1,566 research outputs found
A strong negative correlation between radio loudness and optical-to-X-ray spectral index in low-luminosity AGNs
It has been argued for years that the accretion mode changes from bright
active galactic nuclei (AGNs) to low-luminosity AGNs (LLAGNs) at a rough
dividing point of bolometric Eddington ratio . In this
work, we strengthen this scenario through investigation of the relationship
between the radio loudness and the optical-to-X-ray spectral index
in LLAGNs with .
We compile from literature a sample of 32 LLAGNs, consisting 18 LINERs and 14
low Eddington ratio Seyfert galaxies, and observe a strong negative -- relationship, with large scatter in both
and . We further demonstrate that this negative correlation,
and the additional two negative relationships reported in literature (-- and -- correlations), can be
understood consistently and comprehensively under the truncated accretion--jet
model, the model that has been applied successfully applied to LLAGNs. We argue
that the scatter in the observations are (mainly) due to the spread in the
viscosity parameter of a hot accretion flow, a parameter that
potentially can serve as a diagnose of the strength and/or configuration of
magnetic fields in accretion flows.Comment: 8 pages, 3 figures, 2 tables. Accepted by MNRA
Hexyl (E)-3-(3,4-dihyÂdroxyÂphenÂyl)acrylate
The title molÂecule, C15H20O4, has an E conformation about its C=C bond and is almost planar (r.m.s. deviation of all non-H atoms = 0.04 Å). The crystal structurere features O—H⋯O and C—H⋯O hydrogen bonds
2,2-Dichloro-1-(2-phenyl-1,3-oxazolidin-3-yl)ethanone
In the title molÂecule, C11H11Cl2NO2, the oxazolidine ring is in an envelope conformation with the O atom forming the flap; the other four essentially planar ring atoms (r.m.s. deviation = 0.012 Å) form a dihedral angle of 91.1 (3)° with the phenyl ring. In the crystal structure, molÂecules are linked by weak interÂmolecular C—H⋯O hydrogen bonds, forming one-dimensional chains
Observation of Zeeman effect in topological surface state with distinct material dependence
The helical Dirac fermions on the surface of topological insulators host
novel relativistic quantum phenomena in solids. Manipulating spins of
topological surface state (TSS) represents an essential step towards exploring
the theoretically predicted exotic states related to time reversal symmetry
(TRS) breaking via magnetism or magnetic field. Understanding Zeeman effect of
TSS and determining its g-factor are pivotal for such manipulations in the
latter form of TRS breaking. Here, we report those direct experimental
observations in Bi2Se3 and Sb2Te2Se by spectroscopic imaging scanning tunneling
microscopy. The Zeeman shifting of zero mode Landau level is identified
unambiguously by judiciously excluding the extrinsic influences associated with
the non-linearity in the TSS band dispersion and the spatially varying
potential. The g-factors of TSS in Bi2Se3 and Sb2Te2Se are determined to be 18
and -6, respectively. This remarkable material dependence opens a new route to
control the spins in the TSS.Comment: main text: 17 pages, 4 figures; supplementary: 15 pages, 7 figure
(E)-Isopentyl 3-(3,4-dihyÂdroxyÂphenÂyl)Âacrylate
The title compound, C14H18O4, a derivative of caffeic acid, has an E configuration about the C=C bond. The benzene ring is almost coplanar with the C=C—C(O)—O—C linker [maximum deviation = 0.050 (2) Å], making a dihedral angle of only 4.53 (2)°. In the molÂecule, the adjacent hyÂdroxy groups form an O—H⋯O interÂaction. In the crystal, molÂecules are linked by O—H⋯O hydrogen bonds, generating a chain propagating in the [110] direction
- …