Probing the Origins of the CIV and Fe Kalpha Baldwin Effect

We use UV/optical and X-ray observations of 272 radio-quiet Type 1 AGNs and quasars to investigate the CIV Baldwin Effect (BEff). The UV/optical spectra are drawn from the Hubble Space Telescope, International Ultraviolet Explorer and Sloan Digital Sky Survey archives. The X-ray spectra are from the Chandra and XMM-Newton archives. We apply correlation and partial-correlation analyses to the equivalent widths, continuum monochromatic luminosities, and alpha_ox, which characterizes the relative X-ray to UV brightness. The equivalent width of the CIV 1549 emission line is correlated with both alpha_ox and luminosity. We find that by regressing l_UV with EW(CIV) and alpha_ox, we can obtain tighter correlations than by regressing l_UV with only EW(CIV). Both correlation and regression analyses imply that l_UV is not the only factor controlling the changes of EW(CIV); alpha_ox (or, equivalently, the soft X-ray emission) plays a fundamental role in the formation and variation of CIV. Variability contributes at least 60% of the scatter of the EW(CIV)-l_UV relation and at least 75% of the scatter of the of the EW(CIV)-alpha_ox relation. In our sample, narrow Fe Kalpha 6.4 keV emission lines are detected in 50 objects. Although narrow Fe Kalpha exhibits a BEff similar to that of CIV, its equivalent width has almost no dependence on either alpha_ox or EW(CIV). This suggests that the majority of narrow Fe Kalpha emission is unlikely to be produced in the broad emission-line region. We do find suggestive correlations between the emission-line luminosities of CIV and Fe Kalpha, which could be potentially used to estimate the detectability of the Fe Kalpha line of quasars from rest-frame UV spectroscopic observations.

Swift UVOT Observations of Core-Collapse SNe

We review recent UV observations of core-collapse supernovae (SNe) with the Swift Ultra-violet/Optical Telescope (UVOT) during its first two years. Rest-frame UV photometry is useful for differentiating SN types by exploiting the UV-optical spectral shape and more subtle UV features. This is useful for the real-time classification of local and high-redshift SNe using only photometry. Two remarkable SNe Ib/c were observed with UVOT -- SN2006jc was a UV bright SN Ib. Swift observations of GRB060218/SN2006aj began shortly after the explosion and show a UV-bright peak followed by a UV-faint SN bump. UV observations are also useful for constraining the temperature and ionization structure of SNe IIP. Rest-frame UV observations of all types are important for understanding the extinction, temperature, and bolometric luminosity of SNe and to interpret the observations of high redshift SNe observed at optical wavelengths.