Browsing by Author "Williams, Jonathan"

Now showing 1 - 4 of 4
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    BASS. XXII. The BASS DR2 AGN Catalog and Data
    (2022) Koss, Michael J. ; Ricci, Claudio ; Trakhtenbrot, Benny ; Oh, Kyuseok ; den Brok, Jakob S. ; Mejía-Restrepo, Julian E. ; Stern, Daniel ; Privon, George C. ; Treister, Ezequiel ; Powell, Meredith C.; Mushotzky, Richard ; Bauer, Franz Erik; Ananna, Tonima T. ; Baloković, Mislav ; Bär, Rudolf ; Becker, George ; Bessiere, Patricia ; Burtscher, Leonard ; Caglar, Turgay ; Congiu, Enrico ; Evans, Phil ; Harrison, Fiona ; Heida, Marianne ; Ichikawa, Kohei ; Kamraj, Nikita; Lamperti, Isabella; Pacucci, Fabio ; Ricci, Federica ; Riffel, Rogério; Rojas, Alejandra F. ; Schawinski, Kevin ; Temple, Matthew J. ; Urry, C. Megan ; Veilleux, Sylvain ; Williams, Jonathan
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    Resolving the FU Orionis System with ALMA: Interacting Twin Disks?
    (2020) Perez, Sebastian; Hales, Antonio; Liu, Hauyu Baobab; Zhu, Zhaohuan; Casassus, Simon; Williams, Jonathan; Zurlo, Alice; Cuello, Nicolas; Cieza, Lucas; Principe, David
    FU Orionis objects are low-mass pre-main sequence stars characterized by dramatic outbursts several magnitudes in brightness. These outbursts are linked to episodic accretion events in which stars gain a significant portion of their mass. The physical processes behind these accretion events are not yet well understood. The archetypal FU Ori system, FU Orionis, is composed of two young stars with detected gas and dust emission. The continuum emitting regions have not been resolved until now. Here, we present 1.3 mm observations of the FU Ori binary system using the Atacama Large Millimeter/submillimeter Array. The disks are resolved at 40 mas resolution. Radiative transfer modeling shows that the emission from FU Ori north (primary) is consistent with a dust disk with a characteristic radius of similar to 11 au. The ratio between the major and minor axes shows that the inclination of the disk is similar to 37 degrees. FU Ori south is consistent with a dust disk of similar inclination and size. Assuming the binary orbit shares the same inclination angle as the disks, the deprojected distance between the north and south components is 06, i.e., similar to 250 au. Maps of (CO)-C-12 emission show a complex kinematic environment with signature disk rotation at the location of the northern component, and also (to a lesser extent) for FU Ori south. The revised disk geometry allows us to update FU Ori accretion models, yielding a stellar mass and mass accretion rate of FU Ori north of 0.6 M and 3.8 x 10(-5) M yr(-1), respectively.
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    Statin Use and Adrenal Aldosterone Production in Hypertensive and Diabetic Subjects
    (2015) Baudrand Biggs, René; Pojoga, Luminita H.; Vaidya, Anand; Garza, Amanda; Vohringer, Paul A.; Jeunemaitre, Xavier; Hopkins, Paul N.; Yao, Tham M.; Williams, Jonathan; Adler, Gail K.; Williams, Gordon H.
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    UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation
    (2023) Koss, Michael J.; Treister, Ezequiel; Kakkad, Darshan; Casey-Clyde, J. Andrew; Kawamuro, Taiki; Williams, Jonathan; Foord, Adi; Trakhtenbrot, Benny; Bauer, Franz E.; Privon, George C.; Ricci, Claudio; Mushotzky, Richard; Barcos-Munoz, Loreto; Blecha, Laura; Connor, Thomas; Harrison, Fiona; Liu, Tingting; Magno, Macon; Mingarelli, Chiara M. F.; Muller-Sanchez, Francisco; Oh, Kyuseok; Shimizu, T. Taro; Smith, Krista Lynne; Stern, Daniel; Tello, Miguel Parra; Urry, C. Megan
    We present multiwavelength high-spatial resolution (similar to 0 ? 1, 70 pc) observations of UGC 4211 at z = 0.03474, a late-stage major galaxy merger at the closest nuclear separation yet found in near-IR imaging (0 " 32, similar to 230 pc projected separation). Using Hubble Space Telescope/Space Telescope Imaging Spectrograph, Very Large Telescope/MUSE+AO, Keck/OSIRIS+AO spectroscopy, and the Atacama Large Millimeter/submillimeter Array (ALMA) observations, we show that the spatial distribution, optical and near-infrared emission lines, and millimeter continuum emission are all consistent with both nuclei being powered by accreting supermassive black holes (SMBHs). Our data, combined with common black hole mass prescriptions, suggest that both SMBHs have similar masses, log (M-BH M-?) similar to 8.1 (south) and log (M-BH M-?) similar to 8.3 (north), respectively. The projected separation of 230 pc (similar to 6x the black hole sphere of influence) represents the closest-separation dual active galactic nuclei (AGN) studied to date with multiwavelength resolved spectroscopy and shows the potential of nuclear (< 50 pc) continuum observations with ALMA to discover hidden growing SMBH pairs. While the exact occurrence rate of close-separation dual AGN is not yet known, it may be surprisingly high, given that UGC 4211 was found within a small, volume-limited sample of nearby hard X-ray detected AGN. Observations of dual SMBH binaries in the subkiloparsec regime at the final stages of dynamical friction provide important constraints for future gravitational wave observatories.