{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2015:MDGXFSTCFGE5PTQRFTOKHYIJ4U","short_pith_number":"pith:MDGXFSTC","canonical_record":{"source":{"id":"1501.07769","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2015-01-30T13:40:16Z","cross_cats_sorted":[],"title_canon_sha256":"98fdae88f583149e02d163fc61147bf989294a7f8396332fa82324895d0f0155","abstract_canon_sha256":"2a21cd84aa25adf91e63af8368c6c23da8c77d71f269d8f6faf3216a145139aa"},"schema_version":"1.0"},"canonical_sha256":"60cd72ca622989d7ce112cdca3e109e53e60017da35584e80678df5de5631dfd","source":{"kind":"arxiv","id":"1501.07769","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1501.07769","created_at":"2026-05-18T01:41:05Z"},{"alias_kind":"arxiv_version","alias_value":"1501.07769v1","created_at":"2026-05-18T01:41:05Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1501.07769","created_at":"2026-05-18T01:41:05Z"},{"alias_kind":"pith_short_12","alias_value":"MDGXFSTCFGE5","created_at":"2026-05-18T12:29:32Z"},{"alias_kind":"pith_short_16","alias_value":"MDGXFSTCFGE5PTQR","created_at":"2026-05-18T12:29:32Z"},{"alias_kind":"pith_short_8","alias_value":"MDGXFSTC","created_at":"2026-05-18T12:29:32Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2015:MDGXFSTCFGE5PTQRFTOKHYIJ4U","target":"record","payload":{"canonical_record":{"source":{"id":"1501.07769","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2015-01-30T13:40:16Z","cross_cats_sorted":[],"title_canon_sha256":"98fdae88f583149e02d163fc61147bf989294a7f8396332fa82324895d0f0155","abstract_canon_sha256":"2a21cd84aa25adf91e63af8368c6c23da8c77d71f269d8f6faf3216a145139aa"},"schema_version":"1.0"},"canonical_sha256":"60cd72ca622989d7ce112cdca3e109e53e60017da35584e80678df5de5631dfd","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:41:05.661498Z","signature_b64":"UXdrcrVZak6EFnkc12ijmPALxFdhc48/HIBvIRso43ltFCWnU6wyoQcAjg11pc5vbwjrnXBdgEcEBFu4bXB/Dw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"60cd72ca622989d7ce112cdca3e109e53e60017da35584e80678df5de5631dfd","last_reissued_at":"2026-05-18T01:41:05.660907Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:41:05.660907Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1501.07769","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":"2026-05-18T01:41:05Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"S4LwOl0xJJMwUwou6GgClfFjFvq2meJjLaz6rGHYtgqpPHht5bKw4bWmL4LBSfqj4uDf91AQJQnQnj43pjgkBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T05:03:26.225293Z"},"content_sha256":"dc3c76afaa2ec87889212bf02a93e1f5c82df5af254a376a89cf333a13dcd396","schema_version":"1.0","event_id":"sha256:dc3c76afaa2ec87889212bf02a93e1f5c82df5af254a376a89cf333a13dcd396"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2015:MDGXFSTCFGE5PTQRFTOKHYIJ4U","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Probability distribution functions of gas in M31 and M51","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Andrew Fletcher, Elly M. Berkhuijsen","submitted_at":"2015-01-30T13:40:16Z","abstract_excerpt":"We present probability distribution functions (PDFs) of the surface densities of ionized and neutral gas in the nearby spiral galaxies M31 and M51, as well as of dust emission and extinction Av in M31. The PDFs are close to lognormal and those for HI and Av in M31 are nearly identical. However, the PDFs for H2 are wider than the HI PDFs and the M51 PDFs have larger dispersions than those for M31. We use a simple model to determine how the PDFs are changed by variations in the line-of-sight (LOS) pathlength L through the gas, telescope resolution and the volume filling factor of the gas, f_v. I"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1501.07769","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":"2026-05-18T01:41:05Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"0hGogEPtLr38TwJchySMWvLKMXQkNwGjeWVyJ55m/KWxfOxoj8LK1Ukxm3XSAkekPVL6fHwu2EvavWRyp6JlCw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T05:03:26.225944Z"},"content_sha256":"f7c379cf16b855f1e748d9e13bc3d075b92a97988944b8f1ba6587fd106822bb","schema_version":"1.0","event_id":"sha256:f7c379cf16b855f1e748d9e13bc3d075b92a97988944b8f1ba6587fd106822bb"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U/bundle.json","state_url":"https://pith.science/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U/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":"2026-05-31T05:03:26Z","links":{"resolver":"https://pith.science/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U","bundle":"https://pith.science/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U/bundle.json","state":"https://pith.science/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U/state.json","well_known_bundle":"https://pith.science/.well-known/pith/MDGXFSTCFGE5PTQRFTOKHYIJ4U/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2015:MDGXFSTCFGE5PTQRFTOKHYIJ4U","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":"2a21cd84aa25adf91e63af8368c6c23da8c77d71f269d8f6faf3216a145139aa","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2015-01-30T13:40:16Z","title_canon_sha256":"98fdae88f583149e02d163fc61147bf989294a7f8396332fa82324895d0f0155"},"schema_version":"1.0","source":{"id":"1501.07769","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1501.07769","created_at":"2026-05-18T01:41:05Z"},{"alias_kind":"arxiv_version","alias_value":"1501.07769v1","created_at":"2026-05-18T01:41:05Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1501.07769","created_at":"2026-05-18T01:41:05Z"},{"alias_kind":"pith_short_12","alias_value":"MDGXFSTCFGE5","created_at":"2026-05-18T12:29:32Z"},{"alias_kind":"pith_short_16","alias_value":"MDGXFSTCFGE5PTQR","created_at":"2026-05-18T12:29:32Z"},{"alias_kind":"pith_short_8","alias_value":"MDGXFSTC","created_at":"2026-05-18T12:29:32Z"}],"graph_snapshots":[{"event_id":"sha256:f7c379cf16b855f1e748d9e13bc3d075b92a97988944b8f1ba6587fd106822bb","target":"graph","created_at":"2026-05-18T01:41:05Z","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 present probability distribution functions (PDFs) of the surface densities of ionized and neutral gas in the nearby spiral galaxies M31 and M51, as well as of dust emission and extinction Av in M31. The PDFs are close to lognormal and those for HI and Av in M31 are nearly identical. However, the PDFs for H2 are wider than the HI PDFs and the M51 PDFs have larger dispersions than those for M31. We use a simple model to determine how the PDFs are changed by variations in the line-of-sight (LOS) pathlength L through the gas, telescope resolution and the volume filling factor of the gas, f_v. I","authors_text":"Andrew Fletcher, Elly M. Berkhuijsen","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2015-01-30T13:40:16Z","title":"Probability distribution functions of gas in M31 and M51"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1501.07769","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:dc3c76afaa2ec87889212bf02a93e1f5c82df5af254a376a89cf333a13dcd396","target":"record","created_at":"2026-05-18T01:41:05Z","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":"2a21cd84aa25adf91e63af8368c6c23da8c77d71f269d8f6faf3216a145139aa","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2015-01-30T13:40:16Z","title_canon_sha256":"98fdae88f583149e02d163fc61147bf989294a7f8396332fa82324895d0f0155"},"schema_version":"1.0","source":{"id":"1501.07769","kind":"arxiv","version":1}},"canonical_sha256":"60cd72ca622989d7ce112cdca3e109e53e60017da35584e80678df5de5631dfd","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"60cd72ca622989d7ce112cdca3e109e53e60017da35584e80678df5de5631dfd","first_computed_at":"2026-05-18T01:41:05.660907Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:41:05.660907Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"UXdrcrVZak6EFnkc12ijmPALxFdhc48/HIBvIRso43ltFCWnU6wyoQcAjg11pc5vbwjrnXBdgEcEBFu4bXB/Dw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:41:05.661498Z","signed_message":"canonical_sha256_bytes"},"source_id":"1501.07769","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:dc3c76afaa2ec87889212bf02a93e1f5c82df5af254a376a89cf333a13dcd396","sha256:f7c379cf16b855f1e748d9e13bc3d075b92a97988944b8f1ba6587fd106822bb"],"state_sha256":"c5cb08a44e0847b6907d699e1cb384cab0f3ab39d83ba40375c4d44bbd13532c"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ODD/X++NfSks8PUcRRJwjIRU0+NyHKUru9oi0PhVpLQ9ZZMFNaXOjFFK3OtyurzsTce9CZgI/7MfV2T1Zj6NDQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-31T05:03:26.229276Z","bundle_sha256":"96f9491e77c2dc56f32846f5c8edadff3dd4a98107fc5340c99e02aa91d42df8"}}