{
  "abstract": "Context. The Gum Nebula is a nearby ionised complex with sight-line-dependent pulsar propagation. Aims. We test whether a smooth ionised structure can explain low-frequency spectral turnovers and pulse broadening, or whether smaller-scale material is required. Methods. We analysed Murchison Widefield Array observations of six pulsars at 80--240 MHz, combining sub-band flux densities with literature data. We compared power-law, free--free absorption (FFA), and turnover-constrained broken-power-law (BPL) spectra, and modelled scattering through pulse-profile convolution. PSR J0820-4114 and the Vela pulsar were fitted jointly across frequency. Results. All six spectra depart from a single power law. FFA is favoured for PSRs J0737-3039A and J0820-4114, and BPL for J0742-2822 and J0835-4510; the other two classifications depend on assumed error floors. Conditional FFA solutions imply emission measures of $10^4$--$10^5$ pc cm$^{-6}$ for electron temperatures of $3\\times10^3$--$10^4$ K, far exceeding smooth-shell expectations. PSRs J0737-3039A and J0837-4135 have scattering laws consistent with $τ_{\\rm sc}\\proptoν^{-4}$. We obtain $α_{\\rm sc}=-3.07\\pm0.11$ for J0742-2822 and $-1.59\\pm0.44$ for J0820-4114 using a joint two-component model. The Vela pulsar is best described by an effective thick-screen model with $α_{\\rm sc}\\simeq-2.74$. Neither tested Galactic electron-density model reproduces both independent distances and low-frequency scattering uniformly. Conclusions. The results favour a structured Gum--Vela magneto-ionic environment in which neighbouring sight lines probe different absorbing and scattering material; these effects need not arise in the same plasma component.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.18146",
  "author_total": 4,
  "authors": [
    {
      "name": "Ting Yu"
    },
    {
      "name": "Zhifu Gao"
    },
    {
      "name": "Zhongli Zhang"
    },
    {
      "name": "Weicong Jing"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fbqccw4pvpwwm.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.18146",
  "fulltext_url": null,
  "id": "fbqccw4pvpwwm",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.18146",
  "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.GA"
    ],
    [
      "arxiv",
      "astro-ph.HE"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.18146",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fbqccw4pvpwwm.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:11Z",
      "native_id": "2610.18146",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.18146"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "Low-frequency spectra and scattering of pulsars towards the Gum Nebula with the MWA",
  "title_text": "Low-frequency spectra and scattering of pulsars towards the Gum Nebula with the MWA",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:11Z",
  "url": "https://research.draconitic.com/paper/fbqccw4pvpwwm",
  "venue": "arXiv",
  "versions": []
}