3,360 research outputs found
The Prevalence of Gas Outflows in Type 2 AGNs. II. 3D Biconical Outflow Models
We present 3D models of biconical outflows combined with a thin dust plane
for investigating the physical properties of the ionized gas outflows and their
effect on the observed gas kinematics in type 2 active galactic nuclei (AGNs).
Using a set of input parameters, we construct a number of models in 3D and
calculate the spatially integrated velocity and velocity dispersion for each
model. We find that three primary parameters, i.e., intrinsic velocity, bicone
inclination, and the amount of dust extinction, mainly determine the simulated
velocity and velocity dispersion. Velocity dispersion increases as the
intrinsic velocity or the bicone inclination increases, while velocity (i.e.,
velocity shifts with respect to systemic velocity) increases as the amount of
dust extinction increases. Simulated emission-line profiles well reproduce the
observed [O III] line profiles, e.g., a narrow core and a broad wing
components. By comparing model grids and Monte Carlo simulations with the
observed [O III] velocity-velocity dispersion (VVD) distribution of ~39,000
type 2 AGNs, we constrain the intrinsic velocity of gas outflows ranging from
~500 km/s to ~1000 km/s for the majority of AGNs, and up to ~1500-2000 km/s for
extreme cases. The Monte Carlo simulations show that the number ratio of AGNs
with negative [O III] velocity to AGNs with positive [O III] velocity
correlates with the outflow opening angle, suggesting that outflows with higher
intrinsic velocity tend to have wider opening angles. These results demonstrate
the potential of our 3D models for studying the physical properties of gas
outflows, applicable to various observations, including spatially integrated
and resolved gas kinematics.Comment: 14 pages, 14 figures, 2 tables; matched with the ApJ published
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Temperature Dependent Current-voltage Characteristics of P-type Crystalline Silicon Solar Cells Fabricated Using Screen-printing Process
We have fabricated p-type crystalline silicon (Si) solar cells using screen-printing process and investigated their electrical properties. Ph screen printing process led to the uniform formation of n+ emitter. As a result of interaction between Ph-dopant paste and Si substrate, a phosphosilicate glass layer was formed on n+ emitter surface. The current-voltage characteristics were carried out in the temperature range of 175 β 450 K in steps of 25 K. The variation in current level at a particular voltage strongly depended on temperature, indicating that the current transport across the junction was a temperature activated process. The reverse leakage current gradually increased with increasing measurement temperature up to 350 K, above which it rapidly increased. Arrhenius plot of the leakage current revealed that reverse leakage current in low and high temperature regions were dominated by the tunneling mechanism, and generation and recombination mechanism, respectively. Keywords: P-type Si solar cell, screen-printing, I-V, tunneling, generation and recombination, reverse leakage curren
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