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

In-situ calibration of the single-photoelectron charge response of the IceCube photomultiplier tubes

Journal of Instrumentation IOP Publishing (2020)

Abstract:

We describe an improved in-situ calibration of the single-photoelectron charge distributions for each of the in-ice Hamamatsu Photonics R7081-02[MOD] photomultiplier tubes in the IceCube Neutrino Observatory. The characterization of the individual PMT charge distributions is important for PMT calibration, data and Monte Carlo simulation agreement, and understanding the effect of hardware differences within the detector. We discuss the single photoelectron identification procedure and how we extract the single-photoelectron charge distribution using a deconvolution of the multiple-photoelectron charge distribution.

Measurements of the Time-Dependent Cosmic-Ray Sun Shadow with Seven Years of IceCube Data -- Comparison with the Solar Cycle and Magnetic Field Models

(2020)

Authors:

MG Aartsen, R Abbasi, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, C Alispach, NM Amin, K Andeen, T Anderson, I Ansseau, G Anton, C Argüelles, J Auffenberg, S Axani, H Bagherpour, X Bai, A Balagopal V., A Barbano, SW Barwick, B Bastian, V Basu, V Baum, S Baur, R Bay, JJ Beatty, K-H Becker, J Becker Tjus, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, S Böser, O Botner, J Böttcher, E Bourbeau, J Bourbeau, F Bradascio, J Braun, S Bron, J Brostean-Kaiser, A Burgman, J Buscher, RS Busse, T Carver, C Chen, E Cheung, D Chirkin, S Choi, BA Clark, K Clark, L Classen, A Coleman, GH Collin, JM Conrad, P Coppin, P Correa, DF Cowen, R Cross, 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, H Dujmovic, M Dunkman, MA DuVernois, E Dvorak, T Ehrhardt, P Eller, R Engel, PA Evenson, S Fahey, AR Fazely, J Felde, H Fichtner, AT Fienberg, K Filimonov, C Finley, D Fox, A Franckowiak, E Friedman, A Fritz, TK Gaisser, J Gallagher, E Ganster, S Garrappa, L Gerhardt, A Ghadimi, T Glauch, T Glüsenkamp, A Goldschmidt, JG Gonzalez, S Goswami, D Grant, T Grégoire, Z Griffith, S Griswold, M Günder, M Gündüz, C Haack, A Hallgren, R Halliday, L Halve, F Halzen, K Hanson, J Hardin, A Haungs, S Hauser, D Hebecker, D Heereman, P Heix, K Helbing, R Hellauer, F Henningsen, S Hickford, J Hignight, C Hill, GC Hill, KD Hoffman, R Hoffmann, T Hoinka, B Hokanson-Fasig, K Hoshina, F Huang, M Huber, T Huber, K Hultqvist, M Hünnefeld, R Hussain, S In, N Iovine, A Ishihara, M Jansson, GS Japaridze, M Jeong, BJP Jones, F Jonske, R Joppe, D Kang, W Kang, A Kappes, D Kappesser, T Karg, M Karl, A Karle, U Katz, M Kauer, M Kellermann, JL Kelley, A Kheirandish, J Kim, K Kin, T Kintscher, J Kiryluk, T Kittler, J Kleimann, SR Klein, R Koirala, H Kolanoski, L Köpke, C Kopper, S Kopper, DJ Koskinen, P Koundal, M Kowalski, K Krings, G Krückl, N Kulacz, N Kurahashi, A Kyriacou, JL Lanfranchi, MJ Larson, F Lauber, JP Lazar, K Leonard, A Leszczyńska, Y Li, QR Liu, E Lohfink, CJ Lozano Mariscal, L Lu, F Lucarelli, A Ludwig, J Lünemann, W Luszczak, Y Lyu, WY Ma, J Madsen, G Maggi, KBM Mahn, Y Makino, P Mallik, S Mancina, IC Mariş, R Maruyama, K Mase, R Maunu, F McNally, K Meagher, M Medici, A Medina, M Meier, S Meighen-Berger, J Merz, T Meures, J Micallef, D Mockler, G Momenté, T Montaruli, RW Moore, R Morse, M Moulai, P Muth, R Nagai, U Naumann, G Neer, LV Nguyen, H Niederhausen, MU Nisa, SC Nowicki, DR Nygren, A Obertacke Pollmann, M Oehler, A Olivas, A O'Murchadha, E O'Sullivan, H Pandya, DV Pankova, N Park, GK Parker, EN Paudel, P Peiffer, C Pérez de los Heros, S Philippen, D Pieloth, S Pieper, E Pinat, A Pizzuto, M Plum, Y Popovych, A Porcelli, M Prado Rodriguez, PB Price, GT Przybylski, C Raab, A Raissi, M Rameez, L Rauch, K Rawlins, IC Rea, A Rehman, R Reimann, B Relethford, M Renschler, G Renzi, E Resconi, W Rhode, M Richman, B Riedel, S Robertson, G Roellinghoff, M Rongen, C Rott, T Ruhe, D Ryckbosch, D Rysewyk Cantu, I Safa, SE Sanchez Herrera, A Sandrock, J Sandroos, M Santander, S Sarkar, S Sarkar, K Satalecka, M Scharf, M Schaufel, H Schieler, P Schlunder, T Schmidt, A Schneider, J Schneider, FG Schröder, L Schumacher, S Sclafani, D Seckel, S Seunarine, S Shefali, M Silva, B Smithers, R Snihur, J Soedingrekso, D Soldin, M Song, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, R Stein, J Stettner, A Steuer, T Stezelberger, RG Stokstad, NL Strotjohann, T Stürwald, T Stuttard, GW Sullivan, I Taboada, F Tenholt, S Ter-Antonyan, A Terliuk, S Tilav, K Tollefson, L Tomankova, C Tönnis, S Toscano, D Tosi, A Trettin, M Tselengidou, CF Tung, A Turcati, R Turcotte, CF Turley, B Ty, E Unger, MA Unland Elorrieta, M Usner, J Vandenbroucke, W Van Driessche, D van Eijk, N van Eijndhoven, D Vannerom, J van Santen, S Verpoest, M Vraeghe, C Walck, A Wallace, M Wallraff, TB Watson, C Weaver, A Weindl, MJ Weiss, J Weldert, C Wendt, J Werthebach, BJ Whelan, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, L Wills, M Wolf, TR Wood, K Woschnagg, G Wrede, J Wulff, XW Xu, Y Xu, JP Yanez, S Yoshida, T Yuan, Z Zhang, M Zöcklein

A Search for Neutrino Point-Source Populations in 7 Years of IceCube Data with Neutrino-count Statistics

The Astrophysical Journal: an international review of astronomy and astronomical physics American Astronomical Society (2020)

Authors:

B Eberhardt, T Ehrhardt, P Eller, R Engel, A Fritz, TK Gaisser, J Gallagher, E Ganster, S Garrappa, L Gerhardt, K Ghorbani, T Glauch, T Glüsenkamp, A Goldschmidt, JG Gonzalez, D Grant, S Griswold, F Huang, M Huber, T Huber, K Hultqvist, GS Japaridze, M Jeong, K Jero, BJP Jones

Abstract:

The presence of a population of point sources in a dataset modifies the underlying neutrino-count statistics from the Poisson distribution. This deviation can be exactly quantified using the non-Poissonian template fitting technique, and in this work we present the first application this approach to the IceCube high-energy neutrino dataset. Using this method, we search in 7 years of IceCube data for point-source populations correlated with the disk of the Milky Way, the Fermi bubbles, the Schlegel, Finkbeiner, and Davis dust map, or with the isotropic extragalactic sky. No evidence for such a population is found in the data using this technique, and in the absence of a signal we establish constraints on population models with source count distribution functions that can be described by a power-law with a single break. The derived limits can be interpreted in the context of many possible source classes. In order to enhance the flexibility of the results, we publish the full posterior from our analysis, which can be used to establish limits on specific population models that would contribute to the observed IceCube neutrino flux.

Transport of high-energy charged particles through spatially-intermittent turbulent magnetic fields

Astrophysical Journal American Astronomical Society 892:2 (2020) 114

Authors:

LE Chen, AFA Bott, Petros Tzeferacos, Alexandra Rigby, Anthony Bell, Robert Bingham, C Graziani, Jonathan Katz, Richard Petrasso, Gianluca Gregori, Francesco Miniati

Abstract:

Identifying the sources of the highest energy cosmic rays requires understanding how they are deflected by the stochastic, spatially intermittent intergalactic magnetic field. Here we report measurements of energetic charged-particle propagation through a laser-produced magnetized plasma with these properties. We characterize the diffusive transport of the particles experimentally. The results show that the transport is diffusive and that, for the regime of interest for the highest-energy cosmic rays, the diffusion coefficient is unaffected by the spatial intermittency of the magnetic field.

ANTARES and IceCube Combined Search for Neutrino Point-like and Extended Sources in the Southern Sky

The Astrophysical Journal: an international review of astronomy and astronomical physics American Astronomical Society (2020)

Authors:

ANTARES Collaboration, A Albert, M André, M Anghinolfi, G Anton, M Ardid, J-J Aubert, J Aublin, B Baret, S Basa, B Belhorma, V Bertin, S Biagi, M Bissinger, J Boumaaza, S Bourret, M Bouta, MC Bouwhuis, H Brânzaş, R Bruijn, J Brunner, J Busto, A Capone, L Caramete, M Chabab, Subir SARKAR, IceCube Collaboration

Abstract:

A search for point-like and extended sources of cosmic neutrinos using data collected by the ANTARES and IceCube neutrino telescopes is presented. The data set consists of all the track-like and shower-like events pointing in the direction of the Southern Sky included in the nine-year ANTARES point-source analysis, combined with the through-going track-like events used in the seven-year IceCube point-source search. The advantageous field of view of ANTARES and the large size of IceCube are exploited to improve the sensitivity in the Southern Sky by a factor $\sim$2 compared to both individual analyses. In this work, the Southern Sky is scanned for possible excesses of spatial clustering, and the positions of preselected candidate sources are investigated. In addition, special focus is given to the region around the Galactic Centre, whereby a dedicated search at the location of SgrA* is performed, and to the location of the supernova remnant RXJ 1713.7-3946. No significant evidence for cosmic neutrino sources is found and upper limits on the flux from the various searches are presented.

51��