{"paper":{"title":"VLBI for Gravity Probe B: The Guide Star IM Pegasi","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.IM","gr-qc"],"primary_cat":"astro-ph.SR","authors_text":"D. E. Lebach, I. I. Shapiro, M. F. Bietenholz, M. I Ratner, N. Bartel, R. R Ransom","submitted_at":"2015-09-24T20:27:47Z","abstract_excerpt":"We review the radio very long baseline interferometry (VLBI) observations of the guide star, IM Peg, and three compact extragalactic reference sources, 3C 454.3, B2250+194, and B2252+172, made in support of the NASA/Stanford gyroscope relativity mission, GP-B. The main goal of the observations was the determination of the proper motion of IM Peg relative to the distant universe. VLBI observations made between 1997 and 2005 yield a proper motion of IM Peg of -20.83 $\\pm$ 0.09 mas yr$^{-1}$ in RA and -27.27 $\\pm$ 0.09 mas yr$^{-1}$ in dec, in a celestial reference frame of extragalactic radio ga"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1509.07529","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"}