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150 results on '"HAWC Collaboration"'

1. Spectral Study of Very-high-energy Gamma Rays from SS 433 with HAWC

Author: R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, J. Cotzomi, E. De la Fuente, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, K. Engel, T. Ergin, C. Espinoza, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. García-González, A. Gonzalez Muñoz, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernández-Cadena, I. Herzog, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, A. Lara, W. H. Lee, J. Lee, C. de León, H. León Vargas, A. L. Longinotti, G. Luis-Raya, K. Malone, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, E. Moreno, M. Mostafá, L. Nellen, M. U. Nisa, R. Noriega-Papaqui, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, E. Ruiz-Velasco, H. Salazar, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, E. Varela, L. Villaseñor, X. Wang, Z. Wang, I. J. Watson, S. Yu, S. Yun-Cárcamo, H. Zhou, and HAWC collaboration
Subjects: Gamma-ray sources, High mass x-ray binary stars, Jets, Astrophysics, QB460-466
Abstract: Very-high-energy (0.1–100 TeV) gamma-ray emissions were observed in High-Altitude Water Cherenkov (HAWC) data from the lobes of the microquasar SS 433, making them the first set of astrophysical jets that were resolved at TeV energies. In this work, we update the analysis of SS 433 using 2565 days of data from the HAWC observatory. Our analysis reports the detection of a point-like source in the east lobe at a significance of 6.6 σ and in the west lobe at a significance of 8.2 σ . For each jet lobe, we localize the gamma-ray emission and identify a best-fit position. The locations are close to the X-ray emission sites “e1” and “w1” for the east and west lobes, respectively. We analyze the spectral energy distributions and find that the energy spectra of the lobes are consistent with a simple power law d N / d E ∝ E ^α with $\alpha =-{2.44}_{-0.12-0.04}^{+0.13+0.04}$ and $\alpha =-{2.35}_{-0.11-0.03}^{+0.12+0.03}$ for the east and west lobes, respectively. The maximum energy of photons from the east and west lobes reaches 56 TeV and 123 TeV, respectively. We compare our observations to various models and conclude that the very-high-energy gamma-ray emission can be produced by a population of electrons that were efficiently accelerated.
Published: 2024
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2. Search for Joint Multimessenger Signals from Potential Galactic Cosmic-Ray Accelerators with HAWC and IceCube

Author: R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, J. C. Díaz-Vélez, K. Engel, T. Ergin, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernández-Cadena, I. Herzog, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, J. Lee, H. León Vargas, G. Luis-Raya, K. Malone, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, E. Moreno, M. Mostafá, L. Nellen, M. U. Nisa, N. Omodei, M. Osorio, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, Y. Son, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, X. Wang, I. J. Watson, K. Whitaker, E. Willox, H. Wu, S. Yu, S. Yun-Cárcamo, H. Zhou, C. de León, HAWC Collaboration, R. Abbasi, M. Ackermann, J. Adams, S. K. Agarwalla, J. A. Aguilar, M. Ahlers, J. M. Alameddine, N. M. Amin, K. Andeen, C. Argüelles, Y. Ashida, S. Athanasiadou, L. Ausborm, S. N. Axani, X. Bai, A. Balagopal V., M. Baricevic, S. W. Barwick, S. Bash, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, J. Beise, C. Bellenghi, C. Benning, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Böttcher, J. Braun, B. Brinson, J. Brostean-Kaiser, L. Brusa, R. T. Burley, D. Butterfield, M. A. Campana, I. Caracas, K. Carloni, J. Carpio, S. Chattopadhyay, N. Chau, Z. Chen, D. Chirkin, S. Choi, B. A. Clark, A. Coleman, G. H. Collin, A. Connolly, J. M. Conrad, P. Coppin, R. Corley, P. Correa, D. F. Cowen, P. Dave, C. De Clercq, J. J. DeLaunay, D. Delgado, S. Deng, A. Desai, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, A. Diaz, P. Dierichs, M. Dittmer, A. Domi, L. Draper, H. Dujmovic, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, P. Eller, E. Ellinger, S. El Mentawi, D. Elsässer, R. Engel, H. Erpenbeck, J. Evans, P. A. Evenson, K. Farrag, A. R. Fazely, A. Fedynitch, N. Feigl, S. Fiedlschuster, C. Finley, L. Fischer, D. Fox, A. Franckowiak, S. Fukami, P. Fürst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, G. Garg, E. Genton, L. Gerhardt, A. Ghadimi, C. Girard-Carillo, C. Glaser, T. Glüsenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, O. Gries, S. Griffin, S. Griswold, K. M. Groth, C. Günther, P. Gutjahr, C. Ha, C. Haack, A. Hallgren, L. Halve, F. Halzen, H. Hamdaoui, M. Ha Minh, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Häußler, K. Helbing, J. Hellrung, J. Hermannsgabner, L. Heuermann, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, K. D. Hoffman, S. Hori, K. Hoshina, M. Hostert, W. Hou, T. Huber, K. Hultqvist, M. Hünnefeld, R. Hussain, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, O. Janik, M. Jansson, G. S. Japaridze, M. Jeong, M. Jin, B. J. P. Jones, N. Kamp, D. Kang, W. Kang, X. Kang, A. Kappes, D. Kappesser, L. Kardum, T. Karg, M. Karl, A. Karle, A. Katil, U. Katz, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, J. Kiryluk, S. R. Klein, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Köpke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kovacevich, M. Kowalski, T. Kozynets, J. Krishnamoorthi, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, N. Lad, C. Lagunas Gualda, M. Lamoureux, M. J. Larson, S. Latseva, F. Lauber, J. P. Lazar, J. W. Lee, K. Leonard DeHolton, A. Leszczyńska, J. Liao, M. Lincetto, Y. T. Liu, M. Liubarska, E. Lohfink, C. Love, C. J. Lozano Mariscal, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, J. Madsen, E. Magnus, K. B. M. Mahn, Y. Makino, E. Manao, S. Mancina, W. Marie Sainte, I. C. Mariş, S. Marka, Z. Marka, M. Marsee, I. Martinez-Soler, R. Maruyama, F. Mayhew, F. McNally, J. V. Mead, K. Meagher, S. Mechbal, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Micallef, J. Mitchell, T. Montaruli, R. W. Moore, Y. Morii, R. Morse, M. Moulai, T. Mukherjee, R. Naab, R. Nagai, M. Nakos, U. Naumann, J. Necker, A. Negi, L. Neste, M. Neumann, H. Niederhausen, K. Noda, A. Noell, A. Novikov, A. Obertacke Pollmann, V. O’Dell, B. Oeyen, A. Olivas, R. Orsoe, J. Osborn, E. O’Sullivan, H. Pandya, N. Park, G. K. Parker, E. N. Paudel, L. Paul, C. Pérez de los Heros, T. Pernice, J. Peterson, S. Philippen, A. Pizzuto, M. Plum, A. Pontén, Y. Popovych, M. Prado Rodriguez, B. Pries, R. Procter-Murphy, G. T. Przybylski, C. Raab, J. Rack-Helleis, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, P. Reichherzer, E. Resconi, S. Reusch, W. Rhode, B. Riedel, A. Rifaie, E. J. Roberts, S. Robertson, S. Rodan, G. Roellinghoff, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, I. Safa, J. Saffer, P. Sampathkumar, A. Sandrock, M. Santander, S. Sarkar, J. Savelberg, P. Savina, P. Schaile, M. Schaufel, H. Schieler, S. Schindler, B. Schlüter, F. Schlüter, N. Schmeisser, T. Schmidt, J. Schneider, F. G. Schröder, L. Schumacher, S. Sclafani, D. Seckel, M. Seikh, M. Seo, S. Seunarine, P. Sevle Myhr, R. Shah, S. Shefali, N. Shimizu, M. Silva, B. Skrzypek, B. Smithers, R. Snihur, J. Soedingrekso, A. Søgaard, D. Soldin, P. Soldin, G. Sommani, C. Spannfellner, G. M. Spiczak, C. Spiering, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stürwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, M. Thiesmeyer, W. G. Thompson, J. Thwaites, S. Tilav, C. Tönnis, S. Toscano, D. Tosi, A. Trettin, R. Turcotte, J. P. Twagirayezu, M. A. Unland Elorrieta, A. K. Upadhyay, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Vandenbroucke, N. van Eijndhoven, D. Vannerom, J. van Santen, J. Vara, J. Veitch-Michaelis, M. Venugopal, M. Vereecken, S. Verpoest, D. Veske, A. Vijai, C. Walck, A. Wang, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, A. Wolf, M. Wolf, G. Wrede, X. W. Xu, J. P. Yanez, E. Yildizci, S. Yoshida, R. Young, T. Yuan, Z. Zhang, P. Zhelnin, P. Zilberman, M. Zimmerman, and IceCube Collaboration
Subjects: Neutrino astronomy, Gamma-ray astronomy, Particle astrophysics, High energy astrophysics, Astrophysics, QB460-466
Abstract: The origin of high-energy galactic cosmic rays is yet to be understood, but some galactic cosmic-ray accelerators can accelerate cosmic rays up to PeV energies. The high-energy cosmic rays are expected to interact with the surrounding material or radiation, resulting in the production of gamma-rays and neutrinos. To optimize for the detection of such associated production of gamma-rays and neutrinos for a given source morphology and spectrum, a multimessenger analysis that combines gamma-rays and neutrinos is required. In this study, we use the Multi-Mission Maximum Likelihood framework with IceCube Maximum Likelihood Analysis software and HAWC Accelerated Likelihood to search for a correlation between 22 known gamma-ray sources from the third HAWC gamma-ray catalog and 14 yr of IceCube track-like data. No significant neutrino emission from the direction of the HAWC sources was found. We report the best-fit gamma-ray model and 90% CL neutrino flux limit from the 22 sources. From the neutrino flux limit, we conclude that, for five of the sources, the gamma-ray emission observed by HAWC cannot be produced purely from hadronic interactions. We report the limit for the fraction of gamma-rays produced by hadronic interactions for these five sources.
Published: 2024
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3. Precise Measurements of TeV Halos around Geminga and Monogem Pulsars with HAWC

Author: A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. de la Fuente, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, M. Durocher, J. C. Díaz-Vélez, K. Engel, C. Espinoza, K. L. Fan, K. Fang, N. Fraija, J. A. García-González, F. Garfias, H. Goksu, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernández-Cadena, I. Herzog, P. Hüntemeyer, D. Huang, F. Hueyotl-Zahuantitla, A. Iriarte, V. Joshi, S. Kaufmann, D. Kieda, A. Lara, W. H. Lee, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, J. A. Morales-Soto, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, R. Noriega-Papaqui, L. Olivera-Nieto, N. Omodei, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, G. Schwefer, J. Serna-Franco, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Urea-Mena, E. Varela, L. Villaseñor, X. Wang, I. J. Watson, E. Willox, H. Wu, S. Yun-Cárcamo, H. Zhou, C. de León, HAWC Collaboration, and M. Di Mauro
Subjects: High energy astrophysics, Particle astrophysics, Pulsars, Pulsar wind nebulae, Astrophysics, QB460-466
Abstract: We present the most precise measurements to date for the spatial extension and energy spectrum of the γ -ray region between a pulsar’s wind nebula and the interstellar medium, better known as the halo, present around Geminga and PSR B0656+14 (Monogem) using ∼2398 days of >1 TeV data collected by the HAWC observatory. We interpret the data using a physically motivated model for the diffuse γ -ray emission generated from positrons and electrons (e ^± ) injected by the pulsar wind nebula and inverse Compton scattering with interstellar radiation fields. We find the morphologies of the regions inside these halos are characterized by an inhibited diffusion that are approximately three orders of magnitudes smaller than the Galactic average. We also obtain the e ^± emission efficiencies of 6.6% and 5.1%, respectively, for Geminga and Monogem. These results have remarkable consequences for the study of the particle diffusion in the region between the pulsar wind nebulae and the interstellar medium, and for the interpretation of the flux of positrons measured by the AMS-02 experiment above 10 GeV.
Published: 2024
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4. Performance of the HAWC Observatory and TeV Gamma-Ray Measurements of the Crab Nebula with Improved Extensive Air Shower Reconstruction Algorithms

Author: A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, F. Carreón, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, D. Depaoli, N. Di Lalla, R. Díaz Hernández, B. L. Dingus, M. A. DuVernois, K. Engel, T. Ergin, C. Espinoza, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. García-González, F. Garfias, H. Goksu, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernández-Cadena, I. Herzog, J. Hinton, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, A. Lara, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, E. Moreno, M. Mostafá, L. Nellen, M. U. Nisa, R. Noriega-Papaqui, L. Olivera-Nieto, N. Omodei, M. Osorio-Archila, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, E. Ruiz-Velasco, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, G. Schwefer, J. Serna-Franco, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, E. Varela, X. Wang, I. J. Watson, K. Whitaker, E. Willox, H. Wu, S. Yu, S. Yun-Cárcamo, H. Zhou, and HAWC Collaboration
Subjects: High energy astrophysics, Gamma-rays, Gamma-ray detectors, Astrophysics, QB460-466
Abstract: The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, located on the side of the Sierra Negra volcano in Mexico, has been fully operational since 2015. The HAWC collaboration has recently significantly improved their extensive air shower reconstruction algorithms, which has notably advanced the observatory performance. The energy resolution for primary gamma rays with energies below 1 TeV was improved by including a noise-suppression algorithm. Corrections have also been made to systematic errors in direction fitting related to the detector and shower plane inclinations, ${ \mathcal O }(0\buildrel{\circ}\over{.} 1)$ biases in highly inclined showers, and enhancements to the core reconstruction. The angular resolution for gamma rays approaching the HAWC array from large zenith angles (>37°) has improved by a factor of 4 at the highest energies (>70 TeV) as compared to previous reconstructions. The inclusion of a lateral distribution function fit to the extensive air shower footprint on the array to separate gamma-ray primaries from cosmic-ray ones based on the resulting χ ^2 values improved the background rejection performance at all inclinations. At large zenith angles, the improvement in significance is a factor of 4 compared to previous HAWC publications. These enhancements have been verified by observing the Crab Nebula, which is an overhead source for the HAWC Observatory. We show that the sensitivity to Crab-like point sources ( E ^−2.63 ) with locations overhead to 30° zenith is comparable to or less than 10% of the Crab Nebula’s flux between 2 and 50 TeV. Thanks to these improvements, HAWC can now detect more sources, including the Galactic center.
Published: 2024
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5. Galactic Gamma-Ray Diffuse Emission at TeV Energies with HAWC Data

Author: R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, V. Baghmanyan, E. Belmont-Moreno, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, O. Chaparro-Amaro, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, R. Diaz Hernandez, M. A. DuVernois, M. Durocher, J. C. Díaz-Vélez, K. Engel, C. Espinoza, K. L. Fan, N. Fraija, A. Galván-Gámez, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, S. Hernandez, B. Hona, D. Huang, F. Hueyotl-Zahuantitla, T. B. Humensky, A. Iriarte, V. Joshi, S. Kaufmann, D. Kieda, G. J. Kunde, A. Lara, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, R. Noriega-Papaqui, E. G. Pérez-Pérez, D. Rosa-González, E. Ruiz-Velasco, H. Salazar, D. Salazar-Gallegos, F. Salesa Greus, A. Sandoval, J. Serna-Franco, A. J. Smith, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, F. Ureña-Mena, L. Villaseñor, E. Willox, H. Zhou, C. de León, O. Fornieri, D. Gaggero, D. Grasso, A. Marinelli, S. Ventura, and HAWC Collaboration
Subjects: Gamma-ray astronomy, High energy astrophysics, Galactic cosmic rays, Milky Way disk, Astrophysics, QB460-466
Abstract: Galactic gamma-ray diffuse emission (GDE) is emitted by cosmic rays (CRs), ultra-relativistic protons, and electrons, interacting with gas and electromagnetic radiation fields in the interstellar medium. Here we present the analysis of teraelectronvolt diffuse emission from a region of the Galactic plane over the range in longitude of l ∈ [43°, 73°], using data collected with the High Altitude Water Cherenkov (HAWC) detector. Spectral, longitudinal, and latitudinal distributions of the teraelectronvolt diffuse emission are shown. The radiation spectrum is compatible with the spectrum of the emission arising from a CR population with an index similar to that of the observed CRs. When comparing with the DRAGON base model , the HAWC GDE flux is higher by about a factor of 2. Unresolved sources such as pulsar wind nebulae and teraelectronvolt halos could explain the excess emission. Finally, deviations of the Galactic CR flux from the locally measured CR flux may additionally explain the difference between the predicted and measured diffuse fluxes.
Published: 2024
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6. Multiwavelength Investigation of $\gamma$-ray Source MGRO J1908+06 Emission Using Fermi-LAT, VERITAS, and HAWC

Author: The VERITAS collaboration, The HAWC collaboration, and collaboration, The Fermi-LAT
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: This paper investigates the origin of the $\gamma$-ray emission from MGRO J1908+06 in the GeV-TeV energy band. By analyzing the data collected by {\it Fermi}-LAT, VERITAS, and HAWC, with the addition of spectral data previously reported by LHAASO, a multiwavelength (MW) study of the morphological and spectral features of MGRO J1908+06 provides insight into the origin of the $\gamma$-ray emission. The mechanism behind the bright TeV emission is studied by constraining the magnetic field strength, the source age and the distance through detailed broadband modeling. Both spectral shape and energy-dependent morphology support the scenario that inverse-Compton (IC) emission of an evolved pulsar wind nebula (PWN) associated with PSR J1907+0602 is responsible for the MGRO J1908+06 $\gamma$-ray emission with a best-fit true age of $T=22\pm 9$ kyr and a magnetic field of $B=5.4 \pm 0.8\ \mu\mathrm{G}$, assuming the distance to the pulsar $d_{\mathrm{PSR}}=3.2$ kpc., Comment: 21 pages, 11 figures, submitted to The Astrophysical Journal
Published: 2024
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7. HAWC Study of the Very-high-energy γ-Ray Spectrum of HAWC J1844−034

Author: A. Albert, C. Alvarez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, M. Breuhaus, T. Capistrán, A. Carramiñana, S. Casanova, J. Cotzomi, S. Coutiño de León, E. De la Fuente, D. Depaoli, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, M. Durocher, K. Engel, C. Espinoza, K. L. Fan, K. Fang, N. Fraija, J. A. García-González, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, I. Herzog, J. Hinton, D. Huang, F. Hueyotl-Zahuantitla, T. B. Humensky, P. Hüntemeyer, V. Joshi, S. Kaufmann, J. Lee, H. León Vargas, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Morales-Soto, E. Moreno, M. Mostafá, L. Nellen, R. Noriega-Papaqui, L. Olivera-Nieto, N. Omodei, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, E. Ruiz-Velasco, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, E. Varela, L. Villaseñor, X. Wang, I. J. Watson, E. Willox, H. Zhou, and HAWC collaboration
Subjects: γ-ray sources, Pulsars, Supernova remnants, Astrophysics, QB460-466
Abstract: Recently, the region surrounding eHWC J1842−035 has been studied extensively by γ-ray observatories due to its extended emission reaching up to a few hundred TeV and potential as a hadronic accelerator. In this work, we use 1910 days of cumulative data from the High Altitude Water Cherenkov (HAWC) observatory to carry out a dedicated systematic source search of the eHWC J1842−035 region. During the search, we found three sources in the region, namely, HAWC J1844−034, HAWC J1843−032, and HAWC J1846−025. We have identified HAWC J1844−034 as the extended source that emits photons with energies up to 175 TeV. We compute the spectrum for HAWC J1844−034, and by comparing with the observational results from other experiments, we have identified HESS J1843−033, LHAASO J1843−0338, and TASG J1844−038 as very-high-energy γ-ray sources with a matching origin. Also, we present and use the multiwavelength data to fit the hadronic and leptonic particle spectra. We have identified four pulsar candidates in the nearby region in which PSR J1844−0346 is found to be the most likely candidate due to its proximity to HAWC J1844−034 and the computed energy budget. We have also found SNR G28.6−0.1 as a potential counterpart source of HAWC J1844−034 for which both leptonic and hadronic scenarios are feasible.
Published: 2023
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8. Search for Gamma-Ray and Neutrino Coincidences Using HAWC and ANTARES Data

Author: H. A. Ayala Solares, S. Coutu, D. Cowen, D. B. Fox, T. Grégoire, F. McBride, M. Mostafá, K. Murase, S. Wissel, AMON Team, A. Albert, S. Alves, M. André, M. Ardid, S. Ardid, J.-J. Aubert, J. Aublin, B. Baret, S. Basa, B. Belhorma, M. Bendahman, F. Benfenati, V. Bertin, S. Biagi, M. Bissinger, J. Boumaaza, M. Bouta, M. C. Bouwhuis, H. Brânzaş, R. Bruijn, J. Brunner, J. Busto, B. Caiffi, D. Calvo, A. Capone, L. Caramete, J. Carr, V. Carretero, S. Celli, M. Chabab, T. N. Chau, R. Cherkaoui El Moursli, T. Chiarusi, M. Circella, J. A. B. Coelho, A. Coleiro, R. Coniglione, P. Coyle, A. Creusot, A. F. Díaz, G. de Wasseige, B. De Martino, C. Distefano, I. Di Palma, A. Domi, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, T. van Eeden, D. van Eijk, N. El Khayati, A. Enzenhöfer, P. Fermani, G. Ferrara, F. Filippini, L. Fusco, J. García, P. Gay, H. Glotin, R. Gozzini, R. Gracia Ruiz, K. Graf, C. Guidi, S. Hallmann, H. van Haren, A. J. Heijboer, Y. Hello, J. J. Hernández-Rey, J. Hößl, J. Hofestädt, F. Huang, G. Illuminati, C. W. James, B. Jisse-Jung, M. de Jong, P. de Jong, M. Kadler, O. Kalekin, U. Katz, A. Kouchner, I. Kreykenbohm, V. Kulikovskiy, R. Lahmann, M. Lamoureux, R. Le Breton, D. Lefèvre, E. Leonora, G. Levi, S. Le Stum, D. Lopez-Coto, S. Loucatos, L. Maderer, J. Manczak, M. Marcelin, A. Margiotta, A. Marinelli, J. A. Martínez-Mora, K. Melis, P. Migliozzi, A. Moussa, R. Muller, L. Nauta, S. Navas, E. Nezri, B. Ó Fearraigh, A. Păun, G. E. Păvălaş, C. Pellegrino, M. Perrin-Terrin, V. Pestel, P. Piattelli, C. Pieterse, C. Poirè, V. Popa, T. Pradier, N. Randazzo, D. Real, S. Reck, G. Riccobene, A. Romanov, A. Sánchez-Losa, D. F. E. Samtleben, M. Sanguineti, P. Sapienza, J. Schnabel, J. Schumann, F. Schüssler, J. Seneca, M. Spurio, Th. Stolarczyk, M. Taiuti, Y. Tayalati, S. J. Tingay, B. Vallage, V. Van Elewyck, F. Versari, S. Viola, D. Vivolo, J. Wilms, S. Zavatarelli, A. Zegarelli, J. D. Zornoza, J. Zúñiga, ANTARES Collaboration, C. Alvarez, J. C. Arteaga-Velázquez, R. Babu, E. Belmont-Moreno, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, O. Chaparro-Amaro, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, R. Diaz Hernandez, M. A. DuVernois, M. Durocher, J. C. Díaz-Vélez, K. Engel, C. Espinoza, K. L. Fan, M. Fernández Alonso, N. Fraija, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, J. P. Harding, S. Hernandez, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, V. Joshi, S. Kaufmann, A. Lara, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, I. Martinez-Castellanos, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Morales-Soto, E. Moreno, A. Nayerhoda, L. Nellen, M. U. Nisa, R. Noriega-Papaqui, N. Omodei, A. Peisker, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, E. Ruiz-Velasco, H. Salazar, F. Salesa Greus, A. Sandoval, M. Schneider, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, E. Varela, X. Wang, K. Whitaker, E. Willox, A. Zepeda, H. Zhou, and HAWC Collaboration
Subjects: High energy astrophysics, Astrophysics, QB460-466
Abstract: In the quest for high-energy neutrino sources, the Astrophysical Multimessenger Observatory Network has implemented a new search by combining data from the High Altitude Water Cherenkov (HAWC) Observatory and the Astronomy with a Neutrino Telescope and Abyss environmental RESearch (ANTARES) neutrino telescope. Using the same analysis strategy as in a previous detector combination of HAWC and IceCube data, we perform a search for coincidences in HAWC and ANTARES events that are below the threshold for sending public alerts in each individual detector. Data were collected between 2015 July and 2020 February with a live time of 4.39 yr. Over this time period, three coincident events with an estimated false-alarm rate of
Published: 2023
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9. Detailed Analysis of the TeV γ-Ray Sources 3HWC J1928+178, 3HWC J1930+188, and the New Source HAWC J1932+192

Author: A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, O. Chaparro-Amaro, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, R. Diaz Hernandez, J. C. Díaz-Vélez, B. L. Dingus, M. A. DuVernois, M. Durocher, K. Engel, C. Espinoza, K. L. Fan, M. Fernández Alonso, N. Fraija, J. A. García-González, F. Garfias, H. Goksu, M. M. González, J. A. Goodman, J. P. Harding, S. Hernandez, J. Hinton, B. Hona, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, S. Kaufmann, D. Kieda, W. H. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, R. López-Coto, K. Malone, V. Marandon, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Morales-Soto, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, L. Olivera-Nieto, N. Omodei, A. Peisker, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, E. Ruiz-Velasco, H. Salazar, D. Salazar-Gallegos, F. Salesa Greus, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, L. Villaseñor, X. Wang, F. Werner, E. Willox, H. Zhou, and HAWC collaboration
Subjects: High energy astrophysics, Gamma-ray astronomy, Pulsars, Pulsar wind nebulae, Non-thermal radiation sources, Astrophysics, QB460-466
Abstract: The latest High Altitude Water Cherenkov (HAWC) point-like source catalog up to 56 TeV reported the detection of two sources in the region of the Galactic plane at galactic longitude 52° < ℓ < 55°, 3HWC J1930+188 and 3HWC J1928+178. The first one is associated with a known TeV source, the supernova remnant SNR G054.1+00.3. It was discovered by one of the currently operating Imaging Atmospheric Cherenkov Telescope (IACT), the Very Energetic Radiation Imaging Telescope Array System (VERITAS), detected by the High Energy Stereoscopic System (H.E.S.S), and identified as a composite SNR. However, the source 3HWC J1928+178, discovered by HAWC and coincident with the pulsar PSR J1928+1746, was not detected by any IACT despite their long exposure on the region, until a recent new analysis of H.E.S.S. data was able to confirm it. Moreover, no X-ray counterpart has been detected from this pulsar. We present a multicomponent fit of this region using the latest HAWC data. This reveals an additional new source, HAWC J1932+192, which is potentially associated with the pulsar PSR J1932+1916, whose γ -ray emission could come from the acceleration of particles in its pulsar wind nebula. In the case of 3HWC J1928+178, several possible explanations are explored, in an attempt to unveil the origins of the very-high-energy γ -ray emission.
Published: 2023
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10. HAWC Study of Very-High-Energy $\gamma$-ray Spectrum of HAWC J1844-034

Author: HAWC Collaboration, Albert, A., Alvarez, C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Breuhaus, M., Capistrán, T., Carramiñana, A., Casanova, S., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Depaoli, D., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Fraija, N., García-González, J. A., González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Herzog, I., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Humensky, T. B., Hüntemeyer, P., Joshi, V., Kaufmann, S., Lee, J., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nellen, L., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Villaseñor, L., Wang, X., Watson, I. J., Willox, E., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Recently, the region surrounding eHWC J1842-035 has been studied extensively by gamma-ray observatories due to its extended emission reaching up to a few hundred TeV and potential as a hadronic accelerator. In this work, we use 1,910 days of cumulative data from the High Altitude Water Cherenkov (HAWC) observatory to carry out a dedicated systematic source search of the eHWC J1842-035 region. During the search we have found three sources in the region, namely, HAWC J1844-034, HAWC J1843-032, and HAWC J1846-025. We have identified HAWC J1844-034 as the extended source that emits photons with energies up to 175 TeV. We compute the spectrum for HAWC J1844-034 and by comparing with the observational results from other experiments, we have identified HESS J1843-033, LHAASO J1843-0338, and TASG J1844-038 as very-high-energy gamma-ray sources with a matching origin. Also, we present and use the multi-wavelength data to fit the hadronic and leptonic particle spectra. We have identified four pulsar candidates in the nearby region from which PSR J1844-0346 is found to be the most likely candidate due to its proximity to HAWC J1844-034 and the computed energy budget. We have also found SNR G28.6-0.1 as a potential counterpart source of HAWC J1844-034 for which both leptonic and hadronic scenarios are feasible., Comment: 13 pages, 9 figures, published in ApJ
Published: 2023
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11. Limits on the Diffuse Gamma-Ray Background above 10 TeV with HAWC

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Kieda, D., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., Zhou, H., de León, C., and Álvarez, J. D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The high-energy Diffuse Gamma-Ray Background (DGRB) is expected to be produced by unresolved isotropically distributed astrophysical objects, potentially including dark matter annihilation or decay emissions in galactic or extragalactic structures. The DGRB has only been observed below 1 TeV; above this energy, upper limits have been reported. Observations or stringent limits on the DGRB above this energy could have significant multi-messenger implications, such as constraining the origin of TeV-PeV astrophysical neutrinos detected by IceCube. The High Altitude Water Cherenkov (HAWC) Observatory, located in central Mexico at 4100 m above sea level, is sensitive to gamma rays from a few hundred GeV to several hundred TeV and continuously observes a wide field-of-view (2 sr). With its high-energy reach and large area coverage, HAWC is well-suited to notably improve searches for the DGRB at TeV energies. In this work, strict cuts have been applied to the HAWC dataset to better isolate gamma-ray air showers from background hadronic showers. The sensitivity to the DGRB was then verified using 535 days of Crab data and Monte Carlo simulations, leading to new limits above 10 TeV on the DGRB as well as prospective implications for multi-messenger studies., Comment: 8 pages, 3 figures
Published: 2022

12. A measurement of the proton plus helium spectrum of cosmic rays in the TeV region with HAWC

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Espinoza, C., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kieda, D., Kunde, G. J., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Noriega-Papaqui, R., Omodei, N., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Serna-Franco, J., Smith, A. J., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., Zhou, H., de León, C., Álvarez, J. D., Yodh, G. B., and Zepeda, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: HAWC is an air-shower detector designed to study TeV gamma and cosmic rays. The observatory is composed of a $22000 \, m^2$ array of $300$ water Cherenkov tanks ($4.5 \, m$ deep x $7.3 \, m$ diameter) with $4$ photomultipliers (PMT) each. The instrument registers the number of hit PMTs, the timing information and the total charge at the PMTs during the event. From these data, shower observables such as the arrival direction, the core position at ground, the lateral age and the primary energy are estimated. In this work, we study the distribution of the shower age vs the primary energy of a sample of shower data collected by HAWC from June 2015 to June 2019 and employ a shower-age cut based on predictions of QGSJET-II-04 to separate a subsample of events dominated by H and He primaries. Using these data and a dedicated analysis, we reconstruct the cosmic ray spectrum of H+He from $6$ to $158$ TeV, which shows the presence of a softening at around $24$ TeV with a statistical significance of $4.1\sigma$., Comment: 6 pages, 6 figures, Submission to SciPost Phys. Proc., ISVHECRI 2022 Conference Proceedings
Published: 2022

13. Cosmic ray spectrum of protons plus helium nuclei between 6 TeV and 158 TeV from HAWC data

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Espinoza, C., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kieda, D., Kunde, G. J., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Noriega-Papaqui, R., Omodei, N., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Serna-Franco, J., Smith, A. J., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., Zhou, H., de León, C., Álvarez, J. D., Yodh, G. B., and Zepeda, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A measurement with high statistics of the differential energy spectrum of light elements in cosmic rays, in particular, of primary H plus He nuclei, is reported. The spectrum is presented in the energy range from $6$ to $158$ TeV per nucleus. Data was collected with the High Altitude Water Cherenkov (HAWC) Observatory between June 2015 and June 2019. The analysis was based on a Bayesian unfolding procedure, which was applied on a subsample of vertical HAWC data that was enriched to $82\%$ of events induced by light nuclei. To achieve the mass separation, a cut on the lateral age of air shower data was set guided by predictions of CORSIKA/QGSJET-II-04 simulations. The measured spectrum is consistent with a broken power-law spectrum and shows a kneelike feature at around $E = 24.0^{+3.6}_{-3.1} $ TeV, with a spectral index $\gamma = -2.51 \pm 0.02$ before the break and with $\gamma = -2.83 \pm 0.02$ above it. The feature has a statistical significance of $4.1 \, \sigma$. Within systematic uncertainties, the significance of the spectral break is $0.8 \, \sigma$., Comment: 32 pages, 24 figures, published in Physical Review D
Published: 2022
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14. Study of the Very High Energy emission of M87 through its broadband spectral energy distribution

Author: HAWC Collaboration, Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Joshi, V., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Noriega-Papaqui, R., Omodei, N., Peisker, A., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Salazar-Gallegos, D., Greus, F. Salesa, Sandoval, A., Serna-Franco, J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., and Zepeda, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The radio galaxy M87 is the central dominant galaxy of the Virgo Cluster. Very High Energy (VHE,$\gtrsim 0.1$ TeV) emission, from M87 has been detected by Imaging Air Cherenkov Telescopes (IACTs ). Recently, marginal evidence for VHE long-term emission has also been observed by the High Altitude Water Cherenkov (HAWC) Observatory, a gamma ray and cosmic-ray detector array located in Puebla, Mexico. The mechanism that produces VHE emission in M87 remains unclear. This emission is originated in its prominent jet, which has been spatially resolved from radio to X-rays. In this paper, we constructed a spectral energy distribution from radio to gamma rays that is representative of the non-flaring activity of the source, and in order to explain the observed emission, we fit it with a lepto-hadronic emission model. We found that this model is able to explain non-flaring VHE emission of M87 as well as an orphan flare reported in 2005., Comment: submitted to ApJ
Published: 2021

15. HAWC Study of the Ultra-High-Energy Spectrum of MGRO J1908+06

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Alonso, M. Fernández, Fraija, N., Garcia, D., García-González, J. A., Garfias, F., Giacinti, G., Goksu, H., González, M. M., Goodman, J. A., Harding, J. P., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Watson, I. J., Willox, E., Zepeda, A., Zhou, H., Li, M. Breuhaus H., and Zhang, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report TeV gamma-ray observations of the ultra-high-energy source MGRO J1908+06 using data from the High Altitude Water Cherenkov (HAWC) Observatory. This source is one of the highest-energy known gamma-ray sources, with emission extending past 200 TeV. Modeling suggests that the bulk of the TeV gamma-ray emission is leptonic in nature, driven by the energetic radio-faint pulsar PSR J1907+0602. Depending on what assumptions are included in the model, a hadronic component may also be allowed. Using the results of the modeling, we discuss implications for detection prospects by multi-messenger campaigns., Comment: accepted by ApJ, in press
Published: 2021
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16. HAWC Contributions to the 37th International Cosmic Ray Conference (ICRC2021)

Author: HAWC Collaboration
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Works submitted to the 37th International Cosmic Ray Conference. Contents: Operation, Calibration, and Analysis Galactic Gamma-Ray Physics Extra Galactic Gamma-Ray Physics Cosmic-Ray Physics, Comment: HAWC (High Altitude Water Cherenkov Gamma-Ray Observatory) Contributions to the 37th International Cosmic Ray Conference
Published: 2021

17. Characterization of the background for a neutrino search with the HAWC observatory

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Espinoza, C., Fan, K. L., Fraija, N., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Kieda, D., Lara, A., Lee, W. H., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Nayerhoda, A., Nellen, L., Noriega-Papaqui, R., Omodei, N., Peisker, A., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Sandoval, A., Serna-Franco, J., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Ureña-Mena, F., Villaseñor, L., Zhou, H., and de León, C.
Subjects: High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The close location of the HAWC observatory to the largest volcano in Mexico allows to perform a search for neutrino-induced horizontal muon and tau charged leptons. The section of the volcano located at the horizon reaches values of slant depth larger than 8 km of rock, making it an excellent shield for the cosmic ray horizontal background. We report the search method and background suppression technique developed for the detection of Earth-skimming neutrinos with HAWC, as well as a model that describes the remaining background produced by scattered muons. We show that by increasing the detection energy threshold we could use HAWC to search for neutrino-induced charged leptons., Comment: Replaced with the accepted version. Added the journal reference and DOI
Published: 2021
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18. HAWC Search for High-Mass Microquasars

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velazquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Cotti, U., Cotzomi, J., De la Fuente, E., de Leon, C., Hernandez, R. Diaz, Diaz-Velez, J. C., Dingus, B. L., Durocher, M., DuVernois, M. A., Ellsworth, R. W., Espinoza, C., Fan, K. L., Fang, K., Fraija, N., Galvan-Gamez, A., Garcia-Gonzalez, J. A., Garfias, F., Gonzalez, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Lara, A., Lee, J., Lee, W. H., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Martinez, O., Martinez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Perez, Rho, C. D., Roh, Y. J., Rosa-Gonzalez, D., Greus, F. Salesa, Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Urena-Mena, F., Villasenor, L., Watson, I. J., Weisgarber, T., Willox, E., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Microquasars with high-mass companion stars are promising very-high-energy (VHE; 0.1-100 TeV) gamma-ray emitters, but their behaviors above 10 TeV are poorly known. Using the High Altitude Water Cherenkov (HAWC) observatory, we search for excess gamma-ray emission coincident with the positions of known high-mass microquasars (HMMQs). No significant emission is observed for LS 5039, Cygnus X-1, Cygnus X-3, and SS 433 with 1,523 days of HAWC data. We set the most stringent limit above 10 TeV obtained to date on each individual source. Under the assumption that HMMQs produce gamma rays via a common mechanism, we have performed source-stacking searches, considering two different scenarios: I) gamma-ray luminosity is a fraction $\epsilon_\gamma$ of the microquasar jet luminosity, and II) very-high-energy gamma rays are produced by relativistic electrons up-scattering the radiation field of the companion star in a magnetic field $B$. We obtain $\epsilon_\gamma < 5.4\times 10^{-6}$ for scenario I, which tightly constrains models that suggest observable high-energy neutrino emission by HMMQs. In the case of scenario II, the non-detection of VHE gamma rays yields a strong magnetic field, which challenges synchrotron radiation as the dominant mechanism of the microquasar emission between 10 keV and 10 MeV., Comment: Accepted for publication in ApJL
Published: 2021
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19. Evidence that Ultra-High-Energy Gamma Rays are a Universal Feature Near Powerful Pulsars

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., Galván-Gámez, A., García-González, J. A., Garfias, F., Giacinti, G., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Lara, A., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Roh, Y. J., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Smith, A. J., Springer, R. W., Surajbali, P., Tanner, M., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Weisgarber, T., Willox, E., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The highest-energy known gamma-ray sources are all located within 0.5 degrees of extremely powerful pulsars. This raises the question of whether ultra-high-energy (UHE; $>$ 56 TeV) gamma-ray emission is a universal feature expected near pulsars with a high spin-down power. Using four years of data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, we present a joint-likelihood analysis of ten extremely powerful pulsars to search for UHE gamma-ray emission correlated with these locations. We report a significant detection ($>$ 3$\sigma$), indicating that UHE gamma-ray emission is a generic feature of powerful pulsars. We discuss the emission mechanisms of the gamma rays and the implications of this result. The individual environment that each pulsar is found in appears to play a role in the amount of emission., Comment: accepted by ApJL
Published: 2021
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20. Spectrum and Morphology of the Very-High-Energy Source HAWC J2019+368

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velàzquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistràn, T., Carramiñana, A., Casanova, S., Cotzomi, J., de León, S. Coutinõ, De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Engel, K., Espinoza, C., Fraija, N., Garcia, D., García-González, J. A., Giacinti, G., González, M. M., Goodman, J. A., Harding, J. P., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Huentemeyer, P., Jardin-Blicq, A., Joshi, V., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., López-Coto, R., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-Gonzàlez, D., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Smith, A. J., Springer, R. W., Surajbali, P., Tollefson, K., Torres, I., Turner, R., Urenã-Mena, F., Weisgarber, T., Willox, E., Zhou, H., and de León, C.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The MGRO J2019+37 region is one of the brightest sources in the sky at TeV energies. It was detected in the 2 year HAWC catalog as 2HWC J2019+367 and here we present a detailed study of this region using data from HAWC. This analysis resolves the region into two sources: HAWC J2019+368 and HAWC J2016+371. We associate HAWC J2016+371 with the evolved supernova remnant CTB 87, although its low significance in this analysis prevents a detailed study at this time. An investigation of the morphology (including possible energy dependent morphology) and spectrum for HAWC J2019+368 is the focus of this work. We associate HAWC J2019+368 with PSR J2021+3651 and its X-ray pulsar wind nebula, the Dragonfly nebula. Modeling the spectrum measured by HAWC and Suzaku reveals a $\sim$7 kyr pulsar and nebula system producing the observed emission at X-ray and ${\gamma}$-ray energies., Comment: Submitted to ApJ: 13 pages, 10 figures
Published: 2021

21. Constraints on the Emission of Gamma Rays from M31 with HAWC

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Engel, K., Espinoza, C., Fleischhack, H., Fraija, N., Galván-Gámez, A., García-Aguilar, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Lee, W. H., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Noriega-Papaqui, R., Peisker, A., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rosa-González, D., Rosenberg, M., Rubenzahl, R., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Tabachnick, E., Tibolla, O., Tollefson, K., Torres, I., Villaseñor, L., Wood, J., Yapici, T., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Cosmic rays, along with stellar radiation and magnetic fields, are known to make up a significant fraction of the energy density of galaxies such as the Milky Way. When cosmic rays interact in the interstellar medium, they produce gamma-ray emission which provides an important indication of how the cosmic rays propagate. Gamma rays from the Andromeda Galaxy (M31), located 785 kpc away, provide a unique opportunity to study cosmic-ray acceleration and diffusion in a galaxy with a structure and evolution very similar to the Milky Way. Using 33 months of data from the High Altitude Water Cherenkov Observatory, we search for TeV gamma rays from the galactic plane of M31. We also investigate past and present evidence of galactic activity in M31 by searching for Fermi Bubble-like structures above and below the galactic nucleus. No significant gamma-ray emission is observed, so we use the null result to compute upper limits on the energy density of cosmic rays $>10$ TeV in M31. The computed upper limits are approximately ten times higher than expected from the extrapolation of the Fermi LAT results., Comment: Accepted for publication in ApJ
Published: 2020
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22. Search for Gamma-ray Spectral Lines from Dark Matter Annihilation in Dwarf Galaxies with the High-Altitude Water Cherenkov Observatory

Author: The HAWC Collaboration
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: Local dwarf spheroidal galaxies (dSphs) are nearby dark-matter dominated systems, making them excellent targets for searching for gamma rays from particle dark matter interactions. If dark matter annihilates or decays directly into two gamma rays (or a gamma ray and a neutral particle), a monochromatic spectral line is created. At TeV energies, no other processes are expected to produce spectral lines, making this a very clean indirect dark matter search channel. With the development of event-by-event energy reconstruction, we can now search for spectral lines with the High Altitude Water Cherenkov (HAWC) Observatory. HAWC is a wide field of view survey instrument located in central Mexico that observes gamma rays from <1 TeV to >100 TeV. In this work we present results from a recent search for spectral lines from local, dark matter dominated dwarf galaxies using 1038 days of HAWC data. We also present updated limits on several continuum channels that were reported in a previous publication. Our gamma-ray spectral line limits are the most constraining obtained so far from 20 TeV to 100 TeV., Comment: submitted to PRD
Published: 2019
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23. Constraints on Lorentz invariance violation from HAWC observations of gamma rays above 100 TeV

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fleischhack, H., Fraija, N., Galván-Gámez, A., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., López-Coto, R., Malone, K., Marinelli, S. S., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Pérez-Pérez, E. G., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Tabachnick, E., Tanner, M., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Weisgarber, T., Yodh, G., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Due to the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The High Altitude Water Cherenkov (HAWC) Observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. HAWC finds evidence of 100 TeV photon emission from at least four astrophysical sources. These observations exclude, for the strongest of the limits set, the LIV energy scale to $2.2\times10^{31}$ eV, over 1800 times the Planck energy and an improvement of 1 to 2 orders of magnitude over previous limits., Comment: Accepted for publication in Physical Review Letters
Published: 2019
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24. Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

Author: HAWC Collaboration, Abeysekara, A. U., Albert, A., Alfaro, R., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fleischhack, H., Fraija, N., Galván-Gámez, A., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Peisker, A., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Tabachnick, E., Tanner, M., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Villaseñor, L., Weisgarber, T., Wood, J., Yapici, T., Zhang, H., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov (HAWC) Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely Galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons., Comment: Accepted by Physical Review Letters
Published: 2019
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25. Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC

Author: HAWC Collaboration, Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Acero, R., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Cabellero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fick, B., Fleischhack, H., Fraija, N., Galván-Gámez, A., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Peisker, A., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Tabachnick, E., Tanner, M., Tibolla, O., Tollefson, K., Torres, I., Weisgarber, T., Westerhoff, S., Wood, J., Yapici, T., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: We present TeV gamma-ray observations of the Crab Nebula, the standard reference source in ground-based gamma-ray astronomy, using data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. In this analysis we use two independent energy-estimation methods that utilize extensive air shower variables such as the core position, shower angle, and shower lateral energy distribution. In contrast, the previously published HAWC energy spectrum roughly estimated the shower energy with only the number of photomultipliers triggered. This new methodology yields a much improved energy resolution over the previous analysis and extends HAWC's ability to accurately measure gamma-ray energies well beyond 100 TeV. The energy spectrum of the Crab Nebula is well fit to a log parabola shape $\left(\frac{dN}{dE} = \phi_0 \left(E/\textrm{7 TeV}\right)^{-\alpha-\beta\ln\left(E/\textrm{7 TeV}\right)}\right)$ with emission up to at least 100 TeV. For the first estimator, a ground parameter that utilizes fits to the lateral distribution function to measure the charge density 40 meters from the shower axis, the best-fit values are $\phi_o$=(2.35$\pm$0.04$^{+0.20}_{-0.21}$)$\times$10$^{-13}$ (TeV cm$^2$ s)$^{-1}$, $\alpha$=2.79$\pm$0.02$^{+0.01}_{-0.03}$, and $\beta$=0.10$\pm$0.01$^{+0.01}_{-0.03}$. For the second estimator, a neural network which uses the charge distribution in annuli around the core and other variables, these values are $\phi_o$=(2.31$\pm$0.02$^{+0.32}_{-0.17}$)$\times$10$^{-13}$ (TeV cm$^2$ s)$^{-1}$, $\alpha$=2.73$\pm$0.02$^{+0.03}_{-0.02}$, and $\beta$=0.06$\pm$0.01$\pm$0.02. The first set of uncertainties are statistical; the second set are systematic. Both methods yield compatible results. These measurements are the highest-energy observation of a gamma-ray source to date., Comment: published in ApJ
Published: 2019
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26. All-Sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., Díaz-Vélez, J. C., De León, C., De la Fuente, E., Dichiara, S., DuVernois, M. A., Espinoza, C., Fiorino, D. W., Fleischhack, H., Fraija, N., Galván-Gámez, A., García-González, J. A., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hona, B., Hueyotl-Zahuantitla, F., Iriarte, A., Jardin-Blicq, A., Joshi, V., Lara, A., Vargas, H. León, Luis-Raya, G., Malone, K., Marinelli, S. S., Martínez-Castro, J., Martinez, O., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Surajbali, P., Taboada, I., Tollefson, K., Torres, I., Villaseño, L., Weisgarber, T., Wood, J., Zepeda, A., Zhou, H., Collaboration, IceCube, Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., Altmann, D., Andeen, K., Anderson, T., Ansseau, I., Anton, G., Argüelles, C., Auffenberg, J., Axani, S., Backes, P., Bagherpour, H., Bai, X., Barbano, A., Barron, J. P., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Becker, K. -H., Tjus, J. Becker, BenZvi, S., Berley, D., Bernardini, E., Besson, D. Z., Binder, G., Bindig, D., Blaufuss, E., Blot, S., Bohm, C., Börner, M., Bos, F., Böser, S., Botner, O., Bourbeau, E., Bourbeau, J., Bradascio, F., Braun, J., Bretz, H. -P., Bron, S., Brostean-Kaiser, J., Burgman, A., Busse, R. S., Carver, T., Chen, C., Cheung, E., Chirkin, D., Clark, K., Classen, L., Collin, G. H., Conrad, J. M., Coppin, P., Correa, P., Cowen, D. F., Cross, R., Dave, P., Day, M., de André, J. P. A. M., De Clercq, C., DeLaunay, J. J., Dembinski, H., Deoskar, K., De Ridder, S., Desiati, P., de Vries, K. D., de Wasseige, G., de With, M., DeYoung, T., Dujmovic, H., Dunkman, M., Dvorak, E., Eberhardt, B., Ehrhardt, T., Eichmann, B., Eller, P., Evenson, P. A., Fahey, S., Fazely, A. R., Felde, J., Filimonov, K., Finley, C., Franckowiak, A., Friedman, E., Fritz, A., Gaisser, T. K., Gallagher, J., Ganster, E., Garrappa, S., Gerhardt, L., Ghorbani, K., Giang, W., Glauch, T., Glüsenkamp, T., Goldschmidt, A., Gonzalez, J. G., Grant, D., Griffith, Z., Haack, C., Hallgren, A., Halve, L., Halzen, F., Hanson, K., Hebecker, D., Heereman, D., Helbing, K., Hellauer, R., Hickford, S., Hignight, J., Hill, G. C., Hoffman, K. D., Hoffmann, R., Hoinka, T., Hokanson-Fasig, B., Hoshina, K., Huang, F., Huber, M., Hultqvist, K., Hünnefeld, M., Hussain, R., In, S., Iovine, N., Ishihara, A., Jacobi, E., Japaridze, G. S., Jeong, M., Jero, K., Jones, B. J. P., Kalaczynski, P., Kang, W., Kappes, A., Kappesser, D., Karg, T., Karle, A., Katz, U., Kauer, M., Keivani, A., Kelley, J. L., Kheirandish, A., Kim, J., Kintscher, T., Kiryluk, J., Kittler, T., Klein, S. R., Koirala, R., Kolanoski, H., Köpke, L., Kopper, C., Kopper, S., Koskinen, D. J., Kowalski, M., Krings, K., Kroll, M., Krückl, G., Kunwar, S., Kurahashi, N., Kyriacou, A., Labare, M., Lanfranchi, J. L., Larson, M. J., Lauber, F., Leonard, K., Leuermann, M., Liu, Q. R., Lohfink, E., Mariscal, C. J. Lozano, Lu, L., Lünemann, J., Luszczak, W., Madsen, J., Maggi, G., Mahn, K. B. M., Makino, Y., Mancina, S., Mariş, I. C., Maruyama, R., Mase, K., Maunu, R., Meagher, K., Medici, M., Medina, A., Meier, M., Menne, T., Merino, G., Meures, T., Miarecki, S., Micallef, J., Momenté, G., Montaruli, T., Moore, R. W., Moulai, M., Nagai, R., Nahnhauer, R., Nakarmi, P., Naumann, U., Neer, G., Niederhausen, H., Nowicki, S. C., Nygren, D. R., Pollmann, A. Obertacke, Olivas, A., O'Murchadha, A., O'Sullivan, E., Palczewski, T., Pandya, H., Pankova, D. V., Peiffer, P., Heros, C. Pérez de los, Pieloth, D., Pinat, E., Pizzuto, A., Plum, M., Price, P. B., Przybylski, G. T., Raab, C., Raissi, A., Rameez, M., Rauch, L., Rawlins, K., Rea, I. C., Reimann, R., Relethford, B., Renzi, G., Resconi, E., Rhode, W., Richman, M., Robertson, S., Rongen, M., Rott, C., Ruhe, T., Ryckbosch, D., Rysewyk, D., Safa, I., Herrera, S. E. Sanchez, Sandrock, A., Sandroos, J., Santander, M., Sarkar, S., Satalecka, K., Schaufel, M., Schlunder, P., Schmidt, T., Schneider, A., Schneider, J., Schöneberg, S., Schumacher, L., Sclafani, S., Seckel, D., Seunarine, S., Soedingrekso, J., Soldin, D., Song, M., Spiczak, G. M., Spiering, C., Stachurska, J., Stamatikos, M., Stanev, T., Stasik, A., Stein, R., Stettner, J., Steuer, A., Stezelberger, T., Stokstad, R. G., Stößl, A., Strotjohann, N. L., Stuttard, T., Sullivan, G. W., Sutherland, M., Tenholt, F., Ter-Antonyan, S., Terliuk, A., Tilav, S., Tobin, M. N., Tönnis, C., Toscano, S., Tosi, D., Tselengidou, M., Tung, C. F., Turcati, A., Turcotte, R., Turley, C. F., Ty, B., Unger, E., Elorrieta, M. A. Unland, Usner, M., Vandenbroucke, J., Van Driessche, W., van Eijk, D., van Eijndhoven, N., Vanheule, S., van Santen, J., Vraeghe, M., Walck, C., Wallace, A., Wallraff, M., Wandkowsky, N., Wandler, F. D., Watson, T. B., Weaver, C., Weiss, M. J., Weldert, J., Wendt, C., Werthebach, J., Westerhoff, S., Whelan, B. J., Whitehorn, N., Wiebe, K., Wiebusch, C. H., Wille, L., Williams, D. R., Wills, L., Wolf, M., Wood, T. R., Woolsey, E., Woschnagg, K., Wrede, G., Xu, D. L., Xu, X. W., Xu, Y., Yanez, J. P., Yodh, G., Yoshida, S., and Yuan, T.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the first full-sky analysis of the cosmic ray arrival direction distribution with data collected by the HAWC and IceCube observatories in the Northern and Southern hemispheres at the same median primary particle energy of 10 TeV. The combined sky map and angular power spectrum largely eliminate biases that result from partial sky coverage and holds a key to probe into the propagation properties of TeV cosmic rays through our local interstellar medium and the interaction between the interstellar and heliospheric magnetic fields. From the map we determine the horizontal dipole components of the anisotropy $\delta_{0h} = 9.16 \times 10^{-4}$ and $\delta_{6h} = 7.25 \times 10^{-4}~(\pm0.04 \times 10^{-4})$. In addition, we infer the direction ($229.2\pm 3.5^\circ$ RA , $11.4\pm 3.0^\circ$ Dec.) of the interstellar magnetic field from the boundary between large scale excess and deficit regions from which we estimate the missing corresponding vertical dipole component of the large scale anisotropy to be $\delta_N \sim -3.97 ^{+1.0}_{-2.0} \times 10^{-4}$., Comment: Accepted by The Astrophysical Journal
Published: 2018
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27. Very high energy particle acceleration powered by the jets of the microquasar SS 433

Author: HAWC Collaboration, Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., De la Fuente, E., Díaz-Vélez, J. C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Engel, K., Espinoza, C., Fang, K., Fleischhack, H., Fraija, N., Galván-Gámez, A., García-González, J. A., Garfias, F., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hinton, J., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kar, P., Kunde, G. J., Lauer, R. J., Lee, W. H., Vargas, H. León, Li, H., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Vianello, G., Villaseñor, L., Weisgarber, T., Werner, F., Westerhoff, S., Wood, J., Yapici, T., Yodh, G., Zepeda, A., Zhang, H., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star). Two jets of ionized matter with a bulk velocity of $\sim0.26c$ extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets. SS 433 differs from other microquasars in that the accretion is believed to be super-Eddington, and the luminosity of the system is $\sim10^{40}$ erg s$^{-1}$. The lobes of W50 in which the jets terminate, about 40 pc from the central source, are expected to accelerate charged particles, and indeed radio and X-ray emission consistent with electron synchrotron emission in a magnetic field have been observed. At higher energies (>100 GeV), the particle fluxes of $\gamma$ rays from X-ray hotspots around SS 433 have been reported as flux upper limits. In this energy regime, it has been unclear whether the emission is dominated by electrons that are interacting with photons from the cosmic microwave background through inverse-Compton scattering or by protons interacting with the ambient gas. Here we report TeV $\gamma$-ray observations of the SS 433/W50 system where the lobes are spatially resolved. The TeV emission is localized to structures in the lobes, far from the center of the system where the jets are formed. We have measured photon energies of at least 25 TeV, and these are certainly not Doppler boosted, because of the viewing geometry. We conclude that the emission from radio to TeV energies is consistent with a single population of electrons with energies extending to at least hundreds of TeV in a magnetic field of $\sim16$~micro-Gauss., Comment: Preprint version of Nature paper. Contacts: S. BenZvi, B. Dingus, K. Fang, C.D. Rho , H. Zhang, H. Zhou
Published: 2018
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28. All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

Author: HAWC Collaboration, Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Barber, A. S., Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., De la Fuente, E., Hernandez, R. Diaz, Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., García-González, J. A., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez-Almada, A., Hinton, J., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Raya, G. Luis, Luna-García, R., López-Cámara, D., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wood, J., Yapici, T., Zepeda, A., Zhou, H., and Álvarez, J. D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of $-2.49\pm0.01$ prior to a break at $(45.7\pm0.1$) TeV, followed by an index of $-2.71\pm0.01$. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy., Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review D
Published: 2017
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29. Data Acquisition Architecture and Online Processing System for the HAWC gamma-ray observatory

Author: HAWC collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Gonzalez, J. Becerra, Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Rosales, M. Bonilla, Braun, J., Caballero-Lopez, R. A., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Diaz-Cruz, J., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Hampel-Arias, Z., Harding, J. P., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linares, E. C., Linnemann, J. T., Proper, M. Longo, Luna-García, R., Malone, K., Marinelli, A., Marinelli, S. S., Martinez, O., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A. J., McEnery, J., Torres, E. Mendoza, Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Ruiz-Velasco, E., Ryan, J., Salazar, H., Greus, F. Salesa, Sanchez, F. E., Sandoval, A., Schneider, M., Silich, S., Sinni, G., Smith, A. J., Woodle, K. Sparks, Springer, R. W., Taboada, I., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The High Altitude Water Cherenkov observatory (HAWC) is an air shower array devised for TeV gamma-ray astronomy. HAWC is located at an altitude of 4100 m a.s.l. in Sierra Negra, Mexico. HAWC consists of 300 Water Cherenkov Detectors, each instrumented with 4 photomultiplier tubes (PMTs). HAWC re-uses the Front-End Boards from the Milagro experiment to receive the PMT signals. These boards are used in combination with Time to Digital Converters (TDCs) to record the time and the amount of light in each PMT hit (light flash). A set of VME TDC modules (128 channels each) is operated in a continuous (dead time free) mode. The TDCs are read out via the VME bus by Single-Board Computers (SBCs), which in turn are connected to a gigabit Ethernet network. The complete system produces ~ 500 MB/s of raw data. A high-throughput data processing system has been designed and built to enable real-time data analysis. The system relies on off-the-shelf hardware components, an open-source software technology for data transfers (ZeroMQ) and a custom software framework for data analysis (AERIE). Multiple trigger and reconstruction algorithms can be combined and run on blocks of data in a parallel fashion, producing a set of output data streams which can be analyzed in real time with minimal latency (< 5 s). This paper provides an overview of the hardware set-up and an in-depth description of the software design, covering both the TDC data acquisition system and the real-time data processing system. The performance of these systems is also discussed., Comment: 14 pages, 3 figures, submitted to Nucl. Instrum. Meth. A
Published: 2017
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30. Combined Analysis of Cosmic-Ray Anisotropy with IceCube and HAWC

Author: The HAWC Collaboration and The IceCube Collaboration
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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., Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contributions, (1) http://www.hawc-observatory.org/collaboration/icrc2017.php, (2) http://icecube.wisc.edu/collaboration/authors/icrc17_icecube
Published: 2017

31. Search for very-high-energy emission from Gamma-ray Bursts using the first 18 months of data from the HAWC Gamma-ray Observatory

Author: The HAWC collaboration, Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Barber, A. S., Bautista-Elivar, N., Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Fiorino, D. W., Fraija, N., García-González, J. A., Garfias, F., Gerhardt, M., Muñoz, A. González, González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez-Almada, A., Hernandez, S., Hona, B., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Raya, G. Luis, Luna-García, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Noriega-Papaqui, R., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Weisgarber, T., Westerhoff, S., Wood, J., Yapici, T., Younk, P. W., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory is an extensive air shower detector operating in central Mexico, which has recently completed its first two years of full operations. If for a burst like GRB 130427A at a redshift of 0.34 and a high-energy component following a power law with index -1.66, the high-energy component is extended to higher energies with no cut-off other than from extragalactic background light attenuation, HAWC would observe gamma rays with a peak energy of $\sim$300 GeV. This paper reports the results of HAWC observations of 64 gamma-ray bursts (GRBs) detected by $\mathit{Swift}$ and $\mathit{Fermi}$, including three GRBs that were also detected by the Large Area Telescope ($\mathit{Fermi}$-LAT). An ON/OFF analysis method is employed, searching on the time scale given by the observed light curve at keV-MeV energies and also on extended time scales. For all GRBs and time scales, no statistically significant excess of counts is found and upper limits on the number of gamma rays and the gamma-ray flux are calculated. GRB 170206A, the third brightest short GRB detected by the Gamma-ray Burst Monitor on board the $\mathit{Fermi}$ satellite ($\mathit{Fermi}$-GBM) and also detected by the LAT, occurred very close to zenith. The LAT measurements can neither exclude the presence of a synchrotron self-Compton (SSC) component nor constrain its spectrum. Instead, the HAWC upper limits constrain the expected cut-off in an additional high-energy component to be less than $100~\rm{GeV}$ for reasonable assumptions about the energetics and redshift of the burst., Comment: 19 pages, 6 figures, published in ApJ
Published: 2017
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32. Full-Sky Analysis of Cosmic-Ray Anisotropy with IceCube and HAWC

Author: The HAWC Collaboration and The IceCube Collaboration
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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. The relative amplitude of the anisotropy is $10^{-4} - 10^{-3}$. However, each of these individual measurements is restricted by limited sky coverage, and so the pseudo-power spectrum of the anisotropy obtained from any one measurement displays a systematic correlation between different multipole modes $C_\ell$. To address this issue, we present the preliminary status of a joint analysis of the anisotropy on all angular scales using cosmic-ray data from the IceCube Neutrino Observatory located at the South Pole ($90^\circ$ S) and the High-Altitude Water Cherenkov (HAWC) Observatory located at Sierra Negra, Mexico ($19^\circ$ N). 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., Comment: (1) http://www.hawc-observatory.org/collaboration/icrc2015.php, (2) http://icecube.wisc.edu/collaboration/authors/icrc15_icecube Presented at the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. See arXiv:1508.03327 for all HAWC contributions
Published: 2015

33. HAWC Contributions to the 34th International Cosmic Ray Conference (ICRC2015)

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Gonzalez, J. Becerra, Becerril, A., Belmont, E., BenZvi, S. Y., Berley, D., Bernal, A., Braun, J., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Diaz-Cruz, L., Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Engel, K., Enriquez-Rivera, O., Fick, B., Fiorino, D. W., Flores, J. L., Fraija, N., Garcia-Torales, G., Garfias, F., González, M. M., Goodman, J. A., Gussert, M., Hampel-Arias, Z., Hansen, P., Harding, J. Patrick, Hernandez, S., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Proper, M. Longo, Raya, G. Luis, Luna-García, R., Malone, K., Marinelli, A., Marinelli, S. S., Martinez, H., Martinez, O., Martínez-Castro, J., Matthews, J. A. J., McEnery, J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. Un, Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Sinnis, G., Smith, A. J., Smith, A. W., Woodle, K. Sparks, Springer, R. W., Taboada, I., Tibolla, O., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: List of proceedings from the HAWC Collaboration presented at the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands., Comment: List of proceedings from the HAWC Collaboration presented at ICRC2015. Follow the "HTML" link to access the list
Published: 2015

34. Search for gamma-rays from the unusually bright GRB 130427A with the HAWC Gamma-ray Observatory

Author: The HAWC collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., BenZvi, S. Y., Rosales, M. Bonilla, Braun, J., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, M. M., Goodman, J. A., Gussert, M., Hampel-Arias, Z., Harding, J. P., Hüntemeyer, P., Hui, C. M., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longo, M., Luna-García, R., Malone, K., Marinelli, A., Marinelli, S. S., Martinez, H., Martinez, O., Martínez-Castro, J., Matthews, J. A., Torres, E. Mendoza, Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T. O., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Sinnis, G., Smith, A. J., Woodle, K. Sparks, Springer, R. W., Taboada, I., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The first limits on the prompt emission from the long gamma-ray burst (GRB) 130427A in the $>100\nobreakspace\rm{GeV}$ energy band are reported. GRB 130427A was the most powerful burst ever detected with a redshift $z\lesssim0.5$ and featured the longest lasting emission above $100\nobreakspace\rm{MeV}$. The energy spectrum extends at least up to $95\nobreakspace\rm{GeV}$, clearly in the range observable by the High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory, a new extensive air shower detector currently under construction in central Mexico. The burst occurred under unfavourable observation conditions, low in the sky and when HAWC was running 10% of the final detector. Based on the observed light curve at MeV-GeV energies, eight different time periods have been searched for prompt and delayed emission from this GRB. In all cases, no statistically significant excess of counts has been found and upper limits have been placed. It is shown that a similar GRB close to zenith would be easily detected by the full HAWC detector, which will be completed soon. The detection rate of the full HAWC detector may be as high as one to two GRBs per year. A detection could provide important information regarding the high energy processes at work and the observation of a possible cut-off beyond the $\mathit{Fermi}$-LAT energy range could be the signature of gamma-ray absorption, either in the GRB or along the line of sight due to the extragalactic background light., Comment: 10 pages, 4 figures, published in ApJ
Published: 2014
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35. The HAWC Gamma-Ray Observatory: Observations of Cosmic Rays

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Belmont, E., BenZvi, S. Y., Berley, D., Rosales, M. Bonilla, Braun, J., Caballero-Lopez, R. A., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fernandez, A., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Hampel-Arias, Z., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linares, E. C., Linnemann, J. T., Longo, M., Luna-GarcIa, R., Marinelli, A., Martinez, H., Martinez, O., Martínez-Castro, J., Matthews, J. A. J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Salazar, H., Salesa, F., Sanchez, F. E., Sandoval, A., Santos, E., Schneider, M., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, R. W., Taboada, I., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We describe measurements of GeV and TeV cosmic rays with the High-Altitude Water Cherenkov Gamma-Ray Observatory, or HAWC. The measurements include the observation of the shadow of the moon; the observation of small-scale and large-scale angular clustering of the TeV cosmic rays; the prospects for measurement of transient solar events with HAWC; and the observation of Forbush decreases with the HAWC engineering array and HAWC-30., Comment: Contributions to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013
Published: 2013

36. The HAWC Gamma-Ray Observatory: Dark Matter, Cosmology, and Fundamental Physics

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Belmont, E., BenZvi, S. Y., Berley, D., Rosales, M. Bonilla, Braun, J., Caballero-Lopez, R. A., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fernandez, A., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Hampel-Arias, Z., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linares, E. C., Linnemann, J. T., Longo, M., Luna-GarcIa, R., Marinelli, A., Martinez, H., Martinez, O., Martínez-Castro, J., Matthews, J. A. J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Salazar, H., Salesa, F., Sanchez, F. E., Sandoval, A., Santos, E., Schneider, M., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, R. W., Taboada, I., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The High-Altitude Water Cherenkov Gamma Ray Observatory (HAWC) is designed to perform a synoptic survey of the TeV sky. The high energy coverage of the experiment will enable studies of fundamental physics beyond the Standard Model, and the large field of view of the detector will enable detailed studies of cosmologically significant backgrounds and magnetic fields. We describe the sensitivity of the full HAWC array to these phenomena in five contributions shown at the 33rd International Cosmic Ray Conference in Rio de Janeiro, Brazil (July 2013)., Comment: Contributions to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013
Published: 2013

37. The HAWC Gamma-Ray Observatory: Design, Calibration, and Operation

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Belmont, E., BenZvi, S. Y., Berley, D., Rosales, M. Bonilla, Braun, J., Caballero-Lopez, R. A., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fernandez, A., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Hampel-Arias, Z., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linares, E. C., Linnemann, J. T., Longo, M., Luna-GarcIa, R., Marinelli, A., Martinez, H., Martinez, O., Martínez-Castro, J., Matthews, J. A. J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Salazar, H., Salesa, F., Sanchez, F. E., Sandoval, A., Santos, E., Schneider, M., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, R. W., Taboada, I., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: The High-Altitude Water Cherenkov Gamma Ray Observatory (HAWC) is under construction 4100 meters above sea level at Sierra Negra, Mexico. We describe the design and cabling of the detector, the characterization of the photomultipliers, and the timing calibration system. We also outline a next-generation detector based on the water Cherenkov technique., Comment: Contributions to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013
Published: 2013

38. The HAWC Gamma-Ray Observatory: Sensitivity to Steady and Transient Sources of Gamma Rays

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., Álvarez, J. D., Arceo, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Belmont, E., BenZvi, S. Y., Berley, D., Rosales, M. Bonilla, Braun, J., Caballero-Lopez, R. A., Caballero-Mora, K. S., Carramiñana, A., Castillo, M., Cotti, U., Cotzomi, J., de la Fuente, E., De León, C., DeYoung, T., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Fernandez, A., Fiorino, D. W., Fraija, N., Galindo, A., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Hampel-Arias, Z., Hui, C. M., Hüntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linares, E. C., Linnemann, J. T., Longo, M., Luna-GarcIa, R., Marinelli, A., Martinez, H., Martinez, O., Martínez-Castro, J., Matthews, J. A. J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., Pérez-Pérez, E. G., Pretz, J., Rivière, C., Rosa-González, D., Salazar, H., Salesa, F., Sanchez, F. E., Sandoval, A., Santos, E., Schneider, M., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, R. W., Taboada, I., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Younk, P. W., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is designed to record air showers produced by cosmic rays and gamma rays between 100 GeV and 100 TeV. Because of its large field of view and high livetime, HAWC is well-suited to measure gamma rays from extended sources, diffuse emission, and transient sources. We describe the sensitivity of HAWC to emission from the extended Cygnus region as well as other types of galactic diffuse emission; searches for flares from gamma-ray bursts and active galactic nuclei; and the first measurement of the Crab Nebula with HAWC-30., Comment: Contributions to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013
Published: 2013

39. On the sensitivity of the HAWC observatory to gamma-ray bursts

Author: HAWC collaboration, Abeysekara, A. U., Aguilar, J. A., Aguilar, S., Alfaro, R., Almaraz, E., Álvarez, C., Álvarez-Romero, J. de D., Álvarez, M., Arceo, R., Arteaga-Velázquez, J. C., Badillo, C., Barber, A., Baughman, B. M., Bautista-Elivar, N., Belmont, E., Benítez, E., BenZvi, S. Y., Berley, D., Bernal, A., Bonamente, E., Braun, J., Caballero-Lopez, R., Cabrera, I., Carramiñana, A., Carrasco, L., Castillo, M., Chambers, L., Conde, R., Condreay, P., Cotti, U., Cotzomi, J., D'Olivo, J. C., de la Fuente, E., De León, C., Delay, S., Delepine, D., DeYoung, T., Diaz, L., Diaz-Cruz, L., Dingus, B. L., Duvernois, M. A., Edmunds, D., Ellsworth, R. W., Fick, B., Fiorino, D. W., Flandes, A., Fraija, N. I., Galindo, A., García-Luna, J. L., García-Torales, G., Garfias, F., González, L. X., González, M. M., Goodman, J. A., Grabski, V., Gussert, M., Guzmán-Ceron, C., Hampel-Arias, Z., Harris, T., Hays, E., Hernandez-Cervantes, L., Hüntemeyer, P. H., Imran, A., Iriarte, A., Jimenez, J. J., Karn, P., Kelley-Hoskins, N., Kieda, D., Langarica, R., Lara, A., Lauer, R., Lee, W. H., Linares, E. C., Linnemann, J. T., Longo, M., Luna-García, R., Martínez, H., Martínez, J., Martínez, L. A., Martínez, O., Martínez-Castro, J., Martos, M., Matthews, J., McEnery, J. E., Medina-Tanco, G., Mendoza-Torres, J. E., Miranda-Romagnoli, P. A., Montaruli, T., Moreno, E., Mostafa, M., Napsuciale, M., Nava, J., Nellen, L., Newbold, M., Noriega-Papaqui, R., Oceguera-Becerra, T., Tapia, A. Olmos, Orozco, V., Pérez, V., Pérez-Pérez, E. G., Perkins, J. S., Pretz, J., Ramirez, C., Ramírez, I., Rebello, D., Rentería, A., Reyes, J., Rosa-González, D., Rosado, A., Ryan, J. M., Sacahui, J. R., Salazar, H., Salesa, F., Sandoval, A., Santos, E., Schneider, M., Shoup, A., Silich, S., Sinnis, G., Smith, A. J., Sparks, K., Springer, W., Suárez, F., Suarez, N., Taboada, I., Tellez, A. F., Tenorio-Tagle, G., Tepe, A., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Valdes-Galicia, J., Vanegas, P., Vasileiou, V., Vázquez, O., Vázquez, X., Villaseñor, L., Wall, W., Walters, J. S., Warner, D., Westerhoff, S., Wisher, I. G., Wood, J., Yodh, G. B., Zaborov, D., and Zepeda, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles.
Published: 2011
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40. The energy spectrum of the H+He mass group of cosmic rays in the TeV region measured with HAWC

Author: Juan Carlos Arteaga Velazquez and Hawc Collaboration
Published: 2023
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41. The High Altitude Water Čerenkov (HAWC) TeV Gamma Ray Observatory

Author: The HAWC Collaboration, de la Fuente, Eduardo, Oceguera–Becerra, Tomas, García–Torales, Guillermo, García–Luna, José Luis, Torres, Diego F., editor, and Reimer, Olaf, editor
Published: 2013
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42. Multiwavelength follow-up of a rare IceCube neutrino multiplet

Author: Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, IceCube Collaboration, ASAS-SN, The Astrophysical Multimessenger Observatory Network, Fermi, HAWC Collaboration, LCO, MASTER, Swift, VERITAS, Arguelles Delgado, Carlos A, Axani, Spencer Nicholas, Collin, G. H., Conrad, Janet Marie, Jones, B.J.P., Moulai, Marjon H., Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, IceCube Collaboration, ASAS-SN, The Astrophysical Multimessenger Observatory Network, Fermi, HAWC Collaboration, LCO, MASTER, Swift, VERITAS, Arguelles Delgado, Carlos A, Axani, Spencer Nicholas, Collin, G. H., Conrad, Janet Marie, Jones, B.J.P., and Moulai, Marjon H.
Abstract: © 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.
Published: 2022

43. Study of the Very High Energy emission of M87 through its broadband spectral energy distribution

Author: HAWC Collaboration, Alfaro, R., Alvarez, C., Arteaga-Velázquez, J., Rojas, D., Solares, H., Belmont-Moreno, E., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S., De la Fuente, E., de León, C., Hernandez, R., DuVernois, M., Durocher, M., Díaz-Vélez, J., Espinoza, C., Fan, K., Alonso, M., Fraija, N., García-González, J., Garfias, F., González, M., Goodman, J., Harding, J., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Joshi, V., Vargas, H., Linnemann, J., Longinotti, A., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Noriega-Papaqui, R., Omodei, N., Peisker, A., Pérez-Pérez, E., Rho, C., Rosa-González, D., Salazar, H., Salazar-Gallegos, D., Greus, F., Sandoval, A., Serna-Franco, J., Son, Y., Springer, R., Tibolla, O., Tollefson, K., Torres, I., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., and Zepeda, A.
Subjects: HAWC - Abteilung Hinton
Abstract: The radio galaxy M87 is the central dominant galaxy of the Virgo Cluster.Very High Energy (VHE,$\gtrsim 0.1$ TeV) emission, from M87 has been detectedby Imaging Air Cherenkov Telescopes (IACTs ). Recently, marginal evidence forVHE long-term emission has also been observed by the High Altitude WaterCherenkov (HAWC) Observatory, a gamma ray and cosmic-ray detector array locatedin Puebla, Mexico. The mechanism that produces VHE emission in M87 remainsunclear. This emission is originated in its prominent jet, which has beenspatially resolved from radio to X-rays. In this paper, we constructed aspectral energy distribution from radio to gamma rays that is representative ofthe non-flaring activity of the source, and in order to explain the observedemission, we fit it with a lepto-hadronic emission model. We found that thismodel is able to explain non-flaring VHE emission of M87 as well as an orphanflare reported in 2005.
Published: 2022

44. The High-Altitude Water Cherenkov Observatory

Author: Mostafá, Miguel A. and for the HAWC Collaboration
Published: 2014
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45. Constraints on spin-dependent dark matter scattering with long-lived mediators from TeV observations of the Sun with HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Avila Rojas, D., Ayala Solares, H. A., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotzomi, J., Coutiño de León, S., De León, C., De la Fuente, E., Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Engel, K., Enríquez-Rivera, O., Espinoza, C., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hona, B., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., León Vargas, H., Luis-Raya, G., Lundeen, J., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Salesa Greus, F., Sandoval, A., Schneider, M., Seglar Arroyo, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Zepeda, A., Zhou, H., Álvarez, J. D., Beacom, J. F., Linden, T., Ng, K. C. Y., Peter, A. H. G., Zhou, B., HAWC Collaboration, Leane, Rebecca K, Massachusetts Institute of Technology. Center for Theoretical Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Leane, Rebecca K, and HAWC Collaboration
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), HAWC - Abteilung Hinton, Elastic scattering, Physics, Annihilation, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Physics beyond the Standard Model, Dark matter, Gamma ray, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Astrophysics - Solar and Stellar Astrophysics, WIMP, Orders of magnitude (time), 13. Climate action, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010306 general physics, Solar and Stellar Astrophysics (astro-ph.SR), Cherenkov radiation
Abstract: We analyze the Sun as a source for the indirect detection of dark matter through a search for gamma rays from the solar disk. Capture of dark matter by elastic interactions with the solar nuclei followed by annihilation to long-lived mediators can produce a detectable gamma-ray flux. We search 3 years of data from the High Altitude Water Cherenkov (HAWC) observatory and find no statistically significant detection of TeV gamma-ray emission from the Sun. Using this, we constrain the spin-dependent elastic scattering cross section of dark matter with protons for dark matter masses above 1 TeV, assuming a sufficiently long-lived mediator. The results complement constraints obtained from Fermi-LAT observations of the Sun and together cover WIMP masses between 4 and 10^{6} GeV. In the optimal scenario, the cross-section constraints for mediator decays to gamma rays can be as strong as ∼10^{-45} cm^{2}, which is more than 4 orders of magnitude stronger than current direct-detection experiments for a 1 TeV dark matter mass. The cross-section constraints at higher masses are even better, nearly 7 orders of magnitude better than the current direct-detection constraints for a 100 TeV dark matter mass. This demonstration of sensitivity encourages detailed development of theoretical models in light of these powerful new constraints., United States. Department of Energy (Grant DESC00012567), United States. Department of Energy (Grant DE-SC0013999)
Published: 2018
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46. Unbiased Long-Term Monitoring at TeV Energies

Author: González, María Magdalena, Dorner, Daniela, Bretz, Thomas, Garcia-Gonzalez, Jose Andres, FACT Collaboration, HAWC Collaboration, and M[at]TE Collaboration
Subjects: ddc:520
Abstract: Galaxies 7(2), 51 (2019). doi:10.3390/galaxies7020051, Published by MDPI, Basel
Published: 2019
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47. All-sky Measurement of the Anisotropy of Cosmic Rays at 10 TeV and Mapping of the Local Interstellar Magnetic Field

Author: HAWC Collaboration, Abeysekara, A. U., Brisbois, C., Becker, K. -H., Tjus, J. Becker, BenZvi, S., Berley, D., Bernardini, E., Besson, D. Z., Binder, G., Bindig, D., Blaufuss, E., Blot, S., Capistrán, T., Bohm, C., Börner, M., Bos, F., Böser, S., Botner, O., Bourbeau, E., Bourbeau, J., Bradascio, F., Braun, J., Bretz, Hans-Peter, Carramiñana, A., Bron, S., Brostean-Kaiser, J., Burgman, A., Busse, R. S., Carver, T., Chen, C., Cheung, E., Chirkin, D., Clark, K., Classen, L., Casanova, S., Collin, G. H., Conrad, J. M., Coppin, P., Correa, P., Cowen, D. F., Cross, R., Dave, P., Day, M., de André, J. P. A. M., De Clercq, C., Cotti, U., DeLaunay, J. J., Dembinski, H., Deoskar, K., De Ridder, S., Desiati, P., de Vries, K. D., de Wasseige, G., de With, M., DeYoung, T., Díaz-Vélez, J. C., Cotzomi, J., Dujmovic, H., Dunkman, M., Dvorak, E., Eberhardt, B., Ehrhardt, T., Eichmann, B., Eller, P., Evenson, P. A., Fahey, S., Fazely, A. R., Felde, J., Filimonov, K., Finley, C., Franckowiak, A., Friedman, E., Fritz, A., Gaisser, T. K., Gallagher, J., Ganster, E., Garrappa, S., De León, C., Gerhardt, L., Ghorbani, K., Giang, W., Glauch, T., Glüsenkamp, T., Goldschmidt, A., Gonzalez, J. G., Grant, D., Griffith, Z., Haack, C., De la Fuente, E., Hallgren, A., Halve, L., Halzen, F., Hanson, K., Hebecker, D., Heereman, D., Helbing, K., Hellauer, R., Hickford, S., Hignight, J., Dichiara, S., Hill, G. C., Hoffman, K. D., Hoffmann, R., Hoinka, T., Hokanson-Fasig, B., Hoshina, K., Lankinen, Aapo, Huang, F., Huber, M., Hultqvist, K., Alfaro, R., DuVernois, M. A., Hünnefeld, M., Hussain, R., In, S., Iovine, N., Ishihara, A., Jacobi, Emanuel, Japaridze, G. S., Jeong, M., Jero, K., Jones, B. J. P., Espinoza, C., Kalaczynski, P., Kang, W., Kappes, A., Kappesser, D., Karg, T., Karle, A., Katz, U., Kauer, M., Keivani, A., Kelley, J. L., Fiorino, D. W., Kheirandish, A., Kim, J., Kintscher, T., Kiryluk, J., Kittler, T., Klein, S. R., Koirala, R., Kolanoski, H., Köpke, L., Kopper, C., Fleischhack, H., Kopper, S., Koskinen, D. J., Kowalski, M., Krings, K., Kroll, M., Krückl, G., Kunwar, S., Kurahashi, N., Kyriacou, A., Labare, M., Fraija, N., Lanfranchi, J. L., Larson, M. J., Lauber, F., Leonard, K., Leuermann, M., Liu, Q. R., Lohfink, E., Mariscal, C. J. Lozano, Lu, L., Lünemann, J., Galván-Gámez, A., Luszczak, W., Madsen, J., Maggi, G., Mahn, K. B. M., Makino, Y., Mancina, S., Mariş, I. C., Maruyama, R., Mase, K., Maunu, R., García-González, J. A., Meagher, K., Medici, M., Medina, A., Meier, M., Menne, T., Merino, G., Meures, T., Miarecki, S., Micallef, J., Momenté, G., González, M. M., Montaruli, T., Moore, R. W., Moulai, M., Nagai, R., Nahnhauer, R., Nakarmi, P., Naumann, U., Neer, G., Niederhausen, H., Nowicki, S. C., Goodman, J. A., Nygren, D. R., Pollmann, A. Obertacke, Olivas, A., O'Murchadha, A., O'Sullivan, E., Palczewski, T., Pandya, H., Pankova, D. V., Peiffer, P., Heros, C. Pérez de los, Hampel-Arias, Z., Pieloth, D., Pinat, E., Pizzuto, A., Plum, M., Price, P. B., Przybylski, G. T., Raab, C., Raissi, A., Rameez, M., Rauch, L., Alvarez, C., Harding, J. P., Rawlins, K., Rea, I. C., Reimann, R., Relethford, B., Renzi, G., Resconi, E., Rhode, W., Richman, M., Robertson, S., Rongen, M., Hernandez, S., Rott, C., Ruhe, T., Ryckbosch, D., Rysewyk, D., Safa, I., Herrera, S. E. Sanchez, Sandrock, A., Sandroos, J., Santander, M., Sarkar, S., Hona, B., Satalecka, K., Schaufel, M., Schlunder, P., Schmidt, T., Schneider, A., Schneider, J., Schöneberg, S., Schumacher, L., Sclafani, S., Hueyotl-Zahuantitla, F., Seckel, D., Seunarine, S., Soedingrekso, J., Soldin, D., Song, M., Spiczak, G. M., Spiering, C., Stachurska, J., Stamatikos, M., Stanev, T., Iriarte, A., Stasik, Alexander, Stein, R., Stettner, J., Steuer, A., Stezelberger, T., Stokstad, R. G., Stößl, A., Strotjohann, N. L., Stuttard, T., Sullivan, G. W., Jardin-Blicq, A., Sutherland, M., Taboada, I., Tenholt, F., Ter-Antonyan, S., Terliuk, A., Tilav, S., Tobin, M. N., Tönnis, C., Toscano, S., Tosi, D., Joshi, V., Tselengidou, M., Tung, C. F., Turcati, A., Turcotte, R., Turley, C. F., Ty, B., Unger, E., Elorrieta, M. A. Unland, Usner, Marcel, Vandenbroucke, J., Lara, A., Van Driessche, W., van Eijk, D., van Eijndhoven, N., Vanheule, S., van Santen, J., Vraeghe, M., Walck, C., Wallace, A., Wallraff, M., Wandkowsky, N., Vargas, H. León, Wandler, F. D., Watson, T. B., Weaver, C., Weiss, M. J., Weldert, J., Wendt, C., Werthebach, J., Westerhoff, S., Whelan, B. J., Whitehorn, N., Luis-Raya, G., Wiebe, K., Wiebusch, C. H., Wille, L., Williams, D. R., Wills, L., Wolf, M., Wood, J., Wood, T. R., Woolsey, E., Woschnagg, K., Álvarez, J. D., Malone, K., Wrede, G., Xu, D. L., Xu, X. W., Xu, Y., Yanez, J. P., Yodh, G., Yoshida, S., Yuan, T., IceCube Collaboration, Marinelli, S. S., Martínez-Castro, J., Martinez, O., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Arceo, R., Nisa, M. U., Noriega-Papaqui, R., Pérez-Pérez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Salazar, H., Arteaga-Velázquez, J. C., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Sinnis, G., Smith, A. J., Surajbali, P., Tollefson, K., Torres, I., Rojas, D. Avila, Villaseño, L., Weisgarber, T., Zepeda, A., Zhou, H., Techn. Koordinator:, J. Spengler, Aartsen, M. G., Ackermann, M., Adams, J., Belmont-Moreno, E., Aguilar, J. A., Ahlers, M., Ahrens, M., Altmann, D., Andeen, K., Anderson, T., Ansseau, I., Anton, G., Argüelles, C., Auffenberg, J., BenZvi, S. Y., Axani, S., Backes, P., Bagherpour, H., Bai, X., Barbano, A., Barron, J. P., Barwick, S. W., Baum, V., Bay, R., Beatty, J. J., Physics, and Elementary Particle Physics
Subjects: 010504 meteorology & atmospheric sciences, TeV [cosmic radiation], magnetic field, Astrophysics, anisotropy [cosmic radiation], 01 natural sciences, cosmic radiation: TeV, IceCube, 3-DIMENSIONAL FEATURES, propagation, Anisotropy, 010303 astronomy & astrophysics, media_common, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, angular dependence [power spectrum], Astrophysics::Instrumentation and Methods for Astrophysics, ENERGY-SPECTRUM, Magnetic field, astroparticle physics, cosmic rays, ISM: magnetic fields, observatory, power spectrum: angular dependence, Physique des particules élémentaires, Astrophysics - High Energy Astrophysical Phenomena, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, LARGE-SCALE ANISOTROPY, Astrophysics::Cosmology and Extragalactic Astrophysics, energy [particle], cosmic radiation: anisotropy, 0103 physical sciences, ARRIVAL DIRECTIONS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, INTENSITY, particle: energy, magnetic fields [ISM], Spectral density, Astronomy and Astrophysics, OUTER HELIOSPHERE, Interstellar medium, Dipole, Physics and Astronomy, Space and Planetary Science, Sky, ROTATION, ddc:520, HAWC, Energy (signal processing), dipole
Abstract: We present the first full-sky analysis of the cosmic ray arrival direction distribution with data collected by the High-Altitude Water Cherenkov and IceCube observatories in the northern and southern hemispheres at the same median primary particle energy of 10 TeV. The combined sky map and angular power spectrum largely eliminate biases that result from partial sky coverage and present a key to probe into the propagation properties of TeV cosmic rays through our local interstellar medium and the interaction between the interstellar and heliospheric magnetic fields. From the map, we determine the horizontal dipole components of the anisotropy δ 0h = 9.16 ×10 -4 and δ 6h = 7.25 ×10 -4 (±0.04 × 10 -4 ). In addition, we infer the direction (229.°2 ± 3.°5 R.A. 11.°4 ± 3.°0 decl.) of the interstellar magnetic field from the boundary between large-scale excess and deficit regions from which we estimate the missing corresponding vertical dipole component of the large-scale anisotropy to be δN ∼ -3.97 +1.0 -2.0 × 10 -4 ., 0, SCOPUS: ar.j, info:eu-repo/semantics/published
Published: 2019
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48. Constraints on spin-dependent dark matter scattering with long-lived mediators from TeV observations of the Sun with HAWC

Author: Massachusetts Institute of Technology. Center for Theoretical Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Leane, Rebecca K, Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Avila Rojas, D., Ayala Solares, H. A., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotzomi, J., Coutiño de León, S., De León, C., De la Fuente, E., Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Engel, K., Enríquez-Rivera, O., Espinoza, C., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hona, B., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., León Vargas, H., Luis-Raya, G., Lundeen, J., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Salesa Greus, F., Sandoval, A., Schneider, M., Seglar Arroyo, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Zepeda, A., Zhou, H., Álvarez, J. D., Beacom, J. F., Linden, T., Ng, K. C. Y., Peter, A. H. G., Zhou, B., HAWC Collaboration, Massachusetts Institute of Technology. Center for Theoretical Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Leane, Rebecca K, Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Avila Rojas, D., Ayala Solares, H. A., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotzomi, J., Coutiño de León, S., De León, C., De la Fuente, E., Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Engel, K., Enríquez-Rivera, O., Espinoza, C., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hona, B., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., León Vargas, H., Luis-Raya, G., Lundeen, J., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Salesa Greus, F., Sandoval, A., Schneider, M., Seglar Arroyo, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Villaseñor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Zepeda, A., Zhou, H., Álvarez, J. D., Beacom, J. F., Linden, T., Ng, K. C. Y., Peter, A. H. G., Zhou, B., and HAWC Collaboration
Abstract: We analyze the Sun as a source for the indirect detection of dark matter through a search for gamma rays from the solar disk. Capture of dark matter by elastic interactions with the solar nuclei followed by annihilation to long-lived mediators can produce a detectable gamma-ray flux. We search 3 years of data from the High Altitude Water Cherenkov (HAWC) observatory and find no statistically significant detection of TeV gamma-ray emission from the Sun. Using this, we constrain the spin-dependent elastic scattering cross section of dark matter with protons for dark matter masses above 1 TeV, assuming a sufficiently long-lived mediator. The results complement constraints obtained from Fermi-LAT observations of the Sun and together cover WIMP masses between 4 and 10^{6} GeV. In the optimal scenario, the cross-section constraints for mediator decays to gamma rays can be as strong as ∼10^{-45} cm^{2}, which is more than 4 orders of magnitude stronger than current direct-detection experiments for a 1 TeV dark matter mass. The cross-section constraints at higher masses are even better, nearly 7 orders of magnitude better than the current direct-detection constraints for a 100 TeV dark matter mass. This demonstration of sensitivity encourages detailed development of theoretical models in light of these powerful new constraints., United States. Department of Energy (Grant DESC00012567), United States. Department of Energy (Grant DE-SC0013999)
Published: 2019

49. Multi-messenger Observations of a Binary Neutron Star Merger

Author: LIGO Scientific Collaboration and Virgo Collaboration, Fermi GBM, INTEGRAL, IceCube Collaboration, AstroSat Cadmium Zinc Telluride Imager Team, IPN Collaboration, The Insight-HXMT Collaboration, ANTARES Collaboration, The Swift Collaboration, AGILE Team, The 1M2H Team, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, GRAWITA: GRAvitational Wave Inaf TeAm, The Fermi Large Area Telescope Collaboration, ATCA: Australia Telescope Compact Array, ASKAP: Australian SKA Pathfinder, Las Cumbres Observatory Group, OzGrav, DWF (Deeper, Wider, Faster Program), AST3, and CAASTRO Collaborations, The VINROUGE Collaboration, MASTER Collaboration, J-GEM, GROWTH, JAGWAR, Caltech-NRAO, TTU-NRAO, and NuSTAR Collaborations, Pan-STARRS, The MAXI Team, TZAC Consortium, KU Collaboration, Nordic Optical Telescope, ePESSTO, GROND, Texas Tech University, SALT Group, TOROS: Transient Robotic Observatory of the South Collaboration, The BOOTES Collaboration, MWA: Murchison Widefield Array, The CALET Collaboration, IKI-GW Follow-up Collaboration, H.E.S.S. Collaboration, LOFAR Collaboration, LWA: Long Wavelength Array, HAWC Collaboration, The Pierre Auger Collaboration, ALMA Collaboration, Euro VLBI Team, Pi of the Sky Collaboration, The Chandra Team at McGill University, DFN: Desert Fireball Network, ATLAS, High Time Resolution Universe Survey, RIMAS and RATIR, and SKA South Africa/MeerKAT
Subjects: stars: neutron, gravitational waves
Abstract: 著者: 所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 海老沢, 研; 磯部, 直樹; 下向, 怜歩; 菅原, 泰晴; 冨田, 洋; 上野, 史郎; 桂川, 美穂; 中島, 真也; 小高, 裕和; 高橋, 忠幸, Author(s): Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS): Ebisawa, Ken; Isobe, Naoki; Shimomukai, Reiho; Sugawara, Yasuharu; Tomida,Hiroshi;Ueno, Shiro; Katsuragawa, Miho; Nakashima, Shinya; Odaka, Hirokazu; Takahashi, Tadayuki, Accepted: 2017-10-06, 資料番号: SA1170283000
Published: 2017

50. HAWC Contributions to the 34th International Cosmic Ray Conference (ICRC2015)

Author: HAWC Collaboration, Abeysekara, A. U., Alfaro, R., Alvarez, C., ��lvarez, J. D., Arceo, R., Arteaga-Vel��zquez, J. C., Solares, H. A. Ayala, Barber, A. S., Baughman, B. M., Bautista-Elivar, N., Gonzalez, J. Becerra, Becerril, A., Belmont, E., BenZvi, S. Y., Berley, D., Bernal, A., Braun, J., Caballero-Mora, K. S., Capistr��n, T., Carrami��ana, A., Castillo, M., Cotti, U., Cotzomi, J., de Le��n, S. Couti��o, de la Fuente, E., De Le��n, C., DeYoung, T., Hernandez, R. Diaz, Diaz-Cruz, L., D��az-V��lez, J. C., Dingus, B. L., DuVernois, M. A., Ellsworth, R. W., Engel, K., Enriquez-Rivera, O., Fick, B., Fiorino, D. W., Flores, J. L., Fraija, N., Garcia-Torales, G., Garfias, F., Gonz��lez, M. M., Goodman, J. A., Gussert, M., Hampel-Arias, Z., Hansen, P., Harding, J. Patrick, Hernandez, S., Hui, C. M., H��ntemeyer, P., Imran, A., Iriarte, A., Karn, P., Kieda, D., Kunde, G. J., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. Le��n, Linnemann, J. T., Proper, M. Longo, Raya, G. Luis, Luna-Garc��a, R., Malone, K., Marinelli, A., Marinelli, S. S., Martinez, H., Martinez, O., Mart��nez-Castro, J., Matthews, J. A. J., McEnery, J., Miranda-Romagnoli, P., Moreno, E., Mostaf��, M., Nellen, L., Newbold, M., Nisa, M. Un, Noriega-Papaqui, R., Oceguera-Becerra, T., Patricelli, B., Pelayo, R., P��rez-P��rez, E. G., Pretz, J., Ren, Z., Rho, C. D., Rivi��re, C., Rosa-Gonz��lez, D., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Sinnis, G., Smith, A. J., Smith, A. W., Woodle, K. Sparks, Springer, R. W., Taboada, I., Tibolla, O., Toale, P. A., Tollefson, K., Torres, I., Ukwatta, T. N., Villase��or, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G. B., Younk, P. W., Zepeda, A., and Zhou, H.
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, High Energy Physics - Experiment (hep-ex), hep-ex, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: List of proceedings from the HAWC Collaboration presented at the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands., List of proceedings from the HAWC Collaboration presented at ICRC2015. Follow the "HTML" link to access the list
Published: 2017

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