{
  "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 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 analyzed 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 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 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": [
    "Indian Institute of Science Education and Research Thiruvananthapuram"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Pragyan Pratim Bordoloi",
      "orcid": "0009-0005-6858-6356"
    },
    {
      "affs": [
        0
      ],
      "name": "Ayush Shivkumar",
      "orcid": "0009-0008-2096-5797"
    },
    {
      "affs": [
        0
      ],
      "name": "Shabnam Iyyani",
      "orcid": "0000-0003-3220-7543"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6y5dfxz8arvmw.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4357/aea6a8",
  "fulltext_url": null,
  "id": "6y5dfxz8arvmw",
  "issns": [
    "0004-637X",
    "1538-4357"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea6a8",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7222343329",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea6a8/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/6y5dfxz8arvmw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:11Z",
      "native_id": "10.3847/1538-4357/aea6a8",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-4357/aea6a8"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Gamma-ray bursts and supernovae",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "E 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": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:11Z",
  "url": "https://research.draconitic.com/paper/6y5dfxz8arvmw",
  "venue": "The Astrophysical Journal",
  "versions": []
}