Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-03T13:38:02.798Z Has data issue: false hasContentIssue false

Photon scattering in a relativistic outflow having velocity shear: a novel mechanism of generation for high energy power-law spectra

Published online by Cambridge University Press:  28 October 2024

Mukesh Kumar Vyas*
Affiliation:
Bar Ilan University, Ramat Gan, Israel. 5290002
Asaf Pe’er
Affiliation:
Bar Ilan University, Ramat Gan, Israel. 5290002
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

. We show that an extragalactic jet with a velocity shear gives rise to Fermi like acceleration process for photons scattering withing the shear layers of the jet. Such photons then gain energy to produce a high energy power law. These power law spectra at high energies are frequently observed in several extragalactic objects such as Gamma Ray Bursts (GRBs). We implement the model on GRBs to show that the obtained range of the photon indices are well within their observed values. The analytic results are confirmed with numerical simulations following Monte Carlo approach.

Type
Contributed Paper
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of International Astronomical Union

References

Band, D., Matteson, J., Ford, L., Schaefer, B., Palmer, D., Teegarden, B., Cline, T., Briggs, M., Paciesas, W., Pendleton, G., Fishman, G., Kouveliotou, C., Meegan, C., Wilson, R., & Lestrade, P. 1993, BATSE Observations of Gamma-Ray Burst Spectra. I. Spectral Diversity, The Astrophysical Journal, 413, 281.CrossRefGoogle Scholar
Barraud, C., Olive, J. F., Lestrade, J. P., Atteia, J. L., Hurley, K., Ricker, G., Lamb, D. Q., Kawai, N., Boer, M., Dezalay, J. P., Pizzichini, G., Vanderspek, R., Crew, G., Doty, J., Monnelly, G., Villasenor, J., Butler, N., Levine, A., Yoshida, A., Shirasaki, Y., Sakamoto, T., Tamagawa, T., Torii, K., Matsuoka, M., Fenimore, E. E., Galassi, M., Tavenner, T., Donaghy, T. Q., Graziani, C., & Jernigan, J. G. 2003, Spectral analysis of 35 GRBs/XRFs observed with HETE-2/FREGATE, Astronomy and Astrophysics, 400, 10211030.CrossRefGoogle Scholar
Blandford, R. & Eichler, D. 1987, Particle acceleration at astrophysical shocks: A theory of cosmic ray origin, Physics Reports, 154(1), 175.CrossRefGoogle Scholar
Blumenthal, G. R. & Gould, R. J. 1970, Bremsstrahlung, Synchrotron Radiation, and Compton Scattering of High-Energy Electrons Traversing Dilute Gases, Reviews of Modern Physics, 42(2), 237271.CrossRefGoogle Scholar
Bošnjak, Ž., Götz, D., Bouchet, L., Schanne, S., & Cordier, B. 2014, The spectral catalogue of INTEGRAL gamma-ray bursts. results of the joint IBIS/SPI spectral analysis, Astronomy and Astrophysics, 561, A25.Google Scholar
Kaneko, Y., Preece, R. D., Briggs, M. S., Paciesas, W. S., Meegan, C. A., & Band, David L., a. 2006, The Complete Spectral Catalog of Bright BATSE Gamma-Ray Bursts, 166(1), 298–340.Google Scholar
Lundman, C., Pe’er, A., & Ryde, F. 2013, A theory of photospheric emission from relativistic, collimated outflows, MNRAS, 428(3), 24302442.CrossRefGoogle Scholar
Nandra, K. & Pounds, K. A. 1994, GINGA observations of the X-ray spectra of Seyfert galaxies, MNRAS, 268, 405429.CrossRefGoogle Scholar
Page, K. L., Reeves, J. N., O’Brien, P. T., & Turner, M. J. L. 2005, XMM-Newton spectroscopy of high-redshift quasars, MNRAS, 364(1), 195207.CrossRefGoogle Scholar
Pe’er, A. 2008, Temporal Evolution of Thermal Emission from Relativistically Expanding Plasma, Astrophysical Journal, 682(1), 463473.CrossRefGoogle Scholar
Pe’er, A. 2015, Physics of Gamma-Ray Bursts Prompt Emission, Advances in Astronomy, 2015, 907321.CrossRefGoogle Scholar
Preece, R. D., Briggs, M. S., Mallozzi, R. S., Pendleton, G. N., Paciesas, W. S., & Band, D. L. 2000, The BATSE Gamma-Ray Burst Spectral Catalog. I. High Time Resolution Spectroscopy of Bright Bursts Using High Energy Resolution Data, Astrophysical Journals, 126(1), 19–36.CrossRefGoogle Scholar
Preece, R. D., Pendleton, G. N., Briggs, M. S., Mallozzi, R. S., Paciesas, W. S., Band, D. L., Matteson, J. L., & Meegan, C. A. 1998, BATSE Observations of Gamma-Ray Burst Spectra. IV. Time-resolved High-Energy Spectroscopy, Astrophysical Journal, 496(2), 849862.CrossRefGoogle Scholar
Reeves, J. N. & Turner, M. J. L. 2000, X-ray spectra of a large sample of quasars with ASCA, MNRAS, 316(2), 234248.CrossRefGoogle Scholar
Rybicki, G. B. & Lightman, A. P. 1986,. Radiative Processes in Astrophysics.CrossRefGoogle Scholar
Vyas, M. K. & Pe’er, A. 2023, Photons’ Scattering in Relativistic Plasma with Velocity Shear: Generation of High Energy Power-law Spectra, Astrophysical Journal, Letters, 943(1), L3.CrossRefGoogle Scholar
Vyas, M. K., Pe’er, A., & Eichler, D. 2021,a A Backscattering-dominated Prompt Emission Model for the Prompt Phase of Gamma-Ray Bursts, Astrophysical Journal, 908a(1), 9.Google Scholar
Vyas, M. K., Pe’er, A., & Eichler, D. 2021,b Predicting Spectral Parameters in the Backscattering-dominated Model for the Prompt Phase of GRBs, Astrophysical Journal, Letters, 918b(1), L12.Google Scholar
Zdziarski, A. A. & Krolik, J. H. 1993, Compton Scattering and the Gamma-Ray Power-Law Spectrum in Markarian 421, Astrophysical Journal, Letters, 409, L33.CrossRefGoogle Scholar