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

Measurement of the energy spectrum of cosmic rays above 10^18 eV using the Pierre Auger Observatory

ArXiv 1002.1975 (2010)

Abstract:

We report a measurement of the flux of cosmic rays with unprecedented precision and statistics using the Pierre Auger Observatory. Based on fluorescence observations in coincidence with at least one surface detector we derive a spectrum for energies above 10^18 eV. We also update the previously published energy spectrum obtained with the surface detector array. The two spectra are combined addressing the systematic uncertainties and, in particular, the influence of the energy resolution on the spectral shape. The spectrum can be described by a broken power law E^-gamma with index gamma=3.3 below the ankle which is measured at log10(E/eV) = 18.6. Above the ankle the spectrum is described by a power law with index 2.6 followed by a flux suppression, above about log10(E/eV) = 19.5, detected with high statistical significance.

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A Study of the Effect of Molecular and Aerosol Conditions in the Atmosphere on Air Fluorescence Measurements at the Pierre Auger Observatory

ArXiv 1002.0366 (2010)

Abstract:

The air fluorescence detector of the Pierre Auger Observatory is designed to perform calorimetric measurements of extensive air showers created by cosmic rays of above 10^18 eV. To correct these measurements for the effects introduced by atmospheric fluctuations, the Observatory contains a group of monitoring instruments to record atmospheric conditions across the detector site, an area exceeding 3,000 km^2. The atmospheric data are used extensively in the reconstruction of air showers, and are particularly important for the correct determination of shower energies and the depths of shower maxima. This paper contains a summary of the molecular and aerosol conditions measured at the Pierre Auger Observatory since the start of regular operations in 2004, and includes a discussion of the impact of these measurements on air shower reconstructions. Between 10^18 and 10^20 eV, the systematic uncertainties due to all atmospheric effects increase from 4% to 8% in measurements of shower energy, and 4 g/cm^2 to 8 g/cm^2 in measurements of the shower maximum.

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Erratum to "Atmospheric effects on extensive air showers observed with the surface detector of the Pierre Auger observatory" [Astroparticle Physics 32(2) (2009), 89-99] (DOI:10.1016/j.astropartphys.2009.06.004)

Astroparticle Physics 33:1 (2010) 65-67

Authors:

J Abraham, P Abreu, M Aglietta, C Aguirre, EJ Ahn, D Allard, I Allekotte, J Allen, P Allison, J Alvarez-Muñiz, M Ambrosio, L Anchordoqui, S Andringa, A Anzalone, C Aramo, E Arganda, S Argirò, K Arisaka, F Arneodo, F Arqueros, T Asch, H Asorey, P Assis, J Aublin, M Ave, G Avila, T Bäcker, D Badagnani, KB Barber, AF Barbosa, SLC Barroso, B Baughman, P Bauleo, JJ Beatty, T Beau, BR Becker, KH Becker, A Bellétoile, JA Bellido, S BenZvi, C Berat, P Bernardini, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, C Bleve, H Blümer, M Boháčová, C Bonifazi, R Bonino, N Borodai, J Brack, P Brogueira, WC Brown, R Bruijn, P Buchholz, A Bueno, RE Burton, NG Busca, KS Caballero-Mora, L Caramete, R Caruso, W Carvalho, A Castellina, O Catalano, L Cazon, R Cester, J Chauvin, A Chiavassa, JA Chinellato, A Chou, J Chudoba, J Chye, RW Clay, E Colombo, R Conceição, B Connolly, F Contreras, J Coppens, A Cordier, U Cotti, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, R Dallier, K Daumiller, BR Dawson, RM de Almeida, M De Domenico, C De Donato, SJ de Jong, G De La Vega, WJM de Mello, JRT de Mello Neto

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Erratum: Search for high-energy Muon neutrinos from the "naked-eye" GRB080319b with the icecube neutrino telescope (The Astrophysical Journal (2009) 701 (1721))

Astrophysical Journal 708:1 (2010) 911-912

Authors:

R Abbasi, Y Abdou, M Ackermann, J Adams, M Ahlers, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JLB Alba, K Beattie, S Bechet, JK Becker, KH Becker, ML Benabderrahmane, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, M Bissok, E Blaufuss, DJ Boersma, C Bohm, J Bolmont, S Böser, O Botner, L Bradley, J Braun, D Breder, T Burgess, T Castermans, D Chirkin, B Christy, J Clem, S Cohen, DF Cowen, MV D'Agostino, M Danninger, CT Day, C De Clercq, L Demirörs, O Depaepe, F Descamps, P Desiati, G De Vries-Uiterweerd, T Deyoung, JC Diaz-Velez, J Dreyer, JP Dumm, MR Duvoort, WR Edwards, R Ehrlich, J Eisch, RW Ellsworth, O Engdegrd, S Euler, PA Evenson, O Fadiran, AR Fazely, T Feusels, K Filimonov, C Finley, MM Foerster, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, R Ganugapati, L Gerhardt, L Gladstone, A Goldschmidt, JA Goodman, R Gozzini, D Grant, T Griesel, A Gro, S Grullon, RM Gunasingha, M Gurtner, C Ha, A Hallgren, F Halzen, K Han, K Hanson, Y Hasegawa, J Heise, K Helbing, P Herquet, S Hickford, GC Hill, KD Hoffman, K Hoshina, D Hubert, W Huelsnitz, JP Hül

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Light asymmetric dark matter

Proceedings of the 6th Patras Workshop on Axions, WIMPs and WISPs, PATRAS 2010 (2010) 158-163

Authors:

MT Frandsen, S Sarkar

Abstract:

Stable relic particles of mass around 5 GeV with an intrinsic matter-antimatter asymmetry would naturally provide the dark matter. They do not annihilate after being captured by the Sun and the capture rate is exponentially enhanced if they have self-interactions (of the right order to solve the excessive substructure problem of collisionless cold dark matter). Such particles can significantly affect heat transport in the Sun and may solve the 'Solar composition problem' - the predicted small changes in low energy neutrino fluxes are potentially measurable by Borexino and the proposed SNO+ and LENS experiments.

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Prof Subir Sarkar

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IceCube

IceCube at Oxford

Measurement of the energy spectrum of cosmic rays above 10^18 eV using the Pierre Auger Observatory

Abstract:

A Study of the Effect of Molecular and Aerosol Conditions in the Atmosphere on Air Fluorescence Measurements at the Pierre Auger Observatory

Abstract:

Erratum to "Atmospheric effects on extensive air showers observed with the surface detector of the Pierre Auger observatory" [Astroparticle Physics 32(2) (2009), 89-99] (DOI:10.1016/j.astropartphys.2009.06.004)

Authors:

Erratum: Search for high-energy Muon neutrinos from the "naked-eye" GRB080319b with the icecube neutrino telescope (The Astrophysical Journal (2009) 701 (1721))

Authors:

Light asymmetric dark matter

Authors:

Abstract:

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Prof Subir Sarkar

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IceCube

IceCube at Oxford

Measurement of the energy spectrum of cosmic rays above 10^18 eV using the Pierre Auger Observatory

Abstract:

A Study of the Effect of Molecular and Aerosol Conditions in the Atmosphere on Air Fluorescence Measurements at the Pierre Auger Observatory

Abstract:

Erratum to "Atmospheric effects on extensive air showers observed with the surface detector of the Pierre Auger observatory" [Astroparticle Physics 32(2) (2009), 89-99] (DOI:10.1016/j.astropartphys.2009.06.004)

Authors:

Erratum: Search for high-energy Muon neutrinos from the "naked-eye" GRB080319b with the icecube neutrino telescope (The Astrophysical Journal (2009) 701 (1721))

Authors:

Light asymmetric dark matter

Authors:

Abstract: