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Theoretical models have suggested an evolutionary model for quasars, in which most of luminous quasars are triggered by major mergers. It is also postulated that reddening as well as powerful outflows indicate an early phase of activity, close to the merger event. We test this model on a sample of quasars with powerful low-ionization outflows seen in broad iron absorption lines (FeLoBAL). This sample of objects show strong reddening in the optical and fast (∼0.1c) high-column density outflows. We present HST WFC3/IR F160W imaging of 10 FeLoBAL host galaxies at redshifts |$z$| ∼ 0.9 (⁠|$\lambda _{\mathrm{ rest}}\sim 8500\, \mathrm{\mathring{\rm A} }$|⁠). We compare the host galaxy morphologies and merger signatures of FeLoBALs to luminous blue non-BAL quasars from Villforth et al. (2017) of comparable luminosity, which show no excess of merger features compared to inactive control samples. If FeLoBAL quasars are indeed in a young evolutionary state, close in time to the initial merging event, they should have strong merger features. We find that the host galaxies of FeLoBAL quasars are of comparable luminosity to the host galaxies of optical quasars and show no enhanced merger rates. When looking only at quasars without strong point spread function residuals, an enhancement in disturbed and merger rates is seen. While FeLoBAL hosts show weak enhancements over a control of blue quasars, their host galaxies are not dominated by recent major mergers. [ABSTRACT FROM AUTHOR]

Broad absorption lines (BALs) in quasar spectra identify high-velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. The variability of BALs can help us understand the structure, evolution and basic physical properties of the outflows. Here we report on our first results from an ongoing BAL monitoring campaign of a sample of 24 luminous quasars at redshifts , focusing on C λ1549 BAL variability in two different time intervals: 4-9 months (short term) and 3.8-7.7 yr (long term) in the quasar rest frame. We find that 39 per cent (7/18) of the quasars varied in the short-term data, whereas 65 per cent (15/23) varied in the long-term data, with a larger typical change in strength in the long-term data. The variability occurs typically in only portions of the BAL troughs. The components at higher outflow velocities are more likely to vary than those at lower velocities, and weaker BALs are more likely to vary than stronger BALs. The fractional change in BAL strength correlates inversely with the strength of the BAL feature, but does not correlate with the outflow velocity. Both the short-term and long-term data indicate the same trends. The observed behaviour is most readily understood as a result of the movement of clouds across the continuum source. If the crossing speeds do not exceed the local Keplerian velocity, then the observed short-term variations imply that the absorbers are <6 pc from the central quasar. [ABSTRACT FROM AUTHOR]

We report the first discovery of the emergence of a high-velocity broad-line outflow in a luminous quasar, J105400.40+034801.2, at redshift z∼ 2.1. The outflow is evident in ultraviolet C iv and Si iv absorption lines with velocity shifts v∼ 26 300 km s−1 and deblended widths FWHM ∼4000 km s−1. These features are marginally strong and broad enough to be considered broad absorption lines (BALs), but their large velocities exclude them from the standard BAL definition. The outflow lines appeared between two observations in the years 2002.18 and 2006.96. A third observation in 2008.48 showed the lines becoming ∼40 per cent weaker and 10 to 15 per cent narrower. There is no evidence for acceleration or for any outflow gas at velocities ≲23 000 km s−1. The lines appear to be optically thick, with the absorber covering just 20 per cent of the quasar continuum source. This indicates a characteristic absorber size of , but with a BAL-like total column density and average space density . We attribute the emergence of the outflow lines to a substantial flow structure moving across our line of sight, possibly near the ragged edge of the main BAL flow or possibly related to the onset of a BAL evolutionary phase. [ABSTRACT FROM AUTHOR]