{'fraction_non_alphanumeric': 0.02556580050293378, 'fraction_numerical': 0.00586756077116513, 'mean_word_length': 5.152061855670103, '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}}
Kennicutt The Structure and Energetics of Active Galactic Nuclei

The black-hole/accretion-disk paradigm for active galactic nuclei (AGNs) is now reasonably secure, but there are still important unresolved issues, some of which will require the capabilities of an 8 to 10-m class UV/optical space-based telescope. Imaging spectroscopy with a diffraction-limited large telescope will be required to measure AGN black-hole masses from stellar dynamics for direct comparison with reverberation mapping-based masses. High spectral resolution in the UV is required to determine the mass and kinetic energy of the outflows observed in the absorption spectra of AGNs and to understand the energetics of the accretion process. As with ground-based astronomy, however, effective use of a large UV/optical space telescope requires complementary smaller facility instruments; a meter-class UV spectroscopic telescope, for example, can fit into a Medium Explorer budget. 1. Key Questions in AGN Astrophysics Not long after the discovery of quasars, it was realized that the fundamental source of energy for these objects must in fact be gravitation, and fairly straightforward arguments led to the long-standing paradigm of a supermassive black hole (SMBH) surrounded by an accretion disk. Observational evidence has been rather ambiguous, although there were early strong clues, such as the near-UV/optical “big blue bump” (Shields 1978; Malkan & Sargent 1982) and the rapid X-ray variability, that supported the model if only because they defied other explanation. But it is only within the last several years that the circumstantial evidence has accumulated to the point that few doubters remain. While there is now general, though not unanimous, agreement about the fundamental nature of AGNs, we cannot claim any real understanding of the quasar phenomenon until we successfully address a number of key questions, including the following: 1. What are the masses of AGN black holes? As described below, we are making progress, but there are still areas where our understanding is dangerously incomplete, especially with regard to the magnitude of possible systematic errors. 2. What are the energetics of the accretion process? In particular, for the various types of AGNs what are the accretion rates and radiative efficiencies and how do these scale with luminosity? How much of the output is