18,181 research outputs found
3-Methoxy-4-[3-(2-methyl-4-nitro-1H-imidazol-1-yl)propoxy]benzaldehyde
In the title molecule, C15H17N3O5, the dihedral angle between the benzene and imidazole rings is 3.69 (2)°. The crystal structure is stabilized by weak intermolecular C—H⋯O hydrogen bonds and π–π stacking interactions with a centroid–centroid distance of 3.614 (1) Å
(E)-3-(9-Anthryl)-1-(4-fluorophenyl)-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-one
The C=C double-bond in the title compound, C25H16FN3O, has an E configuration. The dihedral angle between the fluorophenyl and triazole rings is 80.57 (2)°
A Study of Fermi-LAT GeV gamma-ray Emission towards the Magnetar-harboring Supernova Remnant Kesteven 73 and Its Molecular Environment
We report our independent GeV gamma-ray study of the young shell-type
supernova remnant (SNR) Kes 73 which harbors a central magnetar, and CO-line
millimeter observations toward the SNR. Using 7.6 years of Fermi-LAT
observation data, we detected an extended gamma-ray source ("source A") with
the centroid on the west of the SNR, with a significance of 21.6 sigma in
0.1-300 GeV and an error circle of 5.4 arcminute in angular radius. The
gamma-ray spectrum cannot be reproduced by a pure leptonic emission or a pure
emission from the magnetar, and thus a hadronic emission component is needed.
The CO-line observations reveal a molecular cloud (MC) at V_LSR~90 km/s, which
demonstrates morphological correspondence with the western boundary of the SNR
brightened in multiwavelength. The 12CO (J=2-1)/12CO (J=1-0) ratio in the left
(blue) wing 85-88 km/s is prominently elevated to ~1.1 along the northwestern
boundary, providing kinematic evidence of the SNR-MC interaction. This SNR-MC
association yields a kinematic distance 9 kpc to Kes 73. The MC is shown to be
capable of accounting for the hadronic gamma-ray emission component. The
gamma-ray spectrum can be interpreted with a pure hadronic emission or a
magnetar+hadronic hybrid emission. In the case of pure hadronic emission, the
spectral index of the protons is 2.4, very similar to that of the
radio-emitting electrons, essentially consistent with the diffusive shock
acceleration theory. In the case of magnetar+hadronic hybrid emission, a
magnetic field decay rate >= 10^36 erg/s is needed to power the magnetar's
curvature radiation.Comment: 7 figures, published in Ap
Lasing oscillation condition and group delay control in gain-assisted plasmon-induced transparency
A gain-assisted plasmonic waveguide with two detuned resonators is
investigated in the plasmon-induced transparency window. Phase map is employed
to study power transmittance and group delay for varying gain coefficients and
frequency detunings of the two resonators. The gain coefficient for lasing
oscillation condition is analytically shown to vary quadratically with the
frequency detuning. In the amplification regime below the lasing threshold, the
spectrum implies not only large group delay, but also high transmittance and
narrow linewidth. This is in contrast to those in the loss-compensation regime
and the passive case in which there always exists a trade-off between the
linewidth and the peak transmittance.Comment: 15 pages, 4 figure
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