3,360 research outputs found

    The Prevalence of Gas Outflows in Type 2 AGNs. II. 3D Biconical Outflow Models

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    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 versio

    Temperature Dependent Current-voltage Characteristics of P-type Crystalline Silicon Solar Cells Fabricated Using Screen-printing Process

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    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 – 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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