Disappearing Broad lines in Active Galaxies?

ORAL

Abstract

Active galactic nuclei (AGN) are among the most luminous objects in the universe, and consequently can be studied at large distances. It is therefore of importance to understand both the mechanism and potential time variation of the behavior of these objects. Broad emission lines in spectra from these objects can be used to measure the mass of the supermassive black hole believed to lie at the heart of these galaxies. A sample of approximately 100 AGN in the local universe were observed using the Keck I telescope in order to to estimate black hole masses and to measure stellar velocity dispersions. Of these objects in the survey, all of which had previously been classified according to the characteristic presence of broad emission lines as type I AGN from Sloan Digital Sky Survey spectra, six surprisingly seem to lack broad emission lines in the Keck spectra taken a few years later. We present analysis of the Keck and SDSS spectra and discuss possible implications for our understanding how AGN spectra vary with time, and consequently, the mechanism underlying AGN emission.

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Authors

  • Bryan Scott

    California Polytechnic State University, San Luis Obispo

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department