Publications


All-particle cosmic ray energy spectrum measured with 26 IceTop stations

ArXiv (2012)

I Collaboration, R Abbasi, Y Abdou, T Abu-Zayyad, M Ackermann, J Adams, JA Aguilar, M Ahlers, D Altmann, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, V Baum, R Bay, JLB Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, KH Becker, M Bell, ML Benabderrahmane, S BenZvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, L Brayeur, AM Brown, S Buitink, KS Caballero-Mora, M Carson, M Casier, D Chirkin, B Christy, F Clevermann, S Cohen, DF Cowen, AHC Silva, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, CD Clercq, T Degner, F Descamps, P Desiati, GD Vries-Uiterweerd, T DeYoung, JC Díaz-Vélez, J Dreyer, JP Dumm, M Dunkman, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, S Flis, A Franckowiak, R Franke, TK Gaisser, J Gallagher, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Góra, D Grant, A Groß, S Grullon, M Gurtner, C Ha, AH Ismail, A Hallgren, F Halzen, K Han, K Hanson, P Heimann, D Heinen, K Helbing, R Hellauer, S Hickford, GC Hill, KD Hoffman, B Hoffmann, A Homeier, K Hoshina, W Huelsnitz, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, GS Japaridze, H Johansson, A Kappes, T Karg, A Karle, J Kiryluk, F Kislat, SR Klein, S Klepser, JH Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, M Krasberg, G Kroll, J Kunnen, N Kurahashi, T Kuwabara, M Labare, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészáros, T Meures, S Miarecki, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, SC Nowicki, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, S Panknin, L Paul, CPDL Heros, D Pieloth, J Posselt, PB Price, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, M Richman, B Riedel, JP Rodrigues, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, HG Sander, M Santander, S Sarkar, K Schatto, M Scheel, T Schmidt, S Schöneberg, A Schönwald, A Schukraft, L Schulte, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, MWE Smith, GM Spiczak, C Spiering, M Stamatikos, T Stanev, T Stezelberger, RG Stokstad, A Stößl, EA Strahler, R Ström, M Stüer, GW Sullivan, H Taavola, I Taboada, A Tamburro, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, NV Eijndhoven, AV Overloop, JV Santen, M Vehring, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, R Wasserman, C Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, TR Wood, K Woschnagg, C Xu, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, M Zoll

We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 km^2. The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenith angle ranges between 0{\deg} and 46{\deg}. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles {\theta} < 30{\deg}, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed between 3.5 and 4.32 PeV, depending on composition assumption. Spectral indices above the knee range from -3.08 to -3.11 depending on primary mass composition assumption. Moreover, an indication of a flattening of the spectrum above 22 PeV were observed.


A SEARCH FOR POINT SOURCES OF EeV NEUTRONS

ASTROPHYSICAL JOURNAL 760 (2012) ARTN 148

P Abreu, M Aglietta, M Ahlers, EJ Ahn, IFM Albuquerque, D Allard, I Allekotte, J Allen, P Allison, A Almela, J Alvarez Castillo, J Alvarez-Muniz, RA Batista, M Ambrosio, A Aminaei, L Anchordoqui, S Andringa, T Antici'c, C Aramo, E Arganda, F Arqueros, H Asorey, P Assis, J Aublin, M Ave, M Avenier, G Avila, AM Badescu, M Balzer, KB Barber, AF Barbosa, R Bardenet, SLC Barroso, B Baughman, J Baeuml, C Baus, JJ Beatty, KH Becker, A Belletoile, JA Bellido, S BenZvi, C Berat, X Bertou, PL Biermann, P Billoir, F Blanco, M Blanco, C Bleve, H Bluemer, M Bohacova, D Boncioli, C Bonifazi, R Bonino, N Borodai, J Brack, I Brancus, P Brogueira, WC Brown, R Bruijn, P Buchholz, A Bueno, L Buroker, RE Burton, KS Caballero-Mora, B Caccianiga, L Caramete, R Caruso, A Castellina, O Catalano, G Cataldi, L Cazon, R Cester, J Chauvin, SH Cheng, A Chiavassa, JA Chinellato, JC Diaz, J Chudoba, M Cilmo, RW Clay, G Cocciolo, L Collica, MR Coluccia, R Conceicao, F Contreras, H Cook, MJ Cooper, J Coppens, A Cordier, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, R Dallier, B Daniel, S Dasso, K Daumiller, BR Dawson, RM de Almeida, M De Domenico, C De Donato, SJ de Jong, G De La Vega, WJM de Mello Junior, JRT de Mello Neto, I De Mitri, V de Souza, KD de Vries, L del Peral, M del Rio, O Deligny, H Dembinski, N Dhital, C Di Giulio, ML Diaz Castro, PN Diep, F Diogo, C Dobrigkeit, W Docters, JC D'Olivo, PN Dong, A Dorofeev, JC dos Anjos, MT Dova, D D'Urso, I Dutan, J Ebr, R Engel, M Erdmann, CO Escobar, J Espadanal, A Etchegoyen, PF San Luis, H Falcke, G Farrar, AC Fauth, N Fazzini, AP Ferguson, B Fick, JM Figueira, A Filevich, A Filipcic, S Fliescher, CE Fracchiolla, ED Fraenkel, O Fratu, U Froehlich, B Fuchs, R Gaior, RF Gamarra, S Gambetta, B Garcia, ST Garcia Roca, D Garcia-Gamez, D Garcia-Pinto, A Gascon Bravo, H Gemmeke, PL Ghia, M Giller, J Gitto, H Glass, MS Gold, G Golup, F Gomez Albarracin, M Gomez Berisso, PF Gomez Vitale, P Goncalves, JG Gonzalez, B Gookin, A Gorgi, P Gouffon, E Grashorn, S Grebe, N Griffith, M Grigat, AF Grillo, Y Guardincerri, F Guarino, GP Guedes, P Hansen, D Harari, TA Harrison, JL Harton, A Haungs, T Hebbeker, D Heck, AE Herve, C Hojvat, N Hollon, VC Holmes, P Homola, JR Horandel, P Horvath, M Hrabovsky, D Huber, T Huege, A Insolia, F Ionita, A Italiano, S Jansen, C Jarne, S Jiraskova, M Josebachuili, K Kadija, KH Kampert, P Karhan, P Kasper, I Katkov, B Kegl, B Keilhauer, A Keivani, JL Kelley, E Kemp, RM Kieckhafer, HO Klages, M Kleifges, J Kleinfeller, J Knapp, D-H Koang, K Kotera, N Krohm, O Kroemer, D Kruppke-Hansen, D Kuempel, JK Kulbartz, N Kunka, G La Rosa, C Lachaud, D LaHurd, L Latronico, R Lauer, P Lautridou, S Le Coz, MSAB Leao, D Lebrun, P Lebrun, MA Leigui de Oliveira, A Letessier-Selvon, I Lhenry-Yvon, K Link, R Lopez, A Lopez Agueera, K Louedec, J Lozano Bahilo, L Lu, A Lucero, M Ludwig, H Lyberis, MC Maccarone, C Macolino, S Maldera, J Maller, D Mandat, P Mantsch, AG Mariazzi, J Marin, V Marin, IC Maris, HR Marquez Falcon, G Marsella, D Martello, L Martin, H Martinez, O Martinez Bravo, D Martraire, JJ Masias Meza, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurel, D Maurizio, PO Mazur, G Medina-Tanco, M Melissas, D Melo, E Menichetti, A Menshikov, P Mertsch, C Meurer, R Meyhandan, S Mi'canovi'c, MI Micheletti, IA Minaya, L Miramonti, L Molina-Bueno, S Mollerach, M Monasor, DM Ragaigne, F Montanet, B Morales, C Morello, E Moreno, JC Moreno, M Mostafa, CA Moura, MA Muller, G Mueller, M Muenchmeyer, R Mussa, G Navarra, JL Navarro, S Navas, P Necesal, L Nellen, A Nelles, J Neuser, PT Nhung, M Niechciol, L Niemietz, N Nierstenhoefer, D Nitz, D Nosek, L Nozka, J Oehlschlaeger, A Olinto, M Ortiz, N Pacheco, D Pakk Selmi-Dei, M Palatka, J Pallotta, N Palmieri, G Parente, E Parizot, A Parra, S Pastor, T Paul, M Pech, J Pekala, R Pelayo, IM Pepe, L Perrone, R Pesce, E Petermann, S Petrera, A Petrolini, Y Petrov, C Pfendner, R Piegaia, T Pierog, P Pieroni, M Pimenta, V Pirronello, M Platino, M Plum, VH Ponce, M Pontz, A Porcelli, P Privitera, M Prouza, EJ Quel, S Querchfeld, J Rautenberg, O Ravel, D Ravignani, B Revenu, J Ridky, S Riggi, M Risse, P Ristori, H Rivera, V Rizi, J Roberts, W Rodrigues de Carvalho, G Rodriguez, I Rodriguez Cabo, J Rodriguez Martino, J Rodriguez Rojo, MD Rodriguez-Frias, G Ros, J Rosado, T Rossler, M Roth, B Rouille-d'Orfeuil, E Roulet, AC Rovero, C Ruehle, A Saftoiu, F Salamida, H Salazar, FS Greus, G Salina, F Sanchez, CE Santo, E Santos, EM Santos, F Sarazin, B Sarkar, S Sarkar, R Sato, N Scharf, V Scherini, H Schieler, P Schiffer, A Schmidt, O Scholten, H Schoorlemmer, J Schovancova, P Schovanek, F Schroeder, S Schulte, D Schuster, SJ Sciutto, M Scuderi, A Segreto, M Settimo, A Shadkam, RC Shellard, I Sidelnik, G Sigl, HH Silva Lopez, O Sima, A 'Smialkowski, R Smida, GR Snow, P Sommers, J Sorokin, H Spinka, R Squartini, YN Srivastava, S Stanic, J Stapleton, J Stasielak, M Stephan, A Stutz, F Suarez, T Suomijaervi, AD Supanitsky, T Susa, MS Sutherland, J Swain, Z Szadkowski, M Szuba, A Tapia, M Tartare, O Tascau, R Tcaciuc, NT Thao, D Thomas, J Tiffenberg, C Timmermans, W Tkaczyk, CJ Todero Peixoto, G Toma, L Tomankova, B Tome, A Tonachini, P Travnicek, DB Tridapalli, G Tristram, E Trovato, M Tueros, R Ulrich, M Unger, M Urban, JF Valdes Galicia, I Valino, L Valore, G van Aar, AM van den Berg, A van Vliet, E Varela, B Vargas Cardenas, JR Vazquez, RA Vazquez, D Veberic, V Verzi, J Vicha, M Videla, L Villasenor, H Wahlberg, P Wahrlich, O Wainberg, D Walz, AA Watson, M Weber, K Weidenhaupt, A Weindl, F Werner, S Westerhoff, BJ Whelan, A Widom, G Wieczorek, L Wiencke, B Wilczynska, H Wilczynski, M Will, C Williams, T Winchen, M Wommer, B Wundheiler, T Yamamoto, T Yapici, P Younk, G Yuan, A Yushkov, B Zamorano Garcia, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, J Zhou, Y Zhu, MZ Silva, M Ziolkowski, PA Collaboration


Dense Electron-Positron Plasmas and Ultraintense gamma rays from Laser-Irradiated Solids

Physical Review Letters 108 (2012) 165006

CP Ridgers, CS Brady, R Duclous, JG Kirk, K Bennett, TD Arber, ALP Robinson, AR Bell


LHC and Tevatron bounds on the dark matter direct detection cross-section for vector mediators

ArXiv (2012)

MT Frandsen, F Kahlhoefer, A Preston, S Sarkar, K Schmidt-Hoberg

We study the interactions of a new spin-1 mediator that connects the Standard Model to dark matter. We constrain its decay channels using monojet and monophoton searches, as well as searches for resonances in dijet, dilepton and diboson final states including those involving a possible Higgs. We then interpret the resulting limits as bounds on the cross-section for dark matter direct detection without the need to specify a particular model. For mediator masses between 300 and 1000 GeV these bounds are considerably stronger than the ones obtained under the assumption that the mediator can be integrated out.


Search for point-like sources of ultra-high energy neutrinos at the Pierre Auger Observatory and improved limit on the diffuse flux of tau neutrinos

Astrophysical Journal Letters 755 (2012)

P Abreu, M Aglietta, M Ahlers, EJ Ahn, IFM Albuquerque, D Allard, I Allekotte, J Allen, P Allison, A Almela, J Alvarez Castillo, J Alvarez-Mũiz, R Alves Batista, M Ambrosio, A Aminaei, L Anchordoqui, S Andringa, T Antii'C, C Aramo, E Arganda, F Arqueros, H Asorey, P Assis, J Aublin, M Ave, M Avenier, G Avila, AM Badescu, M Balzer, KB Barber, AF Barbosa, R Bardenet, SLC Barroso, B Baughman, J Bäuml, C Baus, JJ Beatty, KH Becker, A Bellétoile, JA Bellido, S Benzvi, C Berat, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, M Blanco, C Bleve, H Blümer, M Bohov, D Boncioli, C Bonifazi, R Bonino, N Borodai, J Brack, I Brancus, P Brogueira, WC Brown, R Bruijn, P Buchholz, A Bueno, L Buroker, RE Burton, KS Caballero-Mora, B Caccianiga, L Caramete, R Caruso, A Castellina, O Catalano, G Cataldi, L Cazon, R Cester, J Chauvin, SH Cheng, A Chiavassa, JA Chinellato, J Chirinos Diaz, J Chudoba, M Cilmo, RW Clay, G Cocciolo, L Collica, MR Coluccia, R Conceiço, F Contreras, H Cook, MJ Cooper, J Coppens, A Cordier, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, R Dallier, B Daniel, S Dasso, K Daumiller, BR Dawson, RM De Almeida, M De Domenico, C De Donato, SJ De Jong, G De La Vega, WJM De Mello Junior, JRT De Mello Neto, I De Mitri, V De Souza, KD De Vries, L Del Peral, M Del Río, O Deligny, H Dembinski, N Dhital, C Di Giulio, ML Díaz Castro, PN Diep, F Diogo, C Dobrigkeit, W Docters, JC D'Olivo, PN Dong, A Dorofeev, JC Dos Anjos, MT Dova, D D'Urso, I Dutan, J Ebr, R Engel, M Erdmann, CO Escobar, J Espadanal, A Etchegoyen, P Facal San Luis, H Falcke, G Farrar, AC Fauth, N Fazzini, AP Ferguson, B Fick, JM Figueira, A Filevich, A Filipi, S Fliescher, CE Fracchiolla, ED Fraenkel, O Fratu, U Fröhlich, B Fuchs, R Gaior, RF Gamarra, S Gambetta, B García, STG Roca, D Garcia-Gamez, D Garcia-Pinto, A Gascon Bravo, H Gemmeke, PL Ghia, M Giller, J Gitto, H Glass, MS Gold, G Golup, FG Albarracin, M Gómez Berisso, PF Gómez Vitale, P Gonçalves, JG Gonzalez, B Gookin, A Gorgi, P Gouffon, E Grashorn, S Grebe, N Griffith, M Grigat, AF Grillo, Y Guardincerri, F Guarino, GP Guedes, P Hansen, D Harari, TA Harrison, JL Harton, A Haungs, T Hebbeker, D Heck, AE Herve, C Hojvat, N Hollon, VC Holmes, P Homola, JR Hörandel, P Horvath, M Hrabovsk, D Huber, T Huege, A Insolia, F Ionita, A Italiano, S Jansen, C Jarne, S Jiraskova, M Josebachuili, K Kadija, KH Kampert, P Karhan, P Kasper, I Katkov, B Kégl, B Keilhauer, A Keivani, JL Kelley, E Kemp, RM Kieckhafer, HO Klages, M Kleifges, J Kleinfeller, J Knapp, D-H Koang, K Kotera, N Krohm, O Krömer, D Kruppke-Hansen, D Kuempel, JK Kulbartz, N Kunka, G La Rosa, C Lachaud, D Lahurd, L Latronico, R Lauer, P Lautridou, S Le Coz, MSAB Leo, D Lebrun, P Lebrun, MA Leigui De Oliveira, A Letessier-Selvon, I Lhenry-Yvon, K Link, R López, A Lopez Agüera, K Louedec, J Lozano Bahilo, L Lu, A Lucero, M Ludwig, H Lyberis, MC MacCarone, C MacOlino, S Maldera, J Maller, D Mandat, P Mantsch, AG Mariazzi, J Marin, V Marin, IC Maris, HRM Falcon, G Marsella, D Martello, L Martin, H Martinez, O Martínez Bravo, D Martraire, JJ Masías Meza, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurel, D Maurizio, PO Mazur, G Medina-Tanco, M Melissas, D Melo, E Menichetti, A Menshikov, P Mertsch, C Meurer, R Meyhandan, S Mi'Canovi'C, MI Micheletti, IA Minaya, L Miramonti, L Molina-Bueno, S Mollerach, M Monasor, DM Ragaigne, F Montanet, B Morales, C Morello, E Moreno, JC Moreno, M Mostaf, CA Moura, MA Muller, G Müller, M Münchmeyer, R Mussa, G Navarra, JL Navarro, S Navas, P Necesal, L Nellen, A Nelles, J Neuser, PT Nhung, M Niechciol, L Niemietz, N Nierstenhoefer, D Nitz, D Nosek, L Noka, J Oehlschläger, A Olinto, M Ortiz, N Pacheco, DP Selmi-Dei, M Palatka, J Pallotta, N Palmieri, G Parente, E Parizot, A Parra, S Pastor, T Paul, M Pech, J Pekala, R Pelayo, IM Pepe, L Perrone, R Pesce, E Petermann, S Petrera, A Petrolini, Y Petrov, C Pfendner, R Piegaia, T Pierog, P Pieroni, M Pimenta, V Pirronello, M Platino, M Plum, VH Ponce, M Pontz, A Porcelli, P Privitera, M Prouza, EJ Quel, S Querchfeld, J Rautenberg, O Ravel, D Ravignani, B Revenu, J Ridky, S Riggi, M Risse, P Ristori, H Rivera, V Rizi, J Roberts, W Rodrigues De Carvalho, G Rodriguez, I Rodriguez Cabo, J Rodriguez Martino, J Rodriguez Rojo, MD Rodríguez-Frías, G Ros, J Rosado, T Rossler, M Roth, B Rouillé-D'Orfeuil, E Roulet, AC Rovero, C Rühle, A Saftoiu, F Salamida, H Salazar, F Salesa Greus, G Salina, F Snchez, CE Santo, E Santos, EM Santos, F Sarazin, B Sarkar, S Sarkar, R Sato, N Scharf, V Scherini, H Schieler, P Schiffer, A Schmidt, O Scholten, H Schoorlemmer, J Schovancova, P Schovnek, F Schröder, S Schulte, D Schuster, SJ Sciutto, M Scuderi, A Segreto, M Settimo, A Shadkam, RC Shellard, I Sidelnik, G Sigl, HHS Lopez, O Sima, A 'Smiałkowski, R Mída, GR Snow, P Sommers, J Sorokin, H Spinka, R Squartini, YN Srivastava, S Stanic, J Stapleton, J Stasielak, M Stephan, A Stutz, F Suarez, T Suomijärvi, AD Supanitsky, T Šuša, MS Sutherland, J Swain, Z Szadkowski, M Szuba, A Tapia, M Tartare, O Tacu, R Tcaciuc, NT Thao, D Thomas, J Tiffenberg, C Timmermans, W Tkaczyk, CJ Todero Peixoto, G Toma, L Tomankova, B Tomé, A Tonachini, P Travnicek, DB Tridapalli, G Tristram, E Trovato, M Tueros, R Ulrich, M Unger, M Urban, JFV Galicia, I Valĩo, L Valore, G Van Aar, AM Van Den Berg, A Van Vliet, E Varela, B Vargas Crdenas, JR Vzquez, RA Vzquez, D Veberi, V Verzi, J Vicha, M Videla, L Villasẽor, H Wahlberg, P Wahrlich, O Wainberg, D Walz, AA Watson, M Weber, K Weidenhaupt, A Weindl, F Werner, S Westerhoff, BJ Whelan, A Widom, G Wieczorek, L Wiencke, B Wilczyńska, H Wilczyński, M Will, C Williams, T Winchen, M Wommer, B Wundheiler, T Yamamoto, T Yapici, P Younk, G Yuan, A Yushkov, B Zamorano Garcia, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, J Zhou, Y Zhu, MZ Silva, M Ziolkowski

The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E ν between 1017 eV and 10 20 eV from point-like sources across the sky south of +55° and north of -65° declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of ∼3.5years of a full surface detector array for the Earth-skimming channel and ∼2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k PS E -2ν from a point-like source, 90% confidence level upper limits for k PS at the level of ≈5 × 10-7 and 2.5 × 10-6 GeV cm-2 s-1 have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos, respectively. © 2012 The American Astronomical Society. All rights reserved.


Searching for soft relativistic jets in core-collapse supernovae with the IceCube optical follow-up program

Astronomy and Astrophysics 539 (2012)

R Abbasi, Y Abdou, T Abu-Zayyad, M Ackermann, J Adams, JA Aguilar, M Ahlers, MM Allen, D Altmann, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JL Bazo Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, K-H Becker, ML Benabderrahmane, S Benzvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, AM Brown, S Buitink, KS Caballero-Mora, M Carson, D Chirkin, B Christy, F Clevermann, S Cohen, C Colnard, DF Cowen, AH Cruz Silva, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, C De Clercq, T Degner, L Demirörs, F Descamps, P Desiati, G De Vries-Uiterweerd, T Deyoung, JC Díaz-Vélez, M Dierckxsens, J Dreyer, JP Dumm, M Dunkman, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Góra, D Grant, T Griesel, A Groß, S Grullon, M Gurtner, C Ha, A Haj Ismail, A Hallgren, F Halzen, K Han, K Hanson, D Heinen, K Helbing, R Hellauer, P Herquet, S Hickford, GC Hill, KD Hoffman, B Hoffmann, A Homeier, K Hoshina, W Huelsnitz, J-P Hülß, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, GS Japaridze, H Johansson, K-H Kampert, A Kappes, T Karg, A Karle, P Kenny, J Kiryluk, F Kislat, SR Klein, J-H Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, T Kowarik, M Krasberg, G Kroll, N Kurahashi, T Kuwabara, M Labare, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, A Marotta, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészáros, T Meures, S Miarecki, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, S Panknin, L Paul, C Pérez De Los Heros, J Petrovic, A Piegsa, D Pieloth, R Porrata, J Posselt, PB Price, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, M Richman, JP Rodrigues, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, H-G Sander, M Santander, S Sarkar, K Schatto, T Schmidt, A Schönwald, A Schukraft, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, GM Spiczak, C Spiering, M Stamatikos, T Stanev, T Stezelberger, RG Stokstad, A Stössl, EA Strahler, R Ström, M Stüer, GW Sullivan, Q Swillens, H Taavola, I Taboada, A Tamburro, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, N Van Eijndhoven, J Vandenbroucke, A Van Overloop, J Van Santen, M Vehring, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, C Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, TR Wood, K Woschnagg, C Xu, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, M Zoll, CW Akerlof, SB Pandey, F Yuan, W Zheng

Context. Transient neutrino sources such as gamma-ray bursts (GRBs) and supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of ≲ 100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusions. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3 × 10 51 erg, respectively, does not exceed 4.2% at 90% confidence. © 2012 ESO.


Connecting the cosmic web to the spin of dark halos: implications for galaxy formation

ArXiv (2012)

S Codis, C Pichon, J Devriendt, A Slyz, D Pogosyan, Y Dubois, T Sousbie

We investigate the alignment of the spin of dark matter halos relative (i) to the surrounding large-scale filamentary structure, and (ii) to the tidal tensor eigenvectors using the Horizon 4pi dark matter simulation which resolves over 43 million dark matter halos at redshift zero. We detect a clear mass transition: the spin of dark matter halos above a critical mass tends to be perpendicular to the closest filament, and aligned with the intermediate axis of the tidal tensor, whereas the spin of low-mass halos is more likely to be aligned with the closest filament. Furthermore, this critical mass of 5 10^12 is redshift-dependent and scales as (1+z)^-2.5. We propose an interpretation of this signal in terms of large-scale cosmic flows. In this picture, most low-mass halos are formed through the winding of flows embedded in misaligned walls; hence they acquire a spin parallel to the axis of the resulting filaments forming at the intersection of these walls. On the other hand, more massive halos are typically the products of later mergers along such filaments, and thus they acquire a spin perpendicular to this direction when their orbital angular momentum is converted into spin. We show that this scenario is consistent with both the measured excess probabilities of alignment w.r.t. the eigen-directions of the tidal tensor, and halo merger histories. On a more qualitative level, it also seems compatible with 3D visualization of the structure of the cosmic web as traced by "smoothed" dark matter simulations or gas tracer particles. Finally, it provides extra support to the disc forming paradigm presented by Pichon et al (2011) as it extends it by characterizing the geometry of secondary infall at high redshift.


Second-order Fermi acceleration as the origin of the Fermi bubbles

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 692 (2012) 265-268

P Mertsch, S Sarkar


Searching for soft relativistic jets in Core-collapse Supernovae with the IceCube Optical Follow-up Program

ArXiv (2011)

TI Collaboration, R Abbasi, Y Abdou, T Abu-Zayyad, M Ackermann, J Adams, JA Aguilar, M Ahlers, MM Allen, D Altmann, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JLB Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, KH Becker, ML Benabderrahmane, S BenZvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, AM Brown, S Buitink, KS Caballero-Mora, M Carson, D Chirkin, B Christy, F Clevermann, S Cohen, C Colnard, DF Cowen, AHC Silva, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, CD Clercq, T Degner, L Demirörs, F Descamps, P Desiati, GD Vries-Uiterweerd, T DeYoung, JC Díaz-Vélez, M Dierckxsens, J Dreyer, JP Dumm, M Dunkman, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Góra, D Grant, T Griesel, A Groß, S Grullon, M Gurtner, C Ha, AH Ismail, A Hallgren, F Halzen, K Han, K Hanson, D Heinen, K Helbing, R Hellauer, P Herquet, S Hickford, GC Hill, KD Hoffman, B Hoffmann, A Homeier, K Hoshina, W Huelsnitz, JP Hülß, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, GS Japaridze, H Johansson, KH Kampert, A Kappes, T Karg, A Karle, P Kenny, J Kiryluk, F Kislat, SR Klein, JH Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, T Kowarik, M Krasberg, G Kroll, N Kurahashi, T Kuwabara, M Labare, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, A Marotta, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészáros, T Meures, S Miarecki, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, S Panknin, L Paul, CPDL Heros, J Petrovic, A Piegsa, D Pieloth, R Porrata, J Posselt, PB Price, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, M Richman, JP Rodrigues, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, HG Sander, M Santander, S Sarkar, K Schatto, T Schmidt, A Schönwald, A Schukraft, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, GM Spiczak, C Spiering, M Stamatikos, T Stanev, T Stezelberger, RG Stokstad, A Stössl, EA Strahler, R Ström, M Stüer, GW Sullivan, Q Swillens, H Taavola, I Taboada, A Tamburro, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, NV Eijndhoven, J Vandenbroucke, AV Overloop, JV Santen, M Vehring, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, C Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, TR Wood, K Woschnagg, C Xu, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, MZTROTSE Collaboration, CW Akerlof, SB Pandey, F Yuan, W Zheng

Context. Transient neutrino sources such as Gamma-Ray Bursts (GRBs) and Supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of \lesssim 100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusion. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3\times10^{51} erg, respectively, does not exceed 4.2% at 90% confidence.


A review of Vlasov-Fokker-Planck numerical modeling of inertial confinement fusion plasma

Journal of Computational Physics 231 (2012) 1051-1079

AGR Thomas, M Tzoufras, APL Robinson, RJ Kingham, CP Ridgers, M Sherlock, AR Bell

The interaction of intense lasers with solid matter generates a hot plasma state that is well described by the Vlasov-Fokker-Planck equation. Accurate and efficient modeling of the physics in these scenarios is highly pertinent, because it relates to experimental campaigns to produce energy by inertial confinement fusion on facilities such as the National Ignition Facility. Calculations involving the Vlasov-Fokker-Planck equation are computationally intensive, but are crucial to proper understanding of a wide variety of physical effects and instabilities in inertial fusion plasmas. In this topical review, we will introduce the background physics related to Vlasov-Fokker-Planck simulation, and then proceed to describe results from numerical simulation of inertial fusion plasma in a pedagogical manner by discussing some key numerical algorithm developments that enabled the research to take place. A qualitative comparison of the techniques is also given. © 2011 Elsevier Inc.


Results of a self-triggered prototype system for radio-detection of extensive air showers at the Pierre Auger Observatory

ArXiv (2012)

TPA Collaboration, S Acounis, D Charrier, TG ccon, C Rivière, P Stassi

We describe the experimental setup and the results of RAuger, a small radio-antenna array, consisting of three fully autonomous and self-triggered radio-detection stations, installed close to the center of the Surface Detector (SD) of the Pierre Auger Observatory in Argentina. The setup has been designed for the detection of the electric field strength of air showers initiated by ultra-high energy cosmic rays, without using an auxiliary trigger from another detection system. Installed in December 2006, RAuger was terminated in May 2010 after 65 registered coincidences with the SD. The sky map in local angular coordinates (i.e., zenith and azimuth angles) of these events reveals a strong azimuthal asymmetry which is in agreement with a mechanism dominated by a geomagnetic emission process. The correlation between the electric field and the energy of the primary cosmic ray is presented for the first time, in an energy range covering two orders of magnitude between 0.1 EeV and 10 EeV. It is demonstrated that this setup is relatively more sensitive to inclined showers, with respect to the SD. In addition to these results, which underline the potential of the radio-detection technique, important information about the general behavior of self-triggering radio-detection systems has been obtained. In particular, we will discuss radio self-triggering under varying local electric-field conditions.


Feeding compact bulges and supermassive black holes with low angular-momentum cosmic gas at high redshift

ArXiv (2011)

Y Dubois, C Pichon, M Haehnelt, T Kimm, A Slyz, J Devriendt, D Pogosyan

We use cosmological hydrodynamical simulations to show that a significant fraction of the gas in high redshift rare massive halos falls nearly radially to their very centre on extremely short timescales. This process results in the formation of very compact bulges with specific angular momentum a factor 5-30$smaller than the average angular momentum of the baryons in the whole halo. Such low angular momentum originates both from segregation and effective cancellation when the gas flows to the centre of the halo along well defined cold filamentary streams. These filaments penetrate deep inside the halo and connect to the bulge from multiple rapidly changing directions. Structures falling in along the filaments (satellite galaxies) or formed by gravitational instabilities triggered by the inflow (star clusters) further reduce the angular momentum of the gas in the bulge. Finally, the fraction of gas radially falling to the centre appears to increase with the mass of the halo; we argue that this is most likely due to an enhanced cancellation of angular momentum in rarer halos which are fed by more isotropically distributed cold streams. Such an increasingly efficient funnelling of low-angular momentum gas to the centre of very massive halos at high redshift may account for the rapid pace at which the most massive supermassive black holes grow to reach observed masses around $10^9$M$_\odot$ at an epoch when the Universe is barely 1 Gyr old.


A filamentation instability for streaming cosmic rays

Monthly Notices of the Royal Astronomical Society 419 (2012) 2433-2440

B Reville, AR Bell

We demonstrate that cosmic rays form filamentary structures in the precursors of supernova remnant shocks due to their self-generated magnetic fields. The cosmic ray filamentation results in the growth of a long-wavelength instability, and naturally couples the rapid non-linear amplification on small scales to larger length-scales. Hybrid magnetohydrodynamics-particle simulations are performed to confirm the effect. The resulting large-scale magnetic field may facilitate the scattering of high-energy cosmic rays as required to accelerate protons beyond the knee in the cosmic ray spectrum at supernova remnant shocks. Filamentation far upstream of the shock may also assist in the escape of cosmic rays from the accelerator. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.


Time-dependent searches for point sources of neutrinos with the 40-string and 22-string configurations of icecube

Astrophysical Journal 744 (2012)

R Abbasi, Y Abdou, T Abu-Zayyad, J Adams, JA Aguilar, M Ahlers, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JL Bazo Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, K-H Becker, ML Benabderrahmane, S Benzvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, J Braun, AM Brown, S Buitink, M Carson, D Chirkin, B Christy, J Clem, F Clevermann, S Cohen, C Colnard, DF Cowen, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, C De Clercq, L Demirörs, T Denger, O Depaepe, F Descamps, P Desiati, G De Vries-Uiterweerd, T Deyoung, JC Díaz-Vélez, M Dierckxsens, J Dreyer, JP Dumm, R Ehrlich, J Eisch, RW Ellsworth, O Engdegrd, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, MM Foerster, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, M Geisler, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Grant, T Griesel, A Groß, S Grullon, M Gurtner, C Ha, A Hallgren, F Halzen, K Han, K Hanson, D Heinen, K Helbing, P Herquet, S Hickford, GC Hill, KD Hoffman, A Homeier, K Hoshina, D Hubert, W Huelsnitz, J-P Hülß, PO Hulth, K Hultqvist, S Hussain, A Ishihara, J Jacobsen, GS Japaridze, H Johansson, JM Joseph, K-H Kampert, A Kappes, T Karg, A Karle, JL Kelley, P Kenny, J Kiryluk, F Kislat, SR Klein, J-H Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, T Kowarik, M Krasberg, T Krings, G Kroll, K Kuehn, N Kurahashi, T Kuwabara, M Labare, S Lafebre, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, P Majumdar, A Marotta, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészros, T Meures, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, P Nießen, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, M Ono, S Panknin, L Paul, C Pérez De Los Heros, J Petrovic, A Piegsa, D Pieloth, R Porrata, J Posselt, PB Price, M Prikockis, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, A Rizzo, JP Rodrigues, P Roth, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, H-G Sander, M Santander, S Sarkar, K Schatto, T Schmidt, A Schönwald, A Schukraft, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, A Slipak, GM Spiczak, C Spiering, M Stamatikos, T Stanev, G Stephens, T Stezelberger, RG Stokstad, A Stössl, S Stoyanov, EA Strahler, T Straszheim, M Stör, GW Sullivan, Q Swillens, H Taavola, I Taboada, A Tamburro, A Tepe, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, D Turçan, N Van Eijndhoven, J Vandenbroucke, A Van Overloop, J Van Santen, M Vehring, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, C Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, K Woschnagg, C Xu, XW Xu, G Yodh, S Yoshida, AP Zarzhitsky

This paper presents four searches for flaring sources of neutrinos using the IceCube neutrino telescope. For the first time, a search is performed over the entire parameter space of energy, direction, and time with sensitivity to neutrino flares lasting between 20 μs and a year duration from astrophysical sources. Searches that integrate over time are less sensitive to flares because they are affected by a larger background of atmospheric neutrinos and muons that can be reduced by the use of additional timing information. Flaring sources considered here, such as active galactic nuclei, soft gamma-ray repeaters, and gamma-ray bursts, are promising candidate neutrino emitters. Two searches are "untriggered" in the sense that they look for any possible flare in the entire sky and from a predefined catalog of sources from which photon flares have been recorded. The other two searches are triggered by multi-wavelength information on flares from blazars and from a soft gamma-ray repeater. One triggered search uses lightcurves from Fermi-LAT which provides continuous monitoring. A second triggered search uses information where the flux states have been measured only for short periods of time near the flares. The untriggered searches use data taken by 40 strings of IceCube between 2008 April 5 and 2009 May 20. The triggered searches also use data taken by the 22-string configuration of IceCube operating between 2007 May 31 and 2008 April 5. The results from all four searches are compatible with a fluctuation of the background.


Quantifying uncertainties in the high energy neutrino cross-section

ArXiv (2011)

A Cooper-Sarkar, P Mertsch, S Sarkar

We compare predictions for high energy neutrino and anti-neutrino deep inelastic scattering cross-sections within the conventional DGLAP formalism of next-to-leading order QCD, using the latest parton distribution functions such as CT10, HERAPDF1.5 and MSTW08 and taking account of PDF uncertainties. From this we derive a benchmark cross-section and uncertainty which is consistent with the results obtained earlier using the ZEUS-S PDFs. We advocate the use of this for analysing data from neutrino telescopes, in order to facilitate comparison between their results.


Description of atmospheric conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)

Astroparticle Physics 35 (2012) 591-607

P Abreu, M Aglietta, M Ahlers, EJ Ahn, IFM Albuquerque, D Allard, I Allekotte, J Allen, P Allison, A Almela, J Alvarez Castillo, J Alvarez-Muñiz, M Ambrosio, A Aminaei, L Anchordoqui, S Andringa, T Antičic, C Aramo, E Arganda, F Arqueros, H Asorey, P Assis, J Aublin, M Ave, M Avenier, G Avila, T Bäcker, AM Badescu, M Balzer, KB Barber, AF Barbosa, R Bardenet, SLC Barroso, B Baughman, J Bäuml, JJ Beatty, BR Becker, KH Becker, A Bellétoile, JA Bellido, S Benzvi, C Berat, X Bertou, PL Biermann, P Billoir, F Blanco, M Blanco, C Bleve, H Blümer, M Boháčová, D Boncioli, C Bonifazi, R Bonino, N Borodai, J Brack, I Brancus, P Brogueira, WC Brown, R Bruijn, P Buchholz, A Bueno, RE Burton, KS Caballero-Mora, B Caccianiga, L Caramete, R Caruso, A Castellina, O Catalano, G Cataldi, L Cazon, R Cester, J Chauvin, SH Cheng, A Chiavassa, JA Chinellato, J Chirinos Diaz, J Chudoba, RW Clay, MR Coluccia, R Conceião, F Contreras, H Cook, MJ Cooper, J Coppens, A Cordier, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, R Dallier, B Daniel, S Dasso, K Daumiller, BR Dawson, RM De Almeida, M De Domenico, C De Donato, SJ De Jong, G De La Vega, WJM De Mello Junior, JRT De Mello Neto, I De Mitri, V De Souza, KD De Vries, L Del Peral, M Del Río, O Deligny, H Dembinski, N Dhital, C Di Giulio, ML Díaz Castro, PN Diep, F Diogo, C Dobrigkeit, W Docters, JC D'Olivo, PN Dong, A Dorofeev, JC Dos Anjos, MT Dova, D D'Urso, I Dutan, J Ebr, R Engel, M Erdmann, CO Escobar, J Espadanal, A Etchegoyen, P Facal San Luis, I Fajardo Tapia, H Falcke, G Farrar, AC Fauth, N Fazzini, AP Ferguson, B Fick, A Filevich, A Filipčič, S Fliescher, CE Fracchiolla, ED Fraenkel, O Fratu, U Fröhlich, B Fuchs, R Gaior, RF Gamarra, S Gambetta, B García, ST Garcia Roca, D Garcia-Gamez, D Garcia-Pinto, A Gascon, H Gemmeke, PL Ghia, U Giaccari, M Giller, H Glass, MS Gold, G Golup, F Gomez Albarracin, M Gómez Berisso, PF Gómez Vitale, P Gonalves, D Gonzalez, JG Gonzalez, B Gookin, A Gorgi, P Gouffon, E Grashorn, S Grebe, N Griffith, M Grigat, AF Grillo, Y Guardincerri, F Guarino, GP Guedes, A Guzman, P Hansen, D Harari, TA Harrison, JL Harton, A Haungs, T Hebbeker, D Heck, AE Herve, C Hojvat, N Hollon, VC Holmes, P Homola, JR Hörandel, A Horneffer, P Horvath, M Hrabovský, D Huber, T Huege, A Insolia, F Ionita, A Italiano, C Jarne, S Jiraskova, M Josebachuili, K Kadija, KH Kampert, P Karhan, P Kasper, B Kégl, B Keilhauer, A Keivani, JL Kelley, E Kemp, RM Kieckhafer, HO Klages, M Kleifges, J Kleinfeller, J Knapp, D-H Koang, K Kotera, N Krohm, O Krömer, D Kruppke-Hansen, F Kuehn, D Kuempel, JK Kulbartz, N Kunka, G La Rosa, C Lachaud, D Lahurd, L Latronico, R Lauer, P Lautridou, S Le Coz, MSAB Leão, D Lebrun, P Lebrun, MA Leigui De Oliveira, A Letessier-Selvon, I Lhenry-Yvon, K Link, R López, A Lopez Agüera, K Louedec, J Lozano Bahilo, L Lu, A Lucero, M Ludwig, H Lyberis, MC MacCarone, C MacOlino, S Maldera, D Mandat, P Mantsch, AG Mariazzi, J Marin, V Marin, IC Maris, HR Marquez Falcon, G Marsella, D Martello, L Martin, H Martinez, O Martínez Bravo, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurel, D Maurizio, PO Mazur, G Medina-Tanco, M Melissas, D Melo, E Menichetti, A Menshikov, P Mertsch, C Meurer, S Mi'Canovi'C, MI Micheletti, IA Minaya, L Miramonti, L Molina-Bueno, S Mollerach, M Monasor, D Monnier Ragaigne, F Montanet, B Morales, C Morello, E Moreno, JC Moreno, M Mostafá, CA Moura, MA Muller, G Müller, M Münchmeyer, R Mussa, G Navarra, JL Navarro, S Navas, P Necesal, L Nellen, A Nelles, J Neuser, PT Nhung, M Niechciol, L Niemietz, N Nierstenhoefer, D Nitz, D Nosek, L Nožka, J Oehlschläger, A Olinto, M Ortiz, N Pacheco, D Pakk Selmi-Dei, M Palatka, J Pallotta, N Palmieri, G Parente, E Parizot, A Parra, S Pastor, T Paul, M Pech, J Pȩkala, R Pelayo, IM Pepe, L Perrone, R Pesce, E Petermann, S Petrera, P Petrinca, A Petrolini, Y Petrov, C Pfendner, R Piegaia, T Pierog, P Pieroni, M Pimenta, V Pirronello, M Platino, VH Ponce, M Pontz, A Porcelli, P Privitera, M Prouza, EJ Quel, S Querchfeld, J Rautenberg, O Ravel, D Ravignani, B Revenu, J Ridky, S Riggi, M Risse, P Ristori, H Rivera, V Rizi, J Roberts, W Rodrigues De Carvalho, G Rodriguez, J Rodriguez Martino, J Rodriguez Rojo, I Rodriguez-Cabo, MD Rodríguez-Frías, G Ros, J Rosado, T Rossler, M Roth, B Rouillé-D'Orfeuil, E Roulet, AC Rovero, C Rühle, A Saftoiu, F Salamida, H Salazar, F Salesa Greus, G Salina, F Sánchez, CE Santo, E Santos, EM Santos, F Sarazin, B Sarkar, S Sarkar, R Sato, N Scharf, V Scherini, H Schieler, P Schiffer, A Schmidt, O Scholten, H Schoorlemmer, J Schovancova, P Schovánek, F Schröder, S Schulte, D Schuster, SJ Sciutto, M Scuderi, A Segreto, M Settimo, A Shadkam, RC Shellard, I Sidelnik, G Sigl, HH Silva Lopez, O Sima, A 'Smiałkowski, R Šmída, GR Snow, P Sommers, J Sorokin, H Spinka, R Squartini, YN Srivastava, S Stanic, J Stapleton, J Stasielak, M Stephan, A Stutz, F Suarez, T Suomijärvi, AD Supanitsky, T Šuša, MS Sutherland, J Swain, Z Szadkowski, M Szuba, A Tapia, M Tartare, O Tacu, CG Tavera Ruiz, R Tcaciuc, NT Thao, D Thomas, J Tiffenberg, C Timmermans, W Tkaczyk, CJ Todero Peixoto, G Toma, L Tomankova, B Tomé, A Tonachini, P Travnicek, DB Tridapalli, G Tristram, E Trovato, M Tueros, R Ulrich, M Unger, M Urban, JF Valdés Galicia, I Valiño, L Valore, AM Van Den Berg, E Varela, B Vargascárdenas, JR Vázquez, RA Vázquez, D Veberič, V Verzi, J Vicha, M Videla, L Villaseñor, H Wahlberg, P Wahrlich, O Wainberg, D Walz, AA Watson, M Weber, K Weidenhaupt, A Weindl, F Werner, S Westerhoff, BJ Whelan, A Widom, G Wieczorek, L Wiencke, B Wilczyńska, H Wilczyński, M Will, C Williams, T Winchen, M Wommer, B Wundheiler, T Yamamoto, T Yapici, P Younk, G Yuan, A Yushkov, B Zamorano, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, Y Zhu, M Zimbres Silva, M Ziolkowski

Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargüe and averaged monthly models, the utility of the GDAS data is shown. © 2012 Elsevier B.V. All rights reserved.


Subcritical fluctuations and suppression of turbulence in differentially rotating gyrokinetic plasmas

PLASMA PHYSICS AND CONTROLLED FUSION 54 (2012) ARTN 055011

AA Schekochihin, EG Highcock, SC Cowley


Searches for periodic neutrino emission from binary systems with 22 and 40 strings of IceCube

ArXiv (2011)

I Collaboration, R Abbasi, Y Abdou, T Abu-Zayyad, M Ackermann, J Adams, JA Aguilar, M Ahlers, MM Allen, D Altmann, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JLB Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, KH Becker, ML Benabderrahmane, S BenZvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, AM Brown, S Buitink, KS Caballero-Mora, M Carson, D Chirkin, B Christy, F Clevermann, S Cohen, C Colnard, DF Cowen, AHC Silva, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, CD Clercq, T Degner, L Demirörs, F Descamps, P Desiati, GD Vries-Uiterweerd, T DeYoung, JC Díaz-Vélez, M Dierckxsens, J Dreyer, JP Dumm, M Dunkman, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Góra, D Grant, T Griesel, A Groß, S Grullon, M Gurtner, C Ha, AH Ismail, A Hallgren, F Halzen, K Han, K Hanson, D Heinen, K Helbing, R Hellauer, S Hickford, GC Hill, KD Hoffman, B Hoffmann, A Homeier, K Hoshina, W Huelsnitz, JP Hülß, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, GS Japaridze, H Johansson, KH Kampert, A Kappes, T Karg, A Karle, P Kenny, J Kiryluk, F Kislat, SR Klein, JH Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, T Kowarik, M Krasberg, G Kroll, N Kurahashi, T Kuwabara, M Labare, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, A Marotta, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészáros, T Meures, S Miarecki, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, S Panknin, L Paul, CPDL Heros, J Petrovic, A Piegsa, D Pieloth, R Porrata, J Posselt, PB Price, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, M Richman, JP Rodrigues, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, HG Sander, M Santander, S Sarkar, K Schatto, T Schmidt, A Schönwald, A Schukraft, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, GM Spiczak, C Spiering, M Stamatikos, T Stanev, T Stezelberger, RG Stokstad, A Stößl, EA Strahler, R Ström, M Stüer, GW Sullivan, Q Swillens, H Taavola, I Taboada, A Tamburro, A Tepe, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, NV Eijndhoven, J Vandenbroucke, AV Overloop, JV Santen, M Vehring, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, C Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, TR Wood, K Woschnagg, C Xu, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, M Zoll

In this paper we present the results of searches for periodic neutrino emission from a catalog of binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. In the analysis, the period is fixed by these photon observations, while the phase and duration of the neutrino emission are treated as free parameters to be fit with the data. If the emission occurs during ~20% or less of the total period, this analysis achieves better sensitivity than a time-integrated analysis. We use the IceCube data taken from May 31, 2007 to April 5, 2008 with its 22-string configuration, and from April 5, 2008 to May 20, 2009 with its 40-string configuration. No evidence for neutrino emission is found, with the strongest excess occurring for Cygnus X-3 at 2.1 sigma significance after accounting for trials. Neutrino flux upper limits for both periodic and time-integrated emission are provided.


Zero-Turbulence Manifold in a Toroidal Plasma

ArXiv (2012)

EG Highcock, AA Schekochihin, SC Cowley, M Barnes, FI Parra, CM Roach, W Dorland

Sheared toroidal flows can cause bifurcations to zero-turbulent-transport states in tokamak plasmas. The maximum temperature gradients that can be reached are limited by subcritical turbulence driven by the parallel velocity gradient. Here it is shown that q/\epsilon (magnetic field pitch/inverse aspect ratio) is a critical control parameter for sheared tokamak turbulence. By reducing q/\epsilon, far higher temperature gradients can be achieved without triggering turbulence, in some instances comparable to those found experimentally in transport barriers. The zero-turbulence manifold is mapped out, in the zero-magnetic-shear limit, over the parameter space (\gamma_E, q/\epsilon, R/L_T), where \gamma_E is the perpendicular flow shear and R/L_T is the normalised inverse temperature gradient scale. The extent to which it can be constructed from linear theory is discussed.


Enhancing and inhibiting star formation: High-resolution simulation studies of the impact of cold accretion, mergers and feedback on individual massive galaxies

Proceedings of the International Astronomical Union 8 (2012) 13-16

LC Powell, S Khochfar, F Bournaud, D Chapon, R Teyssier, J Devriendt, A Slyz, V Gaibler

The quest for a better understanding of the evolution of massive galaxies can be broadly summarised with 2 questions: how did they build up their large (stellar) masses and what eventually quenched their star formation (SF)? To tackle these questions, we use high-resolution ramses simulations (Teyssier 2002) to study several aspects of the detailed interplay between accretion (mergers and cold flows), SF and feedback in individual galaxies. We examine SF in major mergers; a process crucial to stellar mass assembly. We explore whether the merger-induced, clustered SF is as important a mechanism in average mergers, as it is in extreme systems like the Antennae. We find that interaction-induced turbulence drives up the velocity dispersion, and that there is a correlated rise in SFR in all our simulated mergers as the density pdf evolves to have an excess of very dense gas. Next, we introduce a new study into whether mechanical jet feedback can impact upon the ability of hot gas haloes to provide a supply of fuel for SF during mergers and in their remnants. Finally, we briefly review our recent study, in which we examine the effect of supernova (SN) feedback on galaxies accreting via the previously overlooked cold-mode, by resimulating a stream-fed galaxy at z ~ 9. A far-reaching galactic wind results yet it cannot suppress the cold, filamentary accretion or eject significant mass in order to reduce the SFR, suggesting that SN feedback may not be as effective as is often assumed. © 2013 International Astronomical Union.