{'fraction_non_alphanumeric': 0.020887728459530026, 'fraction_numerical': 0.02610966057441253, 'mean_word_length': 4.2534246575342465, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
STIS Spectroscopy of the Central 10 Parsecs of M81: Evidence for a Massive Black Hole

Spectroscopic observations of the central 10 pc of M81 were obtained with STIS on board the Hubble Space Telescope during Cycle 7. Measurements of the Hα+[N II] blend reveal a velocity field indicative of a rotating disk of gas. The two-dimensional velocity field has been modeled as a thin disk rotating in a spherical gravitational potential. Minimizing the difference between the model and the observations allows useful constraints to be placed on the mass of the black hole in this mini Seyfert 1 galaxy. The data suggest that the mass of the nuclear black hole in M81 is 7.0 × 107 M⊙ and that the normal to the disk is inclined at an angle of 14° ± 2° to the line of sight.