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Using high resolution VLT spectra, we study the multi-component outflow systems of two quasars exhibiting intrinsic Fe II absorption (QSO 2359-1241 and SDSS J0318-0600). From the extracted ionic column densities and using photoionization modeling we determine the gas density, total column density, and ionization parameter for several of the components. For each object the largest column density component is also the densest, and all other components have densities of roughly 1/4 of that of the main component. We demonstrate that all the absorbers lie roughly at the same distance from the source. Further, we calculate the total kinetic luminosities and mass outflow rates of all components and show that these quantities are dominated by the main absorption component.
We present a detailed analysis of the Astrophysical Research Consortium 3.5 m telescope spectrum of QSO SDSS J0838+2955. The object shows three broad absorption line (BAL) systems at 22,000, 13,000, and 4900 km s^-1 blueshifted from the systemic reds
We present new VLT spectroscopic observations of the most distant quasar known, SDSS J1030+0524 at z=6.28 which was recently discovered by the Sloan Digital Sky Survey. We confirm the presence of a complete Gunn-Peterson trough caused by neutral hydr
Machine learning techniques, specifically the k-nearest neighbour algorithm applied to optical band colours, have had some success in predicting photometric redshifts of quasi-stellar objects (QSOs): Although the mean of differences between the spect
The local determination of the Hubble Constant sits at a crossroad. Current estimates of the local expansion rate of the Universe differ by about 1.7-sigma, derived from the Cepheid and TRGB based calibrations, applied to type Ia supernovae. To help
As part of the Sloan Digital Sky Survey IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS wil