{"paper":{"title":"Chandra's Discovery of Activity in the Quiescent Nuclear Black Hole of NGC 821","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"A. Baldi, A. Siemiginowska, A. Zezas, G. Fabbiano, J. McDowell, M. Elvis, S. Pellegrini","submitted_at":"2004-05-18T21:14:25Z","abstract_excerpt":"We report the results of the {\\it Chandra} ACIS-S observations of the elliptical galaxy NGC 821, which harbors a supermassive nuclear black hole (of $3.5 \\times 10^7 M_{\\odot}$), but does not show sign of AGN activity. A small, 8.5$^{\\prime\\prime}$ long ($\\sim 1$ kpc at the galaxy's distance of 23 Mpc), S-shaped, jet-like feature centered on the nucleus is detected in the 38 ksec ACIS-S integrated exposure of this region. The luminosity of this feature is $L_X \\sim 2.6 \\times 10^{39} \\rm ergs s^{-1}$ (0.3-10 keV), and its spectrum is hard (described by a power-law of $\\Gamma = 1.8^{+0.7}_{-0.6"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0405358","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"}