<i>Hubble Space Telescope</i>Observations of the Broad Absorption Line QuasarPG 0946+301

Arav, Nahum; Korista, K. T.; Kool, M. de; Junkkarinen, V. T.; Begelman, Mitchell C.

doi:10.1086/307073

Cited by 124 publications

(132 citation statements)

References 24 publications

Supporting

Mentioning

122

Contrasting

Order By: Relevance

“…This supports previous suggestions that at least some narrower and broader absorption phenomena are physically related (e.g., Arav et al 1999;Gallagher et al 2002;Ganguly & Brotherton 2008;Misawa et al 2008). Flatter hard X-ray spectra observed for QSOs with mini-BAL and especially BAL absorption could be explained by ionized or partial-covering absorber models with high (N H 10 22 cm −2 ) effective column densities.…”

Section: Are Mini-bals Just Narrow Bals?supporting

confidence: 89%

“…The velocity-width distinction used to classify absorbers as BALs (width > 2000 km s −1 ), mini-BALs (intermediate widths), and narrow absorption lines (NALs; width < 500 km s −1 for C iv) is somewhat arbitrary; it has been suggested that BAL absorption is an extension of the same physical processes responsible for narrower absorption features observed in QSO spectra (e.g., Section 4.2.1 of Arav et al 1999;Ganguly & Brotherton 2008). Previous studies of BAL QSOs have found that their UV absorption properties are correlated with the relative X-ray brightness of these sources (e.g., Gallagher et al 2006), indicating a physical link between X-ray absorption and the acceleration of BAL outflows.…”

Section: A Continuum Of Absorber Properties?mentioning

confidence: 99%

See 1 more Smart Citation

X-Ray Insights Into the Physics of Mini-Bal Quasar Outflows

Gibson

Brandt

Gallagher

et al. 2009

ApJ

View full text Add to dashboard Cite

We examine the ultraviolet and X-ray properties of 256 radio-quiet Sloan Digital Sky Survey quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad C iv absorption lines (BALs; width > 2000 km s −1 ) and those with C iv mini-BALs (here defined to have widths of 1000-2000 km s −1 ). Our sample includes 42 BAL and 48 mini-BAL QSOs. The relative X-ray brightness and hard spectral slopes of the mini-BAL population are, on average, intermediate between those of BAL and non-BAL QSOs, as might be expected if narrower and broader absorption line outflows are physically related. However, a significant population of mini-BALs has outflow velocities higher than would be expected for BAL QSOs of the same relative X-ray brightness. Consistently strong X-ray absorption is apparently not required to accelerate at least some mini-BALs to high outflow velocities. Assuming the mini-BAL features are correctly attributed to intrinsic C iv absorption, we suggest that their observed properties may be explained if mini-BALs are "seeds" that can be accelerated to form BALs when sufficient X-ray shielding is present. We also examine several QSOs with broad C iv absorption that have been recently reported to be unusually X-ray bright. Such cases are frequently mini-BAL QSOs, which, as a population, are generally brighter in X-rays than BAL QSOs. Pointed XMM-Newton observations also suggest that these sources (or unresolved neighbors) may have been previously observed in a high-flux state.

show abstract

Section: Are Mini-bals Just Narrow Bals?supporting

confidence: 89%

Section: A Continuum Of Absorber Properties?mentioning

confidence: 99%

X-Ray Insights Into the Physics of Mini-Bal Quasar Outflows

Gibson

Brandt

Gallagher

et al. 2009

ApJ

View full text Add to dashboard Cite

show abstract

“…Velocity and ionization dependent partial covering is often seen in NALs Hamann et al 2001), and has also been reported for mini-BAL and BAL QSOs (Arav et al 1999;Srianand & Petitjean 2000;de Kool et al 2001de Kool et al , 2002bHall et al 2003). The partial covering proves the intrinsic nature of the absorbers.…”

Section: Discussionmentioning

confidence: 56%

VLT + UVES spectroscopy of the low-ionization intrinsic absorber in SDSS J001130.56+005550.7

Hutsemékers

Brinkmann²

2004

A&A

View full text Add to dashboard Cite

Abstract. We analyse high-resolution VLT+UVES spectra of the low-ionization intrinsic absorber observed in the BAL QSO SDSS J001130.56+005550.7. Two narrow absorption systems at velocities −600 km s −1 and −22 000 km s −1 are detected. The low-velocity system is part of the broad absorption line (BAL), while the high-velocity one is well detached. While most narrow absorption components are only detected in the high-ionization species, the lowest velocity component is detected in both highand low-ionization species, including in the excited Si  and C  lines. From the analysis of doublet lines, we find that the narrow absorption lines at the low-velocity end of the BAL trough are completely saturated but do not reach zero flux, their profiles being dominated by a velocity-dependent covering factor. The covering factor is significantly smaller for Mg  than for Si  and N , which demonstrates the intrinsic nature of absorber. From the analysis of the excited Si  and C  lines in the lowest velocity component, we find an electron density 10 3 cm −3 . Assuming photoionization equilibrium, we derive a distance 20 kpc between the low-ionization region and the quasar core. The correspondence in velocity of the high-and low-ionization features suggests that all these species must be closely associated, hence formed at the same distance of ∼20 kpc, much higher than the distance usually assumed for BAL absorbers.

show abstract

“…It is noteworthy that each C iv BAL mentioned above has a comparable 20 line depth to its corresponding Si iv absorption line, providing evidence of saturation in these absorbers and therefore the transverse-motion scenario. Large C iv BAL optical depths would be 'hidden' within the non-zero line depths we measure if the absorbers only partially cover their background light sources (see e.g., Hamann 1999;Arav et al 1999Arav et al , 2001.…”

Section: Evidence For Transverse Motionsmentioning

confidence: 99%

Broad absorption line disappearance and emergence using multiple-epoch spectroscopy from the Sloan Digital Sky Survey

McGraw

Brandt

Grier

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We investigate broad absorption line (BAL) disappearance and emergence using a 470 BAL-quasar sample over ≤ 0.10-5.25 rest-frame years with at least three spectroscopic epochs for each quasar from the Sloan Digital Sky Survey. We identify 14 disappearing BALs over ≤ 1.73-4.62 rest-frame years and 18 emerging BALs over ≤ 1.46-3.66 rest-frame years associated with the C iv λλ1548,1550 and/or Si iv λλ1393,1402 doublets, and report on their variability behavior. BAL quasars in our dataset exhibit disappearing/emerging C iv BALs at a rate of 2.3 +0.9 −0.7 and 3.0 +1.0 −0.8 per cent, respectively, and the frequency for BAL to non-BAL quasar transitions is 1.7 +0.8 −0.6 per cent. We detect four re-emerging BALs over ≤ 3.88 rest-frame years on average and three re-disappearing BALs over ≤ 4.15 rest-frame years on average, the first reported cases of these types. We infer BAL lifetimes along the line of sight to be nominally < ∼ 100-1000 yr using disappearing C iv BALs in our sample. Interpretations of (re-)emerging and (re-)disappearing BALs reveal evidence that collectively supports both transverse-motion and ionization-change scenarios to explain BAL variations. We constrain a nominal C iv/Si iv BAL outflow location of < ∼ 100 pc from the central source and a radial size of > ∼ 1×10 −7 pc (0.02 au) using the ionization-change scenario, and constrain a nominal outflow location of < ∼ 0.5 pc and a transverse size of ∼0.01 pc using the transverse-motion scenario. Our findings are consistent with previous work, and provide evidence in support of BALs tracing compact flow geometries with small filling factors.

show abstract

Hubble Space TelescopeObservations of the Broad Absorption Line QuasarPG 0946+301

Cited by 124 publications

References 24 publications

X-Ray Insights Into the Physics of Mini-Bal Quasar Outflows

X-Ray Insights Into the Physics of Mini-Bal Quasar Outflows

VLT + UVES spectroscopy of the low-ionization intrinsic absorber in SDSS J001130.56+005550.7

Broad absorption line disappearance and emergence using multiple-epoch spectroscopy from the Sloan Digital Sky Survey

Contact Info

Product

Resources

About