We analyze the optical spectra of Fairall 9,a luminous Seyfert 1 galaxy.They are obtained from the AGN Watch program that has monitored this object for 9 months.The flux and variation of the optical FeII complex is measured using multi-component profile modeling with FeⅡ templates.A convincing intrinsic Baldwin Effect(BEff) of optical FeⅡ emission blends in Fairall 9 is discovered for the first time.The variation of FeⅡ/Hβ(RFe) in Fairall 9 is obtained.We also detect a marginal anti-correla tion between RFe and the continuum flux in its spectra.This anti-correlation and the relatively broad profile of Hβ in this galaxy support the dichotomy reported by Wang et al.(2005).
HAN XuHuiWANG JingWEI JianYanYANG DaWeiHOU JinLiang
An NUV-optical diagram composed from sources from the second Galaxy Evolution Explorer(GALEX) Ultraviolet Variability(GUVV-2) Catalog provides us with a method to tentatively classify the unknown GUVV-2 sources by their NUV-optical magnitudes.For the purpose of testing the correctness and generality of the method,we carry out a program on the spectroscopic observations of the unidentified GUVV-2 sources.The spectroscopic identification of these 37 sources are 19 type-A to-F stars,10 type-G to-K stars and 7 M dwarf stars together with an AGN.We also present the light curves in the R-band for two RR Lyrae star candidates selected from the NUV-optical diagram,both of which undergo cyclic variations.Combining their light curves and colors,we classify them as RR Lyrae stars.To confirm the re-sults,we show a color-color diagram for the 37 newly identified spectroscopic objects compared with previously identified ones,which are consistent with our previous re-sults,indicating that the ultraviolet variable sources can initially be classified by their NUV/optical color-color diagram.
The correlation between distant Gamma-Ray Bursts(GRBs) and fore-ground galaxy clusters is re-examined by using the well localized(with an accuracy down to a few arcsec) Swift/XRT GRBs.The galaxy clusters are compiled from both the X-ray selected ROSAT brightest cluster sample(BCS) and the BCS extension by requiring δ≥ 0° and b ≥ 20°.The Swift/XRT GRBs fulfilling the above selection criteria are cross-correlated with the clusters.Both Nearest-Neighbor analysis and the angular two-point cross-correlation function show that there is not enough evidence supporting the correlation between the GRBs and foreground clusters.We suggest that the non-correlation is probably related to the GRB number-flux relation slope.
We present a brief overview of follow-up observations of GRB afterglows made by the 0.8-m TNT and other telescopes at the Xinglong observatory during the last three years.Our system,dedicated to the measurement of early-time optical afterglow emission,responded to 50 GRBs from Jan.2006 to Apr.2009.Among them,about 50% have been successfully detected.The fastest response time is 76 sec(GRB 061110A and GRB 090426) after the space-borne GRB detector was triggered.The redshift distribution spans the range from z = 0.033(GRB 060218) to z = 5.6(GRB 060927).We also report the optical photometric follow-up of GRB 080330,which is an X-ray flash,as an example of our observations.
XIN LiPing1,2,DENG JingSong1,ZHENG WeiKang1,2,WEI JianYan1,WANG Jing1,QIU YuLei1 & HU JingYao1 1 National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China
