| The Warped nuclear disk of radio galaxy 3C 449 (2006) | |||||||||||||||
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| Accepted for publication ApJ Preprint typeset using TEX style emulateapj THE WARPED NUCLEAR DISK RADIO GALAXY Grant Tremblay Alice Quillen David Floyd Jacob Noel Storr Stefi Baum David Axon Christopher Dea Marco Chiaberge Duccio Macchetto William Sparks George Miley Alessandro Capetti Juan Madrid and Eric Perlman Accepted for publication ApJ arXiv astro Jan ABSTRACT Among radio galaxies containing nuclear dust disks the bipolar jet axis generally observed perpendicular the disk major axis The radio source outlier this statistical majority possesses nearly parallel jet disk orientation the sky examine the dusty disk this galaxy with images from the Hubble Space Telescope find that colormap the disk exhibits twist its isocolor contours isochromes model the colormap integrating galactic starlight through absorptive disk and find that the anomalous twist the isochromes can reproduced the model with vertically thin warped disk The model predicts that the disk nearly perpendicular the jet axis within the nucleus discuss physical mechanisms capable causing such warp show that precessional models torque the disk arising from possible binary black hole the AGN causes precession timescale that too long account for the predicted disk morphology However estimate that the pressure the ray emitting interstellar medium large enough perturb the disk and argue that jet driven anisotropy the excited ISM may the cause the warp this way the warped disk may new manifestation feedback from active . Among radio galaxies containing nuclear dust disks, the bipolar jet axis is generally observed to be perpendicular to the disk major axis. The FR I radio source 3C 449 is an outlier to this statistical majority, as it possesses a nearly parallel jet/disk orientation on the sky. We examine the 600 pc dusty disk in this galaxy with images from the Hubble Space Telescope. We find that a 1.6 µm/0.7 µm colormap of the disk exhibits a twist in its isocolor contours (isochromes). We model the colormap by integrating galactic starlight through an absorptive disk, and find that the anomalous twist in the isochromes can be reproduced in the model with a vertically thin, warped disk. The model predicts that the disk is nearly perpendicular to the jet axis within 100 pc of the nucleus. We discuss physical mechanisms capable of causing such a warp. We show that precessional models or a torque on the disk arising from a possible binary black hole in the AGN causes precession on a timescale that is too long to account for the predicted disk morphology. However, we estimate that the pressure in the X-ray emitting interstellar medium is large enough to perturb the disk, and argue that jet-driven anisotropy in the excited ISM may be the cause of the warp. In this way, the warped disk in 3C 449 may be a new manifestation of feedback from an active galactic nucleus. (Refer to PDF file for exact formulas).. This work was based on observations with the NASA/ESA Hubble Space Telescope, obtained in collaboration with the Space Telescope Science Institute (STScI), operated by AURA for NASA. Support for this work was provided by NASA/STScI through grant HSTGO- 10173. G. R. T. and A. C. Q. acknowledge support in part by NSF awards AST-0406823, PHY-0242483, and NASA/STScI grant HST-GO-10173.09-A. This research has made extensive use of the NASA Astrophysics Data System (ADS) and the NASA/IPAC Extragalactic Database (NED), operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. | |||||||||||||||
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