Broad-line region structure and line profile variations in the changing look AGN HE1136-2304

Abstract

A strong X-ray outburst was detected in HE1136-2304 in 2014. Accompanying optical spectra revealed that the spectral type has changed from a nearly Seyfert 2 type (1.95), classified by spectra taken 10 and 20 years ago, to a Seyfert 1.5 in our most recent observations. We seek to investigate a detailed spectroscopic campaign on the spectroscopic properties and spectral variability behavior of this changing look AGN and compare this to other variable Seyfert galaxies. We carried out a detailed spectroscopic variability campaign of HE1136-2304 with the 10 m Southern African Large Telescope (SALT) between 2014 December and 2015 July. The broad-line region (BLR) of HE1136-2304 is stratified with respect to the distance of the line-emitting regions. The integrated emission line intensities of Halpha, Hbeta, HeI 5876, and HeII 4686 originate at distances of 15.0 (+4.2,-3.8), 7.5 (+4.6,-5.7), 7.3 (+2.8,-4.4), and 3.0 (+5.3,-3.7) light days with respect to the optical continuum at 4570AA. The variability amplitudes of the integrated emission lines are a function of distance to the ionizing continuum source as well. We derived a central black hole mass of 3.8 (+-3.1) 10exp(7) M_solar based on the line widths and distances of the BLR. The outer line wings of all BLR lines respond much faster to continuum variations indicating a Keplerian disk component for the BLR. The response in the outer wings is about two light days shorter than the response of the adjacent continuum flux with respect to the ionizing continuum flux. The vertical BLR structure in HE1136-2304 confirms a general trend that the emission lines of narrow line active galactic nuclei (AGNs) originate at larger distances from the midplane in comparison to AGNs showing broader emission lines. Otherwise, the variability behavior of this changing look AGN is similar to that of other AGN.

arXiv comment21 pages, 33 figures

References in corpus (46)

• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• A Cosmology Calculator for the World Wide Web
• The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
• Supermassive Black Holes in Active Galactic Nuclei. II. Calibration of the M-sigma Relationship for AGNs
• An expanded M_bh-sigma diagram, and a new calibration of active galactic nuclei masses
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies
• A Systematic Search for Changing-Look Quasars in SDSS
• Space Telescope and Optical Reverberation Mapping Project. III. Optical Continuum Emission and Broad-Band Time Delays in NGC 5548
• Space Telescope and Optical Reverberation Mapping Project. II. Swift and HST Reverberation Mapping of the Accretion Disk of NGC 5548
• Optical Continuum and Emission-Line Variability of Seyfert 1 Galaxies
• Completion of a Survey and Detailed Study of Double-Peaked Emission Lines in Radio-Loud AGNs
• What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
• Reverberation Mapping Results for Five Seyfert 1 Galaxies
• Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
• AGN Type-casting: Mrk 590 No Longer Fits the Role
• The Structure of the Broad Line Region in AGN: I. Reconstructed Velocity-Delay Maps
• What broad emission lines tell us about how active galactic nuclei work
• Diverse Broad Line Region Kinematic Signatures From Reverberation Mapping
• Accretion disk wind in the AGN broad-line region: Spectroscopically resolved line profile variations in Mrk110
• Discovery of superstrong, fading, iron line emission and double-peaked Balmer lines of the galaxy SDSSJ0952+2143 - the light echo of a huge flare
• Evolution of the Nuclear Accretion Disk Emission in NGC 1097: Getting Closer to the Black Hole
• Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-Line Analysis for NGC 5548
• The Lick AGN Monitoring Project: Velocity-Delay Maps from the Maximum-Entropy Method for Arp 151
• The broad emission-line region: the confluence of the outer accretion disc with the inner edge of the dusty torus
• Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. VI. Velocity-resolved Reverberation Mapping of H$\beta$ Line
• Long-Term Profile Variability of Double Peaked Emission Lines in Active Galactic Nuclei
• Double-peaked profiles: ubiquitous signatures of disks in the Broad Emission Lines of Active Galactic Nuclei
• The Lick AGN Monitoring Project 2011: Reverberation Mapping of Markarian 50
• The shape of broad-line profiles in AGN
• The detection and X-ray view of the changing look AGN HE 1136-2304
• Short-term emission line and continuum variations in Mrk110
• Spectral optical monitoring of 3C390.3 in 1995-2007: I. Light curves and flux variation of the continuum and broad lines
• Photometric Reverberation Mapping of the Broad Emission Line Region in Quasars
• Vertical broad-line region structure in nearby active galactic nuclei
• On the Scatter in the Radius - Luminosity Relationship for Active Galactic Nuclei
• Determination of the Central Mass in Active Galactic Nuclei Using Cross-Correlation Lags and Velocity Dispersions
• Broad-line region structure and kinematics in the radio galaxy 3C 120
• Geometry and Kinematics in the Central Broad-Line Region of a Seyfert 1 Galaxy
• Long-term optical, UV, and X-ray continuum variations in the changing-look AGN HE 1136-2304
• Accretion disk wind as explanation for the broad-line region structure in NGC 5548
• The location of the dust causing internal reddening of active galactic nuclei
• Spectral optical monitoring of a double-peaked emission line AGN Arp 102B: I. Variability of spectral lines and continuum
• Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926

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• Long-term optical, UV, and X-ray continuum variations in the changing-look AGN HE 1136-2304
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• Investigating Changing-Look Active Galactic Nuclei with Long-term Optical and X-Ray Observations
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