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 Diels-Alder Additions to 2,2’-Biaceanthrylene

2021 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Photophysical Properties ◽  
Major Product ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Polycyclic Aromatic ◽  
Single Addition ◽  
Quinone Derivative

A series of Diels-Alder reactions between the diene 2,2’-biaceanthylene and several dienophiles is presented. The diene is a cyclopenta-fused polycyclic aromatic hydrocarbon with anthracene units linked by two cyclopentene rings. Depending on the dienophile, the major product was the result of a single addition (dimethyl acetylenedicarboxylate) or double addition (quinone, benzyne) to the diene. Single crystal X-ray analysis of the quinone-derivative shows a propeller-like structure composed of mixed enantiomers. The synthesis and photophysical properties of these compounds is presented.<br>

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 THE 3.3 μm POLYCYCLIC AROMATIC HYDROCARBON EMISSION AS A STAR FORMATION RATE INDICATOR

2012 ◽  
Vol 760 (2) ◽  
pp. 120 ◽  
Author(s):  
Ji Hoon Kim ◽  
Myungshin Im ◽  
Hyung Mok Lee ◽  
Myung Gyoon Lee ◽  
Hyunsung David Jun ◽  
...  
Keyword(s):  
Star Formation ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Emission ◽  
Polycyclic Aromatic Hydrocarbon Emission

scholarly journals Diels-Alder Additions to 2,2’-Biaceanthrylene

2021 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Photophysical Properties ◽  
Major Product ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Polycyclic Aromatic ◽  
Single Addition ◽  
Quinone Derivative

A series of Diels-Alder reactions between the diene 2,2’-biaceanthylene and several dienophiles is presented. The diene is a cyclopenta-fused polycyclic aromatic hydrocarbon with anthracene units linked by two cyclopentene rings. Depending on the dienophile, the major product was the result of a single addition (dimethyl acetylenedicarboxylate) or double addition (quinone, benzyne) to the diene. Single crystal X-ray analysis of the quinone-derivative shows a propeller-like structure composed of mixed enantiomers. The synthesis and photophysical properties of these compounds is presented.<br>

scholarly journals Deexcitation Dynamics of Superhydrogenated Polycyclic Aromatic Hydrocarbon Cations after Soft-x-Ray Absorption

2014 ◽  
Vol 113 (5) ◽  
Author(s):  
G. Reitsma ◽  
L. Boschman ◽  
M. J. Deuzeman ◽  
O. González-Magaña ◽  
S. Hoekstra ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
X Ray ◽  
Polycyclic Aromatic ◽  
X Ray Absorption
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