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1,216 results on '"Espinoza, C."'

1. Spectral study of very high energy gamma rays from SS 433 with HAWC

Author: Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotzomi, J., De la Fuente, E., Depaoli, D., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L ., DuVernois, M. A., Engel, K., Ergin, T., Espinoza, C ., Fan, K. L., Fang, K., Fraija, N., Fraija, S., García-González, J. A., Muñoz, A. González, González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Hernández-Cadena, S., Herzog, I., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Kaufmann, S., Lara, A ., Lee, W. H., Lee, J., de León, C., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Montes, J. A., Moreno, E., Mostafá, M., Nellen, L., Nisa, M. U ., Noriega-Papaqui, R ., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E ., Salazar, H., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W ., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E ., Villaseñor, L., Wang, X., Wang, Z., Watson, I. J., Yu, S ., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Very-high-energy (0.1-100 TeV) gamma-ray emission was observed in HAWC data from the lobes of the microquasar SS 433, making them the first set of astrophysical jets that were resolved at TeV energies. In this work, we update the analysis of SS 433 using 2,565 days of data from the High Altitude Water Cherenkov (HAWC) observatory. Our analysis reports the detection of a point-like source in the east lobe at a significance of $6.6\,\sigma$ and in the west lobe at a significance of $8.2\,\sigma$. For each jet lobe, we localize the gamma-ray emission and identify a best-fit position. The locations are close to the X-ray emission sites "e1" and "w1" for the east and west lobes, respectively. We analyze the spectral energy distributions and find that the energy spectra of the lobes are consistent with a simple power-law $\text{d}N/\text{d}E\propto E^{\alpha}$ with $\alpha = -2.44^{+0.13+0.04}_{-0.12-0.04}$ and $\alpha = -2.35^{+0.12+0.03}_{-0.11-0.03}$ for the east and west lobes, respectively. The maximum energy of photons from the east and west lobes reaches 56 TeV and 123 TeV, respectively. We compare our observations to various models and conclude that the very-high-energy gamma-ray emission can be produced by a population of electrons that were efficiently accelerated.
Published: 2024

2. Ultra-High-Energy Gamma-Ray Bubble around Microquasar V4641 Sgr

Author: Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Depaoli, D., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Fraija, N., Fraija, S., García-González, J. A., Garfias, F., Muñoz, A. Gonzalez, González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Herzog, I., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Kieda, D., de León, C., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Osorio, M., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Villaseñor, L., Wang, X., Watson, I. J., Willox, E., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Microquasars are laboratories for the study of jets of relativistic particles produced by accretion onto a spinning black hole. Microquasars are near enough to allow detailed imaging of spatial features across the multiwavelength spectrum. The recent extension of the spatial morphology of a microquasar, SS 433, to TeV gamma rays \cite{abeysekara2018very} localizes the acceleration of electrons at shocks in the jet far from the black hole \cite{hess2024ss433}. Here we report TeV gamma-ray emission from another microquasar, V4641~Sgr, which reveals particle acceleration at similar distances from the black hole as SS~433. Additionally, the gamma-ray spectrum of V4641 is among the hardest TeV spectra observed from any known gamma-ray source and is detected up to 200 TeV. Gamma rays are produced by particles, either electrons or hadrons, of higher energies. Because electrons lose energy more quickly the higher their energy, such a spectrum either very strongly constrains the electron production mechanism or points to the acceleration of high-energy hadrons. This observation suggests that large-scale jets from microquasars could be more common than previously expected and that microquasars could be a significant source of Galactic cosmic rays. high energy gamma-rays also provide unique constraints on the acceleration mechanisms of extra-Galactic cosmic rays postulated to be produced by the supermassive black holes and relativistic jets of quasars. The distance to quasars limits imaging studies due to insufficient angular resolution of gamma-rays and due to attenuation of the highest energy gamma-rays by the extragalactic background light.
Published: 2024
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3. Testing the Molecular Cloud Paradigm for Ultra-High-Energy Gamma Ray Emission from the Direction of SNR G106.3+2.7

Author: Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Bernal, A., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Depaoli, D., Desiati, P., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Engel, K., Ergin, T., Espinoza, C., Fan, K. L., Fang, K., Fraija, N., Fraija, S., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Hernández-Cadena, S., Herzog, I., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Humensky, T. B., Hüntemeyer, P., Kaufmann, S., Kieda, D., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Montes, J. A., Moreno, E., Mostafá, M., Nellen, L., Nisa, M. U., Olivera-Nieto, L., Omodei, N., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Villaseñor, L., Wang, X., Wang, Z., Watson, I. J., Willox, E., Yu, S., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Supernova remnants (SNRs) are believed to be capable of accelerating cosmic rays (CRs) to PeV energies. SNR G106.3+2.7 is a prime PeVatron candidate. It is formed by a head region, where the pulsar J2229+6114 and its boomerang-shaped pulsar wind nebula are located, and a tail region containing SN ejecta. The lack of observed gamma ray emission from the two regions of this SNR has made it difficult to assess which region would be responsible for the PeV CRs. We aim to characterize the very-high-energy (VHE, 0.1-100 TeV) gamma ray emission from SNR G106.3+2.7 by determining the morphology and spectral energy distribution of the region. This is accomplished using 2565 days of data and improved reconstruction algorithms from the HAWC Observatory. We also explore possible gamma ray production mechanisms for different energy ranges. Using a multi-source fitting procedure based on a maximum-likelihood estimation method, we evaluate the complex nature of this region. We determine the morphology, spectrum, and energy range for the source found in the region. Molecular cloud information is also used to create a template and evaluate the HAWC gamma ray spectral properties at ultra-high-energies (UHE, >56 TeV). This will help probe the hadronic nature of the highest-energy emission from the region. We resolve one extended source coincident with all other gamma ray observations of the region. The emission reaches above 100~TeV and its preferred log-parabola shape in the spectrum shows a flux peak in the TeV range. The molecular cloud template fit on the higher energy data reveals that the SNR's energy budget is fully capable of producing a purely hadronic source for UHE gamma rays.
Published: 2024
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4. TeV Analysis of a Source Rich Region with HAWC Observatory: Is HESS J1809-193 a Potential Hadronic PeVatron?

Author: Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Babu, R., Belmont-Moreno, E., Bernal, A., Breuhaus, M., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotzomi, J., De la Fuente, E., Depaoli, D., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Espinoza, C., Fan, K. L., Fang, K., Fick, B., Fraija, N., García-González, J. A., Garfias, F., Munoz, A. Gonzalez, González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Hernández-Cadena, S., Herzog, I., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Lara, A., Lee, J., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Montes, J. A., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Osorio, M., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Wang, X., Watson, I. J., Willox, E., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: HESS J1809-193 is an unidentified TeV source, first detected by the High Energy Stereoscopic System (H.E.S.S.) Collaboration. The emission originates in a source-rich region that includes several Supernova Remnants (SNR) and Pulsars (PSR) including SNR G11.1+0.1, SNR G11.0-0.0, and the young radio pulsar J1809-1917. Originally classified as a pulsar wind nebula (PWN) candidate, recent studies show the peak of the TeV region overlapping with a system of molecular clouds. This resulted in the revision of the original leptonic scenario to look for alternate hadronic scenarios. Marked as a potential PeVatron candidate, this region has been studied extensively by H.E.S.S. due to its emission extending up-to several tens of TeV. In this work, we use 2398 days of data from the High Altitude Water Cherenkov (HAWC) observatory to carry out a systematic source search for the HESS J1809-193 region. We were able to resolve emission detected as an extended component (modelled as a Symmetric Gaussian with a 1 $\sigma$ radius of 0.21 $^\circ$) with no clear cutoff at high energies and emitting photons up-to 210 TeV. We model the multi-wavelength observations for the region HESS J1809-193 using a time-dependent leptonic model and a lepto-hadronic model. Our model indicates that both scenarios could explain the observed data within the region of HESS J1809-193.
Published: 2024

5. Observation of the Galactic Center PeVatron Beyond 100 TeV with HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Andrés, A., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Bernal, A., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Depaoli, D., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Engel, K., Ergin, T., Espinoza, C., Fan, K. L., Fang, K., Fraija, N., Fraija, S., García-González, J. A., Garfias, F., Goksu, H., González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Hernández-Cadena, S., Herzog, I., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Humensky, T. B., Hüntemeyer, P., Iriarte, A., Kaufmann, S., Kieda, D., Lara, A., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Montes, J. A., Morales-Soto, J. A., Moreno, E., Mostafá, M., Najafi, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Osorio-Archila, M., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Schwefer, G., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Wang, X., Wang, Z., Watson, I. J., Willox, E., Wu, H., Yu, S., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report an observation of ultra-high energy (UHE) gamma rays from the Galactic Center region, using seven years of data collected by the High-Altitude Water Cherenkov (HAWC) Observatory. The HAWC data are best described as a point-like source (HAWC J1746-2856) with a power-law spectrum ($\mathrm{d}N/\mathrm{d}E=\phi(E/26 \,\text{TeV})^{\gamma}$), where $\gamma=-2.88 \pm 0.15_{\text{stat}} - 0.1_{\text{sys}} $ and $\phi=1.5 \times 10^{-15}$ (TeV cm$^{2}$s)$^{-1}$ $\pm\, 0.3_{\text{stat}}\,^{+0.08_{\text{sys}}}_{-0.13_{\text{sys}}}$ extending from 6 to 114 TeV. We find no evidence of a spectral cutoff up to $100$ TeV using HAWC data. Two known point-like gamma-ray sources are spatially coincident with the HAWC gamma-ray excess: Sgr A$^{*}$ (HESS J1745-290) and the Arc (HESS J1746-285). We subtract the known flux contribution of these point sources from the measured flux of HAWC J1746-2856 to exclude their contamination and show that the excess observed by HAWC remains significant ($>$5$\sigma$) with the spectrum extending to $>$100 TeV. Our result supports that these detected UHE gamma rays can originate via hadronic interaction of PeV cosmic-ray protons with the dense ambient gas and confirms the presence of a proton PeVatron at the Galactic Center.
Published: 2024

6. Understanding the Emission and Morphology of the Unidentified Gamma-Ray Source TeV J2032+4130

Author: Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Depaoli, D., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Engel, K., Ergin, T., Espinoza, C., Fan, K. L., Fraija, N., García-González, J. A., González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Hernández-Cadena, S., Herzog, I., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Kaufmann, S., Lee, J., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Montes, . A., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Villaseñor, L., Wang, X., Wang, Zhen, Watson, I. J., Yu, S., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: The first TeV gamma-ray source with no lower energy counterparts, TeV J2032+4130, was discovered by HEGRA. It appears in the third HAWC catalog as 3HWC J2031+415 and it is a bright TeV gamma-ray source whose emission has previously been resolved as 2 sources: HAWC J2031+415 and HAWC J2030+409. While HAWC J2030+409 has since been associated with the \emph{Fermi-LAT} Cygnus Cocoon, no such association for HAWC J2031+415 has yet been found. In this work, we investigate the spectrum and energy-dependent morphology of HAWC J2031+415. We associate HAWC J2031+415 with the pulsar PSR J2032+4127 and perform a combined multi-wavelength analysis using radio, X-ray, and $\gamma$-ray emission. We conclude that HAWC J2031+415 and, by extension, TeV J2032+4130 are most probably a pulsar wind nebula (PWN) powered by PSR J2032+4127.
Published: 2024

7. Timing irregularities and glitches from the pulsar monitoring campaign at IAR

Author: Zubieta, E., Garcia, F., del Palacio, S., Furlan, S. B. Araujo, Gancio, G., Lousto, C. O., Combi, J. A., and Espinoza, C. M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract: Context. Pulsars have a very stable rotation. However, sudden increases in their rotation frequency known as glitches, perturb their evolution. While large glitches are commonly detected, small glitches are harder to detect because of the lack of daily-cadence observations over long periods of time. Aims. We aim to explore the timing behaviour of young pulsars at daily timescales looking for small glitches and other irregularities. This will further our comprehension of the distribution of glitch sizes, which has also consequences for the theoretical modeling of the glitch mechanism. Methods. We observed six pulsars with up to daily cadence during 5 years with the antennas of the Argentine Institute of Radio Astronomy (IAR). We used standard pulsar timing tools to characterise the rotation of pulsars and developed an algorithm to look for small timing events in the data and calculate the changes in $\nu$ and $\dot\nu$ at those epochs. Results. We found that the rotation of pulsars in this dataset is affected by small step changes in $\nu$ and $\dot\nu$. We found three glitches that had not been reported before: two in PSR J1048-5832 with relative sizes $\Delta\nu / \nu= 9.1(4) \times 10^{-10}$ and $\Delta\nu / \nu = 4.5(1) \times 10^{-10}$, and one in the Vela pulsar with a size $\Delta\nu / \nu = 2.0(2) \times 10^{-10}$. We also report new decay terms on the 2021 Vela giant glitch, and on the 2022 giant glitches in PSR J0742-2822 and PSR J1740-3015 respectively. Besides, we found that the red noise contribution significantly diminished in PSR J0742-2822 after its giant glitch in 2022. Conclusions. Our results highlight the importance of high-cadence monitoring with an exhaustive analysis of the residuals to better characterize the distribution of glitch sizes and to deepen our understanding of the mechanisms behind glitches, red noise and timing irregularities.
Published: 2024

8. Performance of the HAWC Observatory and TeV Gamma-Ray Measurements of the Crab Nebula with Improved Extensive Air Shower Reconstruction Algorithms

Author: Albert, A ., Alfaro, R., Alvarez, C., Andrés, A ., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Depaoli, D., Di Lalla, N., Hernandez, R. Diaz, Dingus, B. L ., DuVernois, M. A., Engel, K., Ergin, T., Espinoza, C ., Fan, K. L., Fang, K., Fraija, N., Fraija, S., García-González, J. A., Garfias, F., Goksu, H ., González, M. M., Goodman, J. A., Groetsch, S., Harding, J. P., Hernández-Cadena, S., Herzog, I., Hinton, J ., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Kaufmann, S., Lara, A ., Lee, J., Vargas, H. León, Linnemann, J. T ., Longinotti, A. L., Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Montes, J. A., Moreno, E., Mostafá, M., Nellen, L., Nisa, M. U ., Noriega-Papaqui, R ., Olivera-Nieto, L ., Omodei, N., Osorio, M., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E ., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Schwefer, G ., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W ., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E ., Wang, X., Watson, I. J., Whitaker, K., Willox, E., Wu, H., Yu, S ., Yun-Cárcamo, S., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
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, $\mathcal{O}(0.1^{\circ})$ biases in highly inclined showers, as well as enhancements to the core reconstruction. The angular resolution for gamma rays approaching the HAWC array from large zenith angles ($> 37^{\circ}$) has improved by a factor of four 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 $\chi^{2}$ values, improved the background rejection performance at all inclinations. At large zenith angles, the improvement in significance is a factor of four 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$^{\circ}$ zenith is comparable 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

9. Modeling and Testing Superconducting Artificial CPW Lines Suitable for Parametric Amplification

Author: Mena, F. P., Valenzuela, D., Espinoza, C., Pizarro, F., Tan, B. -K., Thoen, D. J., Baselmans, J. J. A., and Finger, R.
Subjects: Physics - Applied Physics
Abstract: Achieving amplification with high gain and quantum-limited noise is a difficult problem to solve. Parametric amplification using a superconducting transmission line with high kinetic inductance is a promising technology not only to solve this problem but also adding several benefits. When compared with other technologies, they have the potential of improving power saturation, achieving larger fractional bandwidths and operating at higher frequencies. In this type of amplifiers, selecting the proper transmission line is a key element in their design. Given current fabrication limitations, traditional lines such as coplanar waveguides (CPW), are not ideal for this purpose since it is difficult to make them with the proper characteristic impedance for good matching and slow-enough phase velocity for making them more compact. Capacitively-loaded lines, also known as artificial lines, are a good solution to this problem. However, few design rules or models have been presented to guide their accurate design. This fact is even more crucial considering that they are usually fabricated in the form of Floquet lines that have to be designed carefully to suppress undesired harmonics appearing in the parametric process. In this article we present, firstly, a new modelling strategy, based on the use of electromagnetic-simulation software, and, secondly, a first-principles model that facilitate and speed the design of CPW artificial lines and of Floquet lines made out of them. Then, we present comparisons with experimental results that demonstrate their accuracy. Finally, the theoretical model allows to predict the high-frequency behaviour of the artificial lines showing that they are good candidates for implementing parametric amplifiers above 100 GHz., Comment: 7 pages, 11 figures, submitted to IEEE Transactions on Applied Superconductivity
Published: 2023

10. Galactic Gamma-Ray Diffuse Emission at TeV energies with HAWC Data

Author: Alfaro, R., Alvarez, C., Arteaga-Velazquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Babu, R., Baghmanyan, V., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de Leon, S. Coutino, De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Dıaz-Velez, J. C., Engel, K., Espinoza, C., Fan, K. L., Fraija, N., Galvan-Gamez, A., Garcıa-Gonzalez, J. A., Garfias, F., Gonzalez, M. M., Goodman, J. A., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Humensky, T. B., Iriarte, A., Joshi, V., Kaufmann, S., Kieda, D., Kunde, G. J., Lara, A., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martınez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Noriega-Papaqui, R., Perez-Perez, E. G., Rosa-Gonzalez, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Greus, F. Salesa, Sandoval, A., Serna-Franco, J., Smith, A. J., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Urena-Mena, F., Villasenor, L., Willox, E., Zhou, H., de Leon, C., Fornieri, O., Gaggero, D., Grasso, D., Marinelli, A., and Ventura, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Galactic gamma-ray diffuse emission (GDE) is emitted by cosmic rays (CRs), ultra-relativistic protons and electrons, interacting with gas and electromagnetic radiation fields in the interstellar medium. Here we present the analysis of TeV diffuse emission from a region of the Galactic Plane over the range in longitude of $l\in[43^\circ,73^\circ]$, using data collected with the High Altitude Water Cherenkov (HAWC) detector. Spectral, longitudinal and latitudinal distributions of the TeV diffuse emission are shown. The radiation spectrum is compatible with the spectrum of the emission arising from a CR population with an "index" similar to that of the observed CRs. When comparing with the \texttt{DRAGON} \textit{base model}, the HAWC GDE flux is higher by about a factor of two. Unresolved sources such as pulsar wind nebulae and TeV halos could explain the excess emission. Finally, deviations of the Galactic CR flux from the locally measured CR flux may additionally explain the difference between the predicted and measured diffuse fluxes.
Published: 2023

11. HAWC Study of Very-High-Energy $\gamma$-ray Spectrum of HAWC J1844-034

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

Author: Adams, D. J., Barlas, B., McIntyre, R. E., Salguero, I., van der Weyden, L., Barros, A., Vicente, J. R., Karimpour, N., Haider, A., Ranzani, M., Turner, G., Thompson, N. A., Harle, V., Olvera-León, R., Robles-Espinoza, C. D., Speak, A. O., Geisler, N., Weninger, W. J., Geyer, S. H., Hewinson, J., Karp, N. A., Fu, B., Yang, F., Kozik, Z., Choudhary, J., Yu, L., van Ruiten, M. S., Rowland, B. D., Lelliott, C. J., del Castillo Velasco-Herrera, M., Verstraten, R., Bruckner, L., Henssen, A. G., Rooimans, M. A., de Lange, J., Mohun, T. J., Arends, M. J., Kentistou, K. A., Coelho, P. A., Zhao, Y., Zecchini, H., Perry, J. R. B., Jackson, S. P., and Balmus, G.
Published: 2024
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13. An optimized search for dark matter in the galactic halo with HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velazquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Dıaz-Velez, J. C., Espinoza, C., Fan, K. L., Fraija, N., Garcıa-Gonzalez, J. A., Garfias, F., Gonzalez, M. M., Goodman, J. A., Harding, J. P., Huang, D., Hueyotl-Zahuantitla, F., Iriarte, A., Joshi, V., Kunde, G. J., Lee, J., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Martinez, O., Martınez-Castro, J., Matthews, J. A., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Peisker, A., Perez-Perez, E. G., Rho, C. D., Rosa-Gonzalez, D., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Serna-Franco, J., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Urena-Mena, F., Villasenor, L., Wang, X., Zhou, H., and de Leon, C.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Phenomenology
Abstract: The Galactic Halo is a key target for indirect dark matter detection. The High Altitude Water Cherenkov (HAWC) observatory is a high-energy (~300 GeV to >100 TeV) gamma-ray detector located in central Mexico. HAWC operates via the water Cherenkov technique and has both a wide field of view of 2 sr and a >95% duty cycle, making it ideal for analyses of highly extended sources. We made use of these properties of HAWC and a new background-estimation technique optimized for extended sources to probe a large region of the Galactic Halo for dark matter signals. With this approach, we set improved constraints on dark matter annihilation and decay between masses of 10 and 100 TeV. Due to the large spatial extent of the HAWC field of view, these constraints are robust against uncertainties in the Galactic dark matter spatial profile., Comment: 19 pages, 14 figures
Published: 2023

14. A new small glitch in Vela discovered with a hidden Markov model

Author: Dunn, L., Melatos, A., Espinoza, C. M., Antonopoulou, D., and Dodson, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A striking feature of the Vela pulsar (PSR J0835$-$4510) is that it undergoes sudden increases in its spin frequency, known as glitches, with a fractional amplitude on the order of $10^{-6}$ approximately every 900 days. Glitches of smaller magnitudes are also known to occur in Vela. Their distribution in both time and amplitude is less well constrained but equally important for understanding the physical process underpinning these events. In order to better understand these small glitches in Vela, an analysis of high-cadence observations from the Mount Pleasant Observatory is presented. A hidden Markov model (HMM) is used to search for small, previously undetected glitches across 24 years of observations covering MJD 44929 to MJD 53647. One previously unknown glitch is detected around MJD 48636 (Jan 15 1992), with fractional frequency jump $\Delta f/f = (8.19 \pm 0.04) \times 10^{-10}$ and frequency derivative jump $\Delta\dot{f}/\dot{f} = (2.98 \pm 0.01) \times 10^{-4}$. Two previously reported small glitches are also confidently re-detected, and independent estimates of their parameters are reported. Excluding these events, 90% confidence frequentist upper limits on the sizes of missed glitches are also set, with a median upper limit of $\Delta f^{90\%}/f = 1.35 \times 10^{-9}$. Upper limits of this kind are enabled by the semi-automated and computationally efficient nature of the HMM, and are crucial to informing studies which are sensitive to the lower end of the glitch size distribution., Comment: 10 pages, 7 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society
Published: 2023
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15. A Contribution of the HAWC Observatory to the TeV era in the High Energy Gamma-Ray Astrophysics: The case of the TeV-Halos

Author: Torres-Escobedo, Ramiro, Zhou, Hao, de la Fuente, Eduardo, Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Baghmanyan, V., Barber, A. S., Gonzalez, J. Becerra, Belmont-Moreno, E., BenZvi, S. Y., Berley, D., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, de León, C., Diaz-Cruz, L., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., Durocher, M., DuVernois, M. A., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Alonso, M. Fernández, Fick, B., Fleischhack, H., Flores, J. L., Fraija, N. I., Garcia, D., García-González, J. A., García-Torales, G., Garfias, F., Giacinti, G., Goksu, H., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Herzog, I., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hui, C. M., Humensky, B., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Jhee, H., Joshi, V., Kieda, D., Kunde, G J., Kunwar, S., Lara, A., Lee, J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J., Longinotti, A. L., López-Coto, R., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Martinez, O., Martinez-Castellanos, I., Martínez-Huerta, H., Martínez-Castro, J., Matthews, J. A. J., McEnery, J., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rivière, C., Rosa-Gonzalez, D., Ruiz-Velasco, E., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tanner, M., Tollefson, K., Torres, I., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Watson, I. J., Weisgarber, T., Werner, F., Willox, E., Wood, J., Yodh, G. B., and Zepeda, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present a short overview of the TeV-Halos objects as a discovery and a relevant contribution of the High Altitude Water \v{C}erenkov (HAWC) observatory to TeV astrophysics. We discuss history, discovery, knowledge, and the next step through a new and more detailed analysis than the original study in 2017. TeV-Halos will contribute to resolving the problem of the local positron excess observed on the Earth. To clarify the latter, understanding the diffusion process is mandatory., Comment: Work presented in the 21st International Symposium on Very High Energy Cosmic Ray Interactions(ISVHECRI 2022) as part of the Ph. D. Thesis of Ramiro Torres-Escobedo (SJTU, Shanghai, China). Accepted for publication in SciPost Physics Proceedings (ISSN 2666-4003). 11 pages, 3 Figures. Short overview of HAWC and TeV Halos objects until 2022
Published: 2023

16. The High-Altitude Water Cherenkov (HAWC) Observatory in M\'exico: The Primary Detector

Author: Abeysekara, A. U., Albert, A., Alfaro, R., Álvarez, C., Álvarez, J. D., Araya, M., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Barber, A. S., Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Blanco, O., Braun, J., Brisbois, C., Caballero-Mora, K. S., Martínez, J. I. Cabrera, Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, de la Fuente, E., de León, C., De Young, T., Hernández, R. Díaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Fick, U. B., Fleischhack, H., Flores, J. L., Fraija, N., García-González, J. A., García-Torales, G., Garfias, F., Giacinti, G., Goksu, H., González, M. M., González-Muñoz, A., Goodman, J. A., Harding, J. P., Hernández, E., Hernández, S., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hui, C. M., Humensky, T. B., Hüntemeyer, P., Iriarte, A., Imran, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Kunde, G. J., Lara, A., Lauer, R., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Marinelli, A., Martínez, O., Martínez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Montaruli, T., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Oceguera-Becerra, T., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Ponce, E., Pretz, J., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Sinnis, G., Smith, A. J., Son, Y., Woodle, K. Sparks, Springer, R. W., Taboada, I., Tepe, A., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Ukwatta, T. N., Varela, E., Vargas-Magaña, M., Villaseñor, L., Wang, X., Watson, I. J., Werner, F., Westerhoff, S., Willox, E., Wisher, I., Wood, J., Yodh, G. B., Zaborov, D., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC observatory and its analysis techniques build on experience of the Milagro experiment in using ground-based water Cherenkov detectors for gamma-ray astronomy. HAWC is located on the Sierra Negra volcano in M\'exico at an elevation of 4100 meters above sea level. The completed HAWC observatory principal detector (HAWC) consists of 300 closely spaced water Cherenkov detectors, each equipped with four photomultiplier tubes to provide timing and charge information to reconstruct the extensive air shower energy and arrival direction. The HAWC observatory has been optimized to observe transient and steady emission from sources of gamma rays within an energy range from several hundred GeV to several hundred TeV. However, most of the air showers detected are initiated by cosmic rays, allowing studies of cosmic rays also to be performed. This paper describes the characteristics of the HAWC main array and its hardware., Comment: Accepted for publications in Nuclear Inst. and Methods in Physics Research, A (2023) 168253 ( https://www.sciencedirect.com/science/article/abs/pii/S0168900223002437 ); 39 pages, 14 Figures
Published: 2023
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17. Detailed Analysis of the TeV {\gamma}-Ray Sources 3HWC J1928+178, 3HWC J1930+188, and the New Source HAWC J1932+192

Author: Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrń, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., CoutiñodeLeón, S., De la Fuente, E., de León, C., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Durocher, M., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., García-González, J. A., Garfias, F., Goksu, H., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., López-Coto, R., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Greus, F. Salesa, Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Werner, F., Willox, E., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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\deg < l < 55\deg, 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 gamma-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 a attempt to unveil the origins of the very-high-energy gamma-ray emission.
Published: 2023
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18. Searching for TeV Dark Matter in Irregular dwarf galaxies with HAWC Observatory

Author: Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Espinoza, C., Fan, K. L., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Harding, J. P., Hernández-Cadena, S., Huang, D., Hueyotl-Zahuantitla, F., Iriarte, A., Joshi, V., Kaufmann, S., Kieda, D., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Omodei, N., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Serna-Franco, J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., Zhou, H., de León, C., Gammaldi, V., Karukes, E., and Salucci, P.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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, 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 ($95\%~\text{C.L.}$) for annihilation cross-section and decay lifetime for WIMP candidates with masses between $1$ and $100~\text{TeV}$. 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 contraints are comparable to the limits from classical dSph galaxies and $\thicksim2$ orders of magnitude weaker than the ultrafaint dSph limits., Comment: 22 pages, 11 figures, 3 tables
Published: 2023
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19. HAWC Detection of a TeV Halo Candidate Surrounding a Radio-quiet pulsar

Author: Albert, A., Alfaro, R., Arteaga-Velázquez, J. C., Belmont-Moreno, E., Capistrán, T., Carramiñana, A., Casanova, S., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Díaz-Vélez, J. C., Espinoza, C., Fan, K. L., Fraija, N., Fang, K., García-González, J. A., Garfias, F., Jardin-Blicq, Armelle, González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Huang, D., Hueyotl-Zahuantitla, F., Iriarte, A., Joshi, V., Lara, A., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Wang, X., Whitaker, K., Willox, E., Zhou, H., and de León, C.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Extended very-high-energy (VHE; 0.1-100 TeV) $\gamma$-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 certain subgroup of pulsars. With 2321 days of observation, the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory detected VHE $\gamma$-ray emission at the location of the radio-quiet pulsar PSR J0359+5414 with $>6\sigma$ significance. By performing likelihood tests with different spectral and spatial models and comparing the TeV spectrum with multi-wavelength 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 multi-wavelength follow-ups are needed to confirm this nature. This new halo candidate is located in a non-crowded 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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20. The TeV Sun Rises: Discovery of Gamma rays from the Quiescent Sun with HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velazquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de Leon, S. Coutino, De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Diaz-Velez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Alonso, M. Fernandez, Fleischhack, H., Fraija, N., Garcia-Gonzalez, J. A., Garfia, F., Gonzalez, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Huntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Lee, J., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martinez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Araujo, Y. Pérez, Perez-Perez, E. G., Rho, C. D., Rosa-Gonzalez, D., Ruiz-Velasco, E., Salazar, H., Salazar-Gallegos, D., Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Urena-Mena, F., Wang, X., Watson, I. J., Willox, E., Yun-Cárcamo, S., Zhou, H., de León, C., Beacom, J. F., Linden, T., Ng, K. C. Y., Peter, A. H. G., and Zhou, B.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, High Energy Physics - Experiment
Abstract: We report the first detection of a TeV gamma-ray flux from the solar disk (6.3$\sigma$), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5--2.6 TeV spectrum is well fit by a power law, dN/dE = $A (E/1 \text{ TeV})^{-\gamma}$, with $A = (1.6 \pm 0.3) \times 10^{-12}$ TeV$^{-1}$ cm$^{-2}$ s$^{-1}$ and $\gamma = -3.62 \pm 0.14$. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission., Comment: 15 pages, 8 figures including supplementary material. Accepted for publication in Physical Review Letters
Published: 2022
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21. High Altitude characterization of the Hunga Pressure Wave with Cosmic Rays by the HAWC Observatory

Author: Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotzomi, J., De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Engel, K., Espinoza, C., Fan, K. L., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Hernandez, S., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Lara, A., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Nellen, L., Noriega-Papaqui, R., Omodei, N., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Sandoval, A., Schneider, M., Smith, A. J., Son, Y., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Villaseñor, L., Wang, X., Willox, E., Zhou, H., and de León, C.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract: High-energy cosmic rays that hit the Earth can be used to study large-scale atmospheric perturbations. After a first interaction in the upper parts of the atmosphere, cosmic rays produce a shower of particles that sample the atmosphere down to the detector level. The HAWC (High-Altitude Water Cherenkov) cosmic-ray observatory in Central Mexico at 4,100 m elevation detects air shower particles continuously with 300 water Cherenkov detectors with an active area of 12,500 m$^{2}$. On January 15th, 2022, HAWC detected the passage of the pressure wave created by the explosion of the Hunga volcano in the Tonga islands, 9,000 km away, as an anomaly in the measured rate of shower particles. The HAWC measurements are used to characterize the shape of four pressure wave passages, determine the propagation speed of each one, and correlate the variations of the shower particle rates with the barometric pressure changes, extracting a barometric parameter. The profile of the shower particle rate and atmospheric pressure variations for the first transit of the pressure wave at HAWC is compared to the pressure measurements at Tonga island, near the volcanic explosion. This work opens the possibility of using large particle cosmic-ray air shower detectors to trace large atmospheric transient waves., Comment: Contact about this analysis: A. Sandoval (asandoval@fisica.unam.mx), A. Lara (alara@igeofisica.unam.mx) & H. Le\'on Vargas (hleonvar@fisica.unam.mx)
Published: 2022

22. Search for Gamma-Ray and Neutrino Coincidences Using HAWC and ANTARES Data

Author: Solares, H. A. Ayala, Coutu, S., Cowen, D., Fox, D. B., Grégoire, T., McBride, F., Mostafá, M., Murase, K., Wissel, S., Albert, A., Alves, S., André, M., Ardid, M., Ardid, S., Aubert, J. -J., Aublin, J., Baret, B., Basa, S., Belhorma, B., Bendahman, M., Benfenati, F., Bertin, V., Biagi, S., Bissinger, M., Boumaaza, J., Bouta, M., Bouwhuis, M. C., Brânzaş, H., Bruijn, R., Brunner, J., Busto, J., Caiffi, B., Calvo, D., Capone, A., Caramete, L., Carr, J., Carretero, V., Celli, S., Chabab, M., Chau, T. N., Moursli, R. Cherkaoui El, Chiarusi, T., Circella, M., Coelho, J. A. B., Coleiro, A., Coniglione, R., Coyle, P., Creusot, A., Díaz, A. F., de Wasseige, G., De Martino, B., Distefano, C., Di Palma, I., Domi, A., Donzaud, C., Dornic, D., Drouhin, D., Eberl, T., van Eeden, T., van Eijk, D., Khayati, N. El, Enzenhöfer, A., Fermani, P., Ferrara, G., Filippini, F., Fusco, L., García, J., Gay, P., Glotin, H., Gozzini, R., Ruiz, R. Gracia, Graf, K., Guidi, C., Hallmann, S., van Haren, H., Heijboer, A. J., Hello, Y., Hernández-Rey, J. J., Hößl, J., Hofestädt, J., Huang, F., Illuminati, G., James, C. W., Jisse-Jung, B., de Jong, M., de Jong, P., Kadler, M., Kalekin, O., Katz, U., Kouchner, A., Kreykenbohm, I., Kulikovskiy, V., Lahmann, R., Lamoureux, M., Breton, R. Le, Lefèvre, D., Leonora, E., Levi, G., Stum, S. Le, Lopez-Coto, D., Loucatos, S., Maderer, L., Manczak, J., Marcelin, M., Margiotta, A., Marinelli, A., Martínez-Mora, J. A., Melis, K., Migliozzi, P., Moussa, A., Muller, R., Nauta, L., Navas, S., Nezri, E., Fearraigh, B. Ó, Păaun, A., Păvălaş, G. E., Pellegrino, C., Perrin-Terrin, M., Pestel, V., Piattelli, P., Pieterse, C., Poirè, C., Popa, V., Pradier, T., Randazzo, N., Real, D., Reck, S., Riccobene, G., Romanov, A., Sánchez-Losa, A., Samtleben, D. F. E., Sanguineti, M., Sapienza, P., Schnabel, J., Schumann, J., Schüssler, F., Seneca, J., Spurio, M., Stolarczyk, Th., Taiuti, M., Tayalati, Y., Tingay, S. J., Vallage, B., Van Elewyck, V., Versari, F., Viola, S., Vivolo, D., Wilms, J., Zavatarelli, S., Zegarelli, A., Zornoza, J. D., Zúñiga, J., Alvarez, C., Arteaga-Velázquez, J. C., Babu, R., Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Chaparro-Amaro, O., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Lara, A., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Nayerhoda, A., Nellen, L., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Varela, E., Wang, X., Whitaker, K., Willox, E., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: In the quest for high-energy neutrino sources, the Astrophysical Multimessenger Observatory Network (AMON) 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 July 2015 and February 2020 with a livetime of 4.39 years. Over this time period, 3 coincident events with an estimated false-alarm rate of $< 1$ coincidence per year were found. This number is consistent with background expectations., Comment: 12 pages, 5 figures, 3 tables
Published: 2022
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23. Limits on the Diffuse Gamma-Ray Background above 10 TeV with HAWC

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

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

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

25. Constraints on the very high energy gamma-ray emission from short GRBs with HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, 8 E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, de León, C., De la Fuente, E., Hernandez, R. Diaz, Dichiara, S., Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Fraija, N., Galván-Gámez, A., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Humensky, T. B., Hüntemeyer, P., Iriarte, A., Joshi, V., Kaufmann, S., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Marinelli, S. S., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Noriega-Papaqui, R., Peisker, A., c, Y. Pérez Araujo, Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rosa-González, D., Rosenberg, M., Sacahui, J. R., Salazar, H., Greus, F. Salesa, Sandoval, A., Serna-Franco, J., Smith, A. J., Springer, R. W., Surajbali, P., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Villaseñor, L., Wang, X., Willox, E., Zepeda, A., Zhou, H., and COLLABORATION, THE HAWC
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Many gamma-ray bursts (GRBs) have been observed from radio wavelengths, and a few at very-high energies (VHEs, > 100GeV). The HAWC gamma-ray observatory is well suited to study transient phenomena at VHEs due to its large field of view and duty cycle. These features allow for searches of VHE emission and can probe different model assumptions of duration and spectra. In this paper, we use data collected by HAWC between December 2014 and May 2020 to search for emission in the energy range from 80 to 800 GeV coming from a sample 47 short GRBs that triggered the Fermi, Swift and Konus satellites during this period. This analysis is optimized to search for delayed and extended VHE emission within the first 20 s of each burst. We find no evidence of VHE emission, either simultaneous or delayed, with respect to the prompt emission. Upper limits (90% confidence level) derived on the GRB fluence are used to constrain the synchrotron self-Compton forward-shock model. Constraints for the interstellar density as low as $10^{-2}$ cm$^{-3}$ are obtained when assuming z=0.3 for bursts with the highest keV-fluences such as GRB 170206A and GRB 181222841. Such a low density makes observing VHE emission mainly from the fast cooling regime challenging., Comment: 20 pages, 8 figures
Published: 2022
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26. PKR-like ER kinase (PERK) Haplotypes Are Associated with Depressive Symptoms in People with HIV

Author: Haddadi, S, Jordan-Sciutto, KL, Akay-Espinoza, C, Grelotti, D, Letendre, SL, Tang, B, and Ellis, RJ
Subjects: Biomedical and Clinical Sciences, Clinical Sciences, Brain Disorders, Genetics, Mental Health, Behavioral and Social Science, Depression, HIV/AIDS, Good Health and Well Being, HIV, Haplotypes, PKR-like ER kinase
Abstract: BackgroundDepression is a debilitating and difficult-to-treat condition in people with HIV (PWH) despite viral suppression on antiretroviral therapy (ART). Depression is associated with activation of the PKR-like ER kinase (PERK) pathway, which regulates protein synthesis in response to metabolic stress. We evaluated common PERK haplotypes that influence PERK expression in relation to depressed mood in PWH.MethodsPWH from 6 research centers were enrolled in the study. Genotyping was conducted using targeted sequencing with TaqMan. The major PERK haplotypes A, B, and D were identified. Depressive symptom severity was assessed using the Beck Depression Inventory-II (BDI-II). Covariates including genetically-defined ancestry, demographics, HIV disease/treatment parameters and antidepressant treatments were assessed. Data were analyzed using multivariable regression models.ResultsA total of 287 PWH with a mean (SD) age of 57.1±7.8 years were enrolled. Although the largest ethnic group was non-Hispanic white (n=129, 45.3%), African-American (n=124, 43.5%) and Hispanic (n=30, 10.5%) made up over half the sample. 20.3% were female and 96.5% were virally suppressed. Mean BDI-II was 9.6±9.5, and 28.9% scored above the cutoff for mild depression (BDI-II>13). PERK haplotype frequencies were AA57.8%, AB25.8%, AD 10.1%, and BB4.88%. PERK haplotypes were differentially represented according to genetic ancestry (p=6.84e-6). BDI-II scores were significantly higher in participants with the AB haplotype (F=4.45, p=0.0007).This finding was robust to consideration of potential confounds.ConclusionPERK haplotypes were associated with depressed mood in PWH.Consequently, pharmacological targeting of PERK-related pathways might amelioratedepression in PWH.
Published: 2023

27. Gamma/Hadron Separation with the HAWC Observatory

Author: Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, G. J. Kundem A., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Nayerhoda, A., Nellen, L., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Parkinson, P. M. Saz, Serna-Franco, J., Smith, A. J., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Watson, I. J., Werner, F., Willox, E., Wood, J., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: The High Altitude Water Cherenkov (HAWC) gamma-ray observatory observes atmospheric showers produced by incident gamma rays and cosmic rays with energy from 300 GeV to more than 100 TeV. A crucial phase in analyzing gamma-ray sources using ground-based gamma-ray detectors like HAWC is to identify the showers produced by gamma rays or hadrons. The HAWC observatory records roughly 25,000 events per second, with hadrons representing the vast majority ($>99.9\%$) of these events. The standard gamma/hadron separation technique in HAWC uses a simple rectangular cut involving only two parameters. This work describes the implementation of more sophisticated gamma/hadron separation techniques, via machine learning methods (boosted decision trees and neural networks), and summarizes the resulting improvements in gamma/hadron separation obtained in HAWC., Comment: 35 pages, 9 figures, published in Nuclear Instruments and Methods in Physics Research Section A
Published: 2022
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28. Cosmic ray spectrum of protons plus helium nuclei between 6 TeV and 158 TeV from HAWC data

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

Author: Albert, A., Alfaro, R., Arteaga-Velázquez, J. C., Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., García-González, J. A., Goksu, H., González, M. M., Goodman, J. A., Harding, J. P., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Jardin-Blicq, A., Joshi, V., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar-Gallegos, D., Greus, F. Salesa, Sandoval, A., Schoorlemmer, H., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Watson, I. J., Willox, E., Zhou, H., de León, C., Zepeda, A., Donath, A., and Funk, S.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Ground-based gamma-ray astronomy is still a rather young field of research, with strong historical connections to particle physics. This is why most observations are conducted by experiments with proprietary data and analysis software, as it is usual in the particle physics field. However in recent years, this paradigm has been slowly shifting towards the development and use of open-source data formats and tools, driven by upcoming observatories such as the Cherenkov Telescope Array (CTA). In this context, a community-driven, shared data format (the gamma-astro-data-format or GADF) and analysis tools such as Gammapy and ctools have been developed. So far these efforts have been led by the IACT community, leaving out other types of ground-based gamma-ray instruments.We aim to show that the data from ground particle arrays, such as the High-Altitude Water Cherenkov (HAWC) observatory, is also compatible with the GADF and can thus be fully analysed using the related tools, in this case Gammapy. We reproduce several published HAWC results using Gammapy and data products compliant with GADF standard. We also illustrate the capabilities of the shared format and tools by producing a joint fit of the Crab spectrum including data from six different gamma-ray experiments. We find excellent agreement with the reference results, a powerful check of both the published results and the tools involved. The data from particle detector arrays such as the HAWC observatory can be adapted to the GADF and thus analysed with Gammapy. A common data format and shared analysis tools allow multi-instrument joint analysis and effective data sharing. Given the complementary nature of pointing and wide-field instruments, this synergy will be distinctly beneficial for the joint scientific exploitation of future observatories such as the Southern Wide-field Gamma-ray Observatory and CTA., Comment: Accepted by A&A
Published: 2022
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30. $\gamma$-ray Emission from Classical Nova V392 Per: Measurements from Fermi and HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Blochwitz, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Chaparro-Amaro, O., Cotti, U., Cotzomi, J., de León, E. De la Fuente. C. de León. S. Coutiño, Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Fraija, N., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Lara, A., Lee, W. H., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Salazar-Gallegos, D., Greus, F. Salesa, Serna-Franco, A. Sandoval. J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Willox, E., Zhou, A. Zepeda. H., Chomiuk, L., Aydi, E., Li, K. L., Metzger, B. D., and Vurm, I.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: This paper reports on the $\gamma$-ray properties of the 2018 Galactic nova V392 Per, spanning photon energies $\sim$0.1 GeV to 100 TeV by combining observations from the Fermi Gamma-ray Space Telescope and the HAWC Observatory. In one of the most rapidly evolving $\gamma$-ray signals yet observed for a nova, GeV $\gamma$ rays with a power law spectrum with index $\Gamma = 2.0 \pm 0.1$ were detected over eight days following V392 Per's optical maximum. HAWC observations constrain the TeV $\gamma$-ray signal during this time and also before and after. We observe no statistically significant evidence of TeV $\gamma$-ray emission from V392 Per, but present flux limits. Tests of the extension of the Fermi/LAT spectrum to energies above 5 TeV are disfavored by 2 standard deviations (95\%) or more. We fit V392 Per's GeV $\gamma$ rays with hadronic acceleration models, incorporating optical observations, and compare the calculations with HAWC limits., Comment: 18 pages, 14 figures; revised for referee comments; section 5 revised
Published: 2022
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31. Narrowband searches for continuous and long-duration transient gravitational waves from known pulsars in the LIGO-Virgo third observing run

Author: The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, Abbott, R., Abbott, T. D., Acernese, F., Ackley, K., Adams, C., Adhikari, N., Adhikari, R. X., Adya, V. B., Affeldt, C., Agarwal, D., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O. D., Aiello, L., Ain, A., Ajith, P., Akutsu, T., Albanesi, S., Allocca, A., Altin, P. A., Amato, A., Anand, C., Anand, S., Ananyeva, A., Anderson, S. B., Anderson, W. G., Ando, M., Andrade, T., Andres, N., Andrić, T., Angelova, S. V., Ansoldi, S., Antelis, J. M., Antier, S., Appert, S., Arai, Koji, Arai, Koya, Arai, Y., Araki, S., Araya, A., Araya, M. C., Areeda, J. S., Arène, M., Aritomi, N., Arnaud, N., Aronson, S. M., Arun, K. G., Asada, H., Asali, Y., Ashton, G., Aso, Y., Assiduo, M., Aston, S. M., Astone, P., Aubin, F., Austin, C., Babak, S., Badaracco, F., Bader, M. K. M., Badger, C., Bae, S., Bae, Y., Baer, A. M., Bagnasco, S., Bai, Y., Bailes, M., Baiotti, L., Baird, J., Bajpai, R., Ball, M., Ballardin, G., Ballmer, S. W., Balsamo, A., Baltus, G., Banagiri, S., Bankar, D., Barayoga, J. C., Barbieri, C., Barish, B. C., Barker, D., Barneo, P., Barone, F., Barr, B., Barsotti, L., Barsuglia, M., Barta, D., Bartlett, J., Barton, M. A., Bartos, I., Bassiri, R., Basti, A., Bawaj, M., Bayley, J. C., Baylor, A. C., Bazzan, M., Bécsy, B., Bedakihale, V. M., Bejger, M., Belahcene, I., Benedetto, V., Beniwal, D., Bennett, T. F., Bentley, J. D., BenYaala, M., Bergamin, F., Berger, B. K., Bernuzzi, S., Bersanetti, D., Bertolini, A., Betzwieser, J., Beveridge, D., Bhandare, R., Bhardwaj, U., Bhattacharjee, D., Bhaumik, S., Bilenko, I. A., Billingsley, G., Bini, S., Birney, R., Birnholtz, O., Biscans, S., Bischi, M., Biscoveanu, S., Bisht, A., Biswas, B., Bitossi, M., Bizouard, M. -A., Blackburn, J. K., Blair, C. D., Blair, D. G., Blair, R. M., Bobba, F., Bode, N., Boer, M., Bogaert, G., Boldrini, M., Bonavena, L. D., Bondu, F., Bonilla, E., Bonnand, R., Booker, P., Boom, B. A., Bork, R., Boschi, V., Bose, N., Bose, S., Bossilkov, V., Boudart, V., Bouffanais, Y., Bozzi, A., Bradaschia, C., Brady, P. R., Bramley, A., Branch, A., Branchesi, M., Brau, J. E., Breschi, M., Briant, T., Briggs, J. H., Brillet, A., Brinkmann, M., Brockill, P., Brooks, A. F., Brooks, J., Brown, D. D., Brunett, S., Bruno, G., Bruntz, R., Bryant, J., Bulik, T., Bulten, H. J., Buonanno, A., Buscicchio, R., Buskulic, D., Buy, C., Byer, R. L., Cadonati, L., Cagnoli, G., Cahillane, C., Bustillo, J. Calderón, Callaghan, J. D., Callister, T. A., Calloni, E., Cameron, J., Camp, J. B., Canepa, M., Canevarolo, S., Cannavacciuolo, M., Cannon, K. C., Cao, H., Cao, Z., Capocasa, E., Capote, E., Carapella, G., Carbognani, F., Carlin, J. B., Carney, M. F., Carpinelli, M., Carrillo, G., Carullo, G., Carver, T. L., Diaz, J. Casanueva, Casentini, C., Castaldi, G., Caudill, S., Cavaglià, M., Cavalier, F., Cavalieri, R., Ceasar, M., Cella, G., Cerdá-Durán, P., Cesarini, E., Chaibi, W., Chakravarti, K., Subrahmanya, S. Chalathadka, Champion, E., Chan, C. -H., Chan, C., Chan, C. L., Chan, K., Chan, M., Chandra, K., Chanial, P., Chao, S., Charlton, P., Chase, E. A., Chassande-Mottin, E., Chatterjee, C., Chatterjee, Debarati, Chatterjee, Deep, Chaturvedi, M., Chaty, S., Chen, C., Chen, H. Y., Chen, J., Chen, K., Chen, X., Chen, Y. -B., Chen, Y. -R., Chen, Z., Cheng, H., Cheong, C. K., Cheung, H. Y., Chia, H. Y., Chiadini, F., Chiang, C-Y., Chiarini, G., Chierici, R., Chincarini, A., Chiofalo, M. L., Chiummo, A., Cho, G., Cho, H. S., Choudhary, R. K., Choudhary, S., Christensen, N., Chu, H., Chu, Q., Chu, Y-K., Chua, S., Chung, K. W., Ciani, G., Ciecielag, P., Cieślar, M., Cifaldi, M., Ciobanu, A. A., Ciolfi, R., Cipriano, F., Cirone, A., Clara, F., Clark, E. N., Clark, J. A., Clarke, L., Clearwater, P., Clesse, S., Cleva, F., Coccia, E., Codazzo, E., Cohadon, P. -F., Cohen, D. E., Cohen, L., Colleoni, M., Collette, C. G., Colombo, A., Colpi, M., Compton, C. M., Constancio Jr., M., Conti, L., Cooper, S. J., Corban, P., Corbitt, T. R., Cordero-Carrión, I., Corezzi, S., Corley, K. R., Cornish, N., Corre, D., Corsi, A., Cortese, S., Costa, C. A., Cotesta, R., Coughlin, M. W., Coulon, J. -P., Countryman, S. T., Cousins, B., Couvares, P., Coward, D. M., Cowart, M. J., Coyne, D. C., Coyne, R., Creighton, J. D. E., Creighton, T. D., Criswell, A. W., Croquette, M., Crowder, S. G., Cudell, J. R., Cullen, T. J., Cumming, A., Cummings, R., Cunningham, L., Cuoco, E., Curyło, M., Dabadie, P., Canton, T. Dal, Dall'Osso, S., Dálya, G., Dana, A., DaneshgaranBajastani, L. M., D'Angelo, B., Danilishin, S., D'Antonio, S., Danzmann, K., Darsow-Fromm, C., Dasgupta, A., Datrier, L. E. H., Datta, S., Dattilo, V., Dave, I., Davier, M., Davies, G. S., Davis, D., Davis, M. C., Daw, E. J., Dean, R., DeBra, D., Deenadayalan, M., Degallaix, J., De Laurentis, M., Deléglise, S., Del Favero, V., De Lillo, F., De Lillo, N., Del Pozzo, W., DeMarchi, L. M., De Matteis, F., D'Emilio, V., Demos, N., Dent, T., Depasse, A., De Pietri, R., De Rosa, R., De Rossi, C., DeSalvo, R., De Simone, R., Dhurandhar, S., Díaz, M. C., Diaz-Ortiz Jr., M., Didio, N. A., Dietrich, T., Di Fiore, L., Di Fronzo, C., Di Giorgio, C., Di Giovanni, F., Di Giovanni, M., Di Girolamo, T., Di Lieto, A., Ding, B., Di Pace, S., Di Palma, I., Di Renzo, F., Divakarla, A. K., Dmitriev, A., Doctor, Z., D'Onofrio, L., Donovan, F., Dooley, K. L., Doravari, S., Dorrington, I., Drago, M., Driggers, J. C., Drori, Y., Ducoin, J. -G., Dupej, P., Durante, O., D'Urso, D., Duverne, P. -A., Dwyer, S. E., Eassa, C., Easter, P. J., Ebersold, M., Eckhardt, T., Eddolls, G., Edelman, B., Edo, T. B., Edy, O., Effler, A., Eguchi, S., Eichholz, J., Eikenberry, S. S., Eisenmann, M., Eisenstein, R. A., Ejlli, A., Engelby, E., Enomoto, Y., Errico, L., Essick, R. C., Estellés, H., Estevez, D., Etienne, Z., Etzel, T., Evans, M., Evans, T. M., Ewing, B. E., Fafone, V., Fair, H., Fairhurst, S., Farah, A. M., Farinon, S., Farr, B., Farr, W. M., Farrow, N. W., Fauchon-Jones, E. J., Favaro, G., Favata, M., Fays, M., Fazio, M., Feicht, J., Fejer, M. M., Fenyvesi, E., Ferguson, D. L., Fernandez-Galiana, A., Ferrante, I., Ferreira, T. A., Fidecaro, F., Figura, P., Fiori, I., Fishbach, M., Fisher, R. P., Fittipaldi, R., Fiumara, V., Flaminio, R., Floden, E., Fong, H., Font, J. A., Fornal, B., Forsyth, P. W. F., Franke, A., Frasca, S., Frasconi, F., Frederick, C., Freed, J. P., Frei, Z., Freise, A., Frey, R., Fritschel, P., Frolov, V. V., Fronzé, G. G., Fujii, Y., Fujikawa, Y., Fukunaga, M., Fukushima, M., Fulda, P., Fyffe, M., Gabbard, H. A., Gadre, B. U., Gair, J. R., Gais, J., Galaudage, S., Gamba, R., Ganapathy, D., Ganguly, A., Gao, D., Gaonkar, S. G., Garaventa, B., García-Núñez, C., García-Quirós, C., Garufi, F., Gateley, B., Gaudio, S., Gayathri, V., Ge, G. -G., Gemme, G., Gennai, A., George, J., Gerberding, O., Gergely, L., Gewecke, P., Ghonge, S., Ghosh, Abhirup, Ghosh, Archisman, Ghosh, Shaon, Ghosh, Shrobana, Giacomazzo, B., Giacoppo, L., Giaime, J. A., Giardina, K. D., Gibson, D. R., Gier, C., Giesler, M., Giri, P., Gissi, F., Glanzer, J., Gleckl, A. E., Godwin, P., Goetz, E., Goetz, R., Gohlke, N., Goncharov, B., González, G., Gopakumar, A., Gosselin, M., Gouaty, R., Gould, D. W., Grace, B., Grado, A., Granata, M., Granata, V., Grant, A., Gras, S., Grassia, P., Gray, C., Gray, R., Greco, G., Green, A. C., Green, R., Gretarsson, A. M., Gretarsson, E. M., Griffith, D., Griffiths, W., Griggs, H. L., Grignani, G., Grimaldi, A., Grimm, S. J., Grote, H., Grunewald, S., Gruning, P., Guerra, D., Guidi, G. M., Guimaraes, A. R., Guixé, G., Gulati, H. K., Guo, H. -K., Guo, Y., Gupta, Anchal, Gupta, Anuradha, Gupta, P., Gustafson, E. K., Gustafson, R., Guzman, F., Ha, S., Haegel, L., Hagiwara, A., Haino, S., Halim, O., Hall, E. D., Hamilton, E. Z., Hammond, G., Han, W. -B., Haney, M., Hanks, J., Hanna, C., Hannam, M. D., Hannuksela, O., Hansen, H., Hansen, T. J., Hanson, J., Harder, T., Hardwick, T., Haris, K., Harms, J., Harry, G. M., Harry, I. W., Hartwig, D., Hasegawa, K., Haskell, B., Hasskew, R. K., Haster, C. -J., Hattori, K., Haughian, K., Hayakawa, H., Hayama, K., Hayes, F. J., Healy, J., Heidmann, A., Heidt, A., Heintze, M. C., Heinze, J., Heinzel, J., Heitmann, H., Hellman, F., Hello, P., Helmling-Cornell, A. F., Hemming, G., Hendry, M., Heng, I. S., Hennes, E., Hennig, J., Hennig, M. H., Hernandez, A. G., Vivanco, F. Hernandez, Heurs, M., Hild, S., Hill, P., Himemoto, Y., Hines, A. S., Hiranuma, Y., Hirata, N., Hirose, E., Ho, W. C. G., Hochheim, S., Hofman, D., Hohmann, J. N., Holcomb, D. G., Holland, N. A., Hollows, I. J., Holmes, Z. J., Holt, K., Holz, D. E., Hong, Z., Hopkins, P., Hough, J., Hourihane, S., Howell, E. J., Hoy, C. G., Hoyland, D., Hreibi, A., Hsieh, B-H., Hsu, Y., Huang, G-Z., Huang, H-Y., Huang, P., Huang, Y-C., Huang, Y. -J., Huang, Y., Hübner, M. T., Huddart, A. D., Hughey, B., Hui, D. C. Y., Hui, V., Husa, S., Huttner, S. H., Huxford, R., Huynh-Dinh, T., Ide, S., Idzkowski, B., Iess, A., Ikenoue, B., Imam, S., Inayoshi, K., Ingram, C., Inoue, Y., Ioka, K., Isi, M., Isleif, K., Ito, K., Itoh, Y., Iyer, B. R., Izumi, K., JaberianHamedan, V., Jacqmin, T., Jadhav, S. J., Jadhav, S. P., James, A. L., Jan, A. Z., Jani, K., Janquart, J., Janssens, K., Janthalur, N. N., Jaranowski, P., Jariwala, D., Jaume, R., Jenkins, A. C., Jenner, K., Jeon, C., Jeunon, M., Jia, W., Jin, H. -B., Johns, G. R., Jones, A. W., Jones, D. I., Jones, J. D., Jones, P., Jones, R., Jonker, R. J. G., Ju, L., Jung, P., Jung, k., Junker, J., Juste, V., Kaihotsu, K., Kajita, T., Kakizaki, M., Kalaghatgi, C. 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Subjects: General Relativity and Quantum Cosmology, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully-coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow the frequency and frequency time-derivative of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets., Comment: 37 pages, 9 figures, submitted to ApJ
Published: 2021
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32. Study of the Very High Energy emission of M87 through its broadband spectral energy distribution

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

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

Author: HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Álvarez, J. D., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Babu, R., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Alonso, M. Fernández, Fraija, N., Garcia, D., García-González, J. A., Garfias, F., Giacinti, G., Goksu, H., González, M. M., Goodman, J. A., Harding, J. P., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Kieda, D., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Smith, A. J., Son, Y., Springer, R. W., Tibolla, O., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Watson, I. J., Willox, E., Zepeda, A., Zhou, H., Li, M. Breuhaus H., and Zhang, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report TeV gamma-ray observations of the ultra-high-energy source MGRO J1908+06 using data from the High Altitude Water Cherenkov (HAWC) Observatory. This source is one of the highest-energy known gamma-ray sources, with emission extending past 200 TeV. Modeling suggests that the bulk of the TeV gamma-ray emission is leptonic in nature, driven by the energetic radio-faint pulsar PSR J1907+0602. Depending on what assumptions are included in the model, a hadronic component may also be allowed. Using the results of the modeling, we discuss implications for detection prospects by multi-messenger campaigns., Comment: accepted by ApJ, in press
Published: 2021
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34. VLA proper motion constraints on the origin, age, and potential magnetar future of PSR J1734$-$3333

Author: Espinoza, C. M., Vidal-Navarro, M., Ho, W. C. G., Deller, A., and Chatterjee, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The characteristic age of PSR J1734$-$3333 estimated from its current spin down rate implies that it is a young pulsar ($\tau_c<10$ kyr). But the time derivative of its spin down rate differs markedly from that assumed for normal radio pulsars, meaning its actual age is uncertain. G354.8$-$0.8 is a supernova remnant (SNR) whose centre is located 21 arcmin away of the pulsar, and with a morphology that suggests an association with the pulsar. We want to assess the likelihood of the association between PSR J1734$-$3333 and G354.8$-$0.8 or other nearby supernova remnants quantitatively, with the objective of shedding light on the real age of this pulsar. Observations with the Karl G. Jansky Very Large Array were carried out in 2015 and 2019 that allow precise astrometric measurements and consequently a proper motion estimate for the pulsar. The proper motion was found to be $\mu_\alpha=10\pm10$ mas yr$^{-1}$ and $\mu_\delta=-29\pm11$ mas yr$^{-1}$ (error bars are $1$-$\sigma$). Though marginal, this detection rules out the association with G354.8$-$0.8 because it means the pulsar is not moving away from the centre of the SNR. No SNR consistent with the measured proper motion and an age $\sim\tau_c$ could be found. We also present the first measurement of the spectral index for this pulsar, $\alpha=-1.1\pm0.3$, measured between $1.5$ and $3.0$ GHz. The SNR produced by the birth supernova of PSR J1734$-$3333 could have already faded to undetectable brightness, for which estimates suggest timescales of $10$-$100$ kyr. This and other considerations lead us to conclude that the pulsar is possibly older than $45$-$100$ kyr. PSR J1734$-$3333 is a pulsar with rotational properties that place it between standard radio pulsars and magnetars, and we interpret our result in the context of a possible future life as a magnetar for this pulsar., Comment: 8 pages, 4 figures and 4 tables. Accepted for publication in A&A
Published: 2021
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35. Spontaneous Magnetic Fluctuations and Collisionless Regulation of Turbulence in the Earth's Magnetotail

Author: Espinoza, C. M., Moya, P. S., Stepanova, M., Valdivia, J. A., and Navarro, R. E.
Subjects: Physics - Space Physics, Astrophysics - Earth and Planetary Astrophysics, Physics - Plasma Physics
Abstract: Among the fundamental and most challenging problems of laboratory, space, and astrophysical plasma physics is to understand the relaxation processes of nearly collisionless plasmas toward quasi-stationary states; and the resultant states of electromagnetic plasma turbulence. Recently, it has been argued that solar wind plasma $\beta$ and temperature anisotropy observations may be regulated by kinetic instabilities such as the ion-cyclotron, mirror, electron-cyclotron, and firehose instabilities; and that magnetic fluctuation observations are consistent with the predictions of the Fluctuation-Dissipation theorem, even far below the kinetic instability thresholds. Here, using in-situ magnetic field and plasma measurements by the THEMIS satellite mission, we show that such regulation seems to occur also in the Earth's magnetotail plasma sheet at the ion and electron scales. Regardless of the clear differences between the solar wind and the magnetotail environments, our results indicate that spontaneous fluctuations and their collisionless regulation are fundamental features of space and astrophysical plasmas, thereby suggesting the processes is universal., Comment: 11 pages, 3 figures. Accepted for publication in the Astrophysical Journal
Published: 2021
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36. Cirugía de la enfermedad inflamatoria intestinal en España: ¿cómo lo estamos haciendo? Resultados iniciales de un registro prospectivo nacional (Registro REIC)

Author: Enriquez-Navascues, J.M., Elorza-Echaniz, G., Die Trill, J., Ocaña Jimenez, J., Moro-Valdezate, D., Leon-Espinoza, C., Primo-Romaguera, V., Sancho-Muriel, J., Pascual Migueláñez, I., Saavedra, J., Penín de Oliveira, P., Meceira Quintian, F., Carmona Agúndez, M., Gallarín Salamanca, I.M., Lopez de los Reyes, R., Vives Rodriguez, E., Navarro-Sáncheze, A., Soto-Darias, I., Monjero Ares, I., Torres García, M.I., Aldrey Cao, I., Barreiro Dominguez, E.M., Diz Jueguen, S., Bernal Sprekelsen, J.C., Ivorra García-Moncó, P., Vigorita, V., Nogueira Sixto, M., Martín Dieguez, C., López Bañeres, M., Pérez Pérez, T., Añón Iranzo, E., Vázquez-Bouzán, R., Sánchez Espinel, E., Alberdi San Roman, I., Trujillo Barbadillo, A., Martínez-García, R., Menárguez Pina, F.J., Anula Fernández, R., Mayol Martínez, J.A., Romero de Diego, A., de Andres-Asenjo, B., Ibáñez Cánovas, N., Abrisqueta Carrión, J., Estaire Gómez, M., Lorente Poyatos, R.H., Julià-Bergkvist, D., Gómez-Romeu, N., Romero-Simó, M., Mauri-Barberá, F., Arroyo, A., Alcaide-Quiros, M.J., Hernandis Villalba, J.V., Espinosa Soria, J., Parés, D., Corral, J., Jiménez-Gómez, L.M., Zorrilla Ortúzar, J., Abellán Morcillo, I., Bernabé Peñalver, A., Parra Baños, P.A., Muñoz Camarena, J.M., Abellán Garay, L., Milagros Carrasco, M., Rufas Acín, M.P., Ambrona Zafra, D., Padín Álvarez, M.H., Lora Cumplido, P., Fernández-Cepedal, L., García-González, J.M., Pérez Viejo, E., Huerga Álvarez, D., Valle Rubio, A., Jiménez Carneros, V., Arencibia-Pérez, B., Roque-Castellano, C., Ríos Blanco, R., Espina Pérez, B., Caro Tarrago, A., Saeta Campo, R., Illan Riquelme, A., Bermejo Marcos, E., Rodríguez Sánchez, A., Cagigas Fernández, C., Cristóbal Poch, L., Duque Mallen, M.V., Santero Ramírez, M.P., Aguilar Martínez, M.M., Moreno Navas, A., Gallardo Valverde, J.M., Choolani Bhojwani, E., Veleda Belanche, S., Díaz-Maag, C.R., Rodríguez-García, R., Alberca Páramo, A., Pineda Navarro, N., Ferrer Inaebnit, E., Alonso Hernández, N., Ferrer-Márquez, M., Gómez-Carmona, Z., Ramos Fernandez, M., Sanchiz Cardenas, E., Valdes-Hernandez, J., Pérez Sánchez, A., Labalde Martínez, M., García Borda, F.J., Fernández Arias, S., Fernández Hevia, M., Elosua González, T., Jimenez Alvarez, L., Sánchez-Guillén, L., Blanco-Antona, F., Soler-Silva, Á., and Millán, M.
Published: 2024
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37. Characterization of the background for a neutrino search with the HAWC observatory

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

Author: Abdalla, H., Aharonian, F., Benkhali, F. Ait, Angüner, E. O., Arcaro, C., Armand, C., Armstrong, T., Ashkar, H., Backes, M., Baghmanyan, V., Martins, V. Barbosa, Barnacka, A., Barnard, M., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., de Lavergne, M. de Bony, Breuhaus, M., Brose, R., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Bylund, T., Caroff, S., Carosi, A., Chand, T., Chandra, S., Chen, A., Cotter, G., Curyło, M., Mbarubucyeye, J. Damascene, Davids, I. D., Davies, J., Deil, C., Devin, J., Dirson, L., Djannati-Ataï, A., Dmytriiev, A., Donath, A., Doroshenko, V., Dreyer, L., Duffy, C., Dyks, J., Egberts, K., Eichhorn, F., Einecke, S., Emery, G., Ernenwein, J. -P., Feijen, K., Fegan, S., Fiasson, A., de Clairfontaine, G. Fichet, Fontaine, G., Funk, S., Füßling, M., Gabici, S., Gallant, Y. A., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Hahn, J., Haupt, M., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Hörbe, M., Horns, D., Huber, D., Jamrozy, M., Jankowsky, D., Jankowsky, F., Jung-Richardt, I., Kasai, E., Kastendieck, M. A., Katarzyński, K., Katz, U., Khangulyan, D., Khélifi, B., Klepser, S., Kluźniak, W., Komin, Nu., Konno, R., Kosack, K., Kostunin, D., Kreter, M., Lamanna, G., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leuschner, F., Levy, C., Lohse, T., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Mares, A., Martí-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohrmann, L., Montanari, A., Moore, C., Morris, P., Moulin, E., Muller, J., Murach, T., Nakashima, K., Nayerhoda, A., de Naurois, M., Ndiyavala, H., Niemiec, J., Oakes, L., Brien, P. O, Odaka, H., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Peyaud, B., Piel, Q., Pita, S., Poireau, V., Noel, A. Priyana, Prokhorov, D. A., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Rauth, R., Reichherzer, P., Reimer, A., Reimer, O., Remy, Q., Renaud, M., Rieger, F., Rinchiuso, L., Romoli, C., Rowell, G., Rudak, B., Sahakian, V., Sailer, S., Salzmann, H., Sanchez, D. A., Santangelo, A., Sasaki, M., Schäfer, J., Schüssler, F., Schutte, H. M., Schwanke, U., Seglar-Arroyo, M., Senniappan, M., Seyffert, A. S., Shafi, N., Shapopi, J. N. S., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Specovius, A., Spencer, S., Spir-Jacob, M., Stawarz, Ł., Sun, L., Steenkamp, R., Stegmann, C., Steinmassl, S., Steppa, C., Takahashi, T., Tavernier, T., Taylor, A. M., Terrier, R., Thiersen, J. H. E., Tiziani, D., Tluczykont, M., Tomankova, L., Trichard, C., Tsirou, M., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., Völk, H. J., Wadiasingh, Z., Wagner, S. J., Watson, J., Werner, F., White, R., Wierzcholska, A., Wong, Yu Wun, Yusafzai, A., Zacharias, M., Zanin, R., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zmija, A., Zorn, J., Zouari, S., Żywucka, N., Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Hernandez, R. Diaz, Díaz-Vélez, J. C., Dingus, B. L., DuVernois, M. A., Durocher, M., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., Galván-Gámez, A., Garcia, D., García-González, J. A., Garfias, F., Giacinti, G., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., López-Coto, R., Malone, K., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Schoorlemmer, H., Serna-Franco, J., Smith, A. J., Springer, R. W., Surajbali, P., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Weisgarber, T., Willox, E., and Zhou, H.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The High Altitude Water Cherenkov (HAWC) observatory and the High Energy Stereoscopic System (H.E.S.S.) are two leading instruments in the ground-based very-high-energy gamma-ray domain. HAWC employs the water Cherenkov detection (WCD) technique, while H.E.S.S. is an array of Imaging Atmospheric Cherenkov Telescopes (IACTs). The two facilities therefore differ in multiple aspects, including their observation strategy, the size of their field of view and their angular resolution, leading to different analysis approaches. Until now, it has been unclear if the results of observations by both types of instruments are consistent: several of the recently discovered HAWC sources have been followed up by IACTs, resulting in a confirmed detection only in a minority of cases. With this paper, we go further and try to resolve the tensions between previous results by performing a new analysis of the H.E.S.S. Galactic plane survey data, applying an analysis technique comparable between H.E.S.S. and HAWC. Events above 1 TeV are selected for both datasets, the point spread function of H.E.S.S. is broadened to approach that of HAWC, and a similar background estimation method is used. This is the first detailed comparison of the Galactic plane observed by both instruments. H.E.S.S. can confirm the gamma-ray emission of four HAWC sources among seven previously undetected by IACTs, while the three others have measured fluxes below the sensitivity of the H.E.S.S. dataset. Remaining differences in the overall gamma-ray flux can be explained by the systematic uncertainties. Therefore, we confirm a consistent view of the gamma-ray sky between WCD and IACT techniques.
Published: 2021
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39. Long-term spectra of the blazars Mrk 421 and Mrk 501 at TeV energies seen by HAWC

Author: Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Hernandez, R. Diaz, DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Lara, A., Lee, W. H., Lee, J., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Noriega-Papaqui, R., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Ureña-Mena, F., Villaseñor, L., Wang, X., Weisgarber, T., Willox, E., Zhou, H., and de León, C.
Subjects: 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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40. Constraints from LIGO O3 data on gravitational-wave emission due to r-modes in the glitching pulsar PSR J0537-6910

Author: The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, Abbott, R., Abbott, T. D., Abraham, S., Acernese, F., Ackley, K., Adams, A., Adams, C., Adhikari, R. X., Adya, V. B., Affeldt, C., Agarwal, D., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O. D., Aiello, L., Ain, A., Ajith, P., Akutsu, T., Aleman, K. M., Allen, G., Allocca, A., Altin, P. A., Amato, A., Anand, S., Ananyeva, A., Anderson, S. B., Anderson, W. G., Ando, M., Angelova, S. V., Ansoldi, S., Antelis, J. M., Antier, S., Appert, S., Arai, Koya, Arai, Koji, Arai, Y., Araki, S., Araya, A., Araya, M. C., Areeda, J. S., Arène, M., Aritomi, N., Arnaud, N., Aronson, S. M., Arun, K. G., Asada, H., Asali, Y., Ashton, G., Aso, Y., Aston, S. M., Astone, P., Aubin, F., Aufmuth, P., AultONeal, K., Austin, C., Babak, S., Badaracco, F., Bader, M. K. M., Bae, S., Bae, Y., Baer, A. M., Bagnasco, S., Bai, Y., Baiotti, L., Baird, J., Bajpai, R., Ball, M., Ballardin, G., Ballmer, S. W., Bals, M., Balsamo, A., Baltus, G., Banagiri, S., Bankar, D., Bankar, R. S., Barayoga, J. C., Barbieri, C., Barish, B. C., Barker, D., Barneo, P., Barone, F., Barr, B., Barsotti, L., Barsuglia, M., Barta, D., Bartlett, J., Barton, M. A., Bartos, I., Bassiri, R., Basti, A., Bawaj, M., Bayley, J. C., Baylor, A. C., Bazzan, M., Bécsy, B., Bedakihale, V. M., Bejger, M., Belahcene, I., Benedetto, V., Beniwal, D., Benjamin, M. G., Bennett, T. F., Bentley, J. D., BenYaala, M., Bergamin, F., Berger, B. K., Bernuzzi, S., Bersanetti, D., Bertolini, A., Betzwieser, J., Bhandare, R., Bhandari, A. V., Bhattacharjee, D., Bhaumik, S., Bidler, J., Bilenko, I. A., Billingsley, G., Birney, R., Birnholtz, O., Biscans, S., Bischi, M., Biscoveanu, S., Bisht, A., Biswas, B., Bitossi, M., Bizouard, M. -A., Blackburn, J. K., Blackman, J., Blair, C. D., Blair, D. G., Blair, R. M., Bobba, F., Bode, N., Boer, M., Bogaert, G., Boldrini, M., Bondu, F., Bonilla, E., Bonnand, R., Booker, P., Boom, B. A., Bork, R., Boschi, V., Bose, N., Bose, S., Bossilkov, V., Boudart, V., Bouffanais, Y., Bozzi, A., Bradaschia, C., Brady, P. R., Bramley, A., Branch, A., Branchesi, M., Brau, J. E., Breschi, M., Briant, T., Briggs, J. H., Brillet, A., Brinkmann, M., Brockill, P., Brooks, A. F., Brooks, J., Brown, D. D., Brunett, S., Bruno, G., Bruntz, R., Bryant, J., Buikema, A., Bulik, T., Bulten, H. J., Buonanno, A., Buscicchio, R., Buskulic, D., Byer, R. L., Cadonati, L., Caesar, M., Cagnoli, G., Cahillane, C., Cain III, H. W., Bustillo, J. Calderón, Callaghan, J. D., Callister, T. A., Calloni, E., Camp, J. B., Canepa, M., Cannavacciuolo, M., Cannon, K. C., Cao, H., Cao, J., Cao, Z., Capocasa, E., Capote, E., Carapella, G., Carbognani, F., Carlin, J. B., Carney, M. F., Carpinelli, M., Carullo, G., Carver, T. L., Diaz, J. Casanueva, Casentini, C., Castaldi, G., Caudill, S., Cavaglià, M., Cavalier, F., Cavalieri, R., Cella, G., Cerdá-Durán, P., Cesarini, E., Chaibi, W., Chakravarti, K., Champion, B., Chan, C. -H., Chan, C., Chan, C. L., Chan, M., Chandra, K., Chanial, P., Chao, S., Charlton, P., Chase, E. A., Chassande-Mottin, E., Chatterjee, D., Chaturvedi, M., Chen, A., Chen, C., Chen, H. Y., Chen, J., Chen, K., Chen, X., Chen, Y. -B., Chen, Y. -R., Chen, Z., Cheng, H., Cheong, C. K., Cheung, H. Y., Chia, H. Y., Chiadini, F., Chiang, C-Y., Chierici, R., Chincarini, A., Chiofalo, M. L., Chiummo, A., Cho, G., Cho, H. S., Choate, S., Choudhary, R. K., Choudhary, S., Christensen, N., Chu, H., Chu, Q., Chu, Y-K., Chua, S., Chung, K. W., Ciani, G., Ciecielag, P., Cieślar, M., Cifaldi, M., Ciobanu, A. A., Ciolfi, R., Cipriano, F., Cirone, A., Clara, F., Clark, E. N., Clark, J. A., Clarke, L., Clearwater, P., Clesse, S., Cleva, F., Coccia, E., Cohadon, P. -F., Cohen, D. E., Cohen, L., Colleoni, M., Collette, C. G., Colpi, M., Compton, C. M., Constancio Jr., M., Conti, L., Cooper, S. J., Corban, P., Corbitt, T. R., Cordero-Carrión, I., Corezzi, S., Corley, K. R., Cornish, N., Corre, D., Corsi, A., Cortese, S., Costa, C. A., Cotesta, R., Coughlin, M. W., Coughlin, S. B., Coulon, J. -P., Countryman, S. T., Cousins, B., Couvares, P., Covas, P. B., Coward, D. M., Cowart, M. J., Coyne, D. C., Coyne, R., Creighton, J. D. E., Creighton, T. D., Criswell, A. W., Croquette, M., Crowder, S. G., Cudell, J. R., Cullen, T. J., Cumming, A., Cummings, R., Cuoco, E., Curyło, M., Canton, T. Dal, Dálya, G., Dana, A., DaneshgaranBajastani, L. M., D'Angelo, B., Danilishin, S. L., D'Antonio, S., Danzmann, K., Darsow-Fromm, C., Dasgupta, A., Datrier, L. E. H., Dattilo, V., Dave, I., Davier, M., Davies, G. S., Davis, D., Daw, E. J., Dean, R., DeBra, D., Deenadayalan, M., Degallaix, J., De Laurentis, M., Deléglise, S., Del Favero, V., De Lillo, F., De Lillo, N., Del Pozzo, W., DeMarchi, L. M., De Matteis, F., D'Emilio, V., Demos, N., Dent, T., Depasse, A., De Pietri, R., De Rosa, R., De Rossi, C., DeSalvo, R., De Simone, R., Dhurandhar, S., Díaz, M. C., Diaz-Ortiz Jr., M., Didio, N. A., Dietrich, T., Di Fiore, L., Di Fronzo, C., Di Giorgio, C., Di Giovanni, F., Di Girolamo, T., Di Lieto, A., Ding, B., Di Pace, S., Di Palma, I., Di Renzo, F., Divakarla, A. K., Dmitriev, A., Doctor, Z., D'Onofrio, L., Donovan, F., Dooley, K. L., Doravari, S., Dorosh, O., Dorrington, I., Drago, M., Driggers, J. C., Drori, Y., Du, Z., Ducoin, J. -G., Dupej, P., Durante, O., D'Urso, D., Duverne, P. -A., Dwyer, S. E., Easter, P. J., Ebersold, M., Eddolls, G., Edelman, B., Edo, T. B., Edy, O., Effler, A., Eguchi, S., Eichholz, J., Eikenberry, S. S., Eisenmann, M., Eisenstein, R. A., Ejlli, A., Enomoto, Y., Errico, L., Essick, R. C., Estellés, H., Estevez, D., Etienne, Z., Etzel, T., Evans, M., Evans, T. M., Ewing, B. E., Fafone, V., Fair, H., Fairhurst, S., Fan, X., Farah, A. M., Farinon, S., Farr, B., Farr, W. M., Farrow, N. W., Fauchon-Jones, E. J., Favata, M., Fays, M., Fazio, M., Feicht, J., Fejer, M. M., Feng, F., Fenyvesi, E., Ferguson, D. L., Fernandez-Galiana, A., Ferrante, I., Ferreira, T. A., Fidecaro, F., Figura, P., Fiori, I., Fishbach, M., Fisher, R. P., Fittipaldi, R., Fiumara, V., Flaminio, R., Floden, E., Flynn, E., Fong, H., Font, J. A., Fornal, B., Forsyth, P. W. F., Franke, A., Frasca, S., Frasconi, F., Frederick, C., Frei, Z., Freise, A., Frey, R., Fritschel, P., Frolov, V. V., Fronzé, G. G., Fujii, Y., Fujikawa, Y., Fukunaga, M., Fukushima, M., Fulda, P., Fyffe, M., Gabbard, H. A., Gadre, B. U., Gaebel, S. M., Gair, J. R., Gais, J., Galaudage, S., Gamba, R., Ganapathy, D., Ganguly, A., Gao, D., Gaonkar, S. G., Garaventa, B., García-Núñez, C., García-Quirós, C., Garufi, F., Gateley, B., Gaudio, S., Gayathri, V., Ge, G., Gemme, G., Gennai, A., George, J., Gergely, L., Gewecke, P., Ghonge, S., Ghosh, Abhirup., Ghosh, Archisman, Ghosh, Shaon, Ghosh, Shrobana, Ghosh, Sourath, Giacomazzo, B., Giacoppo, L., Giaime, J. A., Giardina, K. D., Gibson, D. R., Gier, C., Giesler, M., Giri, P., Gissi, F., Glanzer, J., Gleckl, A. E., Godwin, P., Goetz, E., Goetz, R., Gohlke, N., Goncharov, B., González, G., Gopakumar, A., Gosselin, M., Gouaty, R., Grace, B., Grado, A., Granata, M., Granata, V., Grant, A., Gras, S., Grassia, P., Gray, C., Gray, R., Greco, G., Green, A. C., Green, R., Gretarsson, A. M., Gretarsson, E. M., Griffith, D., Griffiths, W., Griggs, H. L., Grignani, G., Grimaldi, A., Grimes, E., Grimm, S. J., Grote, H., Grunewald, S., Gruning, P., Guerrero, J. G., Guidi, G. M., Guimaraes, A. R., Guixé, G., Gulati, H. K., Guo, H. -K., Guo, Y., Gupta, Anchal, Gupta, Anuradha, Gupta, P., Gustafson, E. K., Gustafson, R., Guzman, F., Ha, S., Haegel, L., Hagiwara, A., Haino, S., Halim, O., Hall, E. D., Hamilton, E. Z., Hammond, G., Han, W. -B., Haney, M., Hanks, J., Hanna, C., Hannam, M. D., Hannuksela, O. A., Hansen, H., Hansen, T. J., Hanson, J., Harder, T., Hardwick, T., Haris, K., Harms, J., Harry, G. M., Harry, I. W., Hartwig, D., Hasegawa, K., Haskell, B., Hasskew, R. K., Haster, C. -J., Hattori, K., Haughian, K., Hayakawa, H., Hayama, K., Hayes, F. J., Healy, J., Heidmann, A., Heintze, M. C., Heinze, J., Heinzel, J., Heitmann, H., Hellman, F., Hello, P., Helmling-Cornell, A. F., Hemming, G., Hendry, M., Heng, I. S., Hennes, E., Hennig, J., Hennig, M. H., Vivanco, F. Hernandez, Heurs, M., Hild, S., Hill, P., Himemoto, Y., Hines, A. S., Hiranuma, Y., Hirata, N., Hirose, E., Ho, W. C. G., Hochheim, S., Hofman, D., Hohmann, J. N., Holgado, A. M., Holland, N. A., Hollows, I. J., Holmes, Z. J., Holt, K., Holz, D. E., Hong, Z., Hopkins, P., Hough, J., Howell, E. J., Hoy, C. G., Hoyland, D., Hreibi, A., Hsieh, B-H., Hsu, Y., Huang, G-Z., Huang, H-Y., Huang, P., Huang, Y-C., Huang, Y. -J., Huang, Y. -W., Hübner, M. T., Huddart, A. D., Huerta, E. A., Hughey, B., Hui, D. C. Y., Hui, V., Husa, S., Huttner, S. H., Huxford, R., Huynh-Dinh, T., Ide, S., Idzkowski, B., Iess, A., Ikenoue, B., Imam, S., Inayoshi, K., Inchauspe, H., Ingram, C., Inoue, Y., Intini, G., Ioka, K., Isi, M., Isleif, K., Ito, K., Itoh, Y., Iyer, B. R., Izumi, K., JaberianHamedan, V., Jacqmin, T., Jadhav, S. J., Jadhav, S. P., James, A. L., Jan, A. Z., Jani, K., Janssens, K., Janthalur, N. N., Jaranowski, P., Jariwala, D., Jaume, R., Jenkins, A. C., Jeon, C., Jeunon, M., Jia, W., Jiang, J., Jin, H. -B., Johns, G. R., Jones, A. W., Jones, D. I., Jones, J. D., Jones, P., Jones, R., Jonker, R. J. G., Ju, L., Jung, K., Jung, P., Junker, J., Kaihotsu, K., Kajita, T., Kakizaki, M., Kalaghatgi, C. V., Kalogera, V., Kamai, B., Kamiizumi, M., Kanda, N., Kandhasamy, S., Kang, G., Kanner, J. B., Kao, Y., Kapadia, S. J., Kapasi, D. P., Karat, S., Karathanasis, C., Karki, S., Kashyap, R., Kasprzack, M., Kastaun, W., Katsanevas, S., Katsavounidis, E., Katzman, W., Kaur, T., Kawabe, K., Kawaguchi, K., Kawai, N., Kawasaki, T., Kéfélian, F., Keitel, D., Key, J. S., Khadka, S., Khalili, F. Y., Khan, I., Khan, S., Khazanov, E. A., Khetan, N., Khursheed, M., Kijbunchoo, N., Kim, C., Kim, J. C., Kim, J., Kim, K., Kim, W. S., Kim, Y. -M., Kimball, C., Kimura, N., King, P. J., Kinley-Hanlon, M., Kirchhoff, R., Kissel, J. S., Kita, N., Kitazawa, H., Kleybolte, L., Klimenko, S., Knee, A. M., Knowles, T. D., Knyazev, E., Koch, P., Koekoek, G., Kojima, Y., Kokeyama, K., Koley, S., Kolitsidou, P., Kolstein, M., Komori, K., Kondrashov, V., Kong, A. K. H., Kontos, A., Koper, N., Korobko, M., Kotake, K., Kovalam, M., Kozak, D. B., Kozakai, C., Kozu, R., Kringel, V., Krishnendu, N. V., Królak, A., Kuehn, G., Kuei, F., Kumar, A., Kumar, P., Kumar, Rahul, Kumar, Rakesh, Kume, J., Kuns, K., Kuo, C., Kuo, H-S., Kuromiya, Y., Kuroyanagi, S., Kusayanagi, K., Kwak, K., Kwang, S., Laghi, D., Lalande, E., Lam, T. L., Lamberts, A., Landry, M., Lane, B. B., Lang, R. N., Lange, J., Lantz, B., La Rosa, I., Lartaux-Vollard, A., Lasky, P. D., Laxen, M., Lazzarini, A., Lazzaro, C., Leaci, P., Leavey, S., Lecoeuche, Y. K., Lee, H. K., Lee, H. M., Lee, H. W., Lee, J., Lee, K., Lee, R., Lehmann, J., Lemaître, A., Leon, E., Leonardi, M., Leroy, N., Letendre, N., Levin, Y., Leviton, J. N., Li, A. K. Y., Li, B., Li, J., Li, K. L., Li, T. G. F., Li, X., Lin, C-Y., Lin, F-K., Lin, F-L., Lin, H. L., Lin, L. C. -C., Linde, F., Linker, S. D., Linley, J. N., Littenberg, T. B., Liu, G. C., Liu, J., Liu, K., Liu, X., Llorens-Monteagudo, M., Lo, R. K. L., Lockwood, A., Lollie, M. L., London, L. T., Longo, A., Lopez, D., Lorenzini, M., Loriette, V., Lormand, M., Losurdo, G., Lough, J. D., Lousto, C. O., Lovelace, G., Lück, H., Lumaca, D., Lundgren, A. P., Luo, L. -W., Macas, R., MacInnis, M., Macleod, D. M., MacMillan, I. A. O., Macquet, A., Hernandez, I. Magaña, Magaña-Sandoval, F., Magazzù, C., Magee, R. M., Maggiore, R., Majorana, E., Makarem, C., Maksimovic, I., Maliakal, S., Malik, A., Man, N., Mandic, V., Mangano, V., Mango, J. L., Mansell, G. L., Manske, M., Mantovani, M., Mapelli, M., Marchesoni, F., Marchio, M., Marion, F., Mark, Z., Márka, S., Márka, Z., Markakis, C., Markosyan, A. S., Markowitz, A., Maros, E., Marquina, A., Marsat, S., Martelli, F., Martin, I. W., Martin, R. M., Martinez, M., Martinez, V., Martinovic, K., Martynov, D. V., Marx, E. J., Masalehdan, H., Mason, K., Massera, E., Masserot, A., Massinger, T. J., Masso-Reid, M., Mastrogiovanni, S., Matas, A., Mateu-Lucena, M., Matichard, F., Matiushechkina, M., Mavalvala, N., McCann, J. J., McCarthy, R., McClelland, D. E., McClincy, P., McCormick, S., McCuller, L., McGhee, G. I., McGuire, S. C., McIsaac, C., McIver, J., McManus, D. J., McRae, T., McWilliams, S. T., Meacher, D., Mehmet, M., Mehta, A. K., Melatos, A., Melchor, D. A., Mendell, G., Menendez-Vazquez, A., Menoni, C. S., Mercer, R. A., Mereni, L., Merfeld, K., Merilh, E. L., Merritt, J. D., Merzougui, M., Meshkov, S., Messenger, C., Messick, C., Meyers, P. M., Meylahn, F., Mhaske, A., Miani, A., Miao, H., Michaloliakos, I., Michel, C., Michimura, Y., Middleton, H., Milano, L., Miller, A. L., Millhouse, M., Mills, J. C., Milotti, E., Milovich-Goff, M. C., Minazzoli, O., Minenkov, Y., Mio, N., Mir, Ll. M., Mishkin, A., Mishra, C., Mishra, T., Mistry, T., Mitra, S., Mitrofanov, V. P., Mitselmakher, G., Mittleman, R., Miyakawa, O., Miyamoto, A., Miyazaki, Y., Miyo, K., Miyoki, S., Mo, Geoffrey, Mogushi, K., Mohapatra, S. R. P., Mohite, S. R., Molina, I., Molina-Ruiz, M., Mondin, M., Montani, M., Moore, C. J., Moraru, D., Morawski, F., More, A., Moreno, C., Moreno, G., Mori, Y., Morisaki, S., Moriwaki, Y., Mours, B., Mow-Lowry, C. M., Mozzon, S., Muciaccia, F., Mukherjee, Arunava, Mukherjee, D., Mukherjee, Soma, Mukherjee, Subroto, Mukund, N., Mullavey, A., Munch, J., Muñiz, E. A., Murray, P. G., Musenich, R., Nadji, S. L., Nagano, K., Nagano, S., Nagar, A., Nakamura, K., Nakano, H., Nakano, M., Nakashima, R., Nakayama, Y., Nardecchia, I., Narikawa, T., Naticchioni, L., Nayak, B., Nayak, R. K., Negishi, R., Neil, B. F., Neilson, J., Nelemans, G., Nelson, T. J. N., Nery, M., Neunzert, A., Ng, K. Y., Ng, S. W. S., Nguyen, C., Nguyen, P., Nguyen, T., Quynh, L. Nguyen, Ni, W. -T., Nichols, S. A., Nishizawa, A., Nissanke, S., Nocera, F., Noh, M., Norman, M., North, C., Nozaki, S., Nuttall, L. K., Oberling, J., O'Brien, B. D., Obuchi, Y., O'Dell, J., Ogaki, W., Oganesyan, G., Oh, J. J., Oh, K., Oh, S. H., Ohashi, M., Ohishi, N., Ohkawa, M., Ohme, F., Ohta, H., Okada, M. A., Okutani, Y., Okutomi, K., Olivetto, C., Oohara, K., Ooi, C., Oram, R., O'Reilly, B., Ormiston, R. G., Ormsby, N. D., Ortega, L. F., O'Shaughnessy, R., O'Shea, E., Oshino, S., Ossokine, S., Osthelder, C., Otabe, S., Ottaway, D. J., Overmier, H., Pace, A. E., Pagano, G., Page, M. A., Pagliaroli, G., Pai, A., Pai, S. A., Palamos, J. R., Palashov, O., Palomba, C., Pan, K., Panda, P. K., Pang, H., Pang, P. T. H., Pankow, C., Pannarale, F., Pant, B. C., Paoletti, F., Paoli, A., Paolone, A., Parisi, A., Park, J., Parker, W., Pascucci, D., Pasqualetti, A., Passaquieti, R., Passuello, D., Patel, M., Patricelli, B., Payne, E., Pechsiri, T. C., Pedraza, M., Pegoraro, M., Pele, A., Arellano, F. E. Peña, Penn, S., Perego, A., Pereira, A., Pereira, T., Perez, C. J., Périgois, C., Perreca, A., Perriès, S., Petermann, J., Petterson, D., Pfeiffer, H. P., Pham, K. A., Phukon, K. S., Piccinni, O. J., Pichot, M., Piendibene, M., Piergiovanni, F., Pierini, L., Pierro, V., Pillant, G., Pilo, F., Pinard, L., Pinto, I. M., Piotrzkowski, B. J., Piotrzkowski, K., Pirello, M., Pitkin, M., Placidi, E., Plastino, W., Pluchar, C., Poggiani, R., Polini, E., Pong, D. Y. T., Ponrathnam, S., Popolizio, P., Porter, E. K., Powell, J., Pracchia, M., Pradier, T., Prajapati, A. K., Prasai, K., Prasanna, R., Pratten, G., Prestegard, T., Principe, M., Prodi, G. A., Prokhorov, L., Prosposito, P., Prudenzi, L., Puecher, A., Punturo, M., Puosi, F., Puppo, P., Pürrer, M., Qi, H., Quetschke, V., Quinonez, P. J., Quitzow-James, R., Raab, F. J., Raaijmakers, G., Radkins, H., Radulesco, N., Raffai, P., Rail, S. X., Raja, S., Rajan, C., Ramirez, K. E., Ramirez, T. D., Ramos-Buades, A., Rana, J., Rapagnani, P., Rapol, U. D., Ratto, B., Raymond, V., Raza, N., Razzano, M., Read, J., Rees, L. A., Regimbau, T., Rei, L., Reid, S., Reitze, D. H., Relton, P., Rettegno, P., Ricci, F., Richardson, C. J., Richardson, J. W., Richardson, L., Ricker, P. M., Riemenschneider, G., Riles, K., Rizzo, M., Robertson, N. A., Robie, R., Robinet, F., Rocchi, A., Rocha, J. A., Rodriguez, S., Rodriguez-Soto, R. D., Rolland, L., Rollins, J. G., Roma, V. J., Romanelli, M., Romano, R., Romel, C. L., Romero, A., Romero-Shaw, I. M., Romie, J. H., Rose, C. A., Rosińska, D., Rosofsky, S. G., Ross, M. P., Rowan, S., Rowlinson, S. J., Roy, Santosh, Roy, Soumen, Rozza, D., Ruggi, P., Ryan, K., Sachdev, S., Sadecki, T., Sadiq, J., Sago, N., Saito, S., Saito, Y., Sakai, K., Sakai, Y., Sakellariadou, M., Sakuno, Y., Salafia, O. S., Salconi, L., Saleem, M., Salemi, F., Samajdar, A., Sanchez, E. J., Sanchez, J. H., Sanchez, L. E., Sanchis-Gual, N., Sanders, J. R., Sanuy, A., Saravanan, T. R., Sarin, N., Sassolas, B., Satari, H., Sato, S., Sato, T., Sauter, O., Savage, R. L., Savant, V., Sawada, T., Sawant, D., Sawant, H. L., Sayah, S., Schaetzl, D., Scheel, M., Scheuer, J., Schindler-Tyka, A., Schmidt, P., Schnabel, R., Schneewind, M., Schofield, R. M. S., Schönbeck, A., Schulte, B. W., Schutz, B. F., Schwartz, E., Scott, J., Scott, S. M., Seglar-Arroyo, M., Seidel, E., Sekiguchi, T., Sekiguchi, Y., Sellers, D., Sengupta, A. S., Sennett, N., Sentenac, D., Seo, E. G., Sequino, V., Sergeev, A., Setyawati, Y., Shaffer, T., Shahriar, M. S., Shams, B., Shao, L., Sharifi, S., Sharma, A., Sharma, P., Shawhan, P., Shcheblanov, N. S., Shen, H., Shibagaki, S., Shikauchi, M., Shimizu, R., Shimoda, T., Shimode, K., Shink, R., Shinkai, H., Shishido, T., Shoda, A., Shoemaker, D. H., Shoemaker, D. M., Shukla, K., ShyamSundar, S., Sieniawska, M., Sigg, D., Singer, L. P., Singh, D., Singh, N., Singha, A., Sintes, A. M., Sipala, V., Skliris, V., Slagmolen, B. J. J., Slaven-Blair, T. J., Smetana, J., Smith, J. R., Smith, R. J. E., Somala, S. N., Somiya, K., Son, E. J., Soni, K., Soni, S., Sorazu, B., Sordini, V., Sorrentino, F., Sorrentino, N., Sotani, H., Soulard, R., Souradeep, T., Sowell, E., Spagnuolo, V., Spencer, A. P., Spera, M., Srivastava, A. K., Srivastava, V., Staats, K., Stachie, C., Steer, D. A., Steinlechner, J., Steinlechner, S., Stops, D. J., Stover, M., Strain, K. A., Strang, L. C., Stratta, G., Strunk, A., Sturani, R., Stuver, A. L., Südbeck, J., Sudhagar, S., Sudhir, V., Sugimoto, R., Suh, H. G., Summerscales, T. Z., Sun, H., Sun, L., Sunil, S., Sur, A., Suresh, J., Sutton, P. J., Suzuki, Takamasa, Suzuki, Toshikazu, Swinkels, B. L., Szczepańczyk, M. J., Szewczyk, P., Tacca, M., Tagoshi, H., Tait, S. C., Takahashi, H., Takahashi, R., Takamori, A., Takano, S., Takeda, H., Takeda, M., Talbot, C., Tanaka, H., Tanaka, Kazuyuki, Tanaka, Kenta, Tanaka, Taiki, Tanaka, Takahiro, Tanasijczuk, A. J., Tanioka, S., Tanner, D. B., Tao, D., Tapia, A., Martin, E. N. Tapia San, Tasson, J. D., Telada, S., Tenorio, R., Terkowski, L., Test, M., Thirugnanasambandam, M. P., Thomas, M., Thomas, P., Thompson, J. E., Thondapu, S. R., Thorne, K. A., Thrane, E., Tiwari, Shubhanshu, Tiwari, Srishti, Tiwari, V., Toland, K., Tolley, A. E., Tomaru, T., Tomigami, Y., Tomura, T., Tonelli, M., Torres-Forné, A., Torrie, C. I., Melo, I. Tosta e, Töyrä, D., Trapananti, A., Travasso, F., Traylor, G., Tringali, M. C., Tripathee, A., Troiano, L., Trovato, A., Trozzo, L., Trudeau, R. J., Tsai, D. S., Tsai, D., Tsang, K. W., Tsang, T., Tsao, J-S., Tse, M., Tso, R., Tsubono, K., Tsuchida, S., Tsukada, L., Tsuna, D., Tsutsui, T., Tsuzuki, T., Turconi, M., Tuyenbayev, D., Ubhi, A. S., Uchikata, N., Uchiyama, T., Udall, R. P., Ueda, A., Uehara, T., Ueno, K., Ueshima, G., Ugolini, D., Unnikrishnan, C. S., Uraguchi, F., Urban, A. L., Ushiba, T., Usman, S. A., Utina, A. C., Vahlbruch, H., Vajente, G., Vajpeyi, A., Valdes, G., Valentini, M., Valsan, V., van Bakel, N., van Beuzekom, M., Brand, J. F. J. van den, Broeck, C. Van Den, Vander-Hyde, D. C., van der Schaaf, L., van Heijningen, J. V., Vanosky, J., van Putten, M. H. P. M., Vardaro, M., Vargas, A. F., Varma, V., Vasúth, M., Vecchio, A., Vedovato, G., Veitch, J., Veitch, P. J., Venkateswara, K., Venneberg, J., Venugopalan, G., Verkindt, D., Verma, Y., Veske, D., Vetrano, F., Viceré, A., Viets, A. D., Villa-Ortega, V., Vinet, J. -Y., Vitale, S., Vo, T., Vocca, H., von Reis, E. R. G., von Wrangel, J., Vorvick, C., Vyatchanin, S. P., Wade, L. E., Wade, M., Wagner, K. J., Walet, R. C., Walker, M., Wallace, G. S., Wallace, L., Walsh, S., Wang, J., Wang, J. Z., Wang, W. H., Ward, R. L., Warner, J., Was, M., Washimi, T., Washington, N. Y., Watchi, J., Weaver, B., Wei, L., Weinert, M., Weinstein, A. J., Weiss, R., Weller, C. M., Wellmann, F., Wen, L., Weßels, P., Westhouse, J. W., Wette, K., Whelan, J. T., White, D. D., Whiting, B. F., Whittle, C., Wilken, D., Williams, D., Williams, M. J., Williamson, A. R., Willis, J. L., Willke, B., Wilson, D. J., Winkler, W., Wipf, C. C., Wlodarczyk, T., Woan, G., Woehler, J., Wofford, J. K., Wong, I. C. F., Wu, C., Wu, D. S., Wu, H., Wu, S., Wysocki, D. M., Xiao, L., Xu, W-R., Yamada, T., Yamamoto, H., Yamamoto, Kazuhiro, Yamamoto, Kohei, Yamamoto, T., Yamashita, K., Yamazaki, R., Yang, F. W., Yang, L., Yang, Yang, Yang, Yi, Yang, Z., Yap, M. J., Yeeles, D. W., Yelikar, A. B., Ying, M., Yokogawa, K., Yokoyama, J., Yokozawa, T., Yoon, A., Yoshioka, T., Yu, Hang, Yu, Haocun, Yuzurihara, H., Zadrożny, A., Zanolin, M., Zeidler, S., Zelenova, T., Zendri, J. -P., Zevin, M., Zhan, M., Zhang, H., Zhang, J., Zhang, L., Zhang, R., Zhang, T., Zhao, C., Zhao, G., Zhao, Yue, Zhao, Yuhang, Zhou, Z., Zhu, X. J., Zhu, Z. -H., Zicoschi, A., Zucker, M. E., Zweizig, J., Antonopoulou, D., Arzoumanian, Z., Enoto, T., Espinoza, C. M., and Guillot, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology
Abstract: We present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537-6910 using data from the LIGO-Virgo Collaboration observing run O3. PSR J0537-6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between glitches by using a contemporaneous timing ephemeris obtained from NICER data. We do not detect any signals in the theoretically expected band of 86-97 Hz, and report upper limits on the amplitude of the gravitational waves. Our results improve on previous amplitude upper limits from r-modes in J0537-6910 by a factor of up to 3 and place stringent constraints on theoretical models for r-mode driven spin-down in PSR J0537-6910, especially for higher frequencies at which our results reach below the spin-down limit defined by energy conservation., Comment: 28 pages, 19 figures, accepted in ApJ
Published: 2021
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41. HAWC observations of the acceleration of very-high-energy cosmic rays in the Cygnus Cocoon

Author: Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velazquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Blandford, R., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Cotti, U., de Leon, S. Coutino, De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Diaz-Velez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Fang, K., Fleischhack, H., Fraija, N., Galvan-Gamez, A., Garcia, D., Garcıa-Gonzalez, J. A., Garfias, F., Giacinti, G., Gonzalez, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hinton, J., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Lara, A., Lee, W. H., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Martinez, O., Martinez-Castellanos, I., Martinez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Soto, J. A. Morales, Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Olivera-Nieto, L., Omodei, N., Peisker, A., Araujo, Y. Perez, Perez-Perez, E. G., Ren, Z., Rho, C. D., Rosa-Gonzalez, D., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandova, A., Schneider, M., Schoorlemmer, H., Serna, F., Smith, A. J., Springer, R. W., Surajbali, P., Tollefson, K., Torres, I., Torres-Escobedo, R., Urena-Mena, F., Weisgarber, T., Werner, F., Willox, E., Zepeda, A., Zhou, H., on, C. De Le, and Alvarez, J. D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Cosmic rays with energies up to a few PeV are known to be accelerated within the Milky Way. Traditionally, it has been presumed that supernova remnants were the main source of very-high-energy cosmic rays but theoretically it is difficult to get protons to PeV energies and observationally there simply is no evidence to support the remnants as sources of hadrons with energies above a few tens of TeV. One possible source of protons with those energies is the Galactic Center region. Here we report observations of 1-100 TeV gamma rays coming from the 'Cygnus Cocoon', which is a superbubble surrounding a region of OB2 massive star formation. These gamma rays are likely produced by 10-1000 TeV freshly accelerated CRs originating from the enclosed star forming region Cygnus OB2. Hitherto it was not known that such regions could accelerate particles to these energies. The measured flux is likely originated by hadronic interactions. The spectral shape and the emission profile of the Cocoon changes from GeV to TeV energies, which reveals the transport of cosmic particles and historical activity in the superbubble.
Published: 2021
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42. HAWC Search for High-Mass Microquasars

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

Author: Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Espinoza, C., Fan, K. L., Alonso, M. Fernández, Fraija, N., Galván-Gámez, A., Garcia, D., González, J. A. García-González F. Garfias M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Joshi, V., Kieda, D., Lara, A., Lee, W. H., Lee, J., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Serna-Franco, J., Smith, A. J., Springer, R. W., Surajbali, P., Tanner, M., Tollefson, K., Torres, I., Torres-Escobedo, R., Turner, R., Ureña-Mena, F., Villaseñor, L., Weisgarber, T., Willox, E., Zhou, H., and de León, C.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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., Comment: 6 figures, 6 tables
Published: 2021
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44. Evidence that Ultra-High-Energy Gamma Rays are a Universal Feature Near Powerful Pulsars

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

Author: Akiyama, S., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Colin-Farias, P., Cotti, U., Cotzomi, J., De la Fuente, E., de León, C., Hernandez, R. Diaz, Espinoza, C., Fraija, N., Galván-Gámez, A., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Huntemeyer, P., Iriarte, A., Joshi, V., Kieda, D., Kunde, G. J., Lara, A., Vargas, H. León, Luis-Raya, G., Malone, K., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Nayerhoda, A., Nellen, L., Newbold, M., Niembro, T., Nieves-Chinchilla, T., Noriega-Papaqui, R., Pérez-Pérez, E. G., Preisser, L., Rho, C. D., Ryan, J., Salazar, H., Greus, F. Salesa, Sandoval, A., Springer, R. W., Torres, I., Ureña-Mena, F., Villaseñor, L., and Zepeda, A.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
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: 2021
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46. Spectrum and Morphology of the Very-High-Energy Source HAWC J2019+368

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

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

Author: Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., De la Fuente, E., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Engel, K., Espinoza, C., Fang, K., Fleischhack, H., Fraija, N., Galván-Gámez, A., Garcia, D., García-González, J. A., Garfias, F., Giacinti, G., González, M. M., Goodman, J. A., Harding, J. P., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kunde, G. J., Lara, A., Lee, W. H., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Lundeen, J., Malone, K., Marandon, V., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Araujo, Y. Pérez, Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Serna, F., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Ureña-Mena, F., Villaseñor, L., Willox, E., Zhou, H., and de León, C.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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
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48. Diving below the spin-down limit: Constraints on gravitational waves from the energetic young pulsar PSR J0537-6910

Author: The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, Abbott, R., Abbott, T. D., Abraham, S., Acernese, F., Ackley, K., Adams, A., Adams, C., Adhikari, R. X., Adya, V. B., Affeldt, C., Agarwal, D., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O. D., Aiello, L., Ain, A., Ajith, P., Akutsu, T., Aleman, K. M., Allen, G., Allocca, A., Altin, P. A., Amato, A., Anand, S., Ananyeva, A., Anderson, S. B., Anderson, W. G., Ando, M., Angelova, S. V., Ansoldi, S., Antelis, J. M., Antier, S., Appert, S., Arai, Koya, Arai, Koji, Arai, Y., Araki, S., Araya, A., Araya, M. C., Areeda, J. S., Arène, M., Aritomi, N., Arnaud, N., Aronson, S. M., Arun, K. G., Asada, H., Asali, Y., Ashton, G., Aso, Y., Aston, S. M., Astone, P., Aubin, F., Aufmuth, P., AultONeal, K., Austin, C., Babak, S., Badaracco, F., Bader, M. K. M., Bae, S., Bae, Y., Baer, A. M., Bagnasco, S., Bai, Y., Baiotti, L., Baird, J., Bajpai, R., Ball, M., Ballardin, G., Ballmer, S. W., Bals, M., Balsamo, A., Baltus, G., Banagiri, S., Bankar, D., Bankar, R. S., Barayoga, J. C., Barbieri, C., Barish, B. C., Barker, D., Barneo, P., Barnum, S., Barone, F., Barr, B., Barsotti, L., Barsuglia, M., Barta, D., Bartlett, J., Barton, M. A., Bartos, I., Bassiri, R., Basti, A., Bawaj, M., Bayley, J. C., Baylor, A. C., Bazzan, M., Bécsy, B., Bedakihale, V. M., Bejger, M., Belahcene, I., Benedetto, V., Beniwal, D., Benjamin, M. G., Bennett, T. F., Bentley, J. D., BenYaala, M., Bergamin, F., Berger, B. K., Bernuzzi, S., Bersanetti, D., Bertolini, A., Betzwieser, J., Bhandare, R., Bhandari, A. V., Bhattacharjee, D., Bhaumik, S., Bidler, J., Bilenko, I. A., Billingsley, G., Birney, R., Birnholtz, O., Biscans, S., Bischi, M., Biscoveanu, S., Bisht, A., Biswas, B., Bitossi, M., Bizouard, M. -A., Blackburn, J. K., Blackman, J., Blair, C. D., Blair, D. G., Blair, R. M., Bobba, F., Bode, N., Boer, M., Bogaert, G., Boldrini, M., Bondu, F., Bonilla, E., Bonnand, R., Booker, P., Boom, B. A., Bork, R., Boschi, V., Bose, N., Bose, S., Bossilkov, V., Boudart, V., Bouffanais, Y., Bozzi, A., Bradaschia, C., Brady, P. R., Bramley, A., Branch, A., Branchesi, M., Breschi, M., Briant, T., Briggs, J. H., Brillet, A., Brinkmann, M., Brockill, P., Brooks, A. F., Brooks, J., Brown, D. D., Brunett, S., Bruno, G., Bruntz, R., Bryant, J., Buikema, A., Bulik, T., Bulten, H. J., Buonanno, A., Buscicchio, R., Buskulic, D., Cadonati, L., Caesar, M., Cagnoli, G., Cahillane, C., Cain III, H. W., Bustillo, J. Calderón, Callaghan, J. D., Callister, T. A., Calloni, E., Camp, J. B., Canepa, M., Cannavacciuolo, M., Cannon, K. C., Cao, H., Cao, J., Cao, Z., Capocasa, E., Capote, E., Carapella, G., Carbognani, F., Carlin, J. B., Carney, M. F., Carpinelli, M., Carullo, G., Carver, T. L., Diaz, J. Casanueva, Casentini, C., Castaldi, G., Caudill, S., Cavaglià, M., Cavalier, F., Cavalieri, R., Cella, G., Cerdá-Durán, P., Cesarini, E., Chaibi, W., Chakravarti, K., Champion, B., Chan, C. -H., Chan, C., Chan, C. L., Chan, M., Chandra, K., Chanial, P., Chao, S., Charlton, P., Chase, E. A., Chassande-Mottin, E., Chatterjee, D., Chaturvedi, M., Chatziioannou, K., Chen, A., Chen, C., Chen, H. Y., Chen, J., Chen, K., Chen, X., Chen, Y. -B., Chen, Y. -R., Chen, Z., Cheng, H., Cheong, C. K., Cheung, H. Y., Chia, H. Y., Chiadini, F., Chiang, C-Y., Chierici, R., Chincarini, A., Chiofalo, M. L., Chiummo, A., Cho, G., Cho, H. S., Choate, S., Choudhary, R. K., Choudhary, S., Christensen, N., Chu, H., Chu, Q., Chu, Y-K., Chua, S., Chung, K. W., Ciani, G., Ciecielag, P., Cieślar, M., Cifaldi, M., Ciobanu, A. A., Ciolfi, R., Cipriano, F., Cirone, A., Clara, F., Clark, E. N., Clark, J. A., Clarke, L., Clearwater, P., Clesse, S., Cleva, F., Coccia, E., Cohadon, P. -F., Cohen, D. E., Cohen, L., Colleoni, M., Collette, C. G., Colpi, M., Compton, C. M., Constancio Jr., M., Conti, L., Cooper, S. J., Corban, P., Corbitt, T. R., Cordero-Carrión, I., Corezzi, S., Corley, K. R., Cornish, N., Corre, D., Corsi, A., Cortese, S., Costa, C. A., Cotesta, R., Coughlin, M. W., Coughlin, S. B., Coulon, J. -P., Countryman, S. T., Cousins, B., Couvares, P., Covas, P. B., Coward, D. M., Cowart, M. J., Coyne, D. C., Coyne, R., Creighton, J. D. E., Creighton, T. D., Criswell, A. W., Croquette, M., Crowder, S. G., Cudell, J. R., Cullen, T. J., Cumming, A., Cummings, R., Cuoco, E., Curyło, M., Canton, T. Dal, Dálya, G., Dana, A., DaneshgaranBajastani, L. M., D'Angelo, B., Danilishin, S. L., D'Antonio, S., Danzmann, K., Darsow-Fromm, C., Dasgupta, A., Datrier, L. E. H., Dattilo, V., Dave, I., Davier, M., Davies, G. S., Davis, D., Daw, E. J., Dean, R., Deenadayalan, M., Degallaix, J., De Laurentis, M., Deléglise, S., Del Favero, V., De Lillo, F., De Lillo, N., Del Pozzo, W., DeMarchi, L. M., De Matteis, F., D'Emilio, V., Demos, N., Dent, T., Depasse, A., De Pietri, R., De Rosa, R., De Rossi, C., DeSalvo, R., De Simone, R., Dhurandhar, S., Díaz, M. C., Diaz-Ortiz Jr., M., Didio, N. A., Dietrich, T., Di Fiore, L., Di Fronzo, C., Di Giorgio, C., Di Giovanni, F., Di Girolamo, T., Di Lieto, A., Ding, B., Di Pace, S., Di Palma, I., Di Renzo, F., Divakarla, A. K., Dmitriev, A., Doctor, Z., D'Onofrio, L., Donovan, F., Dooley, K. L., Doravari, S., Dorrington, I., Drago, M., Driggers, J. C., Drori, Y., Du, Z., Ducoin, J. -G., Dupej, P., Durante, O., D'Urso, D., Duverne, P. -A., Dwyer, S. E., Easter, P. J., Ebersold, M., Eddolls, G., Edelman, B., Edo, T. B., Edy, O., Effler, A., Eguchi, S., Eichholz, J., Eikenberry, S. S., Eisenmann, M., Eisenstein, R. A., Ejlli, A., Enomoto, Y., Errico, L., Essick, R. C., Estellés, H., Estevez, D., Etienne, Z., Etzel, T., Evans, M., Evans, T. M., Ewing, B. E., Fafone, V., Fair, H., Fairhurst, S., Fan, X., Farah, A. M., Farinon, S., Farr, B., Farr, W. M., Farrow, N. W., Fauchon-Jones, E. J., Favata, M., Fays, M., Fazio, M., Feicht, J., Fejer, M. M., Feng, F., Fenyvesi, E., Ferguson, D. L., Fernandez-Galiana, A., Ferrante, I., Ferreira, T. A., Fidecaro, F., Figura, P., Fiori, I., Fishbach, M., Fisher, R. P., Fishner, J. M., Fittipaldi, R., Fiumara, V., Flaminio, R., Floden, E., Flynn, E., Fong, H., Font, J. A., Fornal, B., Forsyth, P. W. F., Franke, A., Frasca, S., Frasconi, F., Frederick, C., Frei, Z., Freise, A., Frey, R., Fritschel, P., Frolov, V. V., Fronzé, G. G., Fujii, Y., Fujikawa, Y., Fukunaga, M., Fukushima, M., Fulda, P., Fyffe, M., Gabbard, H. A., Gadre, B. U., Gaebel, S. M., Gair, J. R., Gais, J., Galaudage, S., Gamba, R., Ganapathy, D., Ganguly, A., Gao, D., Gaonkar, S. G., Garaventa, B., García-Núñez, C., García-Quirós, C., Garufi, F., Gateley, B., Gaudio, S., Gayathri, V., Ge, G., Gemme, G., Gennai, A., George, J., Gergely, L., Gewecke, P., Ghonge, S., Ghosh, Abhirup., Ghosh, Archisman, Ghosh, Shaon, Ghosh, Shrobana, Ghosh, Sourath, Giacomazzo, B., Giacoppo, L., Giaime, J. A., Giardina, K. D., Gibson, D. R., Gier, C., Giesler, M., Giri, P., Gissi, F., Glanzer, J., Gleckl, A. E., Godwin, P., Goetz, E., Goetz, R., Gohlke, N., Goncharov, B., González, G., Gopakumar, A., Gosselin, M., Gouaty, R., Grace, B., Grado, A., Granata, M., Granata, V., Grant, A., Gras, S., Grassia, P., Gray, C., Gray, R., Greco, G., Green, A. C., Green, R., Gretarsson, A. M., Gretarsson, E. M., Griffith, D., Griffiths, W., Griggs, H. L., Grignani, G., Grimaldi, A., Grimes, E., Grimm, S. J., Grote, H., Grunewald, S., Gruning, P., Guerrero, J. G., Guidi, G. M., Guimaraes, A. R., Guixé, G., Gulati, H. K., Guo, H. -K., Guo, Y., Gupta, Anchal, Gupta, Anuradha, Gupta, P., Gustafson, E. K., Gustafson, R., Guzman, F., Ha, S., Haegel, L., Hagiwara, A., Haino, S., Halim, O., Hall, E. D., Hamilton, E. Z., Hammond, G., Han, W. -B., Haney, M., Hanks, J., Hanna, C., Hannam, M. D., Hannuksela, O. A., Hansen, H., Hansen, T. J., Hanson, J., Harder, T., Hardwick, T., Haris, K., Harms, J., Harry, G. M., Harry, I. W., Hartwig, D., Hasegawa, K., Haskell, B., Hasskew, R. K., Haster, C. -J., Hattori, K., Haughian, K., Hayakawa, H., Hayama, K., Hayes, F. J., Healy, J., Heidmann, A., Heintze, M. C., Heinze, J., Heinzel, J., Heitmann, H., Hellman, F., Hello, P., Helmling-Cornell, A. F., Hemming, G., Hendry, M., Heng, I. S., Hennes, E., Hennig, J., Hennig, M. H., Vivanco, F. Hernandez, Heurs, M., Hild, S., Hill, P., Himemoto, Y., Hines, A. S., Hiranuma, Y., Hirata, N., Hirose, E., Ho, W. C. G., Hochheim, S., Hofman, D., Hohmann, J. N., Holgado, A. M., Holland, N. A., Hollows, I. J., Holmes, Z. J., Holt, K., Holz, D. E., Hong, Z., Hopkins, P., Hough, J., Howell, E. J., Hoy, C. G., Hoyland, D., Hreibi, A., Hsieh, B., Hsu, Y., Huang, G-Z., Huang, H-Y., Huang, P., Huang, Y-C., Huang, Y. -J., Huang, Y. -W., Hübner, M. T., Huddart, A. D., Huerta, E. A., Hughey, B., Hui, D. C. Y., Hui, V., Husa, S., Huttner, S. H., Huxford, R., Huynh-Dinh, T., Ide, S., Idzkowski, B., Iess, A., Ikenoue, B., Imam, S., Inayoshi, K., Inchauspe, H., Ingram, C., Inoue, Y., Intini, G., Ioka, K., Isi, M., Isleif, K., Ito, K., Itoh, Y., Iyer, B. R., Izumi, K., JaberianHamedan, V., Jacqmin, T., Jadhav, S. J., Jadhav, S. P., James, A. L., Jan, A. Z., Jani, K., Janssens, K., Janthalur, N. N., Jaranowski, P., Jariwala, D., Jaume, R., Jenkins, A. C., Jeon, C., Jeunon, M., Jia, W., Jiang, J., Jin, H. -B., Johns, G. R., Jones, A. W., Jones, D. I., Jones, J. D., Jones, P., Jones, R., Jonker, R. J. G., Ju, L., Jung, K., Jung, P., Junker, J., Kaihotsu, K., Kajita, T., Kakizaki, M., Kalaghatgi, C. V., Kalogera, V., Kamai, B., Kamiizumi, M., Kanda, N., Kandhasamy, S., Kang, G., Kanner, J. B., Kao, Y., Kapadia, S. J., Kapasi, D. P., Karathanasis, C., Karki, S., Kashyap, R., Kasprzack, M., Kastaun, W., Katsanevas, S., Katsavounidis, E., Katzman, W., Kaur, T., Kawabe, K., Kawaguchi, K., Kawai, N., Kawasaki, T., Kéfélian, F., Keitel, D., Key, J. S., Khadka, S., Khalili, F. Y., Khan, I., Khan, S., Khazanov, E. A., Khetan, N., Khursheed, M., Kijbunchoo, N., Kim, C., Kim, J. C., Kim, J., Kim, K., Kim, W. S., Kim, Y. -M., Kimball, C., Kimura, N., King, P. J., Kinley-Hanlon, M., Kirchhoff, R., Kissel, J. S., Kita, N., Kitazawa, H., Kleybolte, L., Klimenko, S., Knee, A. M., Knowles, T. D., Knyazev, E., Koch, P., Koekoek, G., Kojima, Y., Kokeyama, K., Koley, S., Kolitsidou, P., Kolstein, M., Komori, K., Kondrashov, V., Kong, A. K. H., Kontos, A., Koper, N., Korobko, M., Kotake, K., Kovalam, M., Kozak, D. B., Kozakai, C., Kozu, R., Kringel, V., Krishnendu, N. V., Królak, A., Kuehn, G., Kuei, F., Kumar, A., Kumar, P., Kumar, Rahul, Kumar, Rakesh, Kume, J., Kuns, K., Kuo, C., Kuo, H-S., Kuromiya, Y., Kuroyanagi, S., Kusayanagi, K., Kwak, K., Kwang, S., Laghi, D., Lalande, E., Lam, T. L., Lamberts, A., Landry, M., Lane, B. B., Lang, R. N., Lange, J., Lantz, B., La Rosa, I., Lartaux-Vollard, A., Lasky, P. D., Laxen, M., Lazzarini, A., Lazzaro, C., Leaci, P., Leavey, S., Lecoeuche, Y. K., Lee, H. K., Lee, H. M., Lee, H. W., Lee, J., Lee, K., Lee, R., Lehmann, J., Lemaître, A., Leon, E., Leonardi, M., Leroy, N., Letendre, N., Levin, Y., Leviton, J. N., Li, A. K. Y., Li, B., Li, J., Li, K. L., Li, T. G. F., Li, X., Lin, C-Y., Lin, F-K., Lin, F-L., Lin, H. L., Lin, L. C. -C., Linde, F., Linker, S. D., Linley, J. N., Littenberg, T. B., Liu, G. C., Liu, J., Liu, K., Liu, X., Llorens-Monteagudo, M., Lo, R. K. L., Lockwood, A., Lollie, M. L., London, L. T., Longo, A., Lopez, D., Lorenzini, M., Loriette, V., Lormand, M., Losurdo, G., Lough, J. 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Subjects: Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology
Abstract: We present a search for continuous gravitational-wave signals from the young, energetic X-ray pulsar PSR J0537-6910 using data from the second and third observing runs of LIGO and Virgo. The search is enabled by a contemporaneous timing ephemeris obtained using NICER data. The NICER ephemeris has also been extended through 2020 October and includes three new glitches. PSR J0537-6910 has the largest spin-down luminosity of any pulsar and is highly active with regards to glitches. Analyses of its long-term and inter-glitch braking indices provided intriguing evidence that its spin-down energy budget may include gravitational-wave emission from a time-varying mass quadrupole moment. Its 62 Hz rotation frequency also puts its possible gravitational-wave emission in the most sensitive band of LIGO/Virgo detectors. Motivated by these considerations, we search for gravitational-wave emission at both once and twice the rotation frequency. We find no signal, however, and report our upper limits. Assuming a rigidly rotating triaxial star, our constraints reach below the gravitational-wave spin-down limit for this star for the first time by more than a factor of two and limit gravitational waves from the $l=m=2$ mode to account for less than 14% of the spin-down energy budget. The fiducial equatorial ellipticity is limited to less than about 3e-5, which is the third best constraint for any young pulsar., Comment: 21 pages, 5 figures, published in ApJL
Published: 2020
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49. Second nearest neighbor modified embedded atom method interatomic potentials for [formula omitted] ternary systems

Author: Araya-Barr, A., García, G., Arias-Camacho, I., Espinoza, C., Lee, Byeong-Joo, and Ramos-Moore, E.
Published: 2024
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50. HAWC and Fermi-LAT Detection of Extended Emission from the Unidentified Source 2HWC J2006+341

Author: Albert, A., Alfaro, R., Alvarez, C., Camacho, J. R. Angeles, Araya, M., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Baghmanyan, V., Belmont-Moreno, E., Brisbois, C., Caballero-Mora, K. S., Carramiñana, A., Casanova, S., Cotti, U., De la Fuente, E., de León, C., Hernandez, R. Diaz, Dingus, B. L., DuVernois, M. A., Durocher, M., Díaz-Vélez, J. C., Espinoza, C., Fleischhack, H., Fraija, N., Galván-Gámez, A., Garcia, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., López-Coto, R., Luis-Raya, G., Lundeen, J., Malone, K., Martinez, O., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nellen, L., Nisa, M. U., Noriega-Papaqui, R., Omodei, N., Peisker, A., Pérez-Pérez, E. G., Rho, C. D., Rosa-González, D., Greus, F. Salesa, Sandoval, A., Schneider, M., Springer, R. W., Tollefson, K., Torres, I., Torres-Escobedo, R., Ureña-Mena, F., Villaseñor, L., Weisgarber, T., Willox, E., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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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