The interplay between active galactic nuclei and star formation activities of type 1 active galactic nuclei probed by polycyclic aromatic hydrocarbon 3.3 μm emission feature with AKARI

2019 ◽  
Vol 71 (2) ◽  
Author(s):  
Ji Hoon Kim ◽  
Myungshin Im ◽  
Dohyeong Kim ◽  
Jong-Hak Woo ◽  
Marios Karouzos ◽  
...  
Keyword(s):  
Star Formation ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Feature ◽  
Polycyclic Aromatic

The properties of the dusty inner regions of nearby QSOs

2019 ◽  
Vol 15 (S356) ◽  
pp. 95-95
Author(s):  
Itziar Aretxaga
Keyword(s):  
Star Formation ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Stellar Objects ◽  
X Ray ◽  
Mir Spectroscopy ◽  
Polycyclic Aromatic ◽  
Quasi Stellar Objects

AbstractWe present MIR spectroscopy and photometry obtained with CanariCam on the 10.4 m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec. We derive the properties of the dusti tori that surround the nucleus based on these observations and find significant differences in the parameters compared with a sample of Seyfert 1 and 2 nuclei. We also find evidence for polycyclic aromatic hydrocarbon (PAH) features in the spectra, indicative of star formation, more centrally peaked (on scales of a few hundred pc) than previously believed.

scholarly journals Polycyclic aromatic hydrocarbon excitation in nearby spiral galaxies

2020 ◽  
Vol 496 (2) ◽  
pp. 1393-1417 ◽  
Author(s):  
G J Bendo ◽  
N Lu ◽  
A Zijlstra
Keyword(s):  
Star Formation ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Spiral Galaxies ◽  
Dust Emission ◽  
Stellar Populations ◽  
Mid Infrared ◽  
Star Forming ◽  
Evolved Stars ◽  
Polycyclic Aromatic

ABSTRACT We have examined polycyclic aromatic hydrocarbon (PAH) excitation in a sample of 25 nearby face-on spiral galaxies using the ratio of mid-infrared PAH emission to dust mass. Within 11 of the galaxies, we found that the PAH excitation was straightforwardly linked to ultraviolet (UV) or mid-infrared star formation tracers, which, along with other results studying the relation of PAH emission to star formation, indicates that the PAHs are most strongly excited in dusty shells around the star-forming (SF) regions. Within another five galaxies, the PAH emission is enhanced around SF regions only at specific galactocentric radii. In six more galaxies, PAH excitation is more strongly correlated with the evolved stellar populations as traced by 3.6 μm emission. The results for the remaining three galaxies were ambiguous. The radial gradients of the PAH/dust ratios were generally not linked to log(O/H) gradients except when the log(O/H) gradients were relatively steep. Galaxies in which PAHs were excited by evolved stars had relatively high far-UV to mid-infrared ratios, implying that variations in the link between PAH excitation and different stellar populations are connected to changes in dust attenuation within galaxies. Alternately, differences in morphology could make it more likely that PAHs are excited by evolved stars, as five of the six galaxies where this occurs are late-type flocculent spiral galaxies. These heterogeneous results demonstrate the complexity of describing PAH excitation and have broad implications for using PAH emission as a star formation tracer as well as for modelling dust emission and radiative transfer.

scholarly journals POLYCYCLIC AROMATIC HYDROCARBONS IN GALAXIES ATz∼ 0.1: THE EFFECT OF STAR FORMATION AND ACTIVE GALACTIC NUCLEI

2009 ◽  
Vol 705 (1) ◽  
pp. 885-898 ◽  
Author(s):  
Matthew J. O'Dowd ◽  
David Schiminovich ◽  
Benjamin D. Johnson ◽  
Marie A. Treyer ◽  
Christopher D. Martin ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Star Formation ◽  
Active Galactic Nuclei ◽  
Aromatic Hydrocarbons ◽  
Galactic Nuclei ◽  
Polycyclic Aromatic

Modelling the silicate emission features in type 1 AGNs: Dusty torus and disk+outflow models

2019 ◽  
Vol 15 (S359) ◽  
pp. 352-354
Author(s):  
M. Martínez-Paredes ◽  
I. Aretxaga
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Feature ◽  
Two Phase ◽  
Dust Composition ◽  
Dusty Torus

AbstractWe investigated how the most common dusty torus models reproduce both the 10 and 18μm silicate emission features observed in the nuclear infrared (IR) Spitzer spectrum of type 1 active galactic nuclei (AGN). We use a sample of type 1 AGN for which the Spitzer spectrum is mostly dominated by the emission of the AGN (>80%), and the 10μm silicate emission feature is prominent (1σSi10μm > 0.28). The models are the smooth dusty torus models from Fritz et al., the clumpy dusty torus models from Nenkova et al. and Hoenig et al., the two-phase media torus model from Stalevski et al., and the disk+outflow model from Hoenig et al. These models differ by assuming either different geometry or dust composition. We found that in general, all models have difficulties reproducing the shape and peak of the silicate emission features, but the disk+outflow model is the best reproducing the AGN-dominated Spitzer spectrum.

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