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تسجيل مستخدم جديدHST and Ground-Based Spectroscopy of Quasar Outflows: From Mini-BALs to BALs
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Quasar outflows have been posited as a mechanism to couple super-massive black holes to evolution in their host galaxies. We use multi-epoch spectra from the Hubble Space Telescope and ground-based observatories to study the outflows in seven quasars that have CIV outflow lines ranging from a classic BAL to weaker/narrower mini-BALs across rest wavelengths of at least 850 $AA$ to 1650 $AA$. The CIV outflow lines all varied within a time frame of $leq$ 1.9 yrs (rest). This includes equal occurrences of strengthening and weakening plus the emergence of a new BAL system at $-$38,800 km/s accompanied by dramatic strengthening in a mini-BAL at $-$22,800 km/s. We infer from $sim$1:1 doublet ratios in PV and other lines that the BAL system is highly saturated with line-of-sight covering fractions ranging from 0.27 to 0.80 in the highest to lowest column density regions, respectively. Three of the mini-BALs also provide evidence for saturation and partial covering based on $sim$1:1 doublet ratios. We speculate that the BALs and mini-BALs form in similar clumpy/filamentary outflows, with mini-BALs identifying smaller or fewer clumps along our lines of sight. If we attribute the line variabilities to clumps crossing our lines of sight at roughly Keplerian speeds, then a typical variability time in our study, $sim$1.1 yrs, corresponds to a distance $sim$2 pc from the central black hole. Combining this with the speed and minimum total column density inferred from the PV BAL, $N_H gtrsim$ 2.5$times$10$^{22}$ cm$^{-2}$, suggests that the BAL outflow kinetic energy is in the range believed to be sufficient for feedback to galaxy evolution.
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