{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2005:C3U5OYHQZV7N3QQJWHTOFSK7VE","short_pith_number":"pith:C3U5OYHQ","schema_version":"1.0","canonical_sha256":"16e9d760f0cd7eddc209b1e6e2c95fa9392b7f9f4f49ef317de114ff3642d21e","source":{"kind":"arxiv","id":"astro-ph/0504017","version":1},"attestation_state":"computed","paper":{"title":"Constraints on the sound speed of dark energy","license":"","headline":"","cross_cats":["hep-ph"],"primary_cat":"astro-ph","authors_text":"Steen Hannestad (University of Aarhus)","submitted_at":"2005-04-01T09:05:42Z","abstract_excerpt":"We have studied constraints on the equation of state, $w$, and speed of sound, c_s, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current observations have no significant sensitivity to c_s. However, there is a slight difference between models in which there are no dark energy perturbations and models in which dark energy behaves as a fluid. Assuming that there are no dark energy perturbations shifts the allowed region for $w$ to slightly higher values. At present models with and without dark en"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"astro-ph/0504017","kind":"arxiv","version":1},"metadata":{"license":"","primary_cat":"astro-ph","submitted_at":"2005-04-01T09:05:42Z","cross_cats_sorted":["hep-ph"],"title_canon_sha256":"e624516de2f16e4452ea90c812a77087f74f6e4e904e3464290fc2f247d67be7","abstract_canon_sha256":"bf1bed1f0a578e12ebd497e074122182c83a3bc8f1ed6f4327e712ebd02776d7"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-04T16:51:50.552673Z","signature_b64":"RbDM8VFRH4tswE3QtSROmmDpH3oOWPyi6/LMvHPegoS3bXMV3k/TtcJmxdCYspQWfHb0/tMdbooP88MUW20zAA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"16e9d760f0cd7eddc209b1e6e2c95fa9392b7f9f4f49ef317de114ff3642d21e","last_reissued_at":"2026-07-04T16:51:50.552309Z","signature_status":"signed_v1","first_computed_at":"2026-07-04T16:51:50.552309Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Constraints on the sound speed of dark energy","license":"","headline":"","cross_cats":["hep-ph"],"primary_cat":"astro-ph","authors_text":"Steen Hannestad (University of Aarhus)","submitted_at":"2005-04-01T09:05:42Z","abstract_excerpt":"We have studied constraints on the equation of state, $w$, and speed of sound, c_s, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current observations have no significant sensitivity to c_s. However, there is a slight difference between models in which there are no dark energy perturbations and models in which dark energy behaves as a fluid. Assuming that there are no dark energy perturbations shifts the allowed region for $w$ to slightly higher values. At present models with and without dark en"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0504017","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/astro-ph/0504017/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"},"aliases":[{"alias_kind":"arxiv","alias_value":"astro-ph/0504017","created_at":"2026-07-04T16:51:50.552374+00:00"},{"alias_kind":"arxiv_version","alias_value":"astro-ph/0504017v1","created_at":"2026-07-04T16:51:50.552374+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.astro-ph/0504017","created_at":"2026-07-04T16:51:50.552374+00:00"},{"alias_kind":"pith_short_12","alias_value":"C3U5OYHQZV7N","created_at":"2026-07-04T16:51:50.552374+00:00"},{"alias_kind":"pith_short_16","alias_value":"C3U5OYHQZV7N3QQJ","created_at":"2026-07-04T16:51:50.552374+00:00"},{"alias_kind":"pith_short_8","alias_value":"C3U5OYHQ","created_at":"2026-07-04T16:51:50.552374+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":1,"sample":[{"citing_arxiv_id":"2507.11237","citing_title":"Testing Planck 2020 and DESI data on wCDM Models","ref_index":40,"is_internal_anchor":true}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE","json":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE.json","graph_json":"https://pith.science/api/pith-number/C3U5OYHQZV7N3QQJWHTOFSK7VE/graph.json","events_json":"https://pith.science/api/pith-number/C3U5OYHQZV7N3QQJWHTOFSK7VE/events.json","paper":"https://pith.science/paper/C3U5OYHQ"},"agent_actions":{"view_html":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE","download_json":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE.json","view_paper":"https://pith.science/paper/C3U5OYHQ","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=astro-ph/0504017&json=true","fetch_graph":"https://pith.science/api/pith-number/C3U5OYHQZV7N3QQJWHTOFSK7VE/graph.json","fetch_events":"https://pith.science/api/pith-number/C3U5OYHQZV7N3QQJWHTOFSK7VE/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE/action/timestamp_anchor","attest_storage":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE/action/storage_attestation","attest_author":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE/action/author_attestation","sign_citation":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE/action/citation_signature","submit_replication":"https://pith.science/pith/C3U5OYHQZV7N3QQJWHTOFSK7VE/action/replication_record"}},"created_at":"2026-07-04T16:51:50.552374+00:00","updated_at":"2026-07-04T16:51:50.552374+00:00"}