Prof Subir Sarkar: Publications

IceCube

IceCube at Oxford

I am a member since 2004 of the IceCube collaboration which discovered cosmic high energy neutrinos and identified some of their astrophysical sources.

IceCube @ Oxford

Detection methods for the Cherenkov Telescope Array at very-short exposure times

Proceedings of Science 395 (2022)

Authors:

A Di Piano, A Bulgarelli, V Fioretti, L Baroncelli, N Parmiggiani, F Longo, A Stamerra, A López-Oramas, G Stratta, G De Cesare, 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, 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:

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy, with the deployment of tens of highly sensitive and fast-reacting Cherenkov telescopes. It will cover a wide energy range (20 GeV - 300 TeV) with unprecedented sensitivity. To maximize the scientific return, the observatory will be provided with an online software system that will perform the first analysis of scientific data in real-time. This study investigates the precision and accuracy of available science tools and analysis techniques for the short-term detection of gamma-ray sources, in terms of sky localization, detection significance and, if significant detection is achieved, a first estimation of the integral photon flux. The scope is to evaluate the feasibility of the algorithms' implementation in the real-time analysis of CTA. In this contribution we present a general overview of the methods and some of the results for the test case of the short-term detection of a gamma-ray burst afterglow, as the VHE counterpart of a gravitational wave event.

Development of a scintillation and radio hybrid detector array at the South Pole

Proceedings of Science 395 (2022)

Authors:

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, K Filimonov, C Finley, L Fischer

Abstract:

At the IceCube Neutrino Observatory, a Surface Array Enhancement is planned, consisting of 32 hybrid stations, placed within the current IceTop footprint. This surface enhancement will considerably increase the detection sensitivity to cosmic rays in the 100 TeV to 1 EeV primary energy range, measure the effects of snow accumulation on the existing IceTop tanks and serve as R&D for the possible future large-scale surface array of IceCube-Gen2. Each station has one central hybrid DAQ, which reads out 8 scintillation detectors and 3 radio antennas. The radio antenna SKALA-2 is used in this array due to its low-noise, high amplification and sensitivity in the 70-350 MHz frequency band. Every scintillation detector has an active area of 1.5 m2 organic plastic scintillators connected by wavelength-shifting fibers, which are connected to a silicon photomultiplier. The signals from the scintillation detectors are integrated and digitized by a local custom electronics board and transferred to the central DAQ. When triggered by the scintillation detectors, the filtered and amplified analog waveforms from the radio antennas are read out and digitized by the central DAQ. A full prototype station has been developed and built and was installed at the South Pole in January 2020. It is planned to install the full array by 2026. In this contribution the hardware design of the array as well as the installation plans will be presented.

Discrimination of muons for mass composition studies of inclined air showers detected with IceTop

Proceedings of Science 395 (2022)

Authors:

Abstract:

IceTop, the surface array of IceCube, measures air showers from cosmic rays within the energy range of 1 PeV to a few EeV and a zenith angle range of up to ≈ 36◦. This detector array can also measure air showers arriving at larger zenith angles at energies above 20 PeV. Air showers from lighter primaries arriving at the array will produce fewer muons when compared to heavier cosmic-ray primaries. A discrimination of these muons from the electromagnetic component in the shower can therefore allow a measurement of the primary mass. A study to discriminate muons using Monte-Carlo air showers of energies 20-100 PeV and within the zenith angular range of 45◦-60◦ will be presented. The discrimination is done using charge and time-based cuts which allows us to select muon-like signals in each shower. The methodology of this analysis, which aims at categorizing the measured air showers as light or heavy on an event-by-event basis, will be discussed.

Exploring the population of Galactic very-high-energy γ-ray sources

Proceedings of Science 395 (2022)

Authors:

C Steppa, K Egberts, 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

Abstract:

At very high energies (VHE), the emission of γ rays is dominated by discrete sources. Due to the limited resolution and sensitivity of current-generation instruments, only a small fraction of the total Galactic population of VHE γ-ray sources has been detected significantly. The larger part of the population can be expected to contribute as a diffuse signal alongside emission originating from propagating cosmic rays. Without quantifying the source population, it is not possible to disentangle these two components. Based on the H.E.S.S. Galactic plane survey, a numerical approach has been taken to develop a model of the population of Galactic VHE γ-ray sources, which is shown to account accurately for the observational bias. We present estimates of the absolute number of sources in the Galactic Plane and their contribution to the total VHE γ-ray emission for five different spatial source distributions. Prospects for CTA and its ability to constrain the model are discussed. Finally, first results of an extension of our modelling approach using machine learning to extract more information from the available data set are presented.

Gravitational Wave Follow-Up Using Low Energy Neutrinos in IceCube DeepCore

Proceedings of Science 395 (2022)

Authors:

AV Balagopal, R Hussain, A Pizzuto, 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, 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, K Filimonov

Abstract:

The IceCube DeepCore is a dense infill array of the IceCube Neutrino Observatory at the South Pole. While IceCube is best suited for detecting neutrinos with energies of several 100 GeV and above, DeepCore allows to probe neutrinos with lower energies. We focus on a sample of neutrinos with energies above approximately 10 GeV, which was originally optimised for oscillation experiments. Recently, it has been adapted to enable searches for transient sources of astrophysical neutrinos in the sky. In particular, this low-energy dataset can be used to conduct follow-up searches of gravitational wave transients detected by the LIGO-Virgo instruments. A study of this, which complements IceCube's follow-up of gravitational wave events using high-energy neutrino samples, will be discussed here.

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