المؤلفون: L Dunn, A Melatos, C M Espinoza, D Antonopoulou, R Dodson

المصدر: Monthly Notices of the Royal Astronomical Society. 522:5469-5478

مصطلحات موضوعية: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena

الوصف: 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

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a7f538c71c2f5bd042e3ec9b33107134Test
https://doi.org/10.1093/mnras/stad1335Test

المؤلفون: Sina Sadeghzadeh, Jian Yang, Frank Toffoletto, Richard Wolf, Ameneh Mousavi, C. M. Espinoza

المصدر: Journal of Geophysical Research: Space Physics. 128

مصطلحات موضوعية: Geophysics, Space and Planetary Science

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::0e1b6ab2a2d037f239a0179265ab4abfTest
https://doi.org/10.1029/2022ja030673Test

المؤلفون: C. M. Espinoza, M. Vidal-Navarro, W. C. G. Ho, A. Deller, S. Chatterjee

مصطلحات موضوعية: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics

الوصف: The characteristic age of PSR J1734$-$3333 estimated from its current spin down rate implies that it is a young pulsar ($\tau_c
Comment: 8 pages, 4 figures and 4 tables. Accepted for publication in A&A

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::496c8790ba98cc17ef04e0244c847e2bTest
http://arxiv.org/abs/2111.09788Test

المؤلفون: A. V. Eyelade, C. M. Espinoza, M. Stepanova, E. E. Antonova, I. L. Ovchinnikov, I. P. Kirpichev

المصدر: Frontiers in Astronomy and Space Sciences, Vol 8 (2021)

مصطلحات موضوعية: Kappa distributions, 010504 meteorology & atmospheric sciences, lcsh:Astronomy, 01 natural sciences, Eddy diffusion, Ion, Physics::Fluid Dynamics, substorms, lcsh:QB1-991, 0103 physical sciences, 010303 astronomy & astrophysics, plasma sheet, 0105 earth and related environmental sciences, Physics, magnetotail, Turbulence, turbulence, lcsh:QC801-809, Plasma sheet, Astronomy and Astrophysics, Plasma, Vortex, Computational physics, lcsh:Geophysics. Cosmic physics, Distribution (mathematics), Beta (plasma physics), Physics::Space Physics

الوصف: The possible influence of MHD turbulence on the energy distributions of ions in the Earth's plasma sheet was studied using data taken by the THEMIS satellites. Turbulence levels were traced using eddy diffusion coefficients (D), of which we measured one for each Geocentric Solar Magnetospheric (GSM) coordinates every 12 min. Ion fluxes between 1.75 and 210.5 keV during the same time windows that correspond to mainly suprathermal populations were fitted to Kappa distribution functions, which approximate a Maxwellian distribution when theκ-index (κ) is large. We found that the distribution of the eddy diffusion coefficients is bimodal, independently of both the eddy diffusion component and the plasma beta (β) parameter, which is defined as the ratio between plasma and magnetic pressures. The main peak corresponds to turbulent plasma flows withD> 103km2s−1. In such cases, the impact of turbulence on theκindex depends on the value ofβand also on the direction of the turbulent transport. For eddy diffusion perpendicular to the neutral sheet, the values ofκdecrease asDzzincreases forβ< 2; while for higher values ofβ,κincreases withDzz. For the other two directions, the values ofκdecrease asDincreases. This last tendency is stronger forβ~ 1 but almost null forβ~ 10. The secondary peak in the distribution ofDvalues might represent quasi-laminar flows forming part of very large vortices, correct detection and description of which is beyond the scope of this study.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3d8e9c8d37eecb9896d065385058e00dTest
https://doi.org/10.3389/fspas.2021.647121Test

المؤلفون: A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, F. Camilo, P. A. Caraveo, C. Cecchi, E. Charles, S. Chaty, A. Chekhtman, M. Chernyakova, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, S. Corbel, S. Cutini, F. D'Ammando, A. de Angelis, P. R. den Hartog, F. de Palma, C. D. Dermer, S. W. Digel, E. do Couto e Silva, M. Dormody, P. S. Drell, A. Drlica-Wagner, R. Dubois, G. Dubus, D. Dumora, T. Enoto, C. M. Espinoza, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, P. Fortin, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M.-H. Grondin, J. E. Grove, E. Grundstrom, S. Guiriec, C. Gwon, D. Hadasch, A. K. Harding, M. Hayashida, E. Hays, G. Jóhannesson, A. S. Johnson, T. J. Johnson, S. Johnston, T. Kamae, H. Katagiri, J. Kataoka, M. Keith, M. Kerr, J. Knödlseder, M. Kramer, M. Kuss, J. Lande, S.-H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, R. N. Manchester, M. Marelli, M. N. Mazziotta, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, M. Naumann-Godo, A. Neronov, P. L. Nolan, J. P. Norris, A. Noutsos, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, D. Paneque, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, T. A. Porter, A. Possenti, S. Rainò, R. Rando, P. S. Ray, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, H. F.-W. Sadrozinski, J. D. Scargle, C. Sgrò, R. Shannon, E. J. Siskind, P. D. Smith, G. Spandre, P. Spinelli, M. S. Strickman, D. J. Suson, H. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, E. Troja, Y. Uchiyama, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, M. T. Wolff, D. L. Wood, K. S. Wood, Z. Yang, M. Ziegler, S. Zimmer

المساهمون: Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), GLAST, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Abdo, A. A., Ackermann, M., Ajello, M., Allafort, A., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Camilo, F., Caraveo, P. A., Cecchi, C., Charles, E., Chaty, S., Chekhtman, A., Chernyakova, M., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., Cominsky, L. R., Corbel, S., Cutini, S., D'Ammando, F., Angelis, A., Den, P. R., Palma, F., Dermer, C. D., Digel, S. W., E. d. C., Dormody, M., Drell, P. S., Drlica Wagner, A., Dubois, R., Dubus, G., Dumora, D., Enoto, T., Espinoza, C. M., Favuzzi, C., Fegan, S. J., Ferrara, E. C., Focke, W. B., Fortin, P., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grondin, M., Grove, J. E., Grundstrom, E., Guiriec, S., Gwon, C., Hadasch, D., Harding, A. K., Hayashida, M., Hays, E., Johannesson, G., Johnson, A. S., Johnson, T. J., Johnston, S., Kamae, T., Katagiri, H., Kataoka, J., Keith, M., Kerr, M., Kn\odlseder, J., Kramer, M., Kuss, M., Lande, J., Lee, S., Lemoine Goumard, M., Longo, Francesco, Loparco, F., Lovellette, M. N., Lubrano, P., Manchester, R. N., Marelli, M., Mazziotta, M. N., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nakamori, T., Naumann Godo, M., Neronov, A., Nolan, P. L., Norris, J. P., Noutsos, A., Nuss, E., Ohsugi, T., Okumura, A., Omodei, N., Orlando, E., Paneque, D., Parent, D., Pesce Rollins, M., Pierbattista, M., Piron, F., Porter, T. A., Possenti, A., Rain\`o, S., Rando, R., Ray, P. S., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Sadrozinski, H. F., Scargle, J. D., Sgr\`o, C., Shannon, R., Siskind, E. J., Smith, P. D., Spandre, G., Spinelli, P., Strickman, M. S., Suson, D. J., Takahashi, H., Tanaka, T., Thayer, J. G., Thayer, J. B., Thompson, D. J., Thorsett, S. E., Tibaldo, L., Tibolla, O., Torres, D. F., Tosti, G., Troja, E., Uchiyama, Y., Usher, T. L., Vandenbroucke, J., Vasileiou, V., Vianello, G., Vitale, V., Waite, A. P., Wang, P., Winer, B. L., Wolff, M. T., Wood, D. L., Wood, K. S., Yang, Z., Ziegler, M., Zimmer, S., Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Abdo AA, Ackermann M, Ajello M, Allafort A, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bonamente E, Borgland AW, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Camilo F, Caraveo PA, Cecchi C, Charles E, Chaty S, Chekhtman A, Chernyakova M, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Corbel S, Cutini S, DAmmando F, de Angelis A, den Hartog PR, de Palma F, Dermer CD, Digel SW, Silva EDE, Dormody M, Drell PS, Drlica-Wagner A, Dubois R, Dubus G, Dumora D, Enoto T, Espinoza CM, Favuzzi C, Fegan SJ, Ferrara EC, Focke WB, Fortin P, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giglietto N, Giommi P, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Grundstrom E, Guiriec S, Gwon C, Hadasch D, Harding AK, Hayashida M, Hays E, Johannesson G, Johnson AS, Johnson TJ, Johnston S, Kamae T, Katagiri H, Kataoka J, Keith M, Kerr M, Knodlseder J, Kramer M, Kuss M, Lande J, Lee SH, Lemoine-Goumard M, Longo F, Loparco F, Lovellette MN, Lubrano P, Manchester RN, Marelli M, Mazziotta MN, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Naumann-Godo M, Neronov A, Nolan PL, Norris JP, Noutsos A, Nuss E, Ohsugi T, Okumura A, Omodei N, Orlando E, Paneque D, Parent D, Pesce-Rollins M, Pierbattista M, Piron F, Porter TA, Possenti A, Raino S, Rando R, Ray PS, Razzano M, Razzaque S, Reimer A, Reimer O, Reposeur T, Ritz S, Sadrozinski HFW, Scargle JD, Sgro C, Shannon R, Siskind EJ, Smith PD, Spandre G, Spinelli P, Strickman MS, Suson DJ, Takahashi H, Tanaka T, Thayer JG, Thayer JB, Thompson DJ, Thorsett SE, Tibaldo L, Tibolla O, Torres DF, Tosti G, Troja E, Uchiyama Y, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Waite AP, Wang P, Winer BL, Wolff MT, Wood DL, Wood KS, Yang Z, Ziegler M, Zimmer S, Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

المصدر: The Astrophysical journal letters
The Astrophysical journal letters, 2011, 736, pp.L11. ⟨10.1088/2041-8205/736/1/L11⟩
The Astrophysical journal letters, Bristol : IOP Publishing, 2011, 736, pp.L11. ⟨10.1088/2041-8205/736/1/L11⟩

مصطلحات موضوعية: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], binaries: eclipsing, gamma rays: stars, pulsars: individual: PSR B1259–63, X-rays: binaries, Be star, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Astrophysics, gamma rays: stars, 01 natural sciences, star [gamma rays], Luminosity, law.invention, Telescope, X-rays: binaries, eclipsing [binaries], Pulsar, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, binaries: eclipsing, pulsars: individual: PSR B1259{\ndash}63, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, pulsars: individual (PSR B1259−63), 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Gamma ray, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Orbit, Binaries: eclipsing, pulsars: individual (PSR B1259-63), 13. Climate action, Space and Planetary Science, binaries [X-rays], Astrophysics - High Energy Astrophysical Phenomena, individual: PSR B1259{\ndash}63 [pulsars], Fermi Gamma-ray Space Telescope

الوصف: We report on the discovery of \geq 100 MeV {\gamma} rays from the binary system PSR B1259-63/LS 2883 using the Large Area Telescope (LAT) on board Fermi. The system comprises a radio pulsar in orbit around a Be star. We report on LAT observations from near apastron to ~ 60 days after the time of periastron, tp, on 2010 December 15. No {\gamma}-ray emission was detected from this source when it was far from periastron. Faint {\gamma}-ray emission appeared as the pulsar approached periastron. At ~ tp + 30d, the \geq 100 MeV {\gamma}-ray flux increased over a period of a few days to a peak flux 20-30 times that seen during the pre-periastron period, but with a softer spectrum. For the following month, it was seen to be variable on daily time scales, but remained at ~ 1 - 4 \times 10^-6 cm^-2 s^-1 before starting to fade at ~ tp + 57d. The total {\gamma}-ray luminosity observed during this period is comparable to the spin-down power of the pulsar. Simultaneous radio and X-ray observations of the source showed no corresponding dramatic changes in radio and X-ray flux between the pre-periastron and post-periastron flares. We discuss possible explanations for the observed {\gamma}-ray-only flaring of the source.
Comment: Accepted for publication in ApJ Letters Contact authors: A. A. Abdo, S. Johnston, D. Parent, A. Neronov, K. S. Wood

وصف الملف: STAMPA

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::50de1fb179e4809d0441bbd48a8437daTest
https://hal.in2p3.fr/in2p3-00654867Test