{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2012:BHEGZFCUHBHJOBIT2ULPUVYPV3","short_pith_number":"pith:BHEGZFCU","canonical_record":{"source":{"id":"1207.6513","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-07-27T11:10:54Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"20cc3f3ce72f491b89be756125df864c16b758aaab0f274be86e6c9f9acd9de3","abstract_canon_sha256":"739dedcb4b269c4bcb548363fb45fc8cee3fa274d3fd518a94887390a561c0ba"},"schema_version":"1.0"},"canonical_sha256":"09c86c9454384e970513d516fa570faec7c181ef48609cf1a5fc0bb9b3e5dc8e","source":{"kind":"arxiv","id":"1207.6513","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1207.6513","created_at":"2026-05-18T01:56:06Z"},{"alias_kind":"arxiv_version","alias_value":"1207.6513v1","created_at":"2026-05-18T01:56:06Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1207.6513","created_at":"2026-05-18T01:56:06Z"},{"alias_kind":"pith_short_12","alias_value":"BHEGZFCUHBHJ","created_at":"2026-05-18T12:26:58Z"},{"alias_kind":"pith_short_16","alias_value":"BHEGZFCUHBHJOBIT","created_at":"2026-05-18T12:26:58Z"},{"alias_kind":"pith_short_8","alias_value":"BHEGZFCU","created_at":"2026-05-18T12:26:58Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2012:BHEGZFCUHBHJOBIT2ULPUVYPV3","target":"record","payload":{"canonical_record":{"source":{"id":"1207.6513","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-07-27T11:10:54Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"20cc3f3ce72f491b89be756125df864c16b758aaab0f274be86e6c9f9acd9de3","abstract_canon_sha256":"739dedcb4b269c4bcb548363fb45fc8cee3fa274d3fd518a94887390a561c0ba"},"schema_version":"1.0"},"canonical_sha256":"09c86c9454384e970513d516fa570faec7c181ef48609cf1a5fc0bb9b3e5dc8e","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:56:06.706086Z","signature_b64":"hlPx/I8MWq0f2ozJnT6d2D0hmdshuKNoJxfVYHsRdcZ95r8oxn149n8CbAIN7VKbs2afFSuKmevbcT5yIwscBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"09c86c9454384e970513d516fa570faec7c181ef48609cf1a5fc0bb9b3e5dc8e","last_reissued_at":"2026-05-18T01:56:06.705570Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:56:06.705570Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1207.6513","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:56:06Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"bNnjmvbifZZl7ZA/Fk1SrcqCwYpxJXK+VpxH11QTc1gY9AI+6lToimHfR+sRh4dkcH96KbIA4RMa8DysAtUSDQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-10T19:58:49.951815Z"},"content_sha256":"e0e79cf1031c4b00165446f8cfc33990aed6da72a6dcc0d05f4c6ebdb0f3f57a","schema_version":"1.0","event_id":"sha256:e0e79cf1031c4b00165446f8cfc33990aed6da72a6dcc0d05f4c6ebdb0f3f57a"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2012:BHEGZFCUHBHJOBIT2ULPUVYPV3","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Reliable estimation of the column density in Smoothed Particle Hydrodynamic simulations","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.IM","authors_text":"Cathie J. Clarke, Erik Bertram, Matthew D. Young, Nick Moeckel","submitted_at":"2012-07-27T11:10:54Z","abstract_excerpt":"We describe a simple method for estimating the vertical column density in Smoothed Particle Hydrodynamics (SPH) simulations of discs. As in the method of Stamatellos et al. (2007), the column density is estimated using pre-computed local quantities and is then used to estimate the radiative cooling rate. The cooling rate is a quantity of considerable importance, for example, in assessing the probability of disc fragmentation. Our method has three steps: (i) the column density from the particle to the mid plane is estimated using the vertical component of the gravitational acceleration, (ii) th"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1207.6513","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":""},"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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:56:06Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"31ANvvCU2Cv1u/6SKHm98glb3DDNOzl2iwuy8uFWMx9bYEnDdzjn36QuqMXmAeqHl3EZ/JWoRfJ9b91nvY5VDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-10T19:58:49.952170Z"},"content_sha256":"a872cae8e166c55674b7725803571b7519fe65916b0a8447970d31a86c2997f1","schema_version":"1.0","event_id":"sha256:a872cae8e166c55674b7725803571b7519fe65916b0a8447970d31a86c2997f1"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3/bundle.json","state_url":"https://pith.science/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-10T19:58:49Z","links":{"resolver":"https://pith.science/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3","bundle":"https://pith.science/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3/bundle.json","state":"https://pith.science/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3/state.json","well_known_bundle":"https://pith.science/.well-known/pith/BHEGZFCUHBHJOBIT2ULPUVYPV3/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:BHEGZFCUHBHJOBIT2ULPUVYPV3","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"739dedcb4b269c4bcb548363fb45fc8cee3fa274d3fd518a94887390a561c0ba","cross_cats_sorted":["astro-ph.GA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-07-27T11:10:54Z","title_canon_sha256":"20cc3f3ce72f491b89be756125df864c16b758aaab0f274be86e6c9f9acd9de3"},"schema_version":"1.0","source":{"id":"1207.6513","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1207.6513","created_at":"2026-05-18T01:56:06Z"},{"alias_kind":"arxiv_version","alias_value":"1207.6513v1","created_at":"2026-05-18T01:56:06Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1207.6513","created_at":"2026-05-18T01:56:06Z"},{"alias_kind":"pith_short_12","alias_value":"BHEGZFCUHBHJ","created_at":"2026-05-18T12:26:58Z"},{"alias_kind":"pith_short_16","alias_value":"BHEGZFCUHBHJOBIT","created_at":"2026-05-18T12:26:58Z"},{"alias_kind":"pith_short_8","alias_value":"BHEGZFCU","created_at":"2026-05-18T12:26:58Z"}],"graph_snapshots":[{"event_id":"sha256:a872cae8e166c55674b7725803571b7519fe65916b0a8447970d31a86c2997f1","target":"graph","created_at":"2026-05-18T01:56:06Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"We describe a simple method for estimating the vertical column density in Smoothed Particle Hydrodynamics (SPH) simulations of discs. As in the method of Stamatellos et al. (2007), the column density is estimated using pre-computed local quantities and is then used to estimate the radiative cooling rate. The cooling rate is a quantity of considerable importance, for example, in assessing the probability of disc fragmentation. Our method has three steps: (i) the column density from the particle to the mid plane is estimated using the vertical component of the gravitational acceleration, (ii) th","authors_text":"Cathie J. Clarke, Erik Bertram, Matthew D. Young, Nick Moeckel","cross_cats":["astro-ph.GA"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-07-27T11:10:54Z","title":"Reliable estimation of the column density in Smoothed Particle Hydrodynamic simulations"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1207.6513","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:e0e79cf1031c4b00165446f8cfc33990aed6da72a6dcc0d05f4c6ebdb0f3f57a","target":"record","created_at":"2026-05-18T01:56:06Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"739dedcb4b269c4bcb548363fb45fc8cee3fa274d3fd518a94887390a561c0ba","cross_cats_sorted":["astro-ph.GA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-07-27T11:10:54Z","title_canon_sha256":"20cc3f3ce72f491b89be756125df864c16b758aaab0f274be86e6c9f9acd9de3"},"schema_version":"1.0","source":{"id":"1207.6513","kind":"arxiv","version":1}},"canonical_sha256":"09c86c9454384e970513d516fa570faec7c181ef48609cf1a5fc0bb9b3e5dc8e","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"09c86c9454384e970513d516fa570faec7c181ef48609cf1a5fc0bb9b3e5dc8e","first_computed_at":"2026-05-18T01:56:06.705570Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:56:06.705570Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"hlPx/I8MWq0f2ozJnT6d2D0hmdshuKNoJxfVYHsRdcZ95r8oxn149n8CbAIN7VKbs2afFSuKmevbcT5yIwscBw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:56:06.706086Z","signed_message":"canonical_sha256_bytes"},"source_id":"1207.6513","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:e0e79cf1031c4b00165446f8cfc33990aed6da72a6dcc0d05f4c6ebdb0f3f57a","sha256:a872cae8e166c55674b7725803571b7519fe65916b0a8447970d31a86c2997f1"],"state_sha256":"336cf7bfc749481b082bd0bd4ba002067b0fb3f66827563d7f7bf3c776f46710"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"se/7T25z1vzP0XCiJoK0sFOnrqoZpnf93qdhkVY668BO6Xp7xFPtuSecA0c/0PwkalibrxyYx2VpDAmZiYEGAg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-10T19:58:49.954110Z","bundle_sha256":"2e6e561b5211657fab5d1b9d9469eeb137bdb362b5eed76e3610c2bbff040ec4"}}