# Publications by Subir Sarkar

## Extending the Search for Muon Neutrinos Coincident with Gamma-Ray Bursts in IceCube Data

Astrophysical Journal American Astronomical Society 843 (2017) 1-13

M Ackermann, J Adams, S Sarkar

We present an all-sky search for muon neutrinos produced during the prompt γ-ray emission of 1172 gamma-ray bursts (GRBs) with the IceCube Neutrino Observatory. The detection of these neutrinos would constitute evidence for ultra-high-energy cosmic-ray (UHECR) production in GRBs, as interactions between accelerated protons and the prompt γ-ray field would yield charged pions, which decay to neutrinos. A previously reported search for muon neutrino tracks from northern hemisphere GRBs has been extended to include three additional years of IceCube data. A search for such tracks from southern hemisphere GRBs in five years of IceCube data has been introduced to enhance our sensitivity to the highest energy neutrinos. No significant correlation between neutrino events and observed GRBs is seen in the new data. Combining this result with previous muon neutrino track searches and a search for cascade signature events from all neutrino flavors, we obtain new constraints for single-zone fireball models of GRB neutrino and UHECR production.

## Multiwavelength follow-up of a rare IceCube neutrino multiplet

Astronomy and Astrophysics 607 (2017)

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, I Al Samarai, D Altmann, K Andeen, T Anderson, I Ansseau, G Anton, M Archinger, C Argüelles, J Auffenberg, S Axani, X Bai, SW Barwick, V Baum, R Bay, JJ Beatty, JB Tjus, KH Becker, S Benzvi, D Berley, E Bernardini, A Bernhard, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, M Börner, F Bos, D Bose, S Böser, O Botner, J Braun, L Brayeur, HP Bretz, S Bron, A Burgman, T Carver, M Casier, E Cheung, D Chirkin, A Christov, K Clark, L Classen, S Coenders, GH Collin, JM Conrad, DF Cowen, R Cross, M Day, JPAM De André, C De Clercq, E Del Pino Rosendo, H Dembinski, S De Ridder, P Desiati, KD De Vries, G De Wasseige, M De With, T Deyoung, V Di Lorenzo, H Dujmovic, JP Dumm, M Dunkman, B Eberhardt, T Ehrhardt, B Eichmann, P Eller, S Euler, PA Evenson, S Fahey, AR Fazely, J Feintzeig, J Felde, K Filimonov, C Finley, S Flis, CC Fösig, A Franckowiak, E Friedman, T Fuchs, TK Gaisser, J Gallagher, L Gerhardt, K Ghorbani, W Giang, L Gladstone, T Glauch, T Glüsenkamp, A Goldschmidt, JG Gonzalez, D Grant, Z Griffith, C Haack

© ESO, 2017. On February 17, 2016, the IceCube real-time neutrino search identified, for the first time, three muon neutrino candidates arriving within 100 s of one another, consistent with coming from the same point in the sky. Such a triplet is expected once every 13.7 years as a random coincidence of background events. However, considering the lifetime of the follow-up program the probability of detecting at least one triplet from atmospheric background is 32%. Follow-up observatories were notified in order to search for an electromagnetic counterpart. Observations were obtained by Swift's X-ray telescope, by ASAS-SN, LCO and MASTER at optical wavelengths, and by VERITAS in the very-high-energy gamma-ray regime. Moreover, the Swift BAT serendipitously observed the location 100 s after the first neutrino was detected, and data from the Fermi LAT and HAWC observatory were analyzed. We present details of the neutrino triplet and the follow-up observations. No likely electromagnetic counterpart was detected, and we discuss the implications of these constraints on candidate neutrino sources such as gamma-ray bursts, core-collapse supernovae and active galactic nucleus flares. This study illustrates the potential of and challenges for future follow-up campaigns.

## Search for astrophysical sources of neutrinos using cascade events in IceCube

Astrophysical Journal American Astronomical Society 846 (2017) 1-12

M Ackermann, J Adams, S Sarkar

The IceCube neutrino observatory has established the existence of a flux of high-energy astrophysical neutrinos, which is inconsistent with the expectation from atmospheric backgrounds at a significance greater than 5σ. This flux has been observed in analyses of both track events from muon neutrino interactions and cascade events from interactions of all neutrino flavors. Searches for astrophysical neutrino sources have focused on track events due to the significantly better angular resolution of track reconstructions. To date, no such sources have been confirmed. Here we present the first search for astrophysical neutrino sources using cascades interacting in IceCube with deposited energies as small as 1 TeV. No significant clustering was observed in a selection of 263 cascades collected from 2010 May to 2012 May. We show that compared to the classic approach using tracks, this statistically independent search offers improved sensitivity to sources in the southern sky, especially if the emission is spatially extended or follows a soft energy spectrum. This enhancement is due to the low background from atmospheric neutrinos forming cascade events and the additional veto of atmospheric neutrinos at declinations ≲-30.

## Multi-messenger Observations of a Binary Neutron Star Merger

Astrophysical Journal Letters American Astronomical Society 848 (2017) L12-L12

S Sarkar

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼1.7s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of 40+8−8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 M⊙. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼40Mpc) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼9 and ∼16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.

## Search for neutrinos from dark matter self-annihilations in the center of the Milky Way with 3 years of IceCube/DeepCore

European Physical Journal C Springer Verlag 77 (2017) 1-11

M Ackermann, J Adams, S Sarkar

We present a search for a neutrino signal from dark matter self-annihilations in the Milky Way using the IceCube Neutrino Observatory (IceCube). In 1005 days of data we found no significant excess of neutrinos over the background of neutrinos produced in atmospheric air showers from cosmic ray interactions. We derive upper limits on the velocity averaged product of the dark matter self-annihilation cross section and the relative velocity of the dark matter particles $\langle\sigma_{\text{A}}v\rangle$. Upper limits are set for dark matter particle candidate masses ranging from 10 GeV up to 1 TeV while considering annihilation through multiple channels. This work sets the most stringent limit on a neutrino signal from dark matter with mass between 10 GeV and 100 GeV, with a limit of $1.18\cdot10^{-23}\text{cm}^3\text{s}^{-1}$ for 100 GeV dark matter particles self-annihilating via $\tau^+\tau^-$ to neutrinos (assuming the Navarro-Frenk-White dark matter halo profile).

## Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

Astrophysical Journal Letters Institute of Physics Publishing 850 (2017) ARTN L35

## Measurement of the ν<inf>μ</inf> energy spectrum with IceCube-79: IceCube Collaboration

European Physical Journal C 77 (2017)

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, I Al Samarai, D Altmann, K Andeen, T Anderson, I Ansseau, G Anton, M Archinger, C Argüelles, J Auffenberg, S Axani, H Bagherpour, X Bai, SW Barwick, V Baum, R Bay, JJ Beatty, J Becker Tjus, KH Becker, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, M Börner, F Bos, D Bose, S Böser, O Botner, F Bradascio, J Braun, L Brayeur, HP Bretz, S Bron, A Burgman, T Carver, M Casier, E Cheung, D Chirkin, A Christov, K Clark, L Classen, S Coenders, GH Collin, JM Conrad, DF Cowen, R Cross, M Day, JPAM de André, C De Clercq, E del Pino Rosendo, H Dembinski, S De Ridder, P Desiati, KD de Vries, G de Wasseige, M de With, T DeYoung, JC Díaz-Vélez, V di Lorenzo, H Dujmovic, JP Dumm, M Dunkman, B Eberhardt, T Ehrhardt, B Eichmann, P Eller, S Euler, PA Evenson, S Fahey, AR Fazely, J Feintzeig, J Felde, K Filimonov, C Finley, S Flis, CC Fösig, A Franckowiak, E Friedman, T Fuchs, TK Gaisser, J Gallagher, L Gerhardt, K Ghorbani, W Giang, L Gladstone, T Glauch, T Glüsenkamp, A Goldschmidt, JG Gonzalez, D Grant

© 2017, The Author(s). IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The νμ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an Eν-range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9σ in four adjacent bins for neutrino energies Eν≥177.8TeV. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.

Journal of Physics: Conference Series 888 (2017)

D Jason Koskinen

© Published under licence by IOP Publishing Ltd. The IceCube neutrino observatory at the South Pole is the largest operating neutrino detector in the world and spans a wide range of science topics, from astronomy at the PeV-scale to particle physics at the GeV-scale. We present results from the search for a light, O(1) eV 2 , sterile neutrino using the large IceCube array and, separately, using the lower energy extension DeepCore sub-array. Additionally, we review the atmospheric neutrino results and expected sensitivities related to oscillation physics (ν μ disappearance and ν τ appearance) as well as new limits on non-standard interactions. Continuing the success of the IceCube-DeepCore physics program, a proposed next generation in-fill detector with increased sensitivity to neutrinos of O(1) GeV will be covered.

## High redshift radio galaxies and divergence from the CMB dipole

Monthly Notices of the Royal Astronomical Society Oxford University Press 471 (2017) 1045-1055

J Colin, R Mohayaee, M Rameez, S Sarkar

Previous studies have found our velocity in the rest frame of radio galaxies at high redshift to be much larger than that inferred from the dipole anisotropy of the cosmic microwave background. We construct a full sky catalogue, NVSUMSS, by merging the NRAO VLA Sky Survey and the Sydney University Molonglo Sky Survey catalogues and removing local sources by various means including cross-correlating with the 2MASS Redshift Survey catalogue. We take into account both aberration and Doppler boost to deduce our velocity from the hemispheric number count asymmetry, as well as via a three-dimensional linear estimator. Both its magnitude and direction depend on cuts made to the catalogue, e.g. on the lowest source flux; however these effects are small. From the hemispheric number count asymmetry we obtain a velocity of 1729 ± 187 km s−1, i.e. about four times larger than that obtained from the cosmic microwave background dipole, but close in direction, towards RA=149° ± 2°, Dec. = −17° ± 12°. With the three-dimensional estimator, the derived velocity is 1355 ± 174 km s−1 towards RA = 141° ± 11°, Dec. = −9° ± 10°. We assess the statistical significance of these results by comparison with catalogues of random distributions, finding it to be 2.81σ (99.75 per cent confidence).

## Search for high-energy neutrinos from gravitational wave event GW151226 and candidate LVT151012 with ANTARES and IceCube

Physical Review D American Physcial Society 96 (2017) 022005-

A Albert, M André, M Anghinolfi, S Sarkar

The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We find 2 and 4 neutrino candidates detected by IceCube, and 1 and 0 detected by ANTARES, within $\pm500$ s around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use non-detection to constrain isotropic-equivalent high-energy neutrino emission from GW151226 adopting the GW event's 3D localization, to less than $2\times 10^{51}-2\times10^{54}$ erg.

## Constraints on Galactic Neutrino Emission with Seven Years of IceCube Data

Astrophysical Journal University of Chicago Press 849 (2017) ARTN 67

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, I Al Samarai, D Altmann, K Andeen, T Anderson, I Ansseau, G Anton, C Arguelles, J Auffenberg, S Axani, H Bagherpour, X Bai, JP Barron, SW Barwick, V Baum, R Bay, JJ Beatty, JB Tjus, K-H Becker, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, M Borner, F Bos, D Bose, S Boeser, O Botner, J Bourbeau, F Bradascio, J Braun, L Brayeur, M Brenzke, H-P Bretz, S Bron, A Burgman, T Carver, J Casey, M Casier, E Cheung, D Chirkin, A Christov, K Clark, L Classen, S Coenders, GH Collin, JM Conrad, DF Cowen, R Cross, M Day, JPAM de Andre, C De Clercq, JJ DeLaunay, H Dembinski, S De Ridder, P Desiati, KD de Vries, G de Wasseige, M de With, T DeYoung, JC Diaz-Velez, V di Lorenzo, H Dujmovic, JP Dumm, M Dunkmanm, B Eberhardt, T Ehrhardt, B Eichmann, P Ellerm, PA Evenson, S Fahey, AR Fazely, J Felde, K Filimonov, C Finley, S Flis, A Franckowiak, E Friedman, T Fuchs, TK Gaisser, J Gallagher, L Gerhardt, K Ghorbani, W Giang, T Glauch, T Glusenkamp, A Goldschmidt, JG Gonzalez, D Grant, Z Griffith, C Haack, A Hallgren, F Halzen, K Hanson, D Hebecker, D Heereman, K Helbing, R Hellauer, S Hickford, J Hignight, GC Hills, KD Hoffman, R Hoffmann, B Hokanson-Fasig, K Hoshina, F Huang, M Huber, K Hultqvist, S In, A Ishihara, E Jacobi, GS Japaridze, M Jeong, K Jero, BJP Jones, P Kalacynskim, W Kang, A Kappes, T Karg, A Karle, U Katz, M Kauer, A Keivani, JL Kelley, A Kheirandish, J Kim, M Kim, T Kintscher, J Kiryluk, T Kittler, SR Klein, G Kohnen, R Koirala, H Kolanoski, L Kopke, C Kopper, S Kopper, JP Koschinsky, DJ Koskinen, M Kowalski, K Krings, M Kroll, G Kriickl, J Kunnenu, S Kunwar, N Kurahashi, T Kuwabara, A Kyriacou, M Labare, JL Lanfranchim, MJ Larson, F Lauber, D Lennarz, M Lesiak-Bzdak, M Leuermann, QR Liu, L Lu, J Lunemann, W Luszczak, J Madsen, G Maggi, KBM Mahn, S Mancina, R Maruyamau, K Mase, R Maunu, F McNally, K Meagher, M Medici, M Meier, T Menne, G Merino, T Meures, S Miarecki, J Micallef, G Momente, T Montaruli, RW Moore, M Moulai, R Nahnhauer, P Nakarmi, U Naumann, G Neer, H Niederhausen, SC Nowicki, DR Nygren, AO Pollmann, A Olivas, A O'Murchadha, T Palczewski, H Pandya, DV Pankova, P Peiffer, JA Pepper, CPDL Heros, D Pieloth, E Pinat, M Plums, PB Price, GT Przybylski, C Raab, L Radel, M Rameez, K Rawlins, R Reimann, B Relethford, M Relich, E Resconi, W Rhode, M Richman, S Robertson, M Rongen, C Rott, T Ruhe, D Ryckbosch, D Rysewyk, T Salzer, SES Herrera, A Sandrock, J Sandroos, S Sarkar, S Sarkar, K Satalecka, P Schlunder, T Schmidt, A Schneider, S Schoenen, S Schoneberg, L Schumacher, D Seckel, S Seunarine, D Soldin, M Song, GM Spiczak, C Spiering, J Stachurska, T Stanev, A Stasik, J Stettner, A Steuer, T Stezelberger, RG Stokstad, A Stossl, NL Strotjohann, GW Sullivan, M Sutherland, I Taboada, J Tatar, F Tenholt, S Ter-Antonyan, A Terliuk, G Tesic, S Tilav, PA Toale, MN Tobin, S Toscano, D Tosi, M Tselengidou, CF Tung, A Turcati, CF Turley, B Ty, E Unger, M Usner, J Vandenbroucke, W Van Driessche, N van Eijndhoven, S Vanheule, J van Santen, MI Vehring, E Vogel, M Vraeghe, C Walck, A Wallace, M Wallraffm, FD Wandler, N Wandkowsky, A Waza, C Weaver, MJ Weiss, C Wendt, S Westerhoff, BJ Whelan, S Wickmann, K Wiebem, CH Wiebusch, L Wille, DR Williams, L Wills, M Wolf, J Wood, TR Wood, E Woolsey, K Woschnagg, DL Xu, XW Xu, Y Xu, JP Yanez, G Yodh, S Yoshida, T Yuan, M Zoll, I Collaboration

## The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part I: Searches for the Sources of Astrophysical Neutrinos

35th International Cosmic Ray Conference 2017(ICRC2017) International School for Advanced Studies (2017)

M Ackermann, J Adams, S Sarkar

<p>Papers on the searches for the sources of astrophysical neutrinos, submitted to the 35th International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by the IceCube Collaboration</p> <p>Contents</p> <p>1 - Searching for VHE gamma-ray emission associated with IceCube astrophysical neutrinos using FACT, H.E.S.S., MAGIC, and VERITAS</p> <p>2 - Search for point-like sources in the astrophysical muon neutrino flux with IceCube</p> <p>3 - Search for weak neutrino point sources using angular auto-correlation analyses in IceCube</p> <p>4 - All-sky search for correlations in the arrival directions of astrophysical neutrino candidates and ultrahigh-energy cosmic rays</p> <p>5 - Results of IceCube searches for neutrinos from blazars using seven years of through-going muon data</p> <p>6 - IceCube Search for Neutrinos from 1ES 1959+650: Completing the Picture</p> <p>7 - Using all-flavor and all-sky event selections by IceCube to search for neutrino emission from the Galactic plane</p> <p>8 - Constraints on diffuse neutrino emission from the Galactic Plane with 7 years of IceCube data</p> <p>9 - Search for extended sources of neutrino emission with 7 years of IceCube data</p> <p>10 - Search for a cumulative neutrino signal from blazar flares using IceCube data</p> <p>11 - Investigation of Obscured Flat Spectrum Radio AGN with the IceCube Neutrino Observatory</p> <p>12 - Realtime neutrino alerts and follow-up in IceCube</p> <p>13 - Search for High-Energy Neutrino Emission from Fast Radio Bursts</p> <p>14 - IceCube as a Neutrino Follow-up Observatory for Astronomical Transients</p>

## The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part II: Properties of the Atmospheric and Astrophysical Neutrino Flux

35th International Cosmic Ray Conference 2017(ICRC2017) International School for Advanced Studies (2017)

M Ackermann, J Adams, S Sarkar

<p>Papers on the properties of the atmospheric and astrophysical neutrino flux submitted to the 35th International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by the IceCube Collaboration</p> <p>Contents:</p> <p>1 - Search for Astrophysical Tau Neutrinos in Six Years of High-Energy Starting Events in IceCube</p> <p>2 - Multi-flavour PeV neutrino search with IceCube</p> <p>3 - High Energy Astrophysical Neutrino Flux Measurement Using Neutrinoinduced Cascades Observed in 4 Years of IceCube Data</p> <p>4 - A Measurement of the Diffuse Astrophysical Muon Neutrino Flux Using Eight Years of IceCube Data</p> <p>5 - Characterizing the Flux of Atmospheric Neutrinos with IceCube-DeepCore</p> <p>6 - Measurement of High Energy Neutrino – Nucleon Cross Section and Astrophysical Neutrino Flux Anisotropy Study of Cascade Channel with IceCube</p> <p>7 - Observation of Astrophysical Neutrinos in Six Years of IceCube Data</p> <p>8 - All-flavor Multi-Channel Analysis of the Astrophysical Neutrino Spectrum with IceCube</p> <p>9 - Differential limit on an EHE neutrino flux component in the presence of astrophysical background from nine years of IceCube data</p> <p>10 - Improving Future High-Energy Tau Neutrino Searches in IceCube</p> <p>11 - Search for Astrophysical Tau Neutrinos with the IceCube Waveforms</p>

## The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part III: Cosmic Rays

35th International Cosmic Ray Conference 2017(ICRC2017) International School for Advanced Studies (2017)

Aartsen, M Ackermann, J Adams, S Sarkar

## Neutrino Astronomy in the IceCube Era

Proceedings of Frontier Research in Astrophysics – II — PoS(FRAPWS2016) Sissa Medialab (2017)

T Stanev

## The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part IV: Searches for Beyond the Standard Model Physics

35th International Cosmic Ray Conference 2017(ICRC2017) International School for Advanced Studies (2017)

M Ackermann, J Adams, S Sarkar

<p>Papers on searches for beyond the standard model physics, submitted to the 35th International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by the IceCube Collaboration</p> <p>Contents:</p> <p>1 - Delayed light emission to distinguish astrophysical neutrino flavors in IceCube</p> <p>2 - Search for Signatures of Heavy Decaying Dark Matter with IceCube</p> <p>3 - Latest results and sensitivities for solar dark matter searches with IceCube</p> <p>4 - Searches for annihilating dark matter in the Milky Way halo with IceCube</p> <p>5 - Searches for Dark Matter in the center of the Earth with the IceCube detector</p> <p>6 - Measurement of water luminescence – a new detection method for neutrino telescopes</p> <p>7 - Combined Search for Neutrinos from Dark Matter Annihilation in the Galactic Center using IceCube and ANTARES</p>

## The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part V: Solar flares, Supernovae, Event reconstruction, Education &amp; Outreach

35th International Cosmic Ray Conference (ICRC 2017) Proceedings of Science (2017)

Aartsen, M Ackermann, J Adams, S Sarkar

<p>Contents:</p> <p>1 Search for GeV neutrinos associated with solar flares with IceCube</p> <p>2 Estimating the Sensitivity of IceCube to Signatures of Axion Production in a Galactic Supernova</p> <p>3 Searching for Arbitrary Low-Energy Neutrino Transients with IceCube</p> <p>4 Deep Learning in Physics exemplified by the Reconstruction of Muon-Neutrino Events in IceCube</p> <p>5 Connecting Beyond the Research Community: IceCube Education, Outreach, and Communication Efforts</p>

## The IceCube Neutrino Observatory - Contributions to ICRC 2017 Part VI: IceCube-Gen2, the Next Generation Neutrino Observatory

35th International Cosmic Ray Conference (ICRC 2017) Proceedings of Science (2017)

M Ackermann, J Adams, S Sarkar

<p>Contents:</p> <p>1 IceCube-Gen2: the next-generation neutrino observatory for the South Pole</p> <p>2 IceAct: Imaging Air Cherenkov Telescopes with SiPMs at the South Pole for IceCube-Gen2</p> <p>3 Overview and performance of the D-Egg optical sensor for IceCube-Gen2</p> <p>4 Muon track reconstruction and veto performance with D-Egg sensor for IceCube-Gen2</p> <p>5 In-ice self-veto techniques for IceCube-Gen2</p> <p>6 A camera system for IceCube-Gen21</p> <p>7 The mDOM – A multi-PMT Digital Optical Module for the IceCube-Gen2 neutrino telescope</p> <p>8 The IceTop Scintillator Upgrade</p> <p>9 Overview and Performance of the Wavelength-shifting Optical Module (WOM)</p> <p>10 The Precision Optical CAlibration Module for IceCube-Gen2: First Prototype</p>

## All-sky search for correlations in the arrival directions of astrophysical neutrino candidates and ultrahigh-energy cosmic rays

35th International Cosmic Ray Conference (ICRC 2017) Proceedings of Science (2017)

S Sarkar

High-energy neutrinos, being neutral and weakly interacting particles, are powerful probes of the sites of production and acceleration of cosmic rays. The challenging discovery of cosmic neutrinos by the IceCube Collaboration has moved the field closer to realizing the potential of neutrino astronomy. Meanwhile, ground-based cosmic ray detectors like the Pierre Auger Observatory and the Telescope Array have reached an unprecedented accuracy in the determination of the features of the cosmic rays at the highest energies. We report on a collaborative effort between IceCube, the Pierre Auger Observatory and Telescope Array to identify directional correlations between the arrival directions of the highest-energy cosmic rays from both hemispheres and of the most probable cosmic neutrino events detected by IceCube. We describe the updated results of two independent searches using seven years of IceCube neutrino data and the most energetic cosmicray events detected by the Pierre Auger Observatory and the Telescope Array. The directional correlation found between UHECRs and neutrinos is reported with a significance of ~ 2σ.

## Combined Analysis of Cosmic-Ray Anisotropy with IceCube and HAWC

35th International Cosmic Ray Conference 2017(ICRC2017) International School for Advanced Studies (2017)

S Sarkar

During the past two decades, experiments in both the northern and southern hemispheres have observed a small but measurable energy-dependent sidereal anisotropy in the arrival direction distribution of Galactic cosmic rays with relative intensities at the level of one per mille. Individually, these measurements are restricted by limited sky coverage, and so the power spectrum of the anisotropy obtained from any one measurement displays a systematic correlation between different multipole modes $C_\ell$. We present the results of a joint analysis of the anisotropy on all angular scales using cosmic-ray data collected during 336 days of operation of the High-Altitude Water Cherenkov (HAWC) Observatory (located at 19$^\circ$ N) and 5 years of data taking from the IceCube Neutrino Observatory (located at 90$^\circ$ S) The results include a combined sky map and an all-sky power spectrum in the overlapping energy range of the two experiments at around 10 TeV. We describe the methods used to combine the IceCube and HAWC data, address the individual detector systematics, and study the region of overlapping field of view between the two observatories.