{"paper":{"title":"What an Amortized X-ray Posterior Cannot See: Gain Shifts, Silent Miscalibration, and Where Nested Sampling Still Earns Its Cost","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.IM"],"primary_cat":"astro-ph.HE","authors_text":"Karan Akbari","submitted_at":"2026-06-14T05:16:16Z","abstract_excerpt":"Neural posterior estimation (NPE) gives X-ray spectral fits a posterior in milliseconds instead of the minutes nested sampling costs, but without its calibration guarantee or goodness-of-fit. The simulation-based inference (SBI) literature has trust diagnostics for this gap that have not been benchmarked on X-ray spectra. We provide the first such benchmark on one real XMM-Newton EPIC-pn response: a 5-parameter absorbed continuum across three count regimes (~100, 1000, 10000 counts), four misspecification families, and nested sampling on the exact Poisson likelihood as reference. A posterior-p"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.17098","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2606.17098/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}