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1. 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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2. HAWC Detection of a TeV Halo Candidate Surrounding a Radio-quiet Pulsar

Author: A. Albert, R. Alfaro, J. C. Arteaga-Velázquez, H. A. Ayala Solares, E. Belmont-Moreno, T. Capistrán, A. Carramiñana, S. Casanova, J. Cotzomi, S. Coutiño De León, E. De la Fuente, C. de León, R. Diaz Hernandez, M. A. DuVernois, J. C. Díaz-Vélez, C. Espinoza, K. L. Fan, N. Fraija, K. Fang, J. A. García-González, F. Garfias, A. Jardin-Blicq, M. M. González, J. A. Goodman, J. P. Harding, S. Hernandez, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, V. Joshi, A. Lara, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, J. A. Morales-Soto, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, M. Newbold, M. U. Nisa, Y. Pérez Araujo, Y. Son, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, R. W. Springer, K. Tollefson, I. Torres, R. Torres-Escobedo, X. Wang, K. Whitaker, E. Willox, H. Zhou, and THE HAWC COLLABORATION
Subjects: Pulsars, Gamma-ray astronomy, High energy astrophysics, Astrophysics, QB460-466
Abstract: Extended very-high-energy (VHE; 0.1–100 TeV) γ -ray emission has been observed around several middle-aged pulsars and referred to as “TeV halos.” Their formation mechanism remains under debate. It is also unknown whether they are ubiquitous or related to a certain subgroup of pulsars. With 2321 days of observation, the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory detected VHE γ -ray emission at the location of the radio-quiet pulsar PSR J0359+5414 with >6 σ significance. By performing likelihood tests with different spectral and spatial models and comparing the TeV spectrum with multiwavelength observations of nearby sources, we show that this excess is consistent with a TeV halo associated with PSR J0359+5414, though future observation of HAWC and multiwavelength follow-ups are needed to confirm this nature. This new halo candidate is located in a noncrowded region in the outer galaxy. It shares similar properties to the other halos but its pulsar is younger and radio-quiet. Our observation implies that TeV halos could commonly exist around pulsars and their formation does not depend on the configuration of the pulsar magnetosphere.
Published: 2023
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3. 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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4. 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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5. Searching for TeV Dark Matter in Irregular Dwarf Galaxies with HAWC Observatory

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, O. Chaparro-Amaro, U. Cotti, J. Cotzomi, E. De la Fuente, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, M. Durocher, J. C. Díaz-Vélez, C. Espinoza, K. L. Fan, N. Fraija, J. A. García-González, F. Garfias, M. M. González, J. P. Harding, S. Hernández-Cadena, D. Huang, F. Hueyotl-Zahuantitla, A. Iriarte, V. Joshi, S. Kaufmann, D. Kieda, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, N. Omodei, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, H. Salazar, D. Salazar-Gallegos, A. Sandoval, J. Serna-Franco, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, R. Turner, F. Ureña-Mena, L. Villaseñor, X. Wang, E. Willox, H. Zhou, C. de León, The HAWC Collaboration, V. Gammaldi, E. Karukes, and P. Salucci
Subjects: Dark matter, Cold dark matter, Galaxies, Dwarf irregular galaxies, Particle astrophysics, Gamma-rays, Astrophysics, QB460-466
Abstract: We present the results of dark matter (DM) searches in a sample of 31 dwarf irregular (dIrr) galaxies within the field of view of the HAWC Observatory. dIrr galaxies are DM-dominated objects in which astrophysical gamma-ray emission is estimated to be negligible with respect to the secondary gamma-ray flux expected by annihilation or decay of weakly interacting massive particles (WIMPs). While we do not see any statistically significant DM signal in dIrr galaxies, we present the exclusion limits (95% C.L.) for annihilation cross section and decay lifetime for WIMP candidates with masses between 1 and 100 TeV. Exclusion limits from dIrr galaxies are relevant and complementary to benchmark dwarf Spheroidal (dSph) galaxies. In fact, dIrr galaxies are targets kinematically different from benchmark dSph, preserving the footprints of different evolution histories. We compare the limits from dIrr galaxies to those from ultrafaint and classical dSph galaxies previously observed with HAWC. We find that the constraints are comparable to the limits from classical dSph galaxies and ∼2 orders of magnitude weaker than the ultrafaint dSph limits.
Published: 2023
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6. 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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7. HAWC Study of the Ultra-high-energy Spectrum of MGRO J1908+06

Author: A. Albert, R. Alfaro, C. Alvarez, J. D. Álvarez, J. R. Angeles Camacho, 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, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, M. Durocher, J. C. Díaz-Vélez, K. Engel, C. Espinoza, K. L. Fan, K. Fang, M. Fernández Alonso, N. Fraija, D. Garcia, J. A. García-González, F. Garfias, G. Giacinti, H. Goksu, M. M. González, J. A. Goodman, J. P. Harding, 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, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, 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, H. Salazar, F. Salesa Greus, A. Sandoval, M. Schneider, H. Schoorlemmer, 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, I. J. Watson, E. Willox, A. Zepeda, H. Zhou, M. Breuhaus, H. Li, and H. Zhang
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, ddc:530, High Energy Physics, 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: 2022

8. MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources

Author: M. L. Ahnen, S. Ansoldi, L. A. Antonelli, C. Arcaro, D. Baack, A. Babic, B. Banerjee, P. Bangale, U. Barres de Almeida, J. A. Barrio, J. Becerra Gonzalez, W. Bednarek, E. Bernardini, R. Ch. Berse, A. Berti, W. Bhattacharyya, A. Biland, O. Blanch, G. Bonnoli, R. Carosi, A. Carosi, G. Ceribella, A. Chatterjee, S. M. Colak, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, P. Cumani, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, M. Delfino, J. Delgado, F. Di Pierro, A. Domınguez, D. Dominis Prester, D. Dorner, M. Doro, S. Einecke, D. Elsaesser, V. Fallah Ramazani, A. Fernandez-Barral, D. Fidalgo, M. V. Fonseca, L. Font, C. Fruck, D. Galindo, R. J. Garcıa Lopez, M. Garczarczyk, M. Gaug, P. Giammaria, N. Godinovic, D. Gora, D. Guberman, D. Hadasch, A. Hahn, T. Hassan, M. Hayashida, J. Herrera, J. Hose, D. Hrupec, K. Ishio, Y. Konno, H. Kubo, J. Kushida, D. Kuvezdic, D. Lelas, E. Lindfors, S. Lombardi, F. Longo, M. Lopez, C. Maggio, P. Majumdar, M. Makariev, G. Maneva, M. Manganaro, K. Mannheim, L. Maraschi, M. Mariotti, M. Martınez, S. Masuda, D. Mazin, K. Mielke, M. Minev, J. M. Miranda, R. Mirzoyan, A. Moralejo, V. Moreno, E. Moretti, T. Nagayoshi, V. Neustroev, A. Niedzwiecki, M. Nievas Rosillo, C. Nigro, K. Nilsson, D. Ninci, K. Nishijima, K. Noda, L. Nogues, S. Paiano, J. Palacio, D. Paneque, R. Paoletti, J. M. Paredes, G. Pedaletti, M. Peresano, M. Persic, P. G. Prada Moroni, E. Prandini, I. Puljak, J. R. Garcia, I. Reichardt, W. Rhodes, M. Ribo, J. Rico, C. Righi, A. Rugliancich, T. Saito, K. Satalecka, T. Schweizer, J. Sitarek, I. Snidaric, D. Sobczynska, A. Stamerra, M. Strzys, T. Suric, M. Takahashi, L. Takalo, F. Tavecchio, P. Temnikov, T. Terzic, M. Teshima, N. Torres-Alba, A. Treves, S. Tsujimoto, G. Vanzo, M. Vazquez Acosta, I. Vovk, J. E. Ward, M. Will, D. Zaric, A. Albert, R. Alfaro, C. Alvarez, R. Arceo, J. C. Arteaga-Velazquez, D. Avila Rojas, H. A. Ayala Solares, A. Becerril, E. Belmont-Moreno, S. Y. BenZvi, A. Bernal, J. Braun, K. S. Caballero-Mora, T. Capistran, A. Carraminana, S. Casanova, M. Castillo, U. Cotti, J. Cotzomi, S. Coutino de Leon, C. De Leon, E. De la Fuente, R. Diaz Hernandez, S. Dichiara, B. L. Dingus, M. A. DuVernois, J. C. Dıaz-Velez, R. W. Ellsworth, K. Engel, O. Enriquez-Rivera, D. W. Fiorino, H. Fleischhack, N. Fraija, J. A. Garcıa-Gonzalez, F. Garfias, A. Gonzalez-Munoz, M. M. Gonzalez, J. A. Goodman, Z. Hampel-Arias, J. P. Harding, S. Hernandez, F. Hueyotl-Zahuantitla, C. M. Hui, P. Huntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, S. Kaufmann, A. Lara, R. J. Lauer, W. H. Lee, D. Lennarz, H. Leon Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, R. Luna-Garcıa, R. Lopez-Coto, K. Malone, S. S. Marinelli, O. Martinez, I. Martinez-Castellanos, J. Martınez-Castro, H. Martınez-Huerta, J. A. Matthews, P. Miranda-Romagnoli, E. Moreno, A. Nayerhoda, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, R. Pelayo, J. Pretz, E. G. Perez-Perez, Z. Ren, C. D. Rho, C. Riviere, D. Rosa-Gonzalez, M. Rosenberg, E. Ruiz-Velasco, F. Salesa Greus, A. Sandoval, M. Schneider, M. Seglar Arroyo, G. Sinnis, A. J. Smith, R. W. Springer, P. Surajbali, I. Taboada, O. Tibolla, K. Tollefson, I. Torres, T. N. Ukwatta, G. Vianello, L. Villasenor, F. Werner, S. Westerhoff, J. Wood, T. Yapici, G. Yodh, A. Zepeda, H. Zhou, J. D. Alvarez, M. Ajello, L. Baldini, G. Barbiellini, B. Berenji, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, T. J. Brandt, J. Bregeon, P. Bruel, R. A. Cameron, R. Caputo, P. A. Caraveo, D. Castro, E. Cavazzuti, G. Chiaro, S. Ciprini, D. Costantin, F. D'Ammando, F. de Palma, A. Desai, N. Di Lalla, M. Di Mauro, L. Di Venere, C. Favuzzi, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, D. Green, I. A. Grenier, S. Guiriec, A. K. Harding, E. Hays, J. W. Hewitt, D. Horan, G. Johannesson, M. Kuss, S. Larsson, I. Liodakis, F. Loparco, P. Lubrano, J. D. Magill, S. Maldera, A. Manfreda, M. N. Mazziotta, I. Mereu, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Negro, E. Nuss, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, M. Palatiello, V. S. Paliya, M. Pesce-Rollins, V. Petrosian, F. Piron, T. A. Porter, G. Principe, S. Raino, B. Rani, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, C. Sgro, E. J. Siskind, G. Spandre, P. Spinelli, H. Tajima, J. B. Thayer, David J Thompson, D. F. Torres, E. Torresi, E. Troja, J. Valverde, K. Wood, and M. Yassine
Subjects: Astronomy, Astrophysics
Abstract: The HAWC Collaboration released the 2HWC catalogue of TeV sources, in which 19 show no association with any known high-energy (HE; E ≳ 10 GeV) or very-high-energy (VHE; E ≳ 300 GeV) sources. This catalogue motivated follow-up studies by both the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) and Fermi-LAT (Large Area Telescope) observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between High Altitude Water Cherenkov (HAWC), MAGIC, and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084*, and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1° extension (at 95 per cent confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, whilst a simply minimum extension of 0.16° (at 95 per cent confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail.
Published: 2019
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9. First HAWC observations of the Sun constrain steady TeV gamma-ray emission

Author: A. Albert, R. Alfaro, C. Alvarez, R. Arceo, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, E. Belmont-Moreno, S. Y. BenZvi, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, M. Castillo, J. Cotzomi, S. Coutiño de León, C. De León, E. De la Fuente, S. Dichiara, B. L. Dingus, M. A. DuVernois, J. C. Díaz-Vélez, K. Engel, O. Enríquez-Rivera, C. Espinoza, H. Fleischhack, N. Fraija, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, Z. Hampel-Arias, J. P. Harding, S. Hernandez, B. Hona, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, S. Kaufmann, H. León Vargas, G. Luis-Raya, J. Lundeen, R. López-Coto, K. Malone, S. S. Marinelli, O. Martinez, I. Martinez-Castellanos, J. Martínez-Castro, P. Miranda-Romagnoli, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, J. Pretz, E. G. Pérez-Pérez, Z. Ren, C. D. Rho, C. Rivière, D. Rosa-González, M. Rosenberg, E. Ruiz-Velasco, H. Salazar, F. Salesa Greus, A. Sandoval, M. Schneider, H. Schoorlemmer, M. Seglar Arroyo, G. Sinnis, A. J. Smith, R. W. Springer, P. Surajbali, I. Taboada, O. Tibolla, K. Tollefson, I. Torres, L. Villaseñor, T. Weisgarber, S. Westerhoff, I. G. Wisher, J. Wood, T. Yapici, A. Zepeda, H. Zhou, J. D. Álvarez, J. F. Beacom, R. K. Leane, T. Linden, K. C. Y. Ng, A. H. G. Peter, and B. Zhou
Published: 2018
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10. Constraints on spin-dependent dark matter scattering with long-lived mediators from TeV observations of the Sun with HAWC

Author: A. Albert, R. Alfaro, C. Alvarez, R. Arceo, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, E. Belmont-Moreno, S. Y. BenZvi, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, M. Castillo, J. Cotzomi, S. Coutiño de León, C. De León, E. De la Fuente, S. Dichiara, B. L. Dingus, M. A. DuVernois, J. C. Díaz-Vélez, K. Engel, O. Enríquez-Rivera, C. Espinoza, H. Fleischhack, N. Fraija, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, Z. Hampel-Arias, J. P. Harding, S. Hernandez, B. Hona, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, S. Kaufmann, H. León Vargas, G. Luis-Raya, J. Lundeen, R. López-Coto, K. Malone, S. S. Marinelli, O. Martinez, I. Martinez-Castellanos, J. Martínez-Castro, P. Miranda-Romagnoli, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, J. Pretz, E. G. Pérez-Pérez, Z. Ren, C. D. Rho, C. Rivière, D. Rosa-González, M. Rosenberg, E. Ruiz-Velasco, H. Salazar, F. Salesa Greus, A. Sandoval, M. Schneider, M. Seglar Arroyo, G. Sinnis, A. J. Smith, R. W. Springer, P. Surajbali, I. Taboada, O. Tibolla, K. Tollefson, I. Torres, L. Villaseñor, T. Weisgarber, S. Westerhoff, I. G. Wisher, J. Wood, T. Yapici, A. Zepeda, H. Zhou, J. D. Álvarez, J. F. Beacom, R. K. Leane, T. Linden, K. C. Y. Ng, A. H. G. Peter, and B. Zhou
Published: 2018
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11. Study of the Very High Energy Emission of M87 through its Broadband Spectral Energy Distribution

Author: R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, E. Belmont-Moreno, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, 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, 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, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, V. Joshi, 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, N. Omodei, A. Peisker, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, H. Salazar, D. Salazar-Gallegos, F. Salesa Greus, A. Sandoval, J. Serna-Franco, Y. Son, R. W. Springer, O. Tibolla, K. Tollefson, I. Torres, F. Ureña-Mena, L. Villaseñor, X. Wang, E. Willox, and A. Zepeda
Subjects: Space and Planetary Science, Astronomy and Astrophysics, ddc:530
Abstract: The radio galaxy M87 is the central dominant galaxy of the Virgo Cluster. Very high-energy (VHE, ≳0.1 TeV) emission from M87 has been detected by imaging air Cherenkov telescopes. Recently, marginal evidence for VHE long-term emission has also been observed by the High Altitude Water Cherenkov 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 originates in its prominent jet, which has been spatially resolved from radio to X-rays. In this paper, we construct a spectral energy distribution from radio to gamma rays that is representative of the nonflaring 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 nonflaring VHE emission of M87 as well as an orphan flare reported in 2005.
Published: 2022

12. Probing the extragalactic mid-infrared background 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, 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, 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. Hntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, D. Kieda, W. H. Lee, 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, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, N. Omodei, A. Peisker, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, H. Salazar, D. Salazar-Gallegos, F. Salesa Greus, A. Sandoval, 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, T. Weisgarber, E. Willox, H. Zhou, and C. de León
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, ddc:520, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract: The extragalactic background light (EBL) contains all the radiation emitted by nuclear and accretion processes in stars and compact objects since the epoch of recombination. Measuring the EBL density directly is challenging, especially in the near- to far-infrared waveband, mainly due to the zodiacal light foreground. Instead, gamma-ray astronomy offers the possibility to indirectly set limits on the EBL by studying the effects of gamma-ray absorption in the very high energy (VHE:$>$100 GeV) spectra of distant blazars. The High Altitude Water Cherenkov gamma ray observatory (HAWC) is one of the few instruments sensitive to gamma rays with energies above 10 TeV. This offers the opportunity to probe the EBL in the near/mid IR region: $\lambda$ = 1 $\mu$m - 100 $\mu$m. In this study, we fit physically motivated emission models to Fermi Large Area Telescope (LAT) GeV data to extrapolate the intrinsic TeV spectra of blazars. We then simulate a large number of absorbed spectra for different randomly generated EBL model shapes and calculate Bayesian credible bands in the EBL intensity space by comparing and testing the agreement between the absorbed spectra and HAWC extragalactic observations of two blazars. The resulting bands are in agreement with current EBL lower and upper limits, showing a downward trend towards higher wavelength values $\lambda>10\, \mu$m also observed in previous measurements., Comment: Submitted to ApJ
Published: 2022
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13. HAWC Search for High-Mass Microquasars

Author: Ernesto Belmont-Moreno, Elijah Willox, J. A. Goodman, Dezhi Huang, Jorge Cotzomi, Mora Durocher, Petra Hüntemeyer, J. P. Harding, R. W. Springer, A. Carraminana, K. Malone, A. J. Smith, J. C. Arteaga-Velázquez, H. Zhou, Joe Lundeen, C. D. Rho, F. Salesa Greus, R. W. Ellsworth, C. De León, K. P. Arunbabu, A. L. Longinotti, David Kieda, B. Hona, Alison Peisker, L. Nellen, E. Moreno, Fernando Ureña-Mena, Umberto Cotti, R. Torres-Escobedo, C. Brisbois, Sabrina Casanova, R. Diaz Hernandez, Maria Magdalena González, S. Hernandez, Nissim Illich Fraija, Karen S. Caballero-Mora, Michael Newbold, Rhiannon Turner, Fernando Garfias, Michael DuVernois, Thomas Weisgarber, Catalina Espinoza, A. Sandoval, Jose Andres Garcia-Gonzalez, Filiberto Hueyotl-Zahuantitla, Jesús Martínez-Castro, Michael Schneider, H. A. Ayala Solares, Ke Fang, Y. J. Roh, Andrea Albert, T. Capistrán, O. Martinez, Ian James Watson, Miguel Mostafa, Gilgamesh Luis-Raya, V. Baghmanyan, V. Joshi, José Serna-Franco, Alejandro Lara, J. T. Linnemann, R. Noriega-Papaqui, William H. Lee, L. Olivera-Nieto, J. S. H. Lee, A. Galván-Gámez, Brenda Dingus, K. Tollefson, Ruben Alfaro, Pedro Miranda-Romagnoli, Daniel Rosa-Gonzalez, John Matthews, J. A. Morales-Soto, Luis Villaseñor, Kwok Lung Fan, H. León Vargas, A. Jardin-Blicq, Ibrahim Torres, M. U. Nisa, Juan Carlos Diaz-Velez, C. Alvarez, Nicola Omodei, Arturo Iriarte, Y. Pérez Araujo, A. Nayerhoda, Segev BenZvi, E. De la Fuente, D. Avila Rojas, and J. R. Angeles Camacho
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, High mass, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 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

14. Evidence that Ultra-High-Energy Gamma Rays are a Universal Feature Near Powerful Pulsars

Author: R. Diaz Hernandez, Pedro Miranda-Romagnoli, J. A. Goodman, J. R. Angeles Camacho, Michael Newbold, Karen S. Caballero-Mora, Catalina Espinoza, John Matthews, Fernando Garfias, Jesús Martínez-Castro, H. A. Ayala Solares, Andrea Albert, Segev BenZvi, C. D. Rho, Thomas Weisgarber, Nicola Omodei, Dezhi Huang, Nissim Illich Fraija, E. Ruiz-Velasco, R. Torres-Escobedo, Ibrahim Torres, Arturo Iriarte, H. León Vargas, A. Carraminana, Joe Lundeen, R. W. Ellsworth, Meghan Tanner, C. De León, A. Sandoval, O. Martinez, K. Malone, J. C. Arteaga-Velázquez, Ernesto Belmont-Moreno, R. W. Springer, Michael Schneider, Alison Peisker, H. Zhou, E. G. Pérez-Pérez, K. P. Arunbabu, A. L. Longinotti, Kristi Engel, Harm Schoorlemmer, B. Hona, A. Jardin-Blicq, Elijah Willox, J. D. Álvarez, J. A. Morales-Soto, T. Capistrán, A. J. Smith, David Kieda, Humberto Ibarguen Salazar, Y. Pérez Araujo, J. P. Harding, Gwenael Giacinti, Gilgamesh Luis-Raya, L. Nellen, A. Nayerhoda, R. Noriega-Papaqui, Juan Carlos Diaz-Velez, S. Hernandez, Ruben Alfaro, William H. Lee, L. Olivera-Nieto, M. Fernández Alonso, C. Alvarez, Y. J. Roh, Miguel Mostafa, Daniel Rosa-Gonzalez, José Serna-Franco, Luis Villaseñor, Umberto Cotti, E. De la Fuente, Sabrina Casanova, D. Avila Rojas, V. Joshi, F. Salesa Greus, S. Coutiño de León, M. U. Nisa, Jorge Cotzomi, Alejandro Lara, J. T. Linnemann, Rhiannon Turner, Maria Magdalena González, Michael DuVernois, Kwok Lung Fan, Filiberto Hueyotl-Zahuantitla, J. S. H. Lee, E. Moreno, A. Galván-Gámez, Brenda Dingus, V. Marandon, K. Tollefson, C. Brisbois, V. Baghmanyan, Mora Durocher, Petra Hüntemeyer, Pooja Surajbali, Fernando Ureña-Mena, and Jose Andres Garcia-Gonzalez
Subjects: Astroparticle physics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), High energy, High-energy astronomy, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Pulsar, Space and Planetary Science, Feature (computer vision), 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$��$), 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., accepted by ApJL
Published: 2021

15. Long-term spectra of the blazars Mrk 421 and Mrk 501 at TeV energies seen by HAWC

Author: A. Albert, R. Alfaro, C. Alvarez, J. R. Angeles Camacho, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, H. A. Ayala Solares, V. Baghmanyan, 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, R. Diaz Hernandez, M. A. DuVernois, M. Durocher, J. C. Díaz-Vélez, K. Engel, C. Espinoza, K. L. Fan, M. Fernández Alonso, N. Fraija, D. Garcia, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, J. P. Harding, B. Hona, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, V. Joshi, A. Lara, W. H. Lee, J. Lee, H. León Vargas, J. T. Linneman, 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, M. Newbold, R. Noriega-Papaqui, A. Peisker, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, H. Salazar, F. Salesa Greus, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, R. W. Springer, K. Tollefson, I. Torres, R. Torres-Escobedo, F. Ureña-Mena, L. Villaseñor, X. Wang, T. Weisgarber, E. Willox, H. Zhou, and C. de León
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, ddc:530, High Energy Physics::Experiment, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high energy sky in the 300 GeV to $>100$ TeV energy range. HAWC has detected two blazars above $11\sigma$, Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501). The observations are comprised of data taken in the period between June 2015 and July 2018, resulting in a $\sim 1038$ days of exposure. In this work we report the time-averaged spectral analysis for both sources above 0.5 TeV. Taking into account the flux attenuation due to the extragalactic background light (EBL), the intrinsic spectrum of Mrk 421 is described by a power law with an exponential energy cut-off with index $\alpha=2.26\pm(0.12)_{stat}(_{-0.2}^{+0.17})_{sys}$ and energy cut-off $E_c=5.1\pm(1.6)_{stat}(_{-2.5}^{+1.4})_{sys}$ TeV, while the intrinsic spectrum of Mrk 501 is better described by a simple power law with index $\alpha=2.61\pm(0.11)_{stat}(_{-0.07}^{+0.01})_{sys}$. The maximum energies at which the Mrk 421 and Mrk 501 signals are detected are 9 and 12 TeV, respectively. This makes these some of the highest energy detections to date for spectra averaged over years-long timescales. Since the observation of gamma radiation from blazars provides information about the physical processes that take place in their relativistic jets, it is important to study the broad-band spectral energy distribution (SED) of these objects. To this purpose, contemporaneous data in the gamma-ray band to X-ray range, and literature data in the radio to UV range, were used to build time-averaged SEDs that were modeled within a synchrotron self-Compton leptonic scenario., Comment: 16 pages, 5 tables, 9 figures
Published: 2021
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16. Probing the Sea of Cosmic Rays by Measuring Gamma-Ray Emission from Passive Giant Molecular Clouds with HAWC

Author: Segev BenZvi, C. Alvarez, S. Coutiño de León, A. Sandoval, Alejandro Lara, Pooja Surajbali, S. Hernandez, E. De la Fuente, Fernando Ureña-Mena, D. Avila Rojas, R. Diaz Hernandez, Andrea Albert, Michael Schneider, K. Malone, Fernando Garfias, H. Zhou, E. Ruiz-Velasco, C. Brisbois, K. P. Arunbabu, Mora Durocher, Petra Hüntemeyer, A. L. Longinotti, O. Martinez, J. S. H. Lee, D. Garcia, H. León Vargas, J. A. Morales-Soto, A. Galván-Gámez, Nicola Omodei, J. A. Goodman, Meghan Tanner, Arturo Iriarte, Brenda Dingus, Y. Pérez Araujo, J. C. Arteaga-Velázquez, Michael Newbold, Alison Peisker, A. Nayerhoda, Juan Carlos Diaz-Velez, Luis Villaseñor, Jose Andres Garcia-Gonzalez, J. R. Angeles Camacho, Ernesto Belmont-Moreno, E. Moreno, Miguel Mostafa, B. Hona, Kwok Lung Fan, Umberto Cotti, K. Tollefson, Kristi Engel, Nissim Illich Fraija, J. P. Harding, T. Weisgarber, Maria Magdalena González, V. Joshi, Sabrina Casanova, M. U. Nisa, J. A. Matthews, Karen S. Caballero-Mora, Ibrahim Torres, V. Baghmanyan, Elijah Willox, Jorge Cotzomi, Catalina Espinoza, José Serna-Franco, Gilgamesh Luis-Raya, Filiberto Hueyotl-Zahuantitla, Jesús Martínez-Castro, H. A. Ayala Solares, Ruben Alfaro, C. D. Rho, R. Noriega-Papaqui, Dezhi Huang, Pedro Miranda-Romagnoli, J. T. Linnemann, William H. Lee, Daniel Rosa-Gonzalez, T. Capistrán, M. Fernández Alonso, R. Torres-Escobedo, A. J. Smith, R. W. Springer, L. Nellen, E. G. Pérez-Pérez, David Kieda, C. De León, F. Salesa Greus, Rhiannon Turner, Michael DuVernois, A. Carraminana, Joe Lundeen, and R. W. Ellsworth
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), High-energy astronomy, Molecular cloud, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract: The study of high-energy gamma rays from passive Giant Molecular Clouds (GMCs) in our Galaxy is an indirect way to characterize and probe the paradigm of the "sea" of cosmic rays in distant parts of the Galaxy. By using data from the High Altitude Water Cherenkov (HAWC) observatory, we measure the gamma-ray flux above 1 TeV of a set of these clouds to test the paradigm. We selected high-galactic latitude clouds that are in HAWC's field-of-view and which are within 1~kpc distance from the Sun. We find no significant excess emission in the cloud regions, nor when we perform a stacked log-likelihood analysis of GMCs. Using a Bayesian approach, we calculate 95\% credible intervals upper limits of the gamma-ray flux and estimate limits on the cosmic-ray energy density of these regions. These are the first limits to constrain gamma-ray emission in the multi-TeV energy range ($>$1 TeV) using passive high-galactic latitude GMCs. Assuming that the main gamma-ray production mechanism is due to proton-proton interaction, the upper limits are consistent with a cosmic-ray flux and energy density similar to that measured at Earth., 6 figures, 6 tables
Published: 2021
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17. Spectrum and morphology of the very-high-energy source HAWC J2019+368

Author: R. W. Springer, C. D. Rho, E. G. Pérez-Pérez, Alison Peisker, A. J. Smith, J. A. Morales-Soto, E. Moreno, Sabrina Casanova, V. Joshi, Dezhi Huang, Rhiannon Turner, Michael DuVernois, L. Nellen, A. Carraminana, T. Capistrán, Joe Lundeen, J. P. Harding, Gwenael Giacinti, Jorge Cotzomi, J. C. Arteaga-Velázquez, Karen S. Caballero-Mora, Nicola Omodei, Jose Andres Garcia-Gonzalez, S. Coutiño de León, T. Weisgarber, V. Baghmanyan, Catalina Espinoza, J. A. Goodman, D. Garcia, Nissim Illich Fraija, H. Zhou, A. Jardin-Blicq, Jesús Martínez-Castro, H. A. Ayala Solares, K. P. Arunbabu, A. L. Longinotti, A. Sandoval, Ernesto Belmont-Moreno, Humberto Ibarguen Salazar, O. Martinez, Jim Hinton, Andrea Albert, Michael Schneider, P. Huentemeyer, Miguel Mostafa, C. Brisbois, Harm Schoorlemmer, M. U. Nisa, R. Noriega-Papaqui, Binita Hona, Elijah Willox, Pooja Surajbali, Brenda Dingus, William H. Lee, L. Olivera-Nieto, Michael Newbold, José Serna-Franco, R. Diaz Hernandez, Fernando Ureña-Mena, Pedro Miranda-Romagnoli, R. López-Coto, K. Tollefson, Y. Pérez Araujo, E. Ruiz-Velasco, A. Nayerhoda, J. T. Linnemann, F. Salesa Greus, Ibrahim Torres, Mora Durocher, H. León Vargas, C. Alvarez, Maria Magdalena González, E. De la Fuente, C. De León, D. Avila Rojas, Filiberto Hueyotl-Zahuantitla, Gilgamesh Luis-Raya, K. Malone, John Matthews, Ruben Alfaro, Daniel Rosa-Gonzalez, and Kristi Engel
Subjects: Energy dependent, Physics, High energy, Nebula, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Pulsar wind nebula, Pulsar, Space and Planetary Science, Sky, 0103 physical sciences, Supernova remnant, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common
Abstract: The MGRO J2019+37 region is one of the brightest sources in the sky at TeV energies. It was detected in the second 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 ∼7 kyr pulsar and nebula system producing the observed emission at X-ray and γ-ray energies.
Published: 2021

18. Evidence of 200 TeV photons from HAWC J1825-134

Author: R. Noriega-Papaqui, J. R. Angeles Camacho, Gerd J. Kunde, Luis Villaseñor, C. Brisbois, K. Tollefson, J. T. Linnemann, Catalina Espinoza, D. Garcia, F. Serna, Nicola Omodei, A. Iriarte, H. A. Ayala Solares, Lukas Nellen, I. Torres, E. Belmont-Moreno, Gwenael Giacinti, A. Sandoval, B. Hona, Segev BenZvi, J. C. Díaz-Vélez, Vincent Marandon, H. Fleischhack, Michael Schneider, J. Lundeen, Mehr Nisa, K. Engel, Vardan Baghmanyan, F. Salesa Greus, Nissim Fraija, K. P. Arunbabu, A. L. Longinotti, M. Mostafá, J. A. Goodman, M. Durocher, A. Jardin-Blicq, C. De León, Andrea Albert, M. Newbold, U. Cotti, Brenda Dingus, J. P. Harding, J. Martínez-Castro, Alejandro Lara, A. Peisker, E. Moreno, Amid Nayerhoda, Daniel Rosa-Gonzalez, Michael DuVernois, A. Carramiñana, Y. Pérez Araujo, H. León Vargas, R. Diaz Hernandez, E. Willox, P. Miranda-Romagnoli, John Matthews, A. Galván-Gámez, E. De la Fuente, D. Avila Rojas, Oscar Martinez, G. Luis-Raya, Sabrina Casanova, V. Joshi, J.C. Arteaga-Velázquez, P. Hüntemeyer, W. H. Lee, Ke Fang, R. Torres-Escobedo, T. Capistrán, J. Cotzomi, F. Ureña-Mena, F. Garfias, Maria Magdalena González, Hongyan Zhou, Filiberto Hueyotl-Zahuantitla, Ruben Alfaro, C. D. Rho, R. W. Springer, H. Salazar, C. Alvarez, D. Huang, K. Malone, E. G. Pérez-Pérez, and Jose Andres Garcia-Gonzalez
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Photon, 010504 meteorology & atmospheric sciences, Proton, Molecular cloud, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Radiation, 7. Clean energy, 01 natural sciences, Galaxy, 13. Climate action, Space and Planetary Science, Observatory, 0103 physical sciences, Physics::Accelerator Physics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Cherenkov radiation, 0105 earth and related environmental sciences
Abstract: The Earth is bombarded by ultra-relativistic particles, known as cosmic rays (CRs). CRs with energies up to a few PeV (=10$^{15}$ eV), the knee in the particle spectrum, are believed to have a Galactic origin. One or more factories of PeV CRs, or PeVatrons, must thus be active within our Galaxy. The direct detection of PeV protons from their sources is not possible since they are deflected in the Galactic magnetic fields. Hundred TeV $\gamma$-rays from decaying $\pi^0$, produced when PeV CRs collide with the ambient gas, can provide the decisive evidence of proton acceleration up to the knee. Here we report the discovery by the High Altitude Water Cherenkov (HAWC) observatory of the $\gamma$-ray source, HAWC~J1825-134, whose energy spectrum extends well beyond 200 TeV without a break or cutoff. The source is found to be coincident with a giant molecular cloud. The ambient gas density is as high as 700 protons/cm$^3$. While the nature of this extreme accelerator remains unclear, CRs accelerated to energies of several PeV colliding with the ambient gas likely produce the observed radiation., Comment: Accepted for publication in ApJL
Published: 2020

19. Author Correction: HAWC observations of the acceleration of very-high-energy cosmic rays in the Cygnus Cocoon

Author: A. Jardin-Blicq, J. A. Morales-Soto, Juan Carlos Diaz-Velez, A. Sandoval, Mora Durocher, D. Garcia, C. Alvarez, E. De la Fuente, F. Werner, D. Avila Rojas, F. Serna, J. R. Angeles Camacho, Kwok Lung Fan, Petra Hüntemeyer, J. C. Arteaga-Velázquez, Michael Schneider, R. Diaz Hernandez, S. Hernandez, Nicola Omodei, Arturo Iriarte, K. Tollefson, B. Hona, Gilgamesh Luis-Raya, C. De León, V. Baghmanyan, E. Moreno, C. Brisbois, Umberto Cotti, Maria Magdalena González, Kristi Engel, Nissim Illich Fraija, Sabrina Casanova, Fernando Garfias, A. Zepeda, Harm Schoorlemmer, Pooja Surajbali, J. A. Matthews, E. Ruiz-Velasco, Humberto Ibarguen Salazar, H. Zhou, Fernando Ureña-Mena, Alison Peisker, Z. Ren, Ibrahim Torres, R. Noriega-Papaqui, Filiberto Hueyotl-Zahuantitla, K. P. Arunbabu, Ruben Alfaro, A. L. Longinotti, H. León Vargas, J. P. Harding, Henrike Fleischhack, William H. Lee, L. Olivera-Nieto, O. Martinez, T. Weisgarber, Daniel Rosa-Gonzalez, Miguel Mostafa, Michael DuVernois, Anushka Udara Abeysekara, Roger Blandford, S. Coutiño de León, R. W. Springer, Jose Andres Garcia-Gonzalez, Michael Newbold, Alejandro Lara, K. Malone, E. G. Pérez-Pérez, V. Joshi, J. D. Álvarez, E. Belmont-Moreno, A. J. Smith, Ke Fang, C. D. Rho, T. Capistrán, David Kieda, L. Nellen, F. Salesa Greus, A. Carraminana, Joe Lundeen, R. W. Ellsworth, Jim Hinton, Elijah Willox, J. A. Goodman, Dezhi Huang, Pedro Miranda-Romagnoli, M. U. Nisa, A. Galván-Gámez, Brenda Dingus, J. T. Linnemann, Y. Pérez Araujo, A. Nayerhoda, Segev BenZvi, Gwenael Giacinti, I. Martinez-Castellanos, Andrea Albert, R. Torres-Escobedo, Karen S. Caballero-Mora, Catalina Espinoza, Jesús Martínez-Castro, and H. A. Ayala Solares
Subjects: Physics, Acceleration, Astronomy and Astrophysics, Astrophysics, Ultra-high-energy cosmic ray
Published: 2021

20. A survey of active galaxies at TeV photon energies with the HAWC gamma-ray observatory

Author: Andrea Albert, Fernando Garfias, Kristi Engel, K. Tollefson, A. Zepeda, E. Ruiz-Velasco, H. León Vargas, Segev BenZvi, Binita Hona, H. Zhou, K. P. Arunbabu, J. A. Morales-Soto, C. Brisbois, Karen S. Caballero-Mora, Jose Andres Garcia-Gonzalez, Ernesto Belmont-Moreno, Pedro Miranda-Romagnoli, Catalina Espinoza, S. Coutiño de León, J. R. Angeles Camacho, Jesús Martínez-Castro, F. Salesa Greus, H. A. Ayala Solares, A. Carraminana, Luis Villaseñor, Daniel Rosa-Gonzalez, E. Moreno, Alejandro Lara, R. W. Springer, Joe Lundeen, C. De León, Alison Peisker, Kwok Lung Fan, E. G. Pérez-Pérez, O. Martinez, J. C. Arteaga-Velázquez, Elijah Willox, Gerd Joachim Kunde, Henrike Fleischhack, Fernando Ureña-Mena, John Matthews, Harm Schoorlemmer, Ibrahim Torres, R. Torres-Escobedo, Gilgamesh Luis-Raya, David Kieda, V. Baghmanyan, R. Noriega-Papaqui, William H. Lee, L. Olivera-Nieto, I. Martinez-Castellanos, C. D. Rho, Mora Durocher, Petra Hüntemeyer, A. Sandoval, A. J. Smith, M. U. Nisa, K. Malone, Michael Schneider, Jorge Cotzomi, S. Hernandez, J. A. Goodman, Michael DuVernois, A. Jardin-Blicq, Nissim Illich Fraija, Dezhi Huang, D. Garcia, J. P. Harding, T. Weisgarber, A. Nayerhoda, Arturo Iriarte, Michael Newbold, Juan Carlos Diaz-Velez, J. T. Linnemann, Tomás Capistrán, C. Alvarez, E. De la Fuente, D. Avila Rojas, A. Galván-Gámez, Brenda Dingus, Anna Lia Longinotti, Humberto Ibarguen Salazar, Umberto Cotti, Maria Magdalena González, Miguel Mostafa, Sabrina Casanova, M. Fernández Alonso, V. Joshi, Filiberto Hueyotl-Zahuantitla, and L. Nellen
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Active galactic nucleus, Radio galaxy, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Extragalactic background light, Space and Planetary Science, Observatory, Sky, Blazar, Astrophysics - High Energy Astrophysical Phenomena, Cherenkov radiation, media_common
Abstract: The High Altitude Water Cherenkov Gamma-Ray Observatory (HAWC) continuously detects TeV photons and particles within its large field-of-view, accumulating every day a deeper exposure of two thirds of the sky. We analyzed 1523~days of HAWC live data acquired over four and a half years, in a follow-up analysis of {138} nearby ($z, Comment: The HAWC survey of Fermi 3FHL AGNs: 30 pages, 13 figures. Submitted to the Astrophysical Journal
Published: 2020

21. 3HWC: The Third HAWC Catalog of Very-High-Energy Gamma-ray Sources

Author: Michael Newbold, O. Martinez, Segev BenZvi, F. Serna, Pooja Surajbali, Gus Sinnis, Fernando Garfias, S. Hernandez, A. Zepeda, Fernando Ureña-Mena, E. Ruiz-Velasco, H. Zhou, Y. Pérez Araujo, Nicola Omodei, Arturo Iriarte, A. Nayerhoda, L. Diaz-Cruz, K. P. Arunbabu, A. L. Longinotti, R. Diaz Hernandez, Mora Durocher, Petra Hüntemeyer, A. Sandoval, H. León Vargas, J. A. Morales-Soto, Michael Schneider, A. Jardin-Blicq, J. C. Arteaga-Velázquez, Harm Schoorlemmer, B. Hona, Gilgamesh Luis-Raya, K. Malone, T. N. Ukwatta, R. Noriega-Papaqui, Andrea Albert, Tomás Capistrán, Kwok Lung Fan, Humberto Ibarguen Salazar, William H. Lee, L. Olivera-Nieto, V. Baghmanyan, Alison Peisker, C. Brisbois, Henrike Fleischhack, A. Carraminana, Jose Andres Garcia-Gonzalez, C. Rivière, Mehr Nisa, Miguel Mostafa, D. Garcia, Joe Lundeen, Juan Carlos Diaz-Velez, John Matthews, R. López-Coto, J. P. Harding, R. W. Ellsworth, S. Coutiño de León, T. Weisgarber, V. Joshi, J. R. Angeles Camacho, Alejandro Lara, A. J. Smith, Ibrahim Torres, L. Nellen, J. D. Álvarez, Ke Fang, Ruben Alfaro, K. Tollefson, F. Salesa Greus, Daniel Rosa-Gonzalez, M. Fernández Alonso, C. Alvarez, Kristi Engel, Michael DuVernois, C. De León, E. De la Fuente, J. T. Linnemann, F. Werner, D. Avila Rojas, J. A. Goodman, Pedro Miranda-Romagnoli, Dezhi Huang, A. Galván-Gámez, Brenda Dingus, V. Marandon, Karen S. Caballero-Mora, Catalina Espinoza, Jesús Martínez-Castro, H. A. Ayala Solares, Gwenael Giacinti, I. Martinez-Castellanos, R. Torres-Escobedo, E. Moreno, R. W. Springer, E. G. Pérez-Pérez, David Kieda, Umberto Cotti, Sabrina Casanova, Ernesto Belmont-Moreno, Nissim Illich Fraija, Jim Hinton, Maria Magdalena González, Elijah Willox, Z. Ren, Filiberto Hueyotl-Zahuantitla, and C. D. Rho
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), High energy, High-energy astronomy, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Gamma-ray astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Pulsar, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics
Abstract: We present a new catalog of TeV gamma-ray sources using 1523 days of data from the High Altitude Water Cherenkov (HAWC) observatory. The catalog represents the most sensitive survey of the Northern gamma-ray sky at energies above several TeV, with three times the exposure compared to the previous HAWC catalog, 2HWC. We report 65 sources detected at $\geq$ 5 sigma significance, along with the positions and spectral fits for each source. The catalog contains eight sources that have no counterpart in the 2HWC catalog, but are within $1^\circ$ of previously detected TeV emitters, and twenty sources that are more than $1^\circ$ away from any previously detected TeV source. Of these twenty new sources, fourteen have a potential counterpart in the fourth \textit{Fermi} Large Area Telescope catalog of gamma-ray sources. We also explore potential associations of 3HWC sources with pulsars in the ATNF pulsar catalog and supernova remnants in the Galactic supernova remnant catalog., 20 pages, 11 figures. Matches the version published in The Astrophysical Journal. See accompanying data release at https://data.hawc-observatory.org/datasets/3hwc-survey/index.php
Published: 2020

22. HAWC J2227+610 and its association with G106.3+2.7, a new potential Galactic PeVatron

Author: E. Moreno, P. Hüntemeyer, R. Torres-Escobedo, Armelle Jardin-Blicq, R. Noriega-Papaqui, J. T. Linnemann, E. G. Pérez-Pérez, Karen S. Caballero-Mora, J. A. Goodman, J. R. Angeles Camacho, K. Tollefson, Catalina Espinoza, H. León Vargas, H. A. Ayala Solares, J. A. Morales-Soto, Segev BenZvi, A. Galván-Gámez, Luis Villaseñor, Sabrina Casanova, V. Joshi, K. Malone, K. P. Arunbabu, Kwok Lung Fan, D. Garcia, S. Hernandez, U. Cotti, Arnulfo Zepeda, E. De la Fuente, S. S. Marinelli, D. Avila Rojas, E. Belmont-Moreno, Mehr Nisa, Nicola Omodei, H. Schoorlemmer, Andrea Albert, J. P. Harding, F. Garfias, M. Newbold, A. Iriarte, J. D. Álvarez, E. Tabachnick, P. Surajbali, Meghan Tanner, A. J. Smith, B. Hona, C. De León, M. Fernández Alonso, T. Capistrán, P. Miranda-Romagnoli, A. Sandoval, G. Luis-Raya, R. W. Ellsworth, Michael Schneider, Jose Andres Garcia-Gonzalez, E. Ruiz-Velasco, S. Coutiño de León, C. Brisbois, M. Mostafá, Y. Pérez Araujo, J. C. Díaz-Vélez, R. W. Springer, Daniel Rosa-Gonzalez, Amid Nayerhoda, T. Weisgarber, Brenda Dingus, Maria Magdalena González, Nissim Fraija, G. Sinnis, Ke Fang, H. Salazar, Lukas Nellen, Hongyan Zhou, J.C. Arteaga-Velázquez, Michael DuVernois, A. Carramiñana, I. Torres, Gwenael Giacinti, F. Ureña-Mena, Filiberto Hueyotl-Zahuantitla, J. Serna Franco, I. Martinez-Castellanos, C. Alvarez, K. Engel, Ruben Alfaro, C. D. Rho, F. Salesa Greus, A. L. Longinotti, W. H. Lee, A. Peisker, L. Diaz-Cruz, D. Huang, J. Cotzomi, J. Martínez-Castro, O. Tibolla, Henrike Fleischhack, J. Hinton, J. Lundeen, Vardan Baghmanyan, John Matthews, Oscar Martinez, and HAWC Collaboration
Subjects: HAWC - Abteilung Hinton, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Hydrogen compounds, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Lower limit, Galaxy, Space and Planetary Science, Observatory, 0103 physical sciences, Supernova remnant, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract: We present the detection of VHE gamma-ray emission above 100 TeV from HAWC J2227+610 with the HAWC observatory. Combining our observations with previously published results by VERITAS, we interpret the gamma-ray emission from HAWC J2227+610 as emission from protons with a lower limit in their cutoff energy of 800 TeV. The most likely source of the protons is the associated supernova remnant G106.3+2.7, making it a good candidate for a Galactic PeVatron. However, a purely leptonic origin of the observed emission cannot be excluded at this time., Accepted for publication by ApJL
Published: 2020

23. HAWC and Fermi-LAT Detection of Extended Emission from the Unidentified Source 2HWC J2006+341

Author: E. Moreno, Nissim Illich Fraija, Nicola Omodei, Pedro Miranda-Romagnoli, Alison Peisker, Arturo Iriarte, L. Nellen, Henrike Fleischhack, Fernando Ureña-Mena, C. Alvarez, Andrea Albert, F. Salesa Greus, Mora Durocher, Petra Hüntemeyer, A. Zepeda, D. Garcia, R. W. Springer, Mehr Nisa, C. Brisbois, H. Zhou, Miguel Mostafa, E. G. Pérez-Pérez, E. De la Fuente, John Matthews, D. Avila Rojas, K. P. Arunbabu, Michael DuVernois, Ibrahim Torres, V. Joshi, A. Galván-Gámez, C. De León, Jose Andres Garcia-Gonzalez, R. Torres-Escobedo, R. Diaz Hernandez, K. Malone, Miguel Araya, A. Carraminana, V. Baghmanyan, Brenda Dingus, Karen S. Caballero-Mora, Catalina Espinoza, R. López-Coto, Anna Lia Longinotti, Jesús Martínez-Castro, Joe Lundeen, H. A. Ayala Solares, K. Tollefson, O. Martinez, A. Jardin-Blicq, Ruben Alfaro, Gilgamesh Luis-Raya, Juan Carlos Diaz-Velez, J. R. Angeles Camacho, Umberto Cotti, Daniel Rosa-Gonzalez, Sabrina Casanova, R. Noriega-Papaqui, J. T. Linnemann, Dezhi Huang, J. C. Arteaga-Velázquez, B. Hona, J. A. Goodman, Fernando Garfias, Maria Magdalena González, Ernesto Belmont-Moreno, Filiberto Hueyotl-Zahuantitla, H. León Vargas, A. Sandoval, Michael Schneider, Elijah Willox, J. P. Harding, C. D. Rho, T. Weisgarber, and Luis Villaseñor
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Interstellar medium, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Fermi Gamma-ray Space Telescope
Abstract: The discovery of the TeV point source 2HWC J2006+341 was reported in the second HAWC gamma-ray catalog. We present a follow-up study of this source here. The TeV emission is best described by an extended source with a soft spectrum. At GeV energies, an extended source is significantly detected in Fermi-LAT data. The matching locations, sizes and spectra suggest that both gamma-ray detections correspond to the same source. Different scenarios for the origin of the emission are considered and we rule out an association to the pulsar PSR J2004+3429 due to extreme energetics required, if located at a distance of 10.8 kpc., Comment: 12 pages, 2 figures. To appear in ApJL
Published: 2020
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24. Constraining the local burst rate density of primordial black holes with HAWC

Author: E. G. Pérez-Pérez, U. Cotti, S. Hernandez, A. J. Smith, T. Capistrán, J.C. Arteaga-Velázquez, K. Malone, W. H. Lee, J. Cotzomi, E. Tabachnick, R. Noriega-Papaqui, E. Belmont-Moreno, A. Iriarte, Joe Lundeen, B. Hona, S. S. Marinelli, Lukas Nellen, Hao Zhou, Alejandro Lara, G. Sinnis, Michael DuVernois, F. Garfias, I. Torres, A. Carramiñana, K. Tollefson, J. Martínez-Castro, Mehr Nisa, C. D. Rho, J. C. Díaz-Vélez, Nissim Fraija, O. Tibolla, C. De León, I. Martinez-Castellanos, E. De la Fuente, Karen S. Caballero-Mora, G. Luis-Raya, R. W. Ellsworth, H. Fleischhack, R. López-Coto, K. Engel, F. Salesa Greus, C. Brisbois, Jose Andres Garcia-Gonzalez, R. W. Springer, A. Galván-Gámez, Sabrina Casanova, H. Martínez-Huerta, V. Joshi, Brenda Dingus, Catalina Espinoza, John N. Wood, H. Salazar, Segev BenZvi, C. Alvarez, Vardan Baghmanyan, A. L. Longinotti, Alison Peisker, John Matthews, K. P. Arunbabu, Oscar Martinez, D. Avila Rojas, H. A. Ayala Solares, Daniel Rosa-Gonzalez, Amid Nayerhoda, Andrea Albert, M. Newbold, M. J. F. Rosenberg, Meghan Tanner, P. Miranda-Romagnoli, P. Hüntemeyer, R. Torres-Escobedo, J. P. Harding, C. Rivière, J. T. Linnemann, Maria Magdalena González, A. Sandoval, J. A. Goodman, Michael Schneider, H. León Vargas, Dezhi Huang, J. A. Morales-Soto, M. Mostafá, Filiberto Hueyotl-Zahuantitla, T. Weisgarber, Arnulfo Zepeda, Ruben Alfaro, and E. Moreno
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Solar mass, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Primordial black hole, Astrophysics, Universe, High Energy Physics - Experiment, 85-05, Black hole, High Energy Physics - Experiment (hep-ex), RAIOS GAMA, Observatory, Astrophysics - High Energy Astrophysical Phenomena, Cherenkov radiation, Hawking radiation, media_common
Abstract: Primordial Black Holes (PBHs) may have been created by density fluctuations in the early Universe and could be as massive as $> 10^9$ solar masses or as small as the Planck mass. It has been postulated that a black hole has a temperature inversely-proportional to its mass and will thermally emit all species of fundamental particles via Hawking Radiation. PBHs with initial masses of $\sim 5 \times 10^{14}$ g (approximately one gigaton) should be expiring today with bursts of high-energy gamma radiation in the GeV--TeV energy range. The High Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays with energies of $\sim$300 GeV to past 100 TeV, which corresponds to the high end of the PBH burst spectrum. With its large instantaneous field-of-view of $\sim 2$ sr and a duty cycle over 95%, the HAWC Observatory is well suited to perform an all-sky search for PBH bursts. We conducted a search using 959 days of HAWC data and exclude the local PBH burst rate density above $3400~\mathrm{pc^{-3}~yr^{-1}}$ at 99% confidence, the strongest limit on the local PBH burst rate density from any existing electromagnetic measurement., Corresponding authors: K.L. Engel & A. Peisker. 13 pages, 5 figures
Published: 2020

25. Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

Author: J. C. Arteaga-Velázquez, Karen S. Caballero-Mora, S. Hernandez, A. Carraminana, Maria Magdalena González, Z. Ren, Filiberto Hueyotl-Zahuantitla, Dezhi Huang, Catalina Espinoza, J. Pretz, Joe Lundeen, Miguel Mostafa, Gilgamesh Luis-Raya, John Matthews, Jesús Martínez-Castro, R. W. Ellsworth, H. A. Ayala Solares, J. A. Morales-Soto, Tomás Capistrán, S. S. Marinelli, C. Brisbois, Haocheng Zhang, V. Joshi, Luis Villaseñor, Ruben Alfaro, C. Rivière, R. W. Springer, Ibrahim Torres, Anushka Udara Abeysekara, Fernando Garfias, Michael Newbold, Daniel Rosa-Gonzalez, E. G. Pérez-Pérez, A. Nayerhoda, Thomas Weisgarber, A. Galván-Gámez, S. Coutiño de León, E. Ruiz-Velasco, S. Kaufmann, Hao Zhou, Segev BenZvi, J. A. Goodman, Alejandro Lara, Chang Dong Rho, Alison Peisker, Pedro Miranda-Romagnoli, H. León Vargas, E. Moreno, Kristi Engel, Umberto Cotti, Ernesto Belmont-Moreno, K. P. Arunbabu, David Kieda, Jim Hinton, J C Díaz-Vélez, Brenda Dingus, R. López-Coto, Andrea Albert, Henrike Fleischhack, Sabrina Casanova, A. Sandoval, Jorge Cotzomi, R. Torres-Escobedo, Arturo Iriarte, Anna Lia Longinotti, Kelly Malone, Meghan Tanner, Michael Schneider, Harm Schoorlemmer, E. Tabachnick, Nissim Illich Fraija, R. Noriega-Papaqui, M. U. Nisa, O. Tibolla, J. T. Linnemann, William H. Lee, D. Garcia, J. P. Harding, Binita Hona, O. Martinez, I. Martinez-Castellanos, K. Tollefson, Pooja Surajbali, Gus Sinnis, J. Wood, J. R. Angeles Camacho, T. Yapici, H. Martínez-Huerta, Jose Andres Garcia-Gonzalez, Petra Hüntemeyer, E. De la Fuente, D. Avila Rojas, A. J. Smith, L. Nellen, V. Baghmanyan, C. De León, Armelle Jardin-Blicq, Michael DuVernois, F. Salesa Greus, M. J. F. Rosenberg, Simone Dichiara, and HAWC Collaboration
Subjects: Physics, HAWC - Abteilung Hinton, High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, General Physics and Astronomy, Flux, Astronomy, FOS: Physical sciences, ASTROFÍSICA, Effects of high altitude on humans, 01 natural sciences, Spectral line, Observatory, 0103 physical sciences, 010306 general physics, Astrophysics - High Energy Astrophysical Phenomena, Cherenkov radiation
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., Accepted by Physical Review Letters
Published: 2019

26. Constraints on Lorentz invariance violation from HAWC observations of gamma rays above 100 TeV

Author: Maria Magdalena González, Filiberto Hueyotl-Zahuantitla, J. A. Morales-Soto, Gilgamesh Luis-Raya, C. De León, O. Tibolla, G. B. Yodh, Chang Dong Rho, Michael Newbold, H. Martínez-Huerta, Alison Peisker, Pooja Surajbali, Anna Lia Longinotti, Gus Sinnis, V. Baghmanyan, Ibrahim Torres, A. Nayerhoda, A. Sandoval, K. Tollefson, J. R. Angeles Camacho, A. Zepeda, A. J. Smith, Hao Zhou, Henrike Fleischhack, F. Salesa Greus, E. Moreno, Ernesto Belmont-Moreno, A. Carraminana, M. J. F. Rosenberg, Michael Schneider, Joe Lundeen, L. Nellen, S. Hernandez, Humberto Ibarguen Salazar, K. P. Arunbabu, R. López-Coto, Petra Hüntemeyer, Binita Hona, Nicola Omodei, S. Coutiño de León, R. W. Ellsworth, Chad Brisbois, Michael DuVernois, Arturo Iriarte, D. Garcia, Kristi Engel, Alejandro Lara, Andrea Albert, C. Alvarez, K. Malone, R. Torres-Escobedo, M. U. Nisa, V. Joshi, Segev BenZvi, C. Rivière, Meghan Tanner, John Matthews, Harm Schoorlemmer, E. Tabachnick, Pedro Miranda-Romagnoli, R. Noriega-Papaqui, J. A. Goodman, E. De la Fuente, D. Avila Rojas, Jose Andres Garcia-Gonzalez, William H. Lee, Nissim Illich Fraija, Dezhi Huang, Karen S. Caballero-Mora, J. P. Harding, Catalina Espinoza, Ruben Alfaro, Tomás Capistrán, Jesús Martínez-Castro, H. A. Ayala Solares, Daniel Rosa-Gonzalez, S. S. Marinelli, R. W. Springer, Jorge Cotzomi, A. Galván-Gámez, E. G. Pérez-Pérez, Brenda Dingus, Juan Carlos Diaz-Velez, I. Martinez-Castellanos, Umberto Cotti, Sabrina Casanova, J. T. Linnemann, Fernando Garfias, Thomas Weisgarber, E. Ruiz-Velasco, H. León Vargas, and J. C. Arteaga-Velázquez
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Photon, Planck energy, Superluminal motion, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, General Physics and Astronomy, ASTROFÍSICA, Astrophysics, Lorentz covariance, 01 natural sciences, symbols.namesake, Orders of magnitude (time), Observatory, 0103 physical sciences, symbols, 010306 general physics, Astrophysics - High Energy Astrophysical Phenomena, Cherenkov radiation
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., Accepted for publication in Physical Review Letters
Published: 2019

27. Data acquisition architecture and online processing system for the HAWC gamma-ray observatory

Author: Jorge Cotzomi, P. Karn, Fernando Garfias, M. Longo Proper, Anushka Udara Abeysekara, Petra Hüntemeyer, Thomas Weisgarber, J. P. Harding, T. Yapici, F. Salesa Greus, Alberto Carramiñana, A. Imran, Ruben Alfaro, H. León Vargas, Daniel Rosa-Gonzalez, T. N. Ukwatta, Varlen Grabski, R. Arceo, Pedro Miranda-Romagnoli, M. Bonilla Rosales, Michael Newbold, A. J. Smith, O. Martinez, Michael DuVernois, Nissim Illich Fraija, James E. Braun, E. De la Fuente, R. Noriega-Papaqui, R. A. Caballero-Lopez, J. C. Arteaga-Velázquez, Gerd Joachim Kunde, D. Berley, N. Bautista-Elivar, James M. Ryan, A. Sandoval, G. Sinnis, J. Becerra González, L. Nellen, William H. Lee, J. Pretz, S. S. Marinelli, E. Mendoza Torres, James W. Wood, Kelly Malone, C. M. Hui, Hao Zhou, C. De León, Umberto Cotti, H. Martínez-Huerta, Julie McEnery, Michael Schneider, I. G. Wisher, Edna Ruiz-Velasco, R. W. Springer, E. G. Pérez-Pérez, Tyce DeYoung, P. A. Toale, I. Taboada, K. Sparks Woodle, C. Alvarez, Rodrigo Pelayo, E. C. Linares, J. A.J. Matthews, A. Marinelli, A. Zepeda, David Kieda, S. Westerhoff, F. E. Sanchez, M. Castillo, Humberto Ibarguen Salazar, Juan Carlos Diaz-Velez, P. W. Younk, D. W. Fiorino, Dirk Lennarz, E. Moreno, J. D. Álvarez, Maria Magdalena González, Arturo Iriarte, T. Oceguera-Becerra, R. J. Lauer, A. Galindo, Karen S. Caballero-Mora, Jesús Martínez-Castro, H. A. Ayala Solares, K. Tollefson, Alejandro Lara, Z. Hampel-Arias, R. Diaz Hernandez, Ibrahim Torres, D. Zaborov, J. T. Linnemann, G. B. Yodh, A. S. Barber, R. W. Ellsworth, S. Silich, B. M. Baughman, C. Rivière, L. Villaseñor, J. A. Goodman, Ernesto Belmont-Moreno, Miguel Mostafa, Segev BenZvi, J. Diaz-Cruz, M. Gussert, B. Patricelli, Brenda Dingus, and R. Luna-Garcia
Subjects: Physics, Nuclear and High Energy Physics, business.industry, Gigabit Ethernet, Electrical engineering, FOS: Physical sciences, Dead time, 01 natural sciences, Data processing system, Time-to-digital converter, Air shower, Data acquisition, Observatory, 0103 physical sciences, Custom software, Astrophysics - Instrumentation and Methods for Astrophysics, 010306 general physics, business, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Instrumentation, Computer hardware
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., 14 pages, 3 figures, submitted to Nucl. Instrum. Meth. A
Published: 2018

28. Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC

Author: Jorge Cotzomi, Fernando Garfias, Ernesto Belmont-Moreno, S. Kaufmann, Thomas Weisgarber, Jim Hinton, K. Tollefson, E. Ruiz-Velasco, J. A. Morales-Soto, T. Yapici, H. León Vargas, Arturo Iriarte, S. S. Marinelli, R. W. Springer, Simone Dichiara, Harm Schoorlemmer, Umberto Cotti, C. Rivière, Sabrina Casanova, V. Joshi, R. Noriega-Papaqui, E. G. Pérez-Pérez, William H. Lee, Maria Magdalena González, Jose Andres Garcia-Gonzalez, J. C. Arteaga-Velázquez, O. Martinez, S. Hernandez, Andrea Albert, A. Galván-Gámez, V. Baghmanyan, David Kieda, A. Carraminana, J. A. Goodman, M. J. F. Rosenberg, R. Arceo, Brenda Dingus, Joe Lundeen, S. Coutiño de León, Pooja Surajbali, C. Alvarez, C. M. Hui, O. Tibolla, Gus Sinnis, Chad Brisbois, Michael DuVernois, J. Wood, Meghan Tanner, Z. Ren, R. W. Ellsworth, Brian Fick, E. Moreno, Filiberto Hueyotl-Zahuantitla, Alejandro Lara, Hao Zhou, Petra Hüntemeyer, Binita Hona, Karen S. Caballero-Mora, J. D. Álvarez, Catalina Espinoza, J. T. Linnemann, C. De León, Jesús Martínez-Castro, H. A. Ayala Solares, J. Pretz, Nissim Illich Fraija, E. De la Fuente, I. Martinez-Castellanos, D. Avila Rojas, L. Nellen, Armelle Jardin-Blicq, Ruben Alfaro, Ibrahim Torres, Kelly Malone, M. Seglar Arroyo, Alison Peisker, A. Sandoval, A. Nayerhoda, Michael Schneider, J. R. Angeles Camacho, Henrike Fleischhack, F. Salesa Greus, Daniel Rosa-Gonzalez, Segev BenZvi, A. J. Smith, J. P. Harding, Kristi Engel, John Matthews, Juan Carlos Diaz-Velez, Chang Dong Rho, Tomás Capistrán, Humberto Ibarguen Salazar, Mehr Nisa, Michael Newbold, Miguel Mostafa, Anushka Udara Abeysekara, Gilgamesh Luis-Raya, E. Tabachnick, Anna Lia Longinotti, A. Zepeda, K. P. Arunbabu, S. Westerhoff, H. Martínez-Huerta, and Pedro Miranda-Romagnoli
Subjects: HAWC - Abteilung Hinton, High Energy Astrophysical Phenomena (astro-ph.HE), Astroparticle physics, Physics, ISM: individual objects (Crab Nebula), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, gamma rays: general, acceleration of particles, astroparticle physics, Crab Nebula, Space and Planetary Science, ACELERAÇÃO DE PARTÍCULAS, High Energy Physics::Experiment, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
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

29. Science Case for a Wide Field-of-View Very-High-Energy Gamma-Ray Observatory in the Southern Hemisphere

Author: Harm Schoorlemmer, J. C. Arteaga-Velázquez, M. J. Martínez González, A. J. S. Smith, Mosè Mariotti, O. Tibolla, Sergio Dasso, Jose A. Bellido, M. Seglar-Arroyo, L. Nellen, P. Cristofari, F. Schüssler, R. Arceo, S. Coutiño de León, Arturo Iriarte, J. M. Alvarez, Marcos Santander, Chad Brisbois, Nissim Illich Fraija, Michael DuVernois, E. de Oña Wilhelmi, R. D. Parsons, Samridha Kunwar, A. Carosi, A. Pichel, Jose Andres Garcia-Gonzalez, A. Carramiñana, Samuel Timothy Spencer, E. Pueschel, H. Martínez-Huerta, E. Tabachnick, J. P. Harding, Thomas Weisgarber, Henrike Fleischhack, J. L. Rodriguez, C. Alvarez, E. Prandini, E. De la Fuente, S. Y. BenZvi, B. Vallage, T. K. Sako, R. López-Coto, K. Link, Hao Zhou, Ibrahim Torres, F.O. de Oliveira Salles, R. Alfaro, P. M. Chadwick, J. G. Gonzalez, S. Procureur, Aion Viana, Miguel Mostafa, A. Haungs, A. Sandoval, Julien Lefaucheur, A. Zepeda, P. Huentemeyer, A. C. Rovero, Edna Ruiz-Velasco, B. Patricelli, Sarah Kaufmann, R. Yang, Gavin Rowell, Kristi Engel, J-F. Glicenstein, D. Hoyos, Juan Carlos Diaz-Velez, V. de Souza, J. A. Goodman, Armelle Jardin-Blicq, T. Sako, J.-P. Lenain, Pooja Surajbali, A.M. Taylor, F. Werner, Konstancja Satalecka, Stefan Funk, Paolo Desiati, Jim Hinton, Quentin Piel, Halim Ashkar, R. Wischnewski, Daniela Dorner, Sabrina Casanova, V. Joshi, G. Di Sciascio, Thomas Bretz, Francois Brun, A. M. Brown, Karen S. Caballero-Mora, A. Nayerhoda, R. White, Jesús Martínez-Castro, H. A. Ayala Solares, Andrea Albert, Colas Rivière, Binita Hona, K. Kawata, Andreas Reisenegger, Jason John Watson, Brenda Dingus, V. Marandon, and Garret Cotter
Subjects: Physics, 010308 nuclear & particles physics, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Particle accelerator, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Cherenkov Telescope Array, 7. Clean energy, 01 natural sciences, Galaxy, law.invention, Air shower, 13. Climate action, law, Observatory, Sky, 0103 physical sciences, 010303 astronomy & astrophysics, media_common
Abstract: We outline the science motivation for SGSO, the Southern Gamma-Ray Survey Observatory. SGSO will be a next-generation wide field-of-view gamma-ray survey instrument, sensitive to gamma-rays in the energy range from 100 GeV to hundreds of TeV. Its science topics include unveiling galactic and extragalactic particle accelerators, monitoring the transient sky at very high energies, probing particle physics beyond the Standard Model, and the characterization of the cosmic ray flux. SGSO will consist of an air shower detector array, located in South America. Due to its location and large field of view, SGSO will be complementary to other current and planned gamma-ray observatories such as HAWC, LHAASO, and CTA.
Published: 2019

30. Search for Gamma-ray Spectral Lines from Dark Matter Annihilation in Dwarf Galaxies with the High-Altitude Water Cherenkov Observatory

Author: J. A. Morales-Soto, Hao Zhou, K. Malone, C. Alvarez, Ernesto Belmont-Moreno, E. Tabachnick, A. Galván-Gámez, E. De la Fuente, D. Avila Rojas, Tomás Capistrán, C. De León, J. P. Harding, Brenda Dingus, Arturo Iriarte, J. C. Arteaga-Velázquez, O. Martinez, P. Huentemeyer, Andrea Albert, James W. Wood, K. Tollefson, Binita Hona, Juan Carlos Diaz-Velez, Dezhi Huang, Alison Peisker, A. Sandoval, L. Nellen, Michael Schneider, Fernando Garfias, J. T. Linnemann, S. Hernandez, Ibrahim Torres, Nissim Illich Fraija, Thomas Weisgarber, A. Carraminana, Michael DuVernois, R. Noriega-Papaqui, Karen S. Caballero-Mora, Joe Lundeen, H. León Vargas, S. S. Marinelli, C. Brisbois, Catalina Espinoza, I. Martinez-Castellanos, R. W. Springer, Umberto Cotti, Anna Lia Longinotti, E. G. Pérez-Pérez, S. Coutiño de León, Jesús Martínez-Castro, Sabrina Casanova, Kristi Engel, H. A. Ayala Solares, Alejandro Lara, J. A. Goodman, Jose Andres Garcia-Gonzalez, Jorge Cotzomi, F. Salesa Greus, O. Tibolla, Ruben Alfaro, R. Torres-Escobedo, Simone Dichiara, Daniel Rosa-Gonzalez, Chang Dong Rho, John Matthews, Humberto Ibarguen Salazar, Michael Newbold, Miguel Mostafa, V. Joshi, Pedro Miranda-Romagnoli, M. J. F. Rosenberg, A. Zepeda, K. P. Arunbabu, Gilgamesh Luis-Raya, E. Moreno, Maria Magdalena González, Filiberto Hueyotl-Zahuantitla, Segev BenZvi, A. Nayerhoda, and M. U. Nisa
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Annihilation, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, Gamma ray, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Effects of high altitude on humans, Spectral line, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Observatory, Astrophysics - High Energy Astrophysical Phenomena, Cherenkov radiation, Dwarf galaxy
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 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., submitted to PRD
Published: 2019
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31. First HAWC Observations of the Sun Constrain Steady TeV Gamma-Ray Emission

Author: E. Moreno, P. Surajbali, Hao Zhou, Annika H. G. Peter, J. Wood, J. P. Harding, O. Enríquez-Rivera, Fernando Garfias, Z. Ren, A. Iriarte, J. C. Arteaga-Velázquez, F. Salesa Greus, J. Martínez-Castro, E. De la Fuente, Joe Lundeen, D. Avila Rojas, Harm Schoorlemmer, A. Albert, S. Westerhoff, M. Seglar Arroyo, Z. Hampel-Arias, Jose Andres Garcia-Gonzalez, M. J. F. Rosenberg, T. Weisgarber, E. G. Pérez-Pérez, S. Dichiara, R. W. Springer, Edna Ruiz-Velasco, Rebecca K. Leane, I. Torres, Petra Hüntemeyer, R. López-Coto, O. Martinez, M. Mostafá, T. Yapici, H. Salazar, Juan Carlos Diaz-Velez, B. Hona, S. Kaufmann, L. Nellen, I. Martinez-Castellanos, Cristobal M. Espinoza, Kenny C. Y. Ng, C. D. Rho, N. Fraija, M. M. González, T. Capistrán, Filiberto Hueyotl-Zahuantitla, E. Belmont-Moreno, A. Nayerhoda, John F. Beacom, Brenda Dingus, Michael Schneider, I. G. Wisher, S. Coutiño de León, Henrike Fleischhack, C. Alvarez, Segev BenZvi, J. Cotzomi, A. Carramiñana, Sabrina Casanova, O. Tibolla, S. S. Marinelli, G. Sinnis, A. Sandoval, T. Linden, Chad Brisbois, Michael DuVernois, V. Joshi, R. Arceo, P. Miranda-Romagnoli, M. Newbold, Karen S. Caballero-Mora, H. A. Ayala Solares, A. Jardin-Blicq, Kristi Engel, M. Castillo, H. León Vargas, Mehr Nisa, I. Taboada, Bei Zhou, K. Tollefson, C. De León, Jdr Alvarez, C. Rivière, A. Zepeda, Jennifer Pretz, Daniel Rosa-Gonzalez, R. Alfaro, A. J. Smith, R. Noriega-Papaqui, G. Luis-Raya, S. Hernandez, L. Villaseñor, J. A. Goodman, K. Malone, and HAWC Collaboration
Subjects: Solar minimum, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Flux, FOS: Physical sciences, Cosmic ray, Astrophysics, 7. Clean energy, 01 natural sciences, Atmosphere, High Energy Physics - Phenomenology (hep-ph), Observatory, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Cherenkov radiation, Solar and Stellar Astrophysics (astro-ph.SR), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), HAWC - Abteilung Hinton, 010308 nuclear & particles physics, Gamma ray, High Energy Physics - Phenomenology, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Steady gamma-ray emission up to at least 200 GeV has been detected from the solar disk in the Fermi-LAT data, with the brightest, hardest emission occurring during solar minimum. The likely cause is hadronic cosmic rays undergoing collisions in the Sun's atmosphere after being redirected from ingoing to outgoing in magnetic fields, though the exact mechanism is not understood. An important new test of the gamma-ray production mechanism will follow from observations at higher energies. Only the High Altitude Water Cherenkov (HAWC) Observatory has the required sensitivity to effectively probe the Sun in the TeV range. Using three years of HAWC data from November 2014 to December 2017, just prior to the solar minimum, we search for 1--100 TeV gamma rays from the solar disk. No evidence of a signal is observed, and we set strong upper limits on the flux at a few $10^{-12}$ TeV$^{-1}$ cm$^{-2}$ s$^{-1}$ at 1 TeV. Our limit, which is the most constraining result on TeV gamma rays from the Sun, is $\sim10\%$ of the theoretical maximum flux (based on a model where all incoming cosmic rays produce outgoing photons), which in turn is comparable to the Fermi-LAT data near 100 GeV. The prospects for a first TeV detection of the Sun by HAWC are especially high during solar minimum, which began in early 2018., Comment: 14 pages, 6 figures. See also companion paper 1808.05624. Accepted for publication in Physical Review D
Published: 2018

32. Interplanetary Magnetic Flux Rope Observed at Ground Level by HAWC

Author: J. R. Angeles Camacho, A. Iriarte, Nissim Fraija, James Ryan, J. Martínez-Castro, Luis Villaseñor, J.C. Arteaga-Velázquez, D. Garcia, Tatiana Niembro, E. Moreno, F. Salesa Greus, John Matthews, Luis Preisser, Alejandro Lara, E. G. Pérez-Pérez, J. P. Harding, U. Cotti, K. Malone, T. Capistrán, G. Luis-Raya, A. Carramiñana, D. Avila Rojas, E. De la Fuente, M. Newbold, Amid Nayerhoda, Maria Magdalena González, Teresa Nieves-Chinchilla, B. Hona, Filiberto Hueyotl-Zahuantitla, A. Galván-Gámez, Sabrina Casanova, P. Miranda-Romagnoli, V. Joshi, K. P. Arunbabu, E. Belmont-Moreno, R. Noriega-Papaqui, Jose Andres Garcia-Gonzalez, Ruben Alfaro, I. Torres, Sachiko Akiyama, C. D. Rho, Gerd J. Kunde, D. Huang, J. Cotzomi, Karen S. Caballero-Mora, Catalina Espinoza, H. A. Ayala Solares, C. De León, F. Garfias, R. Diaz Hernandez, Arnulfo Zepeda, A. Sandoval, F. Ureña-Mena, H. León Vargas, Lukas Nellen, R. W. Springer, H. Salazar, C. Alvarez, David Kieda, P. Hüntemeyer, J. A. Goodman, and P. Colin-Farias
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Geomagnetic storm, 010504 meteorology & atmospheric sciences, Turbulence, FOS: Physical sciences, Flux, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Magnetic flux, Physics::Geophysics, Magnetic field, Earth's magnetic field, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Interplanetary spaceflight, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract: We report the ground-level detection of a Galactic Cosmic-Ray (GCR) flux enhancement lasting $\sim$ 17 hr and associated with the passage of a magnetic flux rope (MFR) over the Earth. The MFR was associated with a slow Coronal Mass Ejection (CME) caused by the eruption of a filament on 2016 October 9. Due to the quiet conditions during the eruption and the lack of interactions during the interplanetary CME transport to the Earth, the associated MFR preserved its configuration and reached the Earth with a strong magnetic field, low density, and a very low turbulence level compared to the local background, thus generating the ideal conditions to redirect and guide GCRs (in the $\sim$ 8 to 60 GV rigidity range) along the magnetic field of the MFR. An important negative $B_Z$ component inside the MFR caused large disturbances in the geomagnetic field and a relatively strong geomagnetic storm. However, these disturbances are not the main factors behind the GCR enhancement. Instead, we found that the major factor was the alignment between the MFR axis and the asymptotic direction of the observer.
Published: 2020

33. Very-high-energy particle acceleration powered by the jets of the microquasar SS 433

Author: A U, Abeysekara, A, Albert, R, Alfaro, C, Alvarez, J D, Álvarez, R, Arceo, J C, Arteaga-Velázquez, D, Avila Rojas, H A, Ayala Solares, E, Belmont-Moreno, S Y, BenZvi, C, Brisbois, K S, Caballero-Mora, T, Capistrán, A, Carramiñana, S, Casanova, M, Castillo, U, Cotti, J, Cotzomi, S, Coutiño de León, C, De León, E, De la Fuente, J C, Díaz-Vélez, S, Dichiara, B L, Dingus, M A, DuVernois, R W, Ellsworth, K, Engel, C, Espinoza, K, Fang, H, Fleischhack, N, Fraija, A, Galván-Gámez, J A, García-González, F, Garfias, A, González-Muñoz, M M, González, J A, Goodman, Z, Hampel-Arias, J P, Harding, S, Hernandez, J, Hinton, B, Hona, F, Hueyotl-Zahuantitla, C M, Hui, P, Hüntemeyer, A, Iriarte, A, Jardin-Blicq, V, Joshi, S, Kaufmann, P, Kar, G J, Kunde, R J, Lauer, W H, Lee, H, León Vargas, H, Li, J T, Linnemann, A L, Longinotti, G, Luis-Raya, R, López-Coto, K, Malone, S S, Marinelli, O, Martinez, I, Martinez-Castellanos, J, Martínez-Castro, J A, Matthews, P, Miranda-Romagnoli, E, Moreno, M, Mostafá, A, Nayerhoda, L, Nellen, M, Newbold, M U, Nisa, R, Noriega-Papaqui, J, Pretz, E G, Pérez-Pérez, Z, Ren, C D, Rho, C, Rivière, D, Rosa-González, M, Rosenberg, E, Ruiz-Velasco, F, Salesa Greus, A, Sandoval, M, Schneider, H, Schoorlemmer, M, Seglar Arroyo, G, Sinnis, A J, Smith, R W, Springer, P, Surajbali, I, Taboada, O, Tibolla, K, Tollefson, I, Torres, G, Vianello, L, Villaseñor, T, Weisgarber, F, Werner, S, Westerhoff, J, Wood, T, Yapici, G, Yodh, A, Zepeda, H, Zhang, and H, Zhou
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)
Published: 2018

34. Constraining the p¯/p ratio in TeV cosmic rays with observations of the Moon shadow by HAWC

Author: Ernesto Belmont-Moreno, John N. Wood, E. G. Pérez-Pérez, Kelly Malone, R. W. Springer, J. C. Arteaga-Velázquez, M. J. Martínez González, Arturo Iriarte, A. J. S. Smith, S. Hernandez, Ruben Alfaro, E. Moreno, Edna Ruiz-Velasco, Pooja Surajbali, Andrés Sandoval, O. Martinez, Daniel Rosa-Gonzalez, C. M. Hui, Simone Dichiara, A. González Muñoz, F. Salesa Greus, C. De León, Tomás Capistrán, L. Villaseñor, Anushka Udara Abeysekara, Thomas Weisgarber, Nissim Illich Fraija, J. A. Matthews, G. Sinnis, M. Seglar Arroyo, O. Enríquez-Rivera, Pedro Miranda-Romagnoli, James E. Braun, H. León Vargas, Ibrahim Torres, Petra Hüntemeyer, R. López-Coto, Michael Schneider, S. Westerhoff, Armelle Jardin-Blicq, Chang Dong Rho, Henrike Fleischhack, C. Alvarez, Omar Tibolla, Binita Hona, Jorge Cotzomi, Jdr Alvarez, S. Kaufmann, E. De la Fuente, A. Albert, D. Avila Rojas, R. Arceo, G. B. Yodh, T. Yapici, Z. Hampel-Arias, L. Nellen, Chad Brisbois, S. Coutiño de León, M. J. F. Rosenberg, Michael DuVernois, M. Castillo, R. Diaz Hernandez, J. P. Harding, Jose Andres Garcia-Gonzalez, Gilgamesh Luis-Raya, Alejandro Lara, J. Pretz, Anna Lia Longinotti, Kristi Engel, H. Martínez-Huerta, Hongyan Zhou, Umberto Cotti, Z. Ren, Filiberto Hueyotl-Zahuantitla, I. Taboada, Sabrina Casanova, V. Joshi, A. Zepeda, Harm Schoorlemmer, Miguel Mostafa, Michael Newbold, Karen S. Caballero-Mora, Jesús Martínez-Castro, H. A. Ayala Solares, Colas Rivière, R. Pelayo, A. Carraminana, R. Noriega-Papaqui, William H. Lee, S. Y. BenZvi, R. W. Ellsworth, M. U. Nisa, J. T. Linnemann, R. Luna-Garcia, I. Martinez-Castellanos, A. Galván-Gámez, Brenda Dingus, and S. S. Marinelli
Subjects: Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Astrophysics, 01 natural sciences, Magnetic field, Earth's magnetic field, Deflection (physics), Observatory, Antiproton, Physics::Space Physics, 0103 physical sciences, 010306 general physics, Cherenkov radiation
Abstract: An indirect measurement of the antiproton flux in cosmic rays is possible as the particles undergo deflection by the geomagnetic field. This effect can be measured by studying the deficit in the flux, or shadow, created by the Moon as it absorbs cosmic rays that are headed towards the Earth. The shadow is displaced from the actual position of the Moon due to geomagnetic deflection, which is a function of the energy and charge of the cosmic rays. The displacement provides a natural tool for momentum/charge discrimination that can be used to study the composition of cosmic rays. Using 33 months of data comprising more than 80 billion cosmic rays measured by the High Altitude Water Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for TeV antiprotons in cosmic rays. We present our first upper limits on the $\bar{p}/p$ fraction, which in the absence of any direct measurements, provide the tightest available constraints of $\sim1\%$ on the antiproton fraction for energies between 1 and 10 TeV.
Published: 2018

35. A Coincidence Search for Cosmic Neutrino and Gamma-Ray Emitting Sources Using IceCube and Fermi LAT Public Data

Author: Kohta Murase, J. J. DeLaunay, M. Mostafá, Azadeh Keivani, C. F. Turley, D. F. Cowen, Derek B. Fox, and H. A. Ayala Solares
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), COSMIC cancer database, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics, 01 natural sciences, Coincidence, IceCube Neutrino Observatory, Computer Science::Hardware Architecture, Space and Planetary Science, Observatory, 0103 physical sciences, Neutrino, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Fermi Gamma-ray Space Telescope
Abstract: We present results of an archival coincidence analysis between Fermi LAT gamma-ray data and public neutrino data from the IceCube neutrino observatory's 40-string (IC40) and 59-string (IC59) observing runs. Our analysis has the potential to detect either a statistical excess of neutrino + gamma-ray ($\nu$+$\gamma$) emitting transients or, alternatively, individual high gamma-multiplicity events, as might be produced by a neutrino observed by IceCube coinciding with a LAT-detected gamma-ray burst. Dividing the neutrino data into three datasets by hemisphere (IC40, IC59-North, and IC59-South), we construct uncorrelated null distributions by Monte Carlo scrambling of the neutrino datasets. We carry out signal-injection studies against these null distributions, demonstrating sensitivity to individual $\nu$+$\gamma$ events of sufficient gamma-ray multiplicity, and to $\nu$+$\gamma$ transient populations responsible for $>$14% (IC40), $>$9% (IC59-North), or $>$8% (IC59-South) of the gamma-coincident neutrinos observed in these datasets, respectively. Analyzing the unscrambled neutrino data, we identify no individual high-significance neutrino + high gamma-multiplicity events, and no significant deviations from the test statistic null distributions. However, we observe a similar and unexpected pattern in the IC59-North and IC59-South residual distributions that we conclude reflects a possible correlation ($p=7.0\%$) between IC59 neutrino positions and persistently bright portions of the Fermi gamma-ray sky. This possible correlation should be readily testable using eight years of further data already collected by IceCube. We are currently working with Astrophysical Multimessenger Observatory Network (AMON) partner facilities to generate low-latency $\nu$+$\gamma$ alerts from Fermi LAT gamma-ray, IceCube and ANTARES neutrino data and distribute these in real time to AMON follow-up partners., Comment: 12 pages, 9 figures, 1 table
Published: 2018
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36. A Search for Dark Matter in the Galactic Halo with HAWC

Author: E. Moreno, D. W. Fiorino, Andrea Albert, J. Pretz, Benjamin R. Safdi, Dirk Lennarz, Luis Villaseñor, R. Arceo, Chad Brisbois, Michael DuVernois, R. Luna-Garcia, A. Carraminana, Giacomo Vianello, J. A. Goodman, A. Zepeda, J. P. Harding, J. T. Linnemann, Maria Magdalena González, R. J. Lauer, A. Becerril, Fernando Garfias, Thomas Weisgarber, Juan Carlos Diaz-Velez, Karen S. Caballero-Mora, Ruben Alfaro, E. Ruiz-Velasco, Jesús Martínez-Castro, A. Hernandez-Almada, Tomás Capistrán, Nicholas L. Rodd, H. A. Ayala Solares, O. Enríquez-Rivera, I. Martinez-Castellanos, Ernesto Belmont-Moreno, Daniel Rosa-Gonzalez, Z. Ren, Filiberto Hueyotl-Zahuantitla, Miguel Mostafa, Pedro Miranda-Romagnoli, F. Salesa Greus, H. León Vargas, John Matthews, Anushka Udara Abeysekara, Umberto Cotti, C. De León, I. Taboada, Sabrina Casanova, V. Joshi, Segev BenZvi, Michael Newbold, P. W. Younk, E. De la Fuente, D. Avila Rojas, Ibrahim Torres, Jorge Cotzomi, Abel Bernal, J. C. Arteaga-Velázquez, O. Tibolla, Henrike Fleischhack, G. B. Yodh, Kelly Malone, J. D. Álvarez, Kristi Engel, A. Sandoval, Armelle Jardin-Blicq, M. Castillo, R. Noriega-Papaqui, S. Hernandez, M. J. F. Rosenberg, Michael Schneider, I. G. Wisher, A. González Muñoz, William H. Lee, Brenda Dingus, Sarah Kaufmann, James W. Wood, Arturo Iriarte, Gilgamesh Luis-Raya, Kirsten Tollefson, T. Yapici, Rodrigo Pelayo, O. Martinez, S. Westerhoff, Hao Zhou, Petra Hüntemeyer, T. N. Ukwatta, Pooja Surajbali, Gus Sinnis, Jose Andres Garcia-Gonzalez, Nissim Illich Fraija, S. S. Marinelli, R. W. Springer, E. G. Pérez-Pérez, A. J. Smith, C. Alvarez, L. Nellen, Z. Hampel-Arias, R. Diaz Hernandez, Ruben Lopez-Coto, Anna Lia Longinotti, Humberto Ibarguen Salazar, Mehr Nisa, Chang Dong Rho, and HAWC Collaboartion
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, Dark matter, Cosmic background radiation, FOS: Physical sciences, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galactic halo, High Energy Physics - Phenomenology (hep-ph), Observatory, 0103 physical sciences, 010303 astronomy & astrophysics, Cherenkov radiation, Astrophysics::Galaxy Astrophysics, Physics, HAWC - Abteilung Hinton, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, High Energy Physics - Phenomenology, Navarro–Frenk–White profile, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 500 GeV - 100 TeV gamma rays and cosmic rays. With its observations over 2/3 of the sky every day, the HAWC observatory is sensitive to a wide variety of astrophysical sources, including possible gamma rays from dark matter. Dark matter annihilation and decay in the Milky Way Galaxy should produce gamma-ray signals across many degrees on the sky. The HAWC instantaneous field-of-view of 2 sr enables observations of extended regions on the sky, such as those from dark matter in the Galactic halo. Here we show limits on the dark matter annihilation cross-section and decay lifetime from HAWC observations of the Galactic halo with 15 months of data. These are some of the most robust limits on TeV and PeV dark matter, largely insensitive to the dark matter morphology. These limits begin to constrain models in which PeV IceCube neutrinos are explained by dark matter which primarily decays into hadrons., 24 pages, 11 figures
Published: 2017

37. Milagro limits and HAWC sensitivity for the rate-density of evaporating Primordial Black Holes

Author: Humberto Ibarguen Salazar, H. Martinez, J. Braun, Miguel Mostafa, B. Patricelli, Arnulfo Zepeda, Ibrahim Torres, J. McEnery, Varlen Grabski, H. León Vargas, R. Arceo, A. Marinelli, N. Bautista-Elivar, W.H. Lee, E. Moreno, V. Vasileiou, D.A. Williams, J.C. Arteaga-Velázquez, R. Noriega-Papaqui, C. M. Hui, A. A. Abdo, K. Sparks Woodle, F. Salesa, J. P. Harding, Michael DuVernois, Hao Zhou, P. Karn, R. A. Caballero-Lopez, Peter Nemethy, A. Sandoval, D. Berley, James M. Ryan, E. De la Fuente, Michael Schneider, T. Weisgarber, Fernando Garfias, Dirk Lennarz, Tyce DeYoung, E. Mendoza Torres, P.A. Toale, O. Martinez, S. Westerhoff, Petra Hüntemeyer, R. Diaz Hernandez, J. Martínez-Castro, Joshua A. Wood, Rodrigo Pelayo, B. T. Allen, E. Belmont, E. Ruiz-Velasco, A. Galindo, Z. Hampel-Arias, T. N. Ukwatta, A. J. Smith, Alberto Carramiñana, M. Bonilla Rosales, Alejandro Lara, Michael Newbold, J.H. MacGibbon, L. Nellen, Juan Carlos Diaz-Velez, R. Luna-GarcIa, C. M. Hoffman, D. W. Fiorino, C. Rivière, T. Aune, A. Imran, P.W. Younk, Segev BenZvi, J.A.J. Matthews, L. Villaseñor, J. A. Goodman, Ruben Alfaro, Daniel Rosa-Gonzalez, M. Gussert, C. De León, G. Sinnis, J. Becerra González, Daniel R. Stump, E.C. Linares, S.S. Marinelli, Jennifer Pretz, Anushka Udara Abeysekara, T. Morgan, Pedro Miranda-Romagnoli, A. Iriarte, P. M. Saz Parkinson, Jorge Cotzomi, M. Longo, Umberto Cotti, G.J. Kunde, T. Oceguera-Becerra, K. Tollefson, Maria Magdalena González, R. J. Lauer, E. Hays, D. Zaborov, Karen S. Caballero-Mora, H. A. Ayala Solares, J. D. Álvarez, G. B. Yodh, J. T. Linnemann, L. Diaz-Cruz, Allen Mincer, B. M. Baughman, A. S. Barber, G. E. Christopher, R. W. Ellsworth, S. Silich, B.E. Kolterman, M. Castillo, Nissim Illich Fraija, Brenda Dingus, I. Taboada, I.G. Wisher, R. W. Springer, E. G. Pérez-Pérez, C. Alvarez, and David Kieda
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy, FOS: Physical sciences, Primordial black hole, Astronomy and Astrophysics, Gamma-ray astronomy, Astrophysics, Black hole, Observatory, Milagro, Gamma-ray burst, Astrophysics - High Energy Astrophysical Phenomena, Cherenkov radiation
Abstract: Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ~5.0 x 10^14 g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV - TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events., Comment: Accepted to Astroparticle Physics Journal (25 Pages, 3 figures and 7 tables). Corresponding author: T. N. Ukwatta
Published: 2015
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38. Search for very-high-energy emission from Gamma-ray Bursts using the first 18 months of data from the HAWC Gamma-ray Observatory

Author: Ignacio Taboada, Daniel Rosa-Gonzalez, U. Cotti, I. Torres, Kristi Engel, C. De León, A. J. Smith, T. Capistrán, S. S. Marinelli, Michael DuVernois, G. Sinnis, Pooja Surajbali, Armelle Jardin-Blicq, K. Malone, Harm Schoorlemmer, C. Rivière, J. D. Álvarez, Edna Ruiz-Velasco, M. Castillo, A. Hernandez-Almada, Fernando Garfias, P. W. Younk, Thomas Weisgarber, A. Zepeda, S. Coutiño Deleón, D. W. Fiorino, Dirk Lennarz, R. Noriega-Papaqui, J. A. Goodman, J. P. Harding, Ernesto Belmont-Moreno, N. Bautista-Elivar, A. Carraminana, A. S. Barber, H. León Vargas, J. Martínez-Castro, F. Salesa Greus, James W. Wood, P. Hüntemeyer, A. Becerril, C. M. Hui, Z. Hampel-Arias, A. Sandoval, Lukas Nellen, T. N. Ukwatta, S. Hernandez, Hao Zhou, Rodrigo Pelayo, R. Arceo, S. Westerhoff, Binita Hona, A. González Muñoz, Chad Brisbois, N. Fraija, A. Iriarte, J. Pretz, Maria Magdalena González, Juan Carlos Diaz-Velez, R. J. Lauer, Abel Bernal, Jose Andres Garcia-Gonzalez, O. Martinez, R. W. Ellsworth, T. Yapici, Michael Schneider, Giacomo Vianello, M. J. F. Rosenberg, Sarah Kaufmann, M. Mostafá, Z. Ren, Tyce DeYoung, Humberto Ibarguen Salazar, G. Luis Raya, Brenda Dingus, Kirsten Tollefson, H. Martínez-Huerta, J. Braun, E. Moreno, R. Luna-Garcia, Karen S. Caballero-Mora, W. H. Lee, I. Martinez-Castellanos, H. A. Ayala Solares, O. Tibolla, J. Cotzomi, R. W. Springer, J.C. Arteaga-Velázquez, E. G. Pérez-Pérez, C. Alvarez, David Kieda, Pedro Miranda-Romagnoli, Chang Dong Rho, J. A. Matthews, M. Newbold, R. Diaz Hernandez, Segev BenZvi, R. Alfaro, Ruben Lopez-Coto, J. T. Linnemann, Anna Lia Longinotti, Sabrina Casanova, V. Joshi, E. De la Fuente, D. Avila Rojas, and M. Gerhardt
Subjects: HAWC - Abteilung Hinton, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Attenuation, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Synchrotron, Redshift, law.invention, Space and Planetary Science, law, Observatory, 0103 physical sciences, Satellite, Astrophysics - High Energy Astrophysical Phenomena, Gamma-ray burst, 010303 astronomy & astrophysics, Cherenkov radiation
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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39. Search for a very high-energy gamma-ray signal in the northern Fermi bubble region with HAWC

Author: H. A. Ayala Solares
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Galactic Center, Gamma ray, Astronomy, Astrophysics, Power law, Galaxy, law.invention, Telescope, Observatory, law, Cherenkov radiation, Fermi Gamma-ray Space Telescope
Abstract: In 2010, two GeV gamma-ray lobes, known as the Fermi Bubbles, were discovered in the data from The Fermi Large Area Telescope. They extend up to 55o above and below the Galactic Center, forming two regions of spectrally hard gamma-ray emission. One of the ways to understand their origin is through studying the spectrum. The spectrum can be described by hadronic and leptonic models. However, how much each process contributes is uncertain. Recent publications show that the spectrum of the Fermi Bubbles is well described by a power law with an exponential cutoff between 100MeV to 500GeV. Observing the Fermi Bubbles at higher gamma-ray energies will help constrain their spectrum. A steeper spectral cutoff will favor a dominant contribution from inverse Compton scattering.The High Altitude Water Cherenkov (HAWC) Observatory, located 4100m above sea level in Mexico, is sensitive to high-energy gamma rays between 100GeV to 100TeV. With a large field of view and good sensitivity to spatially extended sources, HAW...
Published: 2017

40. Dark Matter Limits From Dwarf Spheroidal Galaxies with The HAWC Gamma-Ray Observatory

Author: A. Albert, R. Alfaro, C. Alvarez, J. D. Álvarez, R. Arceo, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, N. Bautista-Elivar, A. Becerril, E. Belmont-Moreno, S. Y. BenZvi, A. Bernal, J. Braun, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, M. Castillo, U. Cotti, J. Cotzomi, S. Coutiño de León, C. De León, E. De la Fuente, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, J. C. Díaz-Vélez, R. W. Ellsworth, K. Engel, D. W. Fiorino, N. Fraija, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, Z. Hampel-Arias, J. P. Harding, S. Hernandez, A. Hernandez-Almada, B. Hona, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, S. Kaufmann, D. Kieda, R. J. Lauer, D. Lennarz, H. León Vargas, J. T. Linnemann, A. L. Longinotti, M. Longo Proper, G. Luis Raya, R. Luna-García, R. López-Coto, K. Malone, S. S. Marinelli, I. Martinez-Castellanos, J. Martínez-Castro, H. Martínez-Huerta, J. A. Matthews, P. Miranda-Romagnoli, E. Moreno, M. Mostafá, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papaqui, R. Pelayo, J. Pretz, E. G. Pérez-Pérez, Z. Ren, C. D. Rho, C. Rivière, D. Rosa-González, M. Rosenberg, E. Ruiz-Velasco, F. Salesa Greus, A. Sandoval, M. Schneider, H. Schoorlemmer, G. Sinnis, A. J. Smith, R. W. Springer, P. Surajbali, I. Taboada, O. Tibolla, K. Tollefson, I. Torres, G. Vianello, T. Weisgarber, S. Westerhoff, J. Wood, T. Yapici, P. W. Younk, and H. Zhou
Subjects: Physics, HAWC - Abteilung Hinton, High Energy Astrophysical Phenomena (astro-ph.HE), Annihilation, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Wide field, Galaxy, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Space and Planetary Science, Observatory, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Cherenkov radiation
Abstract: The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view observatory sensitive to 500 GeV - 100 TeV gamma rays and cosmic rays. It can also perform diverse indirect searches for dark matter (DM) annihilation and decay. Among the most promising targets for the indirect detection of dark matter are dwarf spheroidal galaxies. These objects are expected to have few astrophysical sources of gamma rays but high dark matter content, making them ideal candidates for an indirect dark matter detection with gamma rays. Here we present individual limits on the annihilation cross section and decay lifetime for 15 dwarf spheroidal galaxies within the HAWC field-of-view, as well as their combined limit. These are the first limits on the annihilation cross section and decay lifetime using data collected with HAWC., Comment: 18 pages, 6 figures, 2 tables
Published: 2017
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41. Searching for dark matter sub-structure with HAWC

Author: E. Moreno, I. Torres, R. W. Springer, Segev BenZvi, H. León Vargas, Maria Magdalena González, H. Salazar, C. Alvarez, S. S. Marinelli, J. P. Harding, A. Iriarte, I. Martinez-Castellanos, John Matthews, S. Dichiara, Filiberto Hueyotl-Zahuantitla, Karen S. Caballero-Mora, H. Fleischhack, J. D. Álvarez, Oscar Martinez, Arnulfo Zepeda, Nissim Fraija, J. C. Díaz-Vélez, Marvin Oliver Schneider, Carmen Espinoza, Ruben Alfaro, H. A. Ayala Solares, R. Noriega-Papaqui, K. Malone, Daniel Rosa-Gonzalez, Giacomo Vianello, R. Arceo, E. G. Pérez-Pérez, Joe Lundeen, Andrea Albert, K. Tollefson, A. Sandoval, J. Martínez-Castro, G. Luis-Raya, M. Newbold, W. H. Lee, T. Weisgarber, Lukas Nellen, J. Cotzomi, Hao Zhou, Anushka Udara Abeysekara, B. Hona, P. Hüntemeyer, C. D. Rho, C. Brisbois, James W. Wood, A. J. Smith, A. L. Longinotti, P. Miranda-Romagnoli, M. J. F. Rosenberg, T. Yapici, M. Mostafá, Jose Andres Garcia-Gonzalez, S. Coutiño de León, Brenda Dingus, Z. Ren, K. Engel, F. Salesa Greus, Alejandro Lara, E. Belmont-Moreno, C. Rivière, Amid Nayerhoda, G. Sinnis, J. T. Linnemann, Michael DuVernois, A. Carramiñana, J. A. Goodman, D. Avila Rojas, A. Galván-Gámez, Sabrina Casanova, E. De la Fuente, J.C. Arteaga-Velázquez, C. De León, and M. U. Nisa
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Milky Way, media_common.quotation_subject, Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Galaxy, Observatory, Sky, 0103 physical sciences, Halo, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics, Cherenkov radiation, Dwarf galaxy, media_common
Abstract: Simulations of dark matter show a discrepancy between the expected number of Galactic dark matter sub-halos and how many have been optically observed. Some of these unseen satellites may exist as dark dwarf galaxies: sub-halos like dwarf galaxies with no luminous counterpart. Assuming WIMP dark matter, it may be possible to detect these unseen sub-halos from gamma-ray signals originating from dark matter annihilation. The High Altitude Water Cherenkov Observatory (HAWC) is a very high energy (500 GeV to 100 TeV) gamma ray detector with a wide field-of-view and near continuous duty cycle, making HAWC ideal for unbiased sky surveys. We perform such a search for gamma ray signals from dark dwarfs in the Milky Way halo. We perform a targeted search of HAWC gamma-ray sources which have no known association with lower-energy counterparts, based on an unbiased search of the entire sky. With no sources found to strongly prefer dark matter models, we calculate the ability of HAWC to observe dark dwarfs. We also compute the HAWC sensitivity to potential future detections for a given model of dark matter substructure., Comment: 20 pages, 10 figures. submitted to JCAP
Published: 2019

42. Publisher Correction: Very-high-energy particle acceleration powered by the jets of the microquasar SS 433

Author: S. Hernandez, S. Dichiara, C. De León, Ernesto Belmont-Moreno, Jim Hinton, Jose Andres Garcia-Gonzalez, Sarah Kaufmann, Harm Schoorlemmer, C. M. Hui, E. Moreno, Hao Zhou, R. Noriega-Papaqui, Armelle Jardin-Blicq, William H. Lee, Gilgamesh Luis-Raya, Hui Li, Maria Magdalena González, R. J. Lauer, C. Rivière, Miguel Mostafa, Kirsten Tollefson, S. S. Marinelli, A. Sandoval, J. P. Harding, O. Tibolla, S. Coutiño de León, Michael Schneider, Luis Villaseñor, J. C. Arteaga-Velázquez, R. W. Springer, J. D. Álvarez, Z. Ren, Ruben Alfaro, Pooja Surajbali, Gus Sinnis, J. A. Goodman, Filiberto Hueyotl-Zahuantitla, Z. Hampel-Arias, E. G. Pérez-Pérez, Daniel Rosa-Gonzalez, C. Alvarez, A. Zepeda, L. Nellen, Petra Hüntemeyer, Brenda Dingus, Anna Lia Longinotti, Fernando Garfias, Thomas Weisgarber, Arturo Iriarte, E. De la Fuente, F. Werner, D. Avila Rojas, E. Ruiz-Velasco, F. Salesa Greus, A. González-Muñoz, A. Carraminana, Kristi Engel, H. León Vargas, M. U. Nisa, R. Arceo, Binita Hona, Henrike Fleischhack, Chang Dong Rho, J. T. Linnemann, Chad Brisbois, Michael DuVernois, M. Seglar Arroyo, T. Yapici, R. W. Ellsworth, Nissim Illich Fraija, Michael Newbold, John Matthews, Giacomo Vianello, I. Martinez-Castellanos, G. B. Yodh, P. Kar, Juan Carlos Diaz-Velez, A. J. Smith, Pedro Miranda-Romagnoli, Jennifer Pretz, Tomás Capistrán, Anushka Udara Abeysekara, James W. Wood, S. Westerhoff, Segev BenZvi, Karen S. Caballero-Mora, Catalina Espinoza, Jesús Martínez-Castro, H. A. Ayala Solares, A. Nayerhoda, Haocheng Zhang, R. López-Coto, Andrea Albert, Kelly Malone, O. Martinez, Jorge Cotzomi, Gerd Joachim Kunde, Ke Fang, Umberto Cotti, A. Galván-Gámez, I. Taboada, Sabrina Casanova, V. Joshi, M. J. F. Rosenberg, M. Castillo, and Ibrahim Torres
Subjects: Physics, Acceleration, Multidisciplinary, High energy particle, 010504 meteorology & atmospheric sciences, 0103 physical sciences, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences, Computational physics
Abstract: In this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.
Published: 2018

43. Search for TeV Gamma-Ray Emission from Point-like Sources in the Inner Galactic Plane with a Partial Configuration of the HAWC Observatory

Author: Karen S. Caballero-Mora, N. Bautista-Elivar, R. W. Springer, H. A. Ayala Solares, E. G. Pérez-Pérez, I. Torres, C. M. Hui, Lukas Nellen, O. Tibolla, C. Alvarez, David Kieda, Hao Zhou, P. Hüntemeyer, Segev BenZvi, B. M. Baughman, E. Moreno, J. Pretz, R. Alfaro, Fernando Garfias, Abel Bernal, Anushka Udara Abeysekara, Thomas Weisgarber, M. Newbold, C. Rivière, H. Martinez, M. Gussert, J.C. Arteaga-Velázquez, G. Luis Raya, O. Enríquez-Rivera, T. Yapici, L. Villaseñor, H. León Vargas, J. T. Linnemann, J. P. Harding, A. Zepeda, P. W. Younk, J. A. Goodman, R. Pelayo, G. Sinnis, A. Carraminana, A. S. Barber, J. Martínez-Castro, S. Hernandez, D. W. Fiorino, Dirk Lennarz, R. W. Ellsworth, A. D. Becerril Reyes, A. Iriarte, Humberto Ibarguen Salazar, D. Zaborov, James W. Wood, S. S. Marinelli, J. Braun, Ignacio Taboada, Brenda Dingus, M. Longo, B. Patricelli, W. H. Lee, Michael Schneider, I. G. Wisher, J. A. Matthews, Sabrina Casanova, Tyce DeYoung, A. Imran, J. Cotzomi, M. Mostafá, S. Westerhoff, J. D. Álvarez, Daniel Rosa-Gonzalez, Kirsten Tollefson, M. Castillo, Pedro Miranda-Romagnoli, G. B. Yodh, Maria Magdalena González, R. J. Lauer, Z. Ren, O. Martinez, R. Noriega-Papaqui, S. Coutiño de León, Alejandro Lara, Michael DuVernois, P. Karn, A. Sandoval, E. De la Fuente, E. Belmont, K. Vrabel, Z. Hampel-Arias, T. N. Ukwatta, K. Malone, U. Cotti, A. J. Smith, T. Capistrán, R. Arceo, F. Salesa Greus, C. De León, K. Sparks Woodle, A. Marinelli, and N. Fraija
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), HAWC - Abteilung Hinton, 010308 nuclear & particles physics, Point source, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Galactic plane, 01 natural sciences, Galaxy, Latitude, Space and Planetary Science, Observatory, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Longitude, 010303 astronomy & astrophysics, Cherenkov radiation
Abstract: A survey of the inner Galaxy region of Galactic longitude l in [+15, +50] degree and latitude b in [-4,+4] degree is performed using one-third of the High Altitude Water Cherenkov (HAWC) Observatory operated during its construction phase. To address the ambiguities arising from unresolved sources in the data, we use a maximum likelihood technique to identify point source candidates. Ten sources and candidate sources are identified in this analysis. Eight of these are associated with known TeV sources but not all have differential fluxes compatible with previous measurements. Three sources are detected with significances $>5\,\sigma$ after accounting for statistical trials, and are associated with known TeV sources., Comment: Submitted to ApJ, 34 pages, 6 figures. Contact authors: Hao Zhou and C. Michelle Hui
Published: 2016

44. Sensitivity of HAWC to high-mass dark matter annihilations

Author: A. S. Barber, A. Imran, T. Oceguera-Becerra, Kevork N. Abazajian, E. C. Linares, Rodrigo Pelayo, B. Patricelli, Petra Hüntemeyer, S. Westerhoff, R. W. Ellsworth, U. Cotti, S. Silich, D. Zaborov, Z. Hampel-Arias, T. N. Ukwatta, D. W. Fiorino, Brenda Dingus, K. Tollefson, L. Villaseñor, J. A. Goodman, A. J. Smith, O. Martinez, E. De la Fuente, R. Luna-Garcia, G. B. Yodh, Anushka Udara Abeysekara, C. De León, M. Castillo, R. W. Springer, E. G. Pérez-Pérez, L. Nellen, Daniel Rosa-Gonzalez, A. Galindo, F. E. Sanchez, E. Belmont, L. Diaz-Cruz, P. W. Younk, J. Pretz, Dirk Lennarz, M. Longo, C. Alvarez, B. M. Baughman, Juan Carlos Diaz-Velez, R. Arceo, David Kieda, Varlen Grabski, R. A. Caballero-Lopez, James M. Ryan, Michael DuVernois, D. Berley, Maria Magdalena González, R. J. Lauer, E. Mendoza Torres, H. Martinez, Tyce DeYoung, P. A. Toale, F. Salesa, Nissim Illich Fraija, J. D. Álvarez, Karen S. Caballero-Mora, Jesús Martínez-Castro, H. A. Ayala Solares, I. Torres, Joshua Wood, Colas Rivière, J. T. Linnemann, M. Bonilla Rosales, Michael Newbold, J. A.J. Matthews, A. Zepeda, Segev BenZvi, Jorge Cotzomi, R. Alfaro, M. Gussert, Pedro Miranda-Romagnoli, Gerd Joachim Kunde, I. Taboada, G. Sinnis, J. Becerra González, A. Sandoval, Michael Schneider, I. G. Wisher, J. P. Harding, Julie McEnery, A. Marinelli, Fernando Garfias, Thomas Weisgarber, Alberto Carramiñana, H. León Vargas, K. Sparks Woodle, Humberto Ibarguen Salazar, J. Braun, Miguel Mostafa, J.C. Arteaga-Velázquez, R. Diaz Hernandez, Arturo Iriarte, N. Bautista-Elivar, C. M. Hui, Hao Zhou, P. Karn, Alejandro Lara, R. Noriega-Papaqui, William H. Lee, and E. Moreno
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Nuclear and High Energy Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Annihilation, Astrophysics::High Energy Astrophysical Phenomena, Hot dark matter, Dark matter, Scalar field dark matter, FOS: Physical sciences, Astronomy, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Observatory, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Dwarf galaxy
Abstract: The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained., Comment: 15 pages, 4 figures, version to be published in PRD
Published: 2014

45. The HAWC Real-time Flare Monitor for Rapid Detection of Transient Events

Author: Humberto Ibarguen Salazar, O. Martinez, Karen S. Caballero-Mora, Mehr Nisa, J. Braun, S. Coutiño de León, H. A. Ayala Solares, Ignacio Taboada, J. P. Harding, M. Newbold, Daniel Rosa-Gonzalez, Brenda Dingus, J. Martínez-Castro, J. Pretz, E. Moreno, J.C. Arteaga-Velázquez, N. Fraija, R. Arceo, P. W. Younk, Abel Bernal, Chad Brisbois, D. W. Fiorino, M. J. F. Rosenberg, J. T. Linnemann, Dirk Lennarz, R. W. Springer, Chang Dong Rho, E. G. Pérez-Pérez, Giacomo Vianello, Michael DuVernois, S. Hernandez, U. Cotti, Michael Schneider, I. G. Wisher, R. Luna-Garcia, C. Alvarez, David Kieda, Fernando Garfias, A. Becerril, A. J. Smith, I. Torres, A. González Muñoz, Ruben Lopez-Coto, A. Iriarte, Thomas Weisgarber, Edna Ruiz-Velasco, I. Martinez-Castellanos, M. Mostafá, T. Capistrán, Anna Lia Longinotti, F. Salesa Greus, M. Castillo, Pooja Surajbali, C. De León, A. Sandoval, H. León Vargas, Kristi Engel, Maria Magdalena González, R. J. Lauer, Sarah Kaufmann, K. Malone, Juan Carlos Diaz-Velez, Kirsten Tollefson, H. Martínez-Huerta, Armelle Jardin-Blicq, Z. Ren, T. Yapici, Harm Schoorlemmer, G. Luis Raya, A. Zepeda, R. Noriega-Papaqui, Sabrina Casanova, C. Rivière, V. Joshi, E. De la Fuente, Z. Hampel-Arias, D. Avila Rojas, T. N. Ukwatta, S. S. Marinelli, M. Gerhardt, J. D. Álvarez, J. A. Goodman, Jose Andres Garcia-Gonzalez, Diego Lopez-Camara, J. Becerra González, Ernesto Belmont-Moreno, P. Hüntemeyer, W. H. Lee, J. Cotzomi, Rodrigo Pelayo, S. Westerhoff, Binita Hona, G. Sinnis, Joshua A. Wood, A. Hernandez-Almada, A. Carraminana, A. S. Barber, Anushka Udara Abeysekara, R. W. Ellsworth, O. Tibolla, N. Bautista-Elivar, Pedro Miranda-Romagnoli, C. M. Hui, Lukas Nellen, Segev BenZvi, Hao Zhou, R. Alfaro, and J. A. Matthews
Subjects: HAWC - Abteilung Hinton, High Energy Astrophysical Phenomena (astro-ph.HE), Astroparticle physics, Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, 01 natural sciences, Rapid detection, law.invention, Space and Planetary Science, law, 0103 physical sciences, Transient (oscillation), Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Flare
Abstract: We present the development of a real-time flare monitor for the High Altitude Water Cherenkov (HAWC) observatory. The flare monitor has been fully operational since 2017 January and is designed to detect very high energy (VHE; $E\gtrsim100$ GeV) transient events from blazars on time scales lasting from 2 minutes to 10 hours in order to facilitate multiwavelength and multimessenger studies. These flares provide information for investigations into the mechanisms that power the blazars' relativistic jets and accelerate particles within them, and they may also serve as probes of the populations of particles and fields in intergalactic space. To date, the detection of blazar flares in the VHE range has relied primarily on pointed observations by imaging atmospheric Cherenkov telescopes. The recently completed HAWC observatory offers the opportunity to study VHE flares in survey mode, scanning 2/3 of the entire sky every day with a field of view of $\sim$1.8 steradians. In this work, we report on the sensitivity of the HAWC real-time flare monitor and demonstrate its capabilities via the detection of three high-confidence VHE events in the blazars Markarian 421 and Markarian 501., Comment: 19 pages, 14 figures, revised version submitted to The Astrophysical Journal on 1 June 2017
Published: 2017

46. Observation of Small-scale Anisotropy in the Arrival Direction Distribution of TeV Cosmic Rays with HAWC

Author: B. M. Baughman, A. Carraminana, A. S. Barber, D. W. Fiorino, R. W. Ellsworth, A. Galindo, Fernando Garfias, Dirk Lennarz, M. Castillo, C. De León, Thomas Weisgarber, E. Ruiz-Velasco, D. Zaborov, H. León Vargas, Brenda Dingus, Arturo Iriarte, A. Imran, R. W. Springer, Gus Sinnis, B. Patricelli, G. B. Yodh, E. G. Pérez-Pérez, J. T. Linnemann, N. Bautista-Elivar, Maria Magdalena González, R. J. Lauer, R. Luna-Garcia, and H. Zhou, C. Alvarez, F. Salesa Greus, C. M. Hui, R. Arceo, Lukas Nellen, David Kieda, Petra Hüntemeyer, C. Rivière, Rodrigo Pelayo, Ruben Alfaro, Jorge Cotzomi, Z. Hampel-Arias, T. N. Ukwatta, P. W. Younk, J. P. Harding, U. Cotti, S. Westerhoff, P. Karn, Nissim Illich Fraija, L. Villaseñor, J. A. Goodman, A. J. Smith, Daniel Rosa-Gonzalez, E. De la Fuente, Pedro Miranda-Romagnoli, D. Berley, James M. Ryan, E. Belmont, Segev BenZvi, A. Sandoval, Tyce DeYoung, P. A. Toale, Anushka Udara Abeysekara, M. Gussert, Juan Carlos Diaz-Velez, E. Mendoza Torres, Michael Schneider, I. G. Wisher, I. Torres, Gerd Joachim Kunde, Joshua Wood, H. Martinez, Karen S. Caballero-Mora, R. Noriega-Papaqui, Jesús Martínez-Castro, William H. Lee, Arnulfo Zepeda, H. A. Ayala Solares, A. Marinelli, Jennifer Pretz, Kirsten Tollefson, I. Taboada, J. A. Matthews, Kelly Malone, S. S. Marinelli, J.C. Arteaga-Velázquez, Alejandro Lara, M. Bonilla Rosales, J. D. Álvarez, Michael Newbold, Michael DuVernois, O. Martinez, Julie McEnery, R. Diaz Hernandez, T. Oceguera-Becerra, K. Sparks Woodle, Humberto Ibarguen Salazar, J. Braun, Miguel Mostafa, M. Longo, and E. Moreno
Subjects: media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Atomic, Physical Chemistry, Particle and Plasma Physics, cosmic rays, Observatory, Nuclear, Cherenkov radiation, media_common, Astroparticle physics, Physics, astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, Molecular, Astronomy and Astrophysics, Space and Planetary Science, Sky, astroparticle physics, Milagro, Astrophysics - High Energy Astrophysical Phenomena, Astronomical and Space Sciences, Physical Chemistry (incl. Structural)
Abstract: The High-Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays and charged cosmic rays at TeV energies. The detector is still under construction, but data acquisition with the partially deployed detector started in 2013. An analysis of the cosmic-ray arrival direction distribution based on $4.9\times 10^{10}$ events recorded between June 2013 and February 2014 shows anisotropy at the $10^{-4}$ level on angular scales of about $10^\circ$. The HAWC cosmic-ray sky map exhibits three regions of significantly enhanced cosmic-ray flux; two of these regions were first reported by the Milagro experiment. A third region coincides with an excess recently reported by the ARGO-YBJ experiment. An angular power spectrum analysis of the sky shows that all terms up to $\ell=15$ contribute significantly to the excesses., Comment: 12 pages, 11 figures. Accepted by The Astrophysical Journal
Published: 2014
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47. VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

Author: D. W. Fiorino, N. Bautista-Elivar, F. Ángeles, C. M. Hui, Umberto Cotti, Hao Zhou, I. Taboada, I. Cabrera, Petra Hüntemeyer, E. Moreno, T. Oceguera-Becerra, Jorge Cotzomi, J. Nava, Z. Hampel-Arias, P. Karn, T. N. Ukwatta, J. A.J. Matthews, A. J. Smith, A. Zepeda, Erika Benítez, Nissim Illich Fraija, O. Martinez, K. Sparks Woodle, R. Arceo, Colas Rivière, S. Tinoco, M. Longo, Michael DuVernois, J. T. Linnemann, F. Ruiz-Sala, Fernando Garfias, Arturo Iriarte, J. D. Álvarez, A. Bernal, Thomas Weisgarber, Varlen Grabski, E. Ruiz-Velasco, E. Belmont, D. Zaborov, R. Langarica, Alberto Carramiñana, H. León Vargas, Karen S. Caballero-Mora, A. Imran, R. W. Springer, W. Wall, A. Rentería, A. González, C. De León, R. Noriega-Papaqui, C. Badillo, K. Tollefson, E. G. Pérez-Pérez, A. Tepe, L. Nellen, Juan Carlos Diaz-Velez, Gerd Joachim Kunde, William H. Lee, I. Ramírez, C. Alvarez, Jesús Martínez-Castro, David Kieda, P. W. Younk, Ibrahim Torres, J. R. Sacahui, H. A. Ayala Solares, M. Martos, A. Galindo, Elton J. G. Santos, Dirk Lennarz, J. F. Valdés Galicia, M. Bonilla Rosales, Dany Page, E. C. Linares, E. De la Fuente, Michael Newbold, L. Castañeda-Martínez, James M. Ryan, B. Patricelli, G. B. Yodh, R. A. Caballero-Lopez, Alejandro Lara, D. Berley, L. Hernandez-Cervantes, E. Mendoza Torres, H. Martinez, F. Salesa, Luis Xavier Gonzalez, Tyce DeYoung, P. A. Toale, L. A. Martínez, Maria Magdalena González, R. J. Lauer, A. Fernandez, Pedro Miranda-Romagnoli, C. Guzmán-Ceron, G. Sinnis, J. Becerra González, Jennifer Pretz, Anushka Udara Abeysekara, Guillermo Garcia-Torales, Rodrigo Pelayo, A. Sandoval, Michael Schneider, I. G. Wisher, S. Westerhoff, A. Marinelli, P. Vanegas, J. P. Harding, A. S. Barber, R. W. Ellsworth, Joshua Wood, F. Suarez, Ruben Alfaro, Daniel Rosa-Gonzalez, A. Avila-Aroche, R. Luna-Garcia, Deborah Dultzin, Segev BenZvi, S. Silich, Brenda Dingus, M. Castillo, A. Diaz-Azuara, L. Diaz-Cruz, M. Gussert, B. M. Baughman, L. Villaseñor, J. A. Goodman, J.C. Arteaga-Velázquez, Julie McEnery, R. Diaz Hernandez, A. Vázquez, Humberto Ibarguen Salazar, J. Braun, G. Lara, and Miguel Mostafa
Subjects: Physics, media_common.quotation_subject, Detector, Gamma ray, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Data acquisition, Pathfinder, Observatory, Sky, Forbush decrease, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Cherenkov radiation, Remote sensing, media_common
Abstract: VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B., Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaborov
Published: 2014
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48. Sensitivity of the High Altitude Water Cherenkov Detector to Sources of Multi-TeV Gamma Rays

Author: F. Salesa, Gerd J. Kunde, James M. Ryan, N. Bautista-Elivar, Ruben Alfaro, Dirk Lennarz, E. Moreno, Pedro Miranda-Romagnoli, D. W. Fiorino, S. Silich, Daniel Rosa-Gonzalez, Alejandro Lara, A. Imran, Michael DuVernois, Miguel Mostafá, C. M. Hui, Lukas Nellen, Hao Zhou, E. C. Linares, Kirsten Tollefson, E. Belmont, J. T. Linnemann, Fernando Garfias, J. D. Álvarez, Humberto Ibarguen Salazar, Guillermo Garcia-Torales, R. A. Caballero-Lopez, D. Berley, K. Sparks, R. Noriega-Papaqui, J. Braun, Maria Magdalena González, R. J. Lauer, M. Castillo, William H. Lee, Juan Carlos Diaz-Velez, Thomas Weisgarber, J. Pretz, Luis Xavier Gonzalez, Tyce DeYoung, P. A. Toale, V. Grabski, P. Karn, J. A. Matthews, Arturo Iriarte, Segev BenZvi, M. Longo, R. Diaz Hernandez, I. Taboada, Jesús Martínez-Castro, H. A. Ayala Solares, S. Westerhoff, I. Torres, Joshua Wood, P. W. Younk, A. Fernandez, Elton J. G. Santos, A. Galindo, M. Bonilla Rosales, M. Gussert, Michael Newbold, E. De la Fuente, J.C. Arteaga-Velázquez, Colas Rivière, H. León Vargas, D. Zaborov, Jorge Cotzomi, G. B. Yodh, B. M. Baughman, Anushka Udara Abeysekara, L. Villaseñor, J. A. Goodman, R. Pelayo, A. Carraminana, A. S. Barber, G. Sinnis, B. Patricelli, R. W. Ellsworth, Jose Luis García-Luna, R. Luna-García, Brenda Dingus, Nissim Illich Fraija, R. W. Springer, E. G. Pérez-Pérez, C. Alvarez, David Kieda, Petra Hüntemeyer, J. Nava, Z. Hampel-Arias, T. N. Ukwatta, O. Martinez, U. Cotti, R. Arceo, A. J. Smith, C. De León, A. Sandoval, Michael Schneider, I. G. Wisher, Arnulfo Zepeda, A. Marinelli, and T. Oceguera-Becerra
Subjects: Cherenkov detector, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, Astrophysics, Atomic, law.invention, Particle and Plasma Physics, law, Observatory, Nuclear, Cherenkov radiation, media_common, Physics, astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), Detector, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Molecular, Astronomy and Astrophysics, Nuclear & Particles Physics, Particle acceleration, TeV gamma-ray astronomy, Water cherenkov, Sky, Astrophysics - High Energy Astrophysical Phenomena, Astronomical and Space Sciences
Abstract: The High Altitude Water Cherenkov (HAWC) observatory is an array of large water Cherenkov detectors sensitive to gamma rays and hadronic cosmic rays in the energy band between 100 GeV and 100 TeV. The observatory will be used to measure high-energy protons and cosmic rays via detection of the energetic secondary particles reaching the ground when one of these particles interacts in the atmosphere above the detector. HAWC is under construction at a site 4100 meters above sea level on the northern slope of the volcano Sierra Negra, which is located in central Mexico at 19 ° N latitude. It is scheduled for completion in 2014. In this paper we estimate the sensitivity of the HAWC instrument to point-like and extended sources of gamma rays. The source fluxes are modeled using both unbroken power laws and power laws with exponential cutoffs. HAWC, in one year, is sensitive to point sources with integral power-law spectra as low as 5 × 10 - 13 cm - 2 sec - 1 above 2 TeV (approximately 50 mCrab) over 5 sr of the sky. This is a conservative estimate based on simple event parameters and is expected to improve as the data analysis techniques are refined. We discuss known TeV sources and the scientific contributions that HAWC can make to our understanding of particle acceleration in these sources.
Published: 2013
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49. Constraints on the Emission of Gamma-Rays from M31 with HAWC.

Author: A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, H. A. Ayala Solares, E. Belmont-Moreno, S. Y. BenZvi, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, and S. Dichiara
Subjects: STELLAR magnetic fields, MILKY Way, COSMIC rays, ANDROMEDA Galaxy, ENERGY density, X-rays, GAMMA ray spectrometry
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 teraelectronvolt 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. [ABSTRACT FROM AUTHOR]
Published: 2020
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50. A Search for Cosmic Neutrino and Gamma-Ray Emitting Transients in 7.3 yr of ANTARES and Fermi LAT Data.

Author: H. A. Ayala Solares, D. F. Cowen, J. J. DeLaunay, D. B. Fox, A. Keivani, M. Mostafá, K. Murase, C. F. Turley, AMON, A. Albert, M. André, M. Anghinolfi, G. Anton, M. Ardid, J.-J. Aubert, J. Aublin, B. Baret, J. Barrios-Martí, S. Basa, and B. Belhorma
Subjects: *MONTE Carlo method, *NEUTRINOS, *FERMI energy, *COSMIC rays, *SKY brightness, *FALSE alarms
Abstract: We analyze 7.3 yr of ANTARES high-energy neutrino and Fermi Large Area Telescope (LAT) γ-ray data in search of cosmic neutrino + γ-ray (ν+γ) transient sources or source populations. Our analysis has the potential to detect either individual ν+γ transient sources (durations s), if they exhibit sufficient γ-ray or neutrino multiplicity, or a statistical excess of ν+γ transients of individually lower multiplicities. Individual high γ-ray multiplicity events could be produced, for example, by a single ANTARES neutrino in coincidence with a LAT-detected γ-ray burst. Treating ANTARES track and cascade event types separately, we establish detection thresholds by Monte Carlo scrambling of the neutrino data, and determine our analysis sensitivity by signal injection against these scrambled data sets. We find our analysis is sensitive to ν+γ transient populations responsible for >5% of the observed gamma-coincident neutrinos in the track data at 90% confidence. Applying our analysis to the unscrambled data reveals no individual ν+γ events of high significance; two ANTARES track + Fermi γ-ray events are identified that exceed a once per decade false alarm rate threshold (p = 17%). No evidence for subthreshold ν+γ source populations is found among the track (p = 39%) or cascade (p = 60%) events. Exploring a possible correlation of high-energy neutrino directions with Fermi γ-ray sky brightness identified in previous work yields no added support for this correlation. While TXS 0506+056, a blazar and variable (nontransient) Fermi γ-ray source, has recently been identified as the first source of high-energy neutrinos, the challenges in reconciling observations of the Fermi γ-ray sky, the IceCube high-energy cosmic neutrinos, and ultrahigh-energy cosmic rays using only blazars suggest a significant contribution by other source populations. Searches for transient sources of high-energy neutrinos thus remain interesting, with the potential for either neutrino clustering or multimessenger coincidence searches to lead to discovery of the first ν+γ transients. [ABSTRACT FROM AUTHOR]
Published: 2019
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