Thanks to its improved energy and angular resolutions as well as significantly larger effective area when compared to the current generation of Cherenkov telescopes, CTA is expected to probe heavier dark matter, with unprecedented sensitivity, reaching the thermal annihilation cross-section at 1 TeV. This talk will summarise the planned dark matter search strategies with CTA, focusing on the signal from the Galactic centre. As observed with the Fermi LAT at lower energies, this region is rather complex and CTA will be the first ground-based observatory sensitive to the large scale diffuse astrophysical emission from that region. We report on the collaboration effort to study the impact of such extended astrophysical backgrounds on the dark matter search, based on Fermi-LAT data in order to guide our observational strategies, taking into account various sources of systematic uncertainty.

Sensitivity of the Cherenkov Telescope Array to emission from the gamma-ray counterparts of neutrino events

Proceedings of Science 395 (2022)

Authors:

O Sergijenko, AM Brown, DFG Fiorillo, AR de León, K Satalecka, CF Tung, R Reimann, T Glauch, I Taboada, H Abdalla, H Abe, S Abe, A Abusleme, F Acero, A Acharyya, V Acín Portella, K Ackley, R Adam, C Adams, SS Adhikari, I Aguado-Ruesga, I Agudo, R Aguilera, A Aguirre-Santaella, F Aharonian, A Alberdi, R Alfaro, J Alfaro, C Alispach, R Aloisio, R Alves Batista, JP Amans, L Amati, E Amato, L Ambrogi, G Ambrosi, M Ambrosio, R Ammendola, J Anderson, M Anduze, EO Angüner, LA Antonelli, V Antonuccio, P Antoranz, R Anutarawiramkul, J Aragunde Gutierrez, C Aramo, A Araudo, M Araya, A Arbet-Engels, C Arcaro, V Arendt, C Armand, T Armstrong, F Arqueros, L Arrabito, B Arsioli, M Artero, K Asano, Y Ascasíbar, J Aschersleben, M Ashley, P Attinà, P Aubert, CB Singh, D Baack, A Babic, M Backes, V Baena, S Bajtlik, A Baktash, C Balazs, M Balbo, O Ballester, J Ballet, B Balmaverde, A Bamba, R Bandiera, A Baquero Larriva, P Barai, C Barbier, V Barbosa Martins, M Barcelo, M Barkov, M Barnard, L Baroncelli, U Barres de Almeida, JA Barrio, D Bastieri, PI Batista, I Batkovic, C Bauer, R Bautista-González, J Baxter, U Becciani, J Becerra González, Y Becherini, G Beck, J Becker Tjus, W Bednarek

Abstract:

We investigate the possibility of detection of the VHE gamma-ray counterparts to the neutrino astrophysical sources within the Neutrino Target of Opportunity (NToO) program of CTA using the populations simulated by the FIRESONG software to resemble the diffuse astrophysical neutrino flux measured by IceCube. We derive the detection probability for different zenith angles and geomagnetic field configurations. The difference in detectability of sources between CTA-North and CTA-South for the average geomagnetic field is not substantial. We investigate the effect of a higher night-sky background and the preliminary CTA Alpha layout on the detection probability.

Study of Mass Composition of Cosmic Rays with IceTop and IceCube

Proceedings of Science 395 (2022)

Authors:

P Koundal, M Plum, J Saffer, R Abbasi, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, C Alispach, AA Alves, NM Amin, R An, K Andeen, T Anderson, G Anton, C Argüelles, Y Ashida, S Axani, X Bai, AV Balagopal, A Barbano, SW Barwick, B Bastian, V Basu, S Baur, R Bay, JJ Beatty, KH Becker, J Becker Tjus, C Bellenghi, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, M Boddenberg, F Bontempo, J Borowka, S Böser, O Botner, J Böttcher, E Bourbeau, F Bradascio, J Braun, S Bron, J Brostean-Kaiser, S Browne, A Burgman, RT Burley, RS Busse, MA Campana, EG Carnie-Bronca, C Chen, D Chirkin, K Choi, BA Clark, K Clark, L Classen, A Coleman, GH Collin, JM Conrad, P Coppin, P Correa, DF Cowen, R Cross, C Dappen, P Dave, C De Clercq, JJ DeLaunay, H Dembinski, K Deoskar, S De Ridder, A Desai, P Desiati, KD de Vries, G de Wasseige, M de With, T DeYoung, S Dharani, A Diaz, JC Díaz-Vélez, M Dittmer, H Dujmovic, M Dunkman, MA DuVernois, E Dvorak, T Ehrhardt, P Eller, R Engel, H Erpenbeck, J Evans, PA Evenson, KL Fan, AR Fazely, S Fiedlschuster, AT Fienberg

Abstract:

The IceCube Neutrino Observatory is a multi-component detector at the South Pole which detects high-energy particles emerging from astrophysical events. These particles provide us with insights into the fundamental properties and behaviour of their sources. Besides its principal usage and merits in neutrino astronomy, using IceCube in conjunction with its surface array, IceTop, also makes it a unique three-dimensional cosmic-ray detector. This distinctive feature helps facilitate detailed cosmic-ray analysis in the transition region from galactic to extragalactic sources. We will present the progress made on multiple fronts to establish a framework for mass-estimation of primary cosmic rays. The first technique relies on a likelihood-based analysis of the surface signal distribution and improves upon the standard reconstruction technique. The second uses advanced methods in graph neural networks to use the full in-ice shower footprint, in addition to global shower-footprint features from IceTop. A comparison between the two methods for composition analysis as well as a possible extension of the analysis techniques for sub-PeV cosmic-ray air-showers will also be discussed.