scholarly journals Mid-infrared microlensing of accretion disc and dusty torus in quasars: effects on flux ratio anomalies

2013 ◽  
Vol 553 ◽  
pp. A53 ◽  
Author(s):  
D. Sluse ◽  
M. Kishimoto ◽  
T. Anguita ◽  
O. Wucknitz ◽  
J. Wambsganss
Keyword(s):  
Flux Ratio ◽  
Accretion Disc ◽  
Mid Infrared ◽  
Dusty Torus

scholarly journals Hyperaccretion

2006 ◽  
Vol 2 (S238) ◽  
pp. 31-36
Author(s):  
Andrew R. King
Keyword(s):  
Electron Scattering ◽  
Stellar Mass ◽  
Accretion Disc ◽  
Close Binaries ◽  
X Ray ◽  
Eddington Limit ◽  
Dusty Torus ◽  
Toroidal Geometry

AbstractAccretion at rates exceeding the Eddington limit is common in close binaries. I summarize the arguments leading to the conclusion that such stellar–mass systems appear as ultraluminous X-ray sources when viewed close the the inner accretion disc axis, and like SS433 when viewed from other angles.I show that AGN are unlikely to achieve electron–scattering Eddington ratios as high as ULXs, so there are few ULX analogues among quasars. However hyperaccretion of dusty matter is common among AGN. The resulting outflow naturally has a toroidal geometry, and may well be the origin of the dusty torus invoked in unified AGN schemes.

scholarly journals Exploring the Mid-infrared SEDs of Six AGN Dusty Torus Models. II. The Data

2019 ◽  
Vol 884 (1) ◽  
pp. 11 ◽  
Author(s):  
Omaira González-Martín ◽  
Josefa Masegosa ◽  
Ismael García-Bernete ◽  
Cristina Ramos Almeida ◽  
José Miguel Rodríguez-Espinosa ◽  
...  
Keyword(s):  
Mid Infrared ◽  
Dusty Torus

scholarly journals A mid-infrared exploration of the dusty environments of active galactic nuclei

2013 ◽  
Vol 9 (S304) ◽  
pp. 44-47
Author(s):  
Almudena Alonso-Herrero
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Mid Infrared ◽  
Full Sample ◽  
Star Formation Activity ◽  
First Results ◽  
Dusty Torus ◽  
Infrared Survey

AbstractWe present the first results from a mid-infrared survey of local Active Galactic Nuclei (AGN) using the CanariCam (CC) instrument on the 10.4 m Gran Telescopio Canarias (GTC). We are obtaining sub-arcsecond angular resolution (0.3 − 0.6 arcsec) mid-IR imaging and spectroscopic observations of a sample of 100 local AGN, which are complemented with data taken with T-ReCS, VISIR, and Michelle. The full sample contains approximately 140 AGN, covers nearly six orders of magnitude in AGN luminosity, and includes low-luminosity AGN (LLAGN), Seyfert 1s and 2s, QSO, radio galaxies, and (U)LIRGs. The main goals of this project are: (1) to test whether the properties of the dusty tori of the AGN Unified Model depend on the AGN type, (2) to study the nuclear star formation activity and obscuration of local AGN, and (3) to explore the role of the dusty torus in LLAGN.

scholarly journals Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy

2016 ◽  
Vol 465 (1) ◽  
pp. 358-382 ◽  
Author(s):  
James S. Collinson ◽  
Martin J. Ward ◽  
Hermine Landt ◽  
Chris Done ◽  
Martin Elvis ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Accretion Disc ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Dusty Torus

scholarly journals Accretion rate in AGN and X-ray-to-optical flux ratio at z ≤ 0.2

2019 ◽  
Vol 15 (S356) ◽  
pp. 314-316
Author(s):  
Asrate Gaulle ◽  
Mirjana Pović ◽  
Dejene Zewdie
Keyword(s):  
Accretion Rate ◽  
Flux Ratio ◽  
Accretion Disc ◽  
Active Galaxies ◽  
X Ray ◽  
Using Data ◽  
Two Parameters ◽  
Optical Flux

AbstractWe explored a sample of 545 local galaxies using data from the 3XMM-DR7 and SDSS-DR8 surveys. We carried out all analyses up to z ˜ 0.2, and we studied the relation between X/O flux ratio and accretion rate for different classes of active galaxies such as LINERs and Seyfert 2. We obtained a slight correlation between the two parameters if the whole sample of AGN is used. However, LINERs and Sy2 galaxies show different properties, slight correlation and slight anti-correlation, respectively. This could confirm that LINERs and Sy2 galaxies have different accretion efficiencies and maybe different accretion disc properties, as has been suggested previously.

scholarly journals Exploring the Mid-infrared SEDs of Six AGN Dusty Torus Models. I. Synthetic Spectra

2019 ◽  
Vol 884 (1) ◽  
pp. 10 ◽  
Author(s):  
Omaira González-Martín ◽  
Josefa Masegosa ◽  
Ismael García-Bernete ◽  
Cristina Ramos Almeida ◽  
José Miguel Rodríguez-Espinosa ◽  
...  
Keyword(s):  
Mid Infrared ◽  
Synthetic Spectra ◽  
Dusty Torus

New Mid‐Infrared Diagnostic of the Dusty Torus Model for Seyfert Nuclei

2000 ◽  
Vol 528 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Takashi Murayama ◽  
Hideaki Mouri ◽  
Yoshiaki Taniguchi
Keyword(s):  
Mid Infrared ◽  
Dusty Torus

scholarly journals Towards a new paradigm of dust structure in AGN: Dissecting the mid-IR emission of Circinus galaxy

2019 ◽  
Vol 15 (S356) ◽  
pp. 50-55
Author(s):  
Marko Stalevski ◽  
Daniel Asmus ◽  
Konrad R. W. Tristram
Keyword(s):  
Active Galactic Nuclei ◽  
Large Scale ◽  
Dust Emission ◽  
Galactic Nuclei ◽  
Polar Regions ◽  
New Paradigm ◽  
Mid Infrared ◽  
Small Scales ◽  
Ir Emission ◽  
Dusty Torus

AbstractRecent mid-infrared (MIR) observations of nearby active galactic nuclei (AGN), revealed that their dust emission appears prominently extended in the polar direction, at odds with the expectations from the canonical dusty torus. This polar dust, tentatively associated with dusty winds driven by radiation pressure, is found to have a major contribution to the MIR flux from a few to hundreds of parsecs. One such source with a clear detection of polar dust is a nearby, well-known AGN in the Circinus galaxy. We proposed a phenomenological model consisting of a compact, thin dusty disk and a large-scale polar outflow in the form of a hyperboloid shell and demonstrated that such a model is able to explain the peculiar MIR morphology on large scales seen by VLT/VISIR and the interferometric data from VLTI/MIDI that probe the small scales. Our results call for caution when attributing dust emission of unresolved sources entirely to the torus and warrant further investigation of the MIR emission in the polar regions of AGN.

scholarly journals A New MIR/submm Diagnostic for Dust-Enshrouded AGN

2002 ◽  
Vol 184 ◽  
pp. 205-212
Author(s):  
Martin Haas
Keyword(s):  
Flux Ratio ◽  
Peak Height ◽  
Dust Grains ◽  
Infrared Galaxies ◽  
Mid Infrared ◽  
Dust Extinction ◽  
Ultraluminous Infrared Galaxies ◽  
Polycyclic Aromatic ◽  
Dust Distribution ◽  
Infrared Extinction

AbstractWe show that the PAH 7.7μm to continuum 850μm flux ratio can be used to reveal high mid-infrared extinction in ultraluminous infrared galaxies (ULIRGs). While the submm radiation is optically thin and represents the emission from essentially all dust grains, the PAH strength (measured by the peak height of the Polycyclic Aromatic Hydocarbonates at 7.7μm) is sensitive to dust extinction in the mid-infrared (MIR). As an application of the new diagnostic, after dereddening of the central MIR continuum and with the assumption of a disk-like dust distribution seen under a tilted angle, we find increasing evidence for a hidden quasar in the archetypal ULIRG Arp220.

Sign in / Sign up

Export Citation Format

Share Document