Paper

{
  "raw_xml": "<entry>\n    <id>http://arxiv.org/abs/2603.09066v1</id>\n    <title>Time-dependent photospheric radiative transfer in structured GRB jets: spectral evolution and polarization diagnostics</title>\n    <updated>2026-03-10T01:18:04Z</updated>\n    <link href='https://arxiv.org/abs/2603.09066v1' rel='alternate' type='text/html'/>\n    <link href='https://arxiv.org/pdf/2603.09066v1' rel='related' title='pdf' type='application/pdf'/>\n    <summary>Photospheric emission from relativistic gamma-ray burst (GRB) jets is a promising mechanism for producing the Band-like spectra observed in the prompt phase, yet the connections between jet structure, dissipation location, and polarization signatures remain unclear.\n  We investigate time-dependent photospheric radiation transfer in structured relativistic jets by coupling two-dimensional axisymmetric special relativistic hydrodynamic (SRHD) simulations with Monte Carlo photon propagation.\n  Photon escape and subphotospheric dissipation are characterized using the residual line-of-sight optical depth tau_out evaluated along each photon trajectory, allowing a direction-dependent treatment of photon decoupling in structured jets. The radiative transfer includes Klein-Nishina Compton scattering and polarization evolution using the Mueller matrix formalism.\n  We perform a systematic parameter study exploring the effects of viewing angle, electron-positron pair loading (Z_pm), and the optical-depth window of subphotospheric dissipation. The model produces time-resolved spectra, peak-energy evolution E_pk(t), Band parameters, polarization degree Pi(E,t), and last-scattering statistics.\n  We find that jet angular structure and the geometry of the line-of-sight optical depth strongly regulate spectral evolution and polarization signatures. The dissipation depth and pair loading jointly control the stability of E_pk, the formation of high-energy spectral tails, and the energy dependence of polarization. These results provide quantitative predictions for GRB prompt-emission spectra and polarization that can be tested with current and upcoming high-energy polarimeters.</summary>\n    <category scheme='http://arxiv.org/schemas/atom' term='astro-ph.HE'/>\n    <published>2026-03-10T01:18:04Z</published>\n    <arxiv:comment>Submitted to The Astrophysical Journal</arxiv:comment>\n    <arxiv:primary_category term='astro-ph.HE'/>\n    <author>\n      <name>Yue Xu</name>\n    </author>\n    <author>\n      <name>Ming Jin</name>\n    </author>\n    <author>\n      <name>Qingwen Tang</name>\n    </author>\n  </entry>"
}