This week's normal Lunch Talk will be given by Huynh Anh, at 11:30AM Nov. 21 (Thursday) in the 19th-floor Observatory Hall (天文台报告厅).  She will present his work on "Comparison of the UV and optical Fe II emission in type 1 AGNs

Abstract: We present the kinematical properties of the UV and optical Fe II emission gas based on the velocity shift and line width measurements of a sample of 223 Type 1 active galactic nuclei (AGNs) at 0.4 <  z <  0.8. We find a strong correlation between the line widths of the UV and optical Fe II emission lines, indicating that both Fe II emission features arise from similar distances in the broad line region (BLR). However, in detail we find differing trends, depending on the width of Fe II. While the velocity shifts and dispersions of the UV Fe II (FeII_uv ) and optical Fe II (FeII_opt ) emission lines are comparable to each other for AGNs with relatively narrow FeII_opt  line widths (i.e., FWHM < 3200 km s/1; Group A), FeII_opt is broader than FeII_uv for AGNs with relatively broad FeII_opt  (i.e., FWHM > 3200 km s/1; Group B). Fe II emission lines are on average narrower than Hbeta and Mg II for Group A, indicating the Fe II emission region is further out in the BLR, while for Group B AGNs FeII_opt is comparable to Hbeta and broader than Mg II. While Fe II emission lines are on average redshifted (40 +/- 141 km s/1 and 182+/-95, respectively for FeII_uv  and FeII_opt ), indicating inflow, the sample as a whole shows a large range of velocity shifts, suggesting complex nature of gas kinematics.

You are welcome to join the discussion. We will provide boxed food from the faculty canteen. Please sign up via WeChat (Journal Club group) before Nov. 21th (Thur) 9 AM. The boxed food contains two meat dishes and two vegetable dishes by default, please add a * after your name if you want a vegetarian meal. Those who sign up but don't attend on time should pay a￥20 fee for the food, which will be used for future academic activities.