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7 results on '"D. Avila Rojas"'

1. Ultra-high-energy gamma-ray bubble around microquasar V4641 Sgr.

Author

Alfaro R, Alvarez C, Arteaga-Velázquez JC, Avila Rojas D, Ayala Solares HA, Babu R, Belmont-Moreno E, Caballero-Mora KS, Capistrán T, Carramiñana A, Casanova S, Cotti U, Cotzomi J, Coutiño de León S, De la Fuente E, Depaoli D, Di Lalla N, Diaz Hernandez R, Dingus BL, DuVernois MA, Durocher M, Díaz-Vélez JC, Engel K, Espinoza C, Fan KL, Fang K, Fraija N, Fraija S, García-González JA, Garfias F, Gonzalez Muñoz A, González MM, Goodman JA, Groetsch S, Harding JP, Herzog I, Hinton J, Huang D, Hueyotl-Zahuantitla F, Hüntemeyer P, Iriarte A, Joshi V, Kaufmann S, Kieda D, de León C, Lee J, León Vargas H, Linnemann JT, Longinotti AL, Luis-Raya G, Malone K, Martinez O, Martínez-Castro J, Matthews JA, Miranda-Romagnoli P, Morales-Soto JA, Moreno E, Mostafá M, Nayerhoda A, Nellen L, Newbold M, Nisa MU, Noriega-Papaqui R, Olivera-Nieto L, Omodei N, Osorio M, Pérez Araujo Y, Pérez-Pérez EG, Rho CD, Rosa-González D, Ruiz-Velasco E, Salazar H, Salazar-Gallegos D, Sandoval A, Schneider M, Serna-Franco J, Smith AJ, Son Y, Springer RW, Tibolla O, Tollefson K, Torres I, Torres-Escobedo R, Turner R, Ureña-Mena F, Varela E, Villaseñor L, Wang X, Watson IJ, Willox E, Yun-Cárcamo S, and Zhou H

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 measurement of the spatial morphology of a microquasar, SS 433, to TeV gamma rays 1 localizes the acceleration of electrons at shocks in the jet far from the black hole 2 . V4641 Sagittarii (V4641 Sgr) is a similar binary system with a black hole and B-type main-sequence companion star and has an orbit period of 2.8 days (refs.  3,4 ). It stands out for its super-Eddington accretion 5 and for its radio jet, which is one of the fastest superluminal jets in the Milky Way. Previous observations of V4641 Sgr did not report gamma-ray emission 6 . Here we report TeV gamma-ray emission from V4641 Sgr that reveals particle acceleration at similar distances from the black hole as SS 433. Furthermore, the gamma-ray spectrum of V4641 Sgr is among the hardest TeV spectra observed from any known gamma-ray source and is detected above 200 TeV. Gamma rays are produced by particles, either electrons or protons, of higher energies. Because energetic 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 protons. This suggests that large-scale jets from microquasars could be more common than previously expected and that they could be a notable source of galactic cosmic rays 7-9 ., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2024
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2. Discovery of Gamma Rays from the Quiescent Sun with HAWC.

Author

Albert A, Alfaro R, Alvarez C, Arteaga-Velázquez JC, Avila Rojas D, Ayala Solares HA, Babu R, Belmont-Moreno E, Brisbois C, Caballero-Mora KS, Capistrán T, Carramiñana A, Casanova S, Chaparro-Amaro O, Cotti U, Cotzomi J, Coutiño de León S, De la Fuente E, Diaz Hernandez R, Dingus BL, DuVernois MA, Durocher M, Díaz-Vélez JC, Ellsworth RW, Engel K, Espinoza C, Fan KL, Fang K, Fernández Alonso M, Fleischhack H, Fraija N, García-González JA, Garfias F, González MM, Goodman JA, Harding JP, Hernandez S, Hinton J, Huang D, Hueyotl-Zahuantitla F, Hüntemeyer P, Iriarte A, Joshi V, Kaufmann S, Lee J, Linnemann JT, Longinotti AL, Luis-Raya G, Malone K, Martinez O, Martínez-Castro J, Matthews JA, Miranda-Romagnoli P, Morales-Soto JA, Moreno E, Mostafá M, Nayerhoda A, Nellen L, Nisa MU, Noriega-Papaqui R, Olivera-Nieto L, Omodei N, Pérez Araujo Y, Pérez-Pérez EG, Rho CD, Rosa-González D, Ruiz-Velasco E, Salazar H, Salazar-Gallegos D, Sandoval A, Schneider M, Serna-Franco J, Smith AJ, Son Y, Springer RW, Tibolla O, Tollefson K, Torres I, Torres-Escobedo R, Turner R, Ureña-Mena F, Varela E, Villaseñor L, Wang X, Watson IJ, Willox E, Yun-Cárcamo S, Zhou H, de León C, Beacom JF, Linden T, Ng KCY, Peter AHG, and Zhou B

Abstract

We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), 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  TeV)^{-γ}, with A=(1.6±0.3)×10^{-12}  TeV^{-1} cm^{-2} s^{-1} and γ=3.62±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.

Published
2023
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3. Constraints on Lorentz Invariance Violation from HAWC Observations of Gamma Rays above 100 TeV.

Author

Albert A, Alfaro R, Alvarez C, Angeles Camacho JR, Arteaga-Velázquez JC, Arunbabu KP, Avila Rojas D, Ayala Solares HA, Baghmanyan V, Belmont-Moreno E, BenZvi SY, Brisbois C, Caballero-Mora KS, Capistrán T, Carramiñana A, Casanova S, Cotti U, Cotzomi J, Coutiño de León S, De la Fuente E, de León C, Dingus BL, DuVernois MA, Díaz-Vélez JC, Ellsworth RW, Engel K, Espinoza C, Fleischhack H, Fraija N, Galván-Gámez A, Garcia D, García-González JA, Garfias F, González MM, Goodman JA, Harding JP, Hernandez S, Hona B, Huang D, Hueyotl-Zahuantitla F, Hüntemeyer P, Iriarte A, Joshi V, Lara A, Lee WH, León Vargas H, Linnemann JT, Longinotti AL, Luis-Raya G, Lundeen J, López-Coto R, Malone K, Marinelli SS, Martinez-Castellanos I, Martínez-Castro J, Martínez-Huerta H, Matthews JA, Miranda-Romagnoli P, Morales-Soto JA, Moreno E, Nayerhoda A, Nellen L, Newbold M, Nisa MU, Noriega-Papaqui R, Omodei N, Peisker A, Pérez-Pérez EG, Rho CD, Rivière C, Rosa-González D, Rosenberg M, Ruiz-Velasco E, Salazar H, Salesa Greus F, Sandoval A, Schneider M, Schoorlemmer H, Sinnis G, Smith AJ, Springer RW, Surajbali P, Tabachnick E, Tanner M, Tibolla O, Tollefson K, Torres I, Torres-Escobedo R, Weisgarber T, Yodh G, Zepeda A, and Zhou H

Abstract

Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. HAWC finds evidence of 100 TeV photon emission from at least four astrophysical sources. These observations exclude, for the strongest of the limits set, the LIV energy scale to 2.2×10^{31}  eV, over 1800 times the Planck energy and an improvement of 1 to 2 orders of magnitude over previous limits.

Published
2020
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4. Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC.

Author

Abeysekara AU, Albert A, Alfaro R, Angeles Camacho JR, Arteaga-Velázquez JC, Arunbabu KP, Avila Rojas D, Ayala Solares HA, Baghmanyan V, Belmont-Moreno E, BenZvi SY, Brisbois C, Caballero-Mora KS, Capistrán T, Carramiñana A, Casanova S, Cotti U, Cotzomi J, Coutiño de León S, De la Fuente E, de León C, Dichiara S, Dingus BL, DuVernois MA, Díaz-Vélez JC, Ellsworth RW, Engel K, Espinoza C, Fleischhack H, Fraija N, Galván-Gámez A, Garcia D, García-González JA, Garfias F, González MM, Goodman JA, Harding JP, Hernandez S, Hinton J, Hona B, Huang D, Hueyotl-Zahuantitla F, Hüntemeyer P, Iriarte A, Jardin-Blicq A, Joshi V, Kaufmann S, Kieda D, Lara A, Lee WH, León Vargas H, Linnemann JT, Longinotti AL, Luis-Raya G, Lundeen J, López-Coto R, Malone K, Marinelli SS, Martinez O, Martinez-Castellanos I, Martínez-Castro J, Martínez-Huerta H, Matthews JA, Miranda-Romagnoli P, Morales-Soto JA, Moreno E, Mostafá M, Nayerhoda A, Nellen L, Newbold M, Nisa MU, Noriega-Papaqui R, Peisker A, Pérez-Pérez EG, Pretz J, Ren Z, Rho CD, Rivière C, Rosa-González D, Rosenberg M, Ruiz-Velasco E, Salesa Greus F, Sandoval A, Schneider M, Schoorlemmer H, Sinnis G, Smith AJ, Springer RW, Surajbali P, Tabachnick E, Tanner M, Tibolla O, Tollefson K, Torres I, Torres-Escobedo R, Villaseñor L, Weisgarber T, Wood J, Yapici T, Zhang H, and Zhou H

Abstract

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

Published
2020
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5. Publisher Correction: Very-high-energy particle acceleration powered by the jets of the microquasar SS 433.

Author

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

Abstract

In this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.

Published
2018
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6. Very-high-energy particle acceleration powered by the jets of the microquasar SS 433.

Author

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

Abstract

SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star) 1-3 . Two jets of ionized matter with a bulk velocity of approximately 0.26c (where c is the speed of light in vacuum) extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets 2,4-8 . SS 433 differs from other microquasars (small-scale versions of quasars that are present within our own Galaxy) in that the accretion is believed to be super-Eddington 9-11 , and the luminosity of the system is about 10 40 ergs per second 2,9,12,13 . The lobes of W50 in which the jets terminate, about 40 parsecs from the central source, are expected to accelerate charged particles, and indeed radio and X-ray emission consistent with electron synchrotron emission in a magnetic field have been observed 14-16 . At higher energies (greater than 100 gigaelectronvolts), the particle fluxes of γ-rays from X-ray hotspots around SS 433 have been reported as flux upper limits 6,17-20 . In this energy regime, it has been unclear whether the emission is dominated by electrons that are interacting with photons from the cosmic microwave background through inverse-Compton scattering or by protons that are interacting with the ambient gas. Here we report teraelectronvolt γ-ray observations of the SS 433/W50 system that spatially resolve the lobes. The teraelectronvolt emission is localized to structures in the lobes, far from the centre of the system where the jets are formed. We have measured photon energies of at least 25 teraelectronvolts, and these are certainly not Doppler-boosted, because of the viewing geometry. We conclude that the emission-from radio to teraelectronvolt energies-is consistent with a single population of electrons with energies extending to at least hundreds of teraelectronvolts in a magnetic field of about 16 microgauss.

Published
2018
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7. Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth.

Author

Abeysekara AU, Albert A, Alfaro R, Alvarez C, Álvarez JD, Arceo R, Arteaga-Velázquez JC, Avila Rojas D, Ayala Solares HA, Barber AS, Bautista-Elivar N, Becerril A, Belmont-Moreno E, BenZvi SY, Berley D, Bernal A, Braun J, Brisbois C, Caballero-Mora KS, Capistrán T, Carramiñana A, Casanova S, Castillo M, Cotti U, Cotzomi J, Coutiño de León S, De León C, De la Fuente E, Dingus BL, DuVernois MA, Díaz-Vélez JC, Ellsworth RW, Engel K, Enríquez-Rivera O, Fiorino DW, Fraija N, García-González JA, Garfias F, Gerhardt M, González Muñoz A, González MM, Goodman JA, Hampel-Arias Z, Harding JP, Hernández S, Hernández-Almada A, Hinton J, Hona B, Hui CM, Hüntemeyer P, Iriarte A, Jardin-Blicq A, Joshi V, Kaufmann S, Kieda D, Lara A, Lauer RJ, Lee WH, Lennarz D, Vargas HL, Linnemann JT, Longinotti AL, Luis Raya G, Luna-García R, López-Coto R, Malone K, Marinelli SS, Martinez O, Martinez-Castellanos I, Martínez-Castro J, Martínez-Huerta H, Matthews JA, Miranda-Romagnoli P, Moreno E, Mostafá M, Nellen L, Newbold M, Nisa MU, Noriega-Papaqui R, Pelayo R, Pretz J, Pérez-Pérez EG, Ren Z, Rho CD, Rivière C, Rosa-González D, Rosenberg M, Ruiz-Velasco E, Salazar H, Salesa Greus F, Sandoval A, Schneider M, Schoorlemmer H, Sinnis G, Smith AJ, Springer RW, Surajbali P, Taboada I, Tibolla O, Tollefson K, Torres I, Ukwatta TN, Vianello G, Weisgarber T, Westerhoff S, Wisher IG, Wood J, Yapici T, Yodh G, Younk PW, Zepeda A, Zhou H, Guo F, Hahn J, Li H, and Zhang H

Abstract

The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin., (Copyright © 2017, American Association for the Advancement of Science.)

Published
2017
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