Successive line-locked C iv doublets in quasar SDSS J115122.14+020426.3

Lin, Ying-Ru; Lu, Wenjuan

doi:10.1093/mnras/staa2037

Cited by 3 publications

(1 citation statement)

References 38 publications

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“…LL is a term describing a state in which the observed velocity difference between distinct kinematic absorption components along our sightline equals the velocity separation of known atomic transitions (Figure 1). For example, Hamann et al (2011) reported multiple NAL systems toward a particular source, which are separated by the velocity difference of the C IV doublet (see also Lin & Lu 2020a, 2020bLu & Lin 2020). LL is perhaps the clearest manifestation of the fact that the radiative driving of gas is dynamically important in the astrophysical context (Goldreich & Sargent 1976, and below).…”

Section: Line Lockingmentioning

confidence: 99%

On the Fine-tuning and Physical Origin of Line-locked Absorption Systems in Active Galaxies

Lewis

Chelouche

2023

ApJ

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Line locking (LL) of absorption-line systems is a clear signature of the dynamical importance of radiation-pressure force in driving astrophysical flows, with recent findings suggesting that it may be common in quasars exhibiting multiple intrinsic narrow absorption-line (NAL) systems. In this work, we probe the phase space conducive to LL and follow the detailed kinematics of those systems that may lock at the velocity separation of the C iv λ λ1548.19, 1550.77 doublet. We find that a small volume of the phase-phase admits LL, suggesting a high degree of fine-tuning between the physical properties of locked systems. The stability of LL against quasar luminosity variations is quantified with implications for the long-term variability amplitude of quasars and the velocity-separation statistic between multiple NAL systems. The high occurrence of LL by the C iv doublet implies that the hidden extreme-UV emission from quasars is unlikely to be significantly underestimated by current models. Further, the ratio of the LL velocity to the outflow velocity may serve as a powerful constraint on the composition of the accelerating medium. We conclude that LL poses significant challenges to current theories for the formation of nonintervening NAL systems, and speculate that it may be a manifestation of expanding circumstellar shells around asymptotic giant branch stars in the quasar-host bulge.

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Section: Line Lockingmentioning

confidence: 99%

On the Fine-tuning and Physical Origin of Line-locked Absorption Systems in Active Galaxies

Lewis

Chelouche

2023

ApJ

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Dust-driven wind as a model of broad absorption line quasars

Naddaf¹,

Martínez-Aldama²,

Marziani³

et al. 2023

A&A

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Context. We test the scenario according to which the broad absorption line (BAL) phenomenon in quasars (QSOs) is not a temporary stage of their life. In this scenario, the BAL effect acts only if the line of sight is within a spatially limited and collimated massive outflow cone covering only a fraction of the sky from the point of view of the nucleus. Aims. The aim is to understand the theoretical mechanism behind the massive outflow in BAL QSOs, which is important for modelling the impact of quasars on the star formation rate in the host galaxy, and, subsequently, on the galaxy evolution. Methods. We applied the specific theoretical model of dust-driven wind that was developed to explain broad emission lines. The model has considerable predictive power. The 2.5D version of the model called failed radiatively accelerated dusty outflow (FRADO) includes the formation of fast funnel-shaped outflow from the disk for a certain range of black hole masses, Eddington ratios, and metallicities. We now interpret BAL QSO as sources that are viewed along the outflowing stream. We calculated the probabilities of seeing the BAL phenomenon as functions of these global parameters, and we compared these probabilities to those seen in the observational data. We included considerations of the presence or absence of obscuring torus. Results. Comparing our theoretical results with observational data for a sample of QSOs consisting of two sub-populations of BAL and non-BAL QSOs, we found that in the model and in the data, the BAL phenomenon mostly occurs for sources with black hole masses higher than 108 M⊙. The effect increases with accretion rate, and high metallicities are also more likely in QSOs showing BAL features if a torus is taken into account. Conclusions. The consistency of the model with the data supports the interpretation of the BAL phenomenon as the result of the orientation of the source. It also supports the underlying theoretical model, although more consistency checks should be made in the future.

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Tracking Outflow Using Line Locking (TOLL). I. The Case Study of Quasar J221531-174408

Chen,

Yi,

et al. 2024

ApJ

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Investigating line-locked phenomena within quasars is crucial for understanding the dynamics of quasar outflows, the role of radiation pressure in astrophysical flows, and the star formation history and metallicity of the early Universe. We have initiated the Tracking Outflow by Line Locking project to study quasar outflow by studying line-locking signatures using high-resolution high-signal-to-noise-ratio quasar spectra. In this paper, we present a case study of the line-locking signatures from QSO J221531-174408. The spectrum was obtained using the Very Large Telescope’s UV Visual Echelle Spectrograph. We first identify associated absorbers in the spectrum using C iv, N v, and Si iv doublets and measure their velocity shifts, covering fractions, and column densities through a line-profile-fitting technique. Then we compare the velocity separations between different absorbers, and detect nine pairs of line-locked C iv doublets, three pairs of line-locked N v doublets, and one pair of line-locked Si iv doublets. This is one of the four quasars known to possess line-locked signatures in C iv, Si iv, and N v at the same time. We also find three complex line-locked systems, where three to five absorbers are locked together through multi-ion doublets. Our study suggests that line locking is a common phenomenon in the quasar outflows, and theoretical models involving more than two clouds and one ionic doublet are needed in the future to explain the formation of these complex line-locking signatures.

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Successive line-locked C iv doublets in quasar SDSS J115122.14+020426.3

Cited by 3 publications

References 38 publications

On the Fine-tuning and Physical Origin of Line-locked Absorption Systems in Active Galaxies

On the Fine-tuning and Physical Origin of Line-locked Absorption Systems in Active Galaxies

Dust-driven wind as a model of broad absorption line quasars

Tracking Outflow Using Line Locking (TOLL). I. The Case Study of Quasar J221531-174408

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