scholarly journals Broad Absorption Line QSOs

1986 ◽  
Vol 119 ◽  
pp. 317-330 ◽  
Author(s):  
David A. Turnshek
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Observational Constraints ◽  
Broad Absorption ◽  
Central Source ◽  
Broad Absorption Line ◽  
Broad Emission ◽  
Line Region ◽  
High Ionization ◽  
Broad Emission Line

Observational constraints on models for broad absorption line (BAL) QSOs are discussed. The picture which emerges is one in which the broad absorption line region (BALR) contributes to the broad emission line region (ELR) as a high ionization component. Depending on QSO luminosity, the limits on the distance of the BALR from the central source are 1–1000 pc. A highly metal enriched and disk-like geometry for the region is indicated. The similarity between the absorption in some radio quiet BAL QSOs and the associated complexes of absorption in some radio loud QSOs may indicate that the BALR outflow can affect the region surrounding a QSO out to distances in excess of several hundred kpc.

scholarly journals Evidence for Radiative Acceleration in Quasars

1997 ◽  
Vol 163 ◽  
pp. 580-584
Author(s):  
Nahum Arav
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Broad Absorption ◽  
Zero Velocity ◽  
Broad Absorption Line ◽  
Broad Emission ◽  
Broad Emission Line ◽  
Radiative Acceleration ◽  
Model Fits

AbstractI give an overview of a promising signature for radiative acceleration in quasars “the ghost of Lyα,” which is seen in the spectra of a few broad absorption line (BAL) QSOs. The ghost appears as an absorption hump in the C IV λ1549 BAL and is centered around 5,900 km s−1 to the blue of the corresponding broad emission line (BEL). This velocity separation is the same as the velocity separation between the N V λ1240 and Lyα lines. Thus, when the N V BAL and the C IV BAL are plotted as a function of velocity (where zero velocity corresponds to the peaks of these BELs), the hump in the C IV BAL appears at the same velocity as the Lyα BEL and qualitatively resembles it. The best examples and model fits are shown and the radiative dynamics explained.

scholarly journals Gaia-assisted discovery of a detached low-ionisation BAL quasar with very large ejection velocities

2020 ◽  
Vol 634 ◽  
pp. A111 ◽  
Author(s):  
J. P. U. Fynbo ◽  
P. Møller ◽  
K. E. Heintz ◽  
J. N. Burchett ◽  
L. Christensen ◽  
...  
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Emission Lines ◽  
Broad Absorption ◽  
Broad Absorption Line ◽  
Red Edge ◽  
First Case ◽  
Bl Lac ◽  
Spatially Extended ◽  
Extended Emission

We report on the discovery of a peculiar broad absorption line (BAL) quasar identified in our Gaia-assisted survey of red quasars. The systemic redshift of this quasar was difficult to establish because of the absence of conspicuous emission lines. Based on deep and broad BAL troughs of at least Si IV, C IV, and Al III, a redshift of z = 2.41 was established under the assumption that the systemic redshift can be inferred from the red edge of the BAL troughs. However, we observe a weak and spatially extended emission line at 4450 Å that is most likely due to Lyman-α emission, which implies a systemic redshift of z = 2.66 if correctly identified. There is also evidence for the onset of Lyman-α forest absorption bluewards of 4450 Å and evidence for Hα emission in the K band consistent with a systemic redshift of z = 2.66. If this redshift is correct, the quasar is an extreme example of a detached low-ionisation BAL quasar. The BALs must originate from material moving with very large velocities ranging from 22 000 km s−1 to 40 000 km s−1. To our knowledge, this is the first case of a systemic-redshift measurement based on extended Lyman-α emission for a BAL quasar. This method could also be useful in cases of sufficiently distant BL Lac quasars without systemic-redshift information.

scholarly journals Near infrared hydrogen emission line ratios as diagnostics of the broad emission line region

2012 ◽  
Vol 372 ◽  
pp. 012069
Author(s):  
Andrea J Ruff ◽  
David J E Floyd ◽  
Kirk T Korista ◽  
Rachel L Webster ◽  
Ryan L Porter ◽  
...  
Keyword(s):  
Emission Line ◽  
Near Infrared ◽  
Hydrogen Emission ◽  
Broad Emission ◽  
Line Region ◽  
Broad Emission Line ◽  
Hydrogen Emission Line

scholarly journals Velocity Diagnostics of the Broad Emission-Line Region of Active Galactic Nuclei

1997 ◽  
Vol 159 ◽  
pp. 175-178 ◽  
Author(s):  
Brian Espey
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Nuclear Region ◽  
Driving Mechanisms ◽  
Broad Emission ◽  
Line Region ◽  
Broad Emission Line ◽  
Ongoing Project

AbstractWe present a brief review of emission-line velocity differences, and describe an ongoing project to determine the driving mechanisms responsible. We conclude with a brief outline of the use of velocity differences as probes of the conditions in the nuclear region of AGNs.

scholarly journals Broad Absorption Line Disappearance/Emergence in Multiple Ions in a Weak Emission-line Quasar

2019 ◽  
Vol 870 (2) ◽  
pp. L25 ◽  
Author(s):  
W. Yi ◽  
M. Vivek ◽  
W. N. Brandt ◽  
T. Wang ◽  
J. Timlin ◽  
...  
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Broad Absorption ◽  
Broad Absorption Line

scholarly journals The contribution of quasar absorption outflows to AGN feedback

2020 ◽  
Vol 499 (1) ◽  
pp. 1522-1529
Author(s):  
Timothy R Miller ◽  
Nahum Arav ◽  
Xinfeng Xu ◽  
Gerard A Kriss
Keyword(s):  
Absorption Line ◽  
Active Galactic Nucleus ◽  
Hubble Space Telescope ◽  
Broad Absorption ◽  
Feedback Effects ◽  
Space Telescope ◽  
Central Source ◽  
Broad Absorption Line

ABSTRACT Determining the distance of quasar absorption outflows from the central source (R) and their kinetic luminosity ($\dot{E}_\mathrm{\scriptstyle k}$) is crucial for understanding their contribution to active galactic nucleus (AGN) feedback. Here, we summarize the results for a sample of nine luminous quasars that were observed with the Hubble Space Telescope. We find that the outflows in more than half of the objects are powerful enough to be the main agents for AGN feedback, and that most outflows are found at R > 100 pc. The sample is representative of the quasar absorption outflow population as a whole and is unbiased towards specific ranges of R and $\dot{E}_\mathrm{\scriptstyle k}$. Therefore, the analysis results can be extended to the majority of such objects, including broad absorption line quasars. We find that these results are consistent with those of another sample (seven quasars) that is also unbiased towards specific ranges of R and $\dot{E}_\mathrm{\scriptstyle k}$. Assuming that all quasars have absorption outflows, we conclude that most luminous quasars produce outflows that can contribute significantly to AGN feedback. We also discuss the criterion for whether an outflow is energetic enough to cause AGN feedback effects.

scholarly journals Constraining the geometry and kinematics of the quasar broad emission line region using gravitational microlensing

2019 ◽  
Vol 629 ◽  
pp. A43 ◽  
Author(s):  
D. Hutsemékers ◽  
L. Braibant ◽  
D. Sluse ◽  
R. Goosmann
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Polar Wind ◽  
Disk Model ◽  
Continuum Source ◽  
Broad Emission ◽  
Gravitational Microlensing ◽  
Line Region ◽  
Broad Emission Line ◽  
Single Epoch

The quadruply lensed quasar HE0435−1223 shows a clear microlensing effect that affects differently the blue and red wings of the Hα line profile in its image D. To interpret these observations, and constrain the broad emission line region (BLR) properties, the effect of gravitational microlensing on quasar broad emission line profiles and their underlying continuum has been simulated considering representative BLR models and microlensing magnification maps. The amplification and distortion of the Hα line profile, characterized by a set of four indices, can be reproduced by the simulations. Although the constraints on the BLR models set by the observed single-epoch microlensing signal are not very robust, we found that flattened geometries (Keplerian disk and equatorial wind) can more easily reproduce the observed line profile deformations than a biconical polar wind. With an additional independent constraint on the size of the continuum source, the Keplerian disk model of the Hα BLR is slightly favored.

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