{
  "abstract": "Gamma-ray bursts (GRBs) are the brightest explosions in the Universe, yet the origin of their emission remains uncertain. Time-resolved spectral analysis offers key insights into the evolution of spectral shapes, constraining both radiation mechanisms and emission-site microphysics. Observationally, GRB spectra are well described by the empirical Band function, characterized by the peak energy ($E_{\\mathrm{peak}}$) and low-energy spectral index ($α$). We investigate the temporal evolution of spectra produced by optically thin inverse-Compton scattering (ICS) within a standard fireball jet framework, focusing on the scenarios that can produce the two commonly observed spectral evolution patterns: hard-to-soft evolution and intensity tracking, within a single emission pulse. The evolution is analysed using both Bayesian block and constant-fluence binning, with the observed spectrum modeled consistently using the Band function. Using this bottom-up approach, we find that optically thin ICS yields a positive $E_{\\mathrm{peak}}$-$α$ correlation, with $α$ evolving from hard (Planck-like, $> +0.5$) to softer ($< -0.67$) values. Such hard $α$ values are inconsistent with standard synchrotron emission. This characteristic evolution in the $E_{\\mathrm{peak}}$-$α$ plane, therefore, provides a diagnostic signature of optically thin ICS as the dominant radiation mechanism during the prompt phase of GRBs. Furthermore, this type of smooth evolution of $α$ within a single pulse does not require invoking a transition between different radiation mechanisms, unless additional observational evidence supports such a change.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.04894",
  "author_total": 3,
  "authors": [
    {
      "name": "Pragyan Pratim Bordoloi"
    },
    {
      "name": "Ayush Shivkumar"
    },
    {
      "name": "Shabnam Iyyani"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c57p19cpe4gc7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.04894",
  "fulltext_url": null,
  "id": "c57p19cpe4gc7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.04894",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7163529382",
  "pdf_url": "https://arxiv.org/pdf/2606.04894",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c57p19cpe4gc7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:12Z",
      "native_id": "2606.04894",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.04894"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "$E_{\\rm peak}$-$α$ Correlation in Time Resolved GRB Spectra: A Bottom-Up Approach with Optically Thin Inverse Compton Scattering Model",
  "title_text": "E_peak-α Correlation in Time Resolved GRB Spectra: A Bottom-Up Approach with Optically Thin Inverse Compton Scattering Model",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:12Z",
  "url": "https://research.draconitic.com/paper/c57p19cpe4gc7",
  "venue": "arXiv",
  "versions": []
}