Indecent Exposure in Seyfert 2 Galaxies: A Close Look

Abstract

NGC 3147, NGC 4698 and 1ES 1927+654 are active galaxies that are classified as Seyfert 2s, based on the line ratios of strong narrow emission lines in their optical spectra. However, they exhibit rapid X-ray spectral variability and/or little indication of obscuration in X-ray spectral fitting, contrary to expectation from the active galactic nucleus (AGN) unification model. Using optical spectropolarimetry with LRIS and near-infrared spectroscopy with NIRSPEC at the W. M. Keck Observatory, we conducted a deep search for hidden polarized broad H-alpha and direct broad Pa-beta or Br-gamma emission lines in these objects. We found no evidence for any broad emission lines from the active nucleus of these galaxies, suggesting that they are unobscured, completely "naked" AGNs that intrinsically lack broad-line regions.

5 pages in emulateapj; ApJL vol. 726, 2011 January 10; v2: minor cosmetic corrections to text to match published version

References in corpus (38)

• A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
• A Method of Correcting Near-Infrared Spectra for Telluric Absorption
• The AGN Obscuring Torus -- End of the "Doughnut" Paradigm?
• A 3 dimensional diagnostic diagram for Seyfert 2s: probing X-ray absorption and Compton thickness
• Chandra Snapshot Observations of Low-Luminosity AGNs with a Compact Radio Source
• Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies
• Occultation measurement of the size of the X-ray emitting region in the Active Galactic Nucleus of NGC 1365
• Broad Emission Line Regions in AGN: the Link with the Accretion Power
• On the Disappearance of the Broad-Line Region in Low-Luminosity Agns
• A 0.8-2.4 microns spectral atlas of Active Galactic Nuclei
• Hidden Broad Line Seyfert 2 Galaxies in the CfA and 12micron Samples
• Unabsorbed Seyfert 2 galaxies
• The Unified Model & Evolution of Active Galaxies: Implications from a Spectropolarimetric Study
• The Lack of BLR in Low Accretion Rate AGN as Evidence of their Origin in the Accretion Disk
• On The Nature of Low Luminosity Narrow Line AGN
• Why X-ray--Selected AGN Appear Optically Dull
• Scattered Nuclear Continuum and Broad H-alpha in Cygnus A
• The X-ray spectra of optically selected Seyfert 2 galaxies. Are there any Sy2 galaxies with no absorption?
• The Unified Model of Active Galactic Nuclei: II. Evolutionary Connection
• XMM-Newton observations of Seyfert galaxies from the Palomar spectroscopic survey: the X-ray absorption distribution
• Unobscured Type 2 AGNs
• Weak-Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-Line Regions?
• Constraints for the accretion disk evaporation rate in AGN from the existence of the Broad Line Region
• The Nature of Optically Dull Active Galactic Nuclei in COSMOS
• The Unified Model of Active Galactic Nuclei: I. Non-hidden Broad Line Region Seyfert 2 and Narrow Line Seyfert 1 Galaxies
• On the nature of unabsorbed Seyfert 2 galaxies
• NGC3147: a "true" Seyfert 2 without the broad-line region
• Unabsorbed Seyfert 2 galaxies: the case of "naked" AGN
• Naked active galactic nuclei
• Type 2 counterparts of narrow-line Seyfert 1 galaxies
• 1ES 1927+654: Persistent and rapid X-ray variability in an AGN with low intrinsic neutral X-ray absorption and narrow optical emission lines
• A Polarimetric Search for Hidden Quasars in Three Radio Selected Ultraluminous Infrared Galaxies
• Chandra observations of NGC4698: a Seyfert-2 with no absorption
• VISIR/VLT mid-infrared imaging of Seyfert nuclei: Nuclear dust emission and the Seyfert-2 dichotomy
• A Chandra view of Naked Active Galactic Nuclei
• On the disappearance of broad-line region in low-luminosity active galactic nuclei: the role of the outflows from advection dominated accretion flows
• Hidden Double-Peaked Emitters in Seyfert 2 Galaxies
• XMM Observations of the Seyfert 2 Galaxy NGC 7590: the Nature of X-ray Absorption

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• 1ES 1927+654: An AGN Caught Changing Look on a Timescale of Months
• Type 1 low z AGN. I. Emission properties
• Type 1 AGN at low z. II. The relative strength of narrow lines and the nature of intermediate type AGN
• On the difference of torus geometry between hidden and non-hidden broad line active galactic nuclei
• Modeling optical and UV polarization of AGNs II. Polarization imaging and complex reprocessing
• The Nuclear Near-Infrared Spectral Properties of Nearby Galaxies
• Detection of Rest-frame Optical Lines from X-shooter Spectroscopy of Weak Emission Line Quasars
• The 450 days X-ray monitoring of the changing-look AGN 1ES 1927+654
• Star formation in the local Universe from the CALIFA sample. II. Activation and quenching mechanisms in bulges, bars, and disks
• Simultaneous X-ray and optical observations of true Type 2 Seyfert galaxies
• The Host Galaxy and Rapidly Evolving Broad-line Region in the Changing-look Active Galactic Nucleus 1ES 1927+654
• Disk Outflows and High-Luminosity True Type 2 AGN
• Testing Black Hole Jet Scaling Relations in Low Luminosity AGN
• HST unveils a compact mildly relativistic Broad Line Region in the candidate true type 2 NGC 3147
• The Low-mass, Highly Accreting Black Hole Associated with the Active Galactic Nucleus 2XMM J123103.2+110648
• Evolution of a Relativistic Outflow and X-ray Corona in the Extreme Changing-Look AGN 1ES 1927+654
• Upholding the Unified Model for Active Galactic Nuclei: VLT/FORS2 Spectropolarimetry of Seyfert 2 galaxies
• The Different Nature in Seyfert 2 Galaxies With and Without Hidden Broad-Line Regions
• 1ES 1927+654: a bare Seyfert 2
• A Search for Optical Variability of Type 2 Quasars in SDSS Stripe 82
• Is IRAS 01072+4954 a True-Seyfert 2? Hints from Near Infrared Integral Field Spectroscopy
• The Type 1 and Type 2 AGN dichotomy according to their ZTF optical variability
• Optically-Selected BLR-less Active Galactic Nuclei from the SDSS Stripe82 Database I: The Sample
• A Cigale module tailored (not only) for Low-Luminosity AGN
• A new sample of X-ray selected narrow emission-line galaxies. II. Looking for True Seyfert 2
• A panchromatic review of thermal and nonthermal active galactic nuclei
• Multiple Flares in the Changing-Look AGN NGC 5273
• A unique X-ray unabsorbed Seyfert 2 galaxy IRAS F01475-0740
• The Suzaku X-ray spectrum of NGC 3147. Further insights on the best "true" Seyfert 2 galaxy candidate
• The NuSTAR view of the true Type 2 Seyfert NGC3147
• Correcting systematic polarization effects in Keck LRISp spectropolarimetry to <0.05%
• TESS Shines Light on the Origin of the Ambiguous Nuclear Transient ASASSN-18el
• Stellar Properties of the Host Galaxy of an Ultraluminous X-ray Source in NGC 5252
• NGC 3147: a prototypical low-luminosity active galactic nucleus with double-peaked optical and ultraviolet lines
• Ionization Mechanisms of HBLR and Non-HBLR Seyfert 2 Galaxies
• Optical spectroscopic classification of 35 hard X-ray sources from the Swift-BAT 70-month catalogue
• SDSS-IV MaNGA: Identification and Multiwavelength Properties of Type-1 AGN in the DR15 sample
• The Broadband X-ray Spectrum of the X-ray Obscured Type 1 AGN 2MASX J193013.80+341049.5
• A Systematic Study of the Short-Term X-ray Variability of Seyfert Galaxies I. Diversity of the X-ray Rms Spectra
• The X-ray Nature of Nucleus in Seyfert 2 Galaxy NGC 7590
• Suzaku Confirms NGC~3660 is an Unabsorbed Seyfert 2
• A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states