{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:LLHTJUNGY3V2HVB67CWJYSK4TE","short_pith_number":"pith:LLHTJUNG","canonical_record":{"source":{"id":"1304.7769","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-04-29T20:00:00Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"ccbc551d4c669e3fb4bcf1135da3fc7e8b756691df948878db2696553ad956f3","abstract_canon_sha256":"2a4b7ac539eac5cf8be2eb276f341e5aef0f770fb3cc065d209e8fd9f444a885"},"schema_version":"1.0"},"canonical_sha256":"5acf34d1a6c6eba3d43ef8ac9c495c990ef852c41ac0890df320b58168aef66d","source":{"kind":"arxiv","id":"1304.7769","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1304.7769","created_at":"2026-05-18T01:50:14Z"},{"alias_kind":"arxiv_version","alias_value":"1304.7769v1","created_at":"2026-05-18T01:50:14Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1304.7769","created_at":"2026-05-18T01:50:14Z"},{"alias_kind":"pith_short_12","alias_value":"LLHTJUNGY3V2","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_16","alias_value":"LLHTJUNGY3V2HVB6","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_8","alias_value":"LLHTJUNG","created_at":"2026-05-18T12:27:51Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:LLHTJUNGY3V2HVB67CWJYSK4TE","target":"record","payload":{"canonical_record":{"source":{"id":"1304.7769","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-04-29T20:00:00Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"ccbc551d4c669e3fb4bcf1135da3fc7e8b756691df948878db2696553ad956f3","abstract_canon_sha256":"2a4b7ac539eac5cf8be2eb276f341e5aef0f770fb3cc065d209e8fd9f444a885"},"schema_version":"1.0"},"canonical_sha256":"5acf34d1a6c6eba3d43ef8ac9c495c990ef852c41ac0890df320b58168aef66d","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:50:14.500015Z","signature_b64":"WDojg7JMz8Ch6svcoYujINYxgDPaPjYdAoFmR3iaW3qXMsrjJD4pUQiJ35YtpL2wL9d3/RTVuoP+euJg4q9JCA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"5acf34d1a6c6eba3d43ef8ac9c495c990ef852c41ac0890df320b58168aef66d","last_reissued_at":"2026-05-18T01:50:14.499536Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:50:14.499536Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1304.7769","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":"2026-05-18T01:50:14Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"7s4GWSF1bJMh4RVdHJm38sfggVMu/h8yZ8Q7BJ8Qe//lgROZJzVI33JFIbWrvi/Rd2fP+25v7zdV/D8oOO/8BQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T10:57:25.171255Z"},"content_sha256":"fa01fd9842eff35efcb53c772a160c31172d1765db4bb89e7365b6d8f80b5d2c","schema_version":"1.0","event_id":"sha256:fa01fd9842eff35efcb53c772a160c31172d1765db4bb89e7365b6d8f80b5d2c"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:LLHTJUNGY3V2HVB67CWJYSK4TE","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"The Stellar Initial Mass Function of Ultra-Faint Dwarf Galaxies: Evidence for IMF Variations with Galactic Environment","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.CO","authors_text":"D. VandenBerg, E. Kirby, H. Ferguson, J.D. Simon, J. Kalirai, J. Tumlinson, M. Geha, P. Guhathakurta, R. Avila, R.M. Munoz, T.M. Brown","submitted_at":"2013-04-29T20:00:00Z","abstract_excerpt":"We present constraints on the stellar initial mass function (IMF) in two ultra-faint dwarf (UFD) galaxies, Hercules and Leo IV, based on deep HST/ACS imaging. The Hercules and Leo IV galaxies are extremely low luminosity (M_V = -6.2, -5.5), metal-poor (<[Fe/H]>= -2.4, -2.5) systems that have old stellar populations (> 11 Gyr). Because they have long relaxation times, we can directly measure the low-mass stellar IMF by counting stars below the main-sequence turnoff without correcting for dynamical evolution. Over the stellar mass range probed by our data, 0.52 - 0.77 Msun, the IMF is best fit b"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1304.7769","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":"2026-05-18T01:50:14Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"wB5576ELigBp0JX9tXtgl9aNXE+UXS+cXSTy1RYom9fugZcho0bxNDq0PPIAuI5Fc3K9LBZY1PD3qesLh4UzBA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T10:57:25.172008Z"},"content_sha256":"501ddb9070a87c3c87e6058c7e032f85f8d9203bb4ecfe7eae1ca2a4a528eb6e","schema_version":"1.0","event_id":"sha256:501ddb9070a87c3c87e6058c7e032f85f8d9203bb4ecfe7eae1ca2a4a528eb6e"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/LLHTJUNGY3V2HVB67CWJYSK4TE/bundle.json","state_url":"https://pith.science/pith/LLHTJUNGY3V2HVB67CWJYSK4TE/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/LLHTJUNGY3V2HVB67CWJYSK4TE/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":"2026-05-31T10:57:25Z","links":{"resolver":"https://pith.science/pith/LLHTJUNGY3V2HVB67CWJYSK4TE","bundle":"https://pith.science/pith/LLHTJUNGY3V2HVB67CWJYSK4TE/bundle.json","state":"https://pith.science/pith/LLHTJUNGY3V2HVB67CWJYSK4TE/state.json","well_known_bundle":"https://pith.science/.well-known/pith/LLHTJUNGY3V2HVB67CWJYSK4TE/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:LLHTJUNGY3V2HVB67CWJYSK4TE","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":"2a4b7ac539eac5cf8be2eb276f341e5aef0f770fb3cc065d209e8fd9f444a885","cross_cats_sorted":["astro-ph.GA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-04-29T20:00:00Z","title_canon_sha256":"ccbc551d4c669e3fb4bcf1135da3fc7e8b756691df948878db2696553ad956f3"},"schema_version":"1.0","source":{"id":"1304.7769","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1304.7769","created_at":"2026-05-18T01:50:14Z"},{"alias_kind":"arxiv_version","alias_value":"1304.7769v1","created_at":"2026-05-18T01:50:14Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1304.7769","created_at":"2026-05-18T01:50:14Z"},{"alias_kind":"pith_short_12","alias_value":"LLHTJUNGY3V2","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_16","alias_value":"LLHTJUNGY3V2HVB6","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_8","alias_value":"LLHTJUNG","created_at":"2026-05-18T12:27:51Z"}],"graph_snapshots":[{"event_id":"sha256:501ddb9070a87c3c87e6058c7e032f85f8d9203bb4ecfe7eae1ca2a4a528eb6e","target":"graph","created_at":"2026-05-18T01:50:14Z","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 constraints on the stellar initial mass function (IMF) in two ultra-faint dwarf (UFD) galaxies, Hercules and Leo IV, based on deep HST/ACS imaging. The Hercules and Leo IV galaxies are extremely low luminosity (M_V = -6.2, -5.5), metal-poor (<[Fe/H]>= -2.4, -2.5) systems that have old stellar populations (> 11 Gyr). Because they have long relaxation times, we can directly measure the low-mass stellar IMF by counting stars below the main-sequence turnoff without correcting for dynamical evolution. Over the stellar mass range probed by our data, 0.52 - 0.77 Msun, the IMF is best fit b","authors_text":"D. VandenBerg, E. Kirby, H. Ferguson, J.D. Simon, J. Kalirai, J. Tumlinson, M. Geha, P. Guhathakurta, R. Avila, R.M. Munoz, T.M. Brown","cross_cats":["astro-ph.GA"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-04-29T20:00:00Z","title":"The Stellar Initial Mass Function of Ultra-Faint Dwarf Galaxies: Evidence for IMF Variations with Galactic Environment"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1304.7769","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:fa01fd9842eff35efcb53c772a160c31172d1765db4bb89e7365b6d8f80b5d2c","target":"record","created_at":"2026-05-18T01:50:14Z","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":"2a4b7ac539eac5cf8be2eb276f341e5aef0f770fb3cc065d209e8fd9f444a885","cross_cats_sorted":["astro-ph.GA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-04-29T20:00:00Z","title_canon_sha256":"ccbc551d4c669e3fb4bcf1135da3fc7e8b756691df948878db2696553ad956f3"},"schema_version":"1.0","source":{"id":"1304.7769","kind":"arxiv","version":1}},"canonical_sha256":"5acf34d1a6c6eba3d43ef8ac9c495c990ef852c41ac0890df320b58168aef66d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"5acf34d1a6c6eba3d43ef8ac9c495c990ef852c41ac0890df320b58168aef66d","first_computed_at":"2026-05-18T01:50:14.499536Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:50:14.499536Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"WDojg7JMz8Ch6svcoYujINYxgDPaPjYdAoFmR3iaW3qXMsrjJD4pUQiJ35YtpL2wL9d3/RTVuoP+euJg4q9JCA==","signature_status":"signed_v1","signed_at":"2026-05-18T01:50:14.500015Z","signed_message":"canonical_sha256_bytes"},"source_id":"1304.7769","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:fa01fd9842eff35efcb53c772a160c31172d1765db4bb89e7365b6d8f80b5d2c","sha256:501ddb9070a87c3c87e6058c7e032f85f8d9203bb4ecfe7eae1ca2a4a528eb6e"],"state_sha256":"d9e9867ddece2698083e59fbc0d815e5b18076b3e7fd4c40d5c3e86d07ffc5a8"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"MvpyT6PD0RDR6TAQKB09izzu5BsiQIbcD5nkbYxeGRbEpGQLqUck/lSYGcHAAYt6ibRBEr/HHxJTNY89qLrjAQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-31T10:57:25.176122Z","bundle_sha256":"6b56395d97a7b5e1229fdf4d4a3a9d60bd36ab760930e99eca6cc84ed69ae1f1"}}