{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/effective-j-factors-for-milky-way-dwarf","title":"Effective $J$-factors for Milky Way dwarf spheroidal galaxies with velocity-dependent annihilation","arxiv_id":"1909.13197","date":"2019-09-29","proceeding":null,"authors":["Kimberly K. Boddy","Jason Kumar","Andrew B. Pace","Jack Runburg","Louis E. Strigari"],"abstract":"We calculate the effective $J$-factors, which determine the strength of indirect detection signals from dark matter annihilation, for 25 dwarf spheroidal galaxies (dSphs). We consider several well-motivated assumptions for the relative velocity dependence of the dark matter annihilation cross section: $\\sigma_A v$: $s$-wave (velocity independent), $p$-wave ($\\sigma_A v \\propto v^2$), $d$-wave ($\\sigma_A v \\propto v^4$), and Sommerfeld-enhancement in the Coulomb limit ($\\sigma_A v \\propto 1/v$). As a result we provide the largest and most updated sample of J-factors for velocity-dependent annihilation models. For each scenario, we use Fermi-LAT gamma-ray data to constrain the annihilation cross section. Due to the assumptions made in our gamma-ray data analysis, our bounds are comparable to previous bounds on both the $p$-wave and Sommerfeld-enhanced cross sections using dSphs. Our bounds on the $d$-wave cross section are the first such bounds using indirect detection data.","url_abs":"https://arxiv.org/abs/1909.13197v2","url_pdf":"https://arxiv.org/pdf/1909.13197v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"effective-j-factors-for-milky-way-dwarf","repo_url":"https://github.com/apace7/J-Factor-Scaling","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}