Evidence for a receding dust sublimation region around a supermassive black hole

Abstract

The near-IR emission in Type 1 AGNs is thought to be dominated by the thermal radiation from dust grains that are heated by the central engine in the UV/optical and are almost at the sublimation temperature. A brightening of the central source can thus further sublimate the innermost dust, leading to an increase in the radius of the near-IR emitting region. Such changes in radius have been indirectly probed by the measurements of the changes in the time lag between the near-IR and UV/optical light variation. Here we report direct evidence for such a receding sublimation region through the near-IR interferometry of the brightest Type 1 AGN in NGC4151. The increase in radius follows a significant brightening of the central engine with a delay of at least a few years, which is thus the implied destruction timescale of the innermost dust distribution. Compiling historic flux variations and radius measurements, we also infer the reformation timescale for the inner dust distribution to be several years in this galactic nucleus. More specifically and quantitatively, we find that the radius at a given time seems to be correlated with a long-term average of the flux over the previous several (~6) years, instead of the instantaneous flux. Finally, we also report measurements of three more Type 1 AGNs newly observed with the Keck interferometer, as well as the second epoch measurements for three other AGNs.

6 pages, 4 figures, accepted for publication in ApJ Letter

References in corpus (5)

• The characteristic blue spectra of accretion disks in quasars as uncovered in the infrared
• Long-term variability of the optical spectra of NGC 4151: I. Light curves and flux correlations
• Variation of Inner Radius of Dust Torus in NGC4151
• VLTI/AMBER observations of the Seyfert nucleus of NGC 3783
• Constraining properties of dusty environments by infrared variability

Cited by in corpus (44)

• Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies
• Dust inflated accretion disc as the origin of the Broad Line Region in Active Galactic Nuclei
• An image of the dust sublimation region in the nucleus of NGC 1068
• A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151
• The dust sublimation radius as an outer envelope to the bulk of the narrow Fe Kalpha line emission in Type 1 AGN
• Mid-IR Variability and Dust Reverberation Mapping of Low-$z$ Quasars. I. Data, Methods and Basic Results
• Reverberation Measurements of the Inner Radii of the Dust Tori in Quasars
• BASS XXXII: Studying the Nuclear Mm-wave Continuum Emission of AGNs with ALMA at Scales $\lesssim$ 100-200 pc
• Radiation-driven outflows from and radiative support in dusty tori of active galactic nuclei
• Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities
• Cosmology with AGN dust time lags -- Simulating the new VEILS survey
• SPARCO : a semi-parametric approach for image reconstruction of chromatic objects
• Spitzer Space Telescope Measurements of Dust Reverberation Lags in the Seyfert 1 Galaxy NGC 6418
• The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548
• Broadband X-Ray Observations of the 2018 Outburst of the Changing-Look Active Galactic Nucleus NGC 1566
• Rapid Luminosity Decline and Subsequent Reformation of the Innermost Dust Distribution in the Changing-look AGN Mrk 590
• The Dusty Heart of NGC 4151 Revealed by $\lambda \sim$1-40 $\mu$m Reverberation Mapping and Variability: A Challenge to Current Clumpy Torus Models
• The post-maximum behaviour of the changing-look Seyfert galaxy NGC 1566
• Dust reverberation mapping in the era of big optical surveys and its cosmological application
• Simultaneous H alpha and dust reverberation mapping of 3C120: Testing the bowl-shaped torus geometry
• Modeling the Infrared Reverberation Response of the Circumnuclear Dusty Torus in AGN: The Effects of Cloud Orientation and Anisotropic Illumination
• Detection of the Intermediate-width Emission Line Region in Quasar OI 287 with the Broad Emission Line Region Obscured by the Dusty Torus
• Reaching the Peak of the quasar spectral energy distribution - II. Exploring the accretion disc, dusty torus and host galaxy
• Monitoring the temperature and reverberation delay of the circumnuclear hot dust in NGC 4151
• X-ray polarimetric signatures induced by spectral variability in the framework of the receding torus model
• Interpreting broad emission-line variations II: Tensions between luminosity, characteristic size and responsivity
• Imaging the AGN Torus in Cygnus
• VLTI/GRAVITY Interferometric Measurements of Innermost Dust Structure Sizes around AGNs
• Parsec-scale obscuring accretion disk with large scale magnetic field in AGN
• Using the Properties of Broad Absorption Line Quasars to Illuminate Quasar Structure
• The dust sublimation region of the Type 1 AGN NGC4151 at a hundred micro-arcsecond scale as resolved by the CHARA Array interferometer
• Dust in the Torus of the AGN Unified Model
• Gamma-Ray Emission in the Seyfert Galaxy NGC 4151: Investigating the Role of Jet and Coronal Activities
• Infrared Interferometry and AGNs: Parsec-scale Disks and Dusty Outflows
• An Extraordinary Response of Iron Emission to the Central Outburst in a Tidal Disruption Event Candidate
• The Relative Wavelength Independence of IR Time Lags in NGC4151 During the Years 2010-2015
• Changing looks of the nucleus of the Seyfert galaxy NGC 1566 compared with other changing-look AGNs
• Modeling the Vertical Structure of Nuclear Starburst Discs: A Possible Source of AGN Obscuration at $z\sim 1$
• Dust Reverberation Mapping and Light-Curve Modelling of Zw229-015
• Hot graphite dust in the inner regime of NGC 4151
• Detection of eccentric close-binary supermassive black holes with incomplete interferometric data
• Ultraviolet Fe II Emission in Fainter Quasars: Luminosity Dependences, and the Influence of Environments
• Strong Optical and UV Intermediate-Width Emission Lines in the Quasar SDSS J232444.80-094600.3: Dust-Free and Intermediate-Density Gas at the Skin of Dusty Torus ?
• The first spectroscopic IR reverberation programme on Mrk 509