On the emergence of thousands of absorption lines in the quasar PG 1411+442: a clumpy high-column density outflow from the broad emission-line region?

Abstract

Quasar outflows are fundamental components of quasar environments that might play an important role in feedback to galaxy evolution. We report on the emergence of a remarkable new outflow absorption-line system in the quasar PG1411+442 (redshift ∼0.089) detected in the UV and visible with the Hubble Space Telescope Cosmic Origins Spectrograph and the Gemini Multi-Object Spectrograph, respectively. This new "transient" system contains thousands of lines, including Fe ii and Fe ii* from excited states up to 3.89 eV, H i* Balmer lines, Na i D λ5890,5896, and the first detection of He i* λ5876 in a quasar. The transient absorber is spatially inhomogeneous and compact, with sizes 0.003 pc, based on covering fractions on the quasar continuum source ranging from ∼0.45 in strong UV lines to ∼0.04 in Na i D. cloudy photoionization simulations show that large total column densities log N H (cm −2 ) 23.4 and an intense radiation field 0.4 pc from the quasar are needed to produce the observed lines in thick zones of both fully-ionised and partially-ionised gas. The densities are conservatively log n H (cm −3 ) 7 based on Fe ii*, H i*, and He i* but they might reach log n H (cm −3 ) 10 based on Na i D. The transient lines appear at roughly the same velocity shift, v ∼ −1900 km s −1 , as a "mini-BAL" outflow detected previously, but with narrower Doppler widths, b ∼ 100 km s −1 , and larger column densities in more compact outflow structures. We propose that the transient lines identify a clumpy outflow from the broad emission-line region that, at its current speed and location, is still gravitationally bound to the central black hole.

Stratified disc wind models for the AGN broad-line region: ultraviolet, optical, and X-ray properties

“…There are relatively strong observational and theoretical arguments for clumping in quasar outflows (e.g. Shlosman et al 1985;Emmering et al 1992;de Kool & Begelman 1995;Hamann et al 2013;McCourt et al 2018;Mas-Ribas 2019;Hamann et al 2019b). Multiple mechanisms for wind clumping have been proposed, including the line-driven instability (LDI;MacGregor et al 1979;Owocki & Rybicki 1984Sundqvist et al 2018), magnetic confinement (Emmering et al 1992;de Kool & Begelman 1995), and various forms of thermal instability, condensation or fragmentation (Shlosman et al 1985;Proga & Waters 2015;Waters et al 2017;Elvis 2017;McCourt et al 2018;Waters & Proga 2019;Waters & Li 2019;Dannen et al 2020).…”

Galactic Winds across the Gas-Rich Merger Sequence: I. Highly Ionized N V and O VI Outflows in the QUEST Quasars

“…) will present the results on our sample of ULIRGs with AGN and compare them with those on the quasars. As stated in Hamann et al (2019b), the quasars in the present sample are valuable for outflow studies in and of themselves because: 1) they fill a largely-unexplored niche between luminous quasars with strong broad absorption lines (BALs) with outflow velocities of up to 0.1 − 0.2 c and low-luminosity Seyfert 1 galaxies with exclusively narrower outflow lines, 2) their low redshift minimizes contamination by the Lyα forest, and 3) the outflow lines are relatively narrow so blending is less severe. Indeed, as we discuss below, the detected outflows often are "mini-BALs" instead of BALs because their velocity widths lie below or near the threshold of 2000 km s −1 used for BALs (Weymann et al 1981(Weymann et al , 1991Hamann & Sabra 2004;Gibson et al 2009b).…”

“…Since most of the Cycle 19 COS data have not yet been the subject of a paper (the exceptions are Mrk 231 and PG 1411+442; Veilleux et al 2013bVeilleux et al , 2016Hamann et al 2019b), we briefly summarize here how they were obtained. A total of 24 orbits were allocated for these 19 targets with most targets requiring one orbit.…”

“…These lines may be used to help constrain the location, ionization, total column densities (N H ) and metal abundances in the absorbing gas (e.g. Hamann et al 2019b). PG 1004+130, one of the highest-redshift sources in our sample, also shows S VI λλ933, 945.…”

“…Telltale signs that the detected lines are formed in a quasar-driven outflow include (1) line profiles that are blueshifted, broad, and smooth compared to the thermal line widths ( 10 − 20 km s −1 for highly ionized N 4+ , P 4+ , and O 5+ ions at T 10 4.5−5.5 K), (2) line ratios within the multiplets N V λ1238/λ1243, O VI λ1032/λ1038, and P V λ1117/λ1128 that imply partial covering of the quasar emission source, and (3) and large column densities in these high-ionization ions (Hamann et al 1997b,a;Tripp et al 2008;Hamann et al 2019b). N V is typically very weak or absent in intervening systems (Werk et al 2016).…”