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 versio

Green growth and green new deal policies in Korea

노트 : A Paper for the GURN/ITUC workshop on "A Green Economy that Works for Social Progress

The effect of CEO turnover on audit report lag and management discretionary report lag: evidence from Korea

This study empirically investigates the effect of a CEO turnover on audit report lag (ARL), discretionary report lag (DRL) and total report lag (TRL). The object of this study is to provide empirical evidence for the responses of both the CEO and the external auditor on audit risk increases and information asymmetry that occur as a result of a CEO turnover. According to the previous study on CEO turnovers, the CEO turnover would increase audit risk and information asymmetry (Sohn et al., 2014). In this situation, the CEO has an incentive to provide timely information to decrease the monitoring costs and cost of debt (Lee et al., 2008). It is expected that an external auditor spends a large amount of time on audit procedures to lower the audit risk when the CEO changes. Therefore, the CEO turnover would have a conflicting effect on the ARL and DRL. The results of the analysis are as follows. First, the ARL increases and DRL decreases when the CEO changes, which suggests that an external auditor spends a great amount of time on audit procedures to lower the audit risk because the audit risk increases when the CEO changes. A new CEO provides information faster to reduce monitoring costs and cost of debt that occur due to information asymmetry. Second, the ARL increases and DRL decreases as the frequency of CEO turnover increases. An external auditor would estimate the audit risk as being high if the CEO changes more frequently. To lower the audit risk to an acceptable level, many audit hours are spent on audit procedures by an external auditor, which increases the ARL. A new CEO has an incentive to provide timely information when the CEO changes more frequently. Thus, the DRL decreases as the frequency of CEO turnover increase