SIMBAD references

2017MNRAS.468.4539M - Mon. Not. R. Astron. Soc., 468, 4539-4555 (2017/July-2)

HST and ground-based spectroscopy of quasar outflows: from mini-BALs to BALs.


Abstract (from CDS):

Quasar outflows have been posited as a mechanism to couple supermassive black holes to evolution in their host galaxies. We use multi-epoch spectra from the Hubble Space Telescope (HST) and ground-based observatories to study the outflows in seven quasars that have C IV outflow lines ranging from a classic broad absorption line (BAL) to weaker/narrower 'mini-BALs' across rest wavelengths of at least 850-1650 Å. The C IV outflow lines all varied within a time frame of <=1.9 yr (rest). This includes equal occurrences of strengthening and weakening plus the emergence of a new BAL system at -38 800 km s–1 accompanied by dramatic strengthening in a mini-BAL at -22 800 km s–1. We infer from ∼1:1 doublet ratios in P V 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 ∼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, ∼1.1 yr, corresponds to a distance ∼2 pc from the central black hole. Combining this with the speed and minimum total column density inferred from the P V BAL, NH >= 2.5 x 1022 cm–2, suggests that the BAL outflow kinetic energy is in the range believed to be sufficient for feedback to galaxy evolution.

Abstract Copyright: © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: active - quasars: absorption lines - quasars: general - quasars: general

Simbad objects: 7

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