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

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 λλ5890, 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 NH(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 ionized and partially ionized gas. The densities are conservatively log nH(cm−3) ≳ 7 based on Fe ii∗, H i∗, and He i∗ but they might reach log nH(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.