High‐Resolution Spectra of Intrinsic Absorption Lines in the Quasi‐stellar Object UM 675

Hamann, Fred; Barlow, T. A.; Junkkarinen, V. T.; Burbidge, E. M.

doi:10.1086/303781

Cited by 178 publications

(283 citation statements)

References 18 publications

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“…Two NALs that have undergone time variability have thereby confirmed themselves as intrinsic and yielded upper limits to their distances in the kiloparsec range: <1 kpc in UM 675 (Hamann et al 1997b), and <2 kpc in QSO 2343+125 (Hamann et al 1997c).…”

Section: Discussionmentioning

confidence: 91%

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

Hutsemékers

Brinkmann²

2004

A&A

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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.

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Section: Discussionmentioning

confidence: 91%

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

Hutsemékers

Brinkmann²

2004

A&A

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“…If the absorbing gas does not fully cover the background light source, as we have assumed above, then there can be unabsorbed light filling in the bottoms of the UV line troughs and the column densities inferred from the lines will be only lower limits. Studies of other sources show that the coverage fraction can differ between ions and vary with velocity (across the line profiles) in the same ion (Hamann et al 1997a(Hamann et al , 1997b. Our column density estimates all assume 100% coverage.…”

Section: The Uv/x-ray Relationshipmentioning

confidence: 81%

“…The best-known intrinsic UV absorption lines in QSOs are the broad absorption lines (BALs), but recent work has shown that some of the observed narrow absorption lines (NALs) and '' mini-BALs '' are also intrinsic to QSO environments (Barlow, Hamann, & Sargent 1997;Hamann et al 1997aHamann et al , 1997b. These features can have velocity shifts comparable to the BALs (up to À51,000 km s À1 in one confirmed case; Hamann et al 1997a), but the narrow line widths (from <100 to a few thousand km s À1 ) require outflows with much smaller line-of-sight velocity dispersions.…”

Section: Introductionmentioning

confidence: 99%

The Nature of the Ultraviolet/X‐Ray Absorber in PG 2302+029

Sabra

Hamann

Jannuzi

et al. 2003

ApJ

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We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029. This quasar has a rare system of ultra-high-velocity (À56,000 km s À1 ) UV absorption lines that form in an outflow from the active nucleus. The Chandra data indicate that soft X-ray absorption is also present. We perform a joint UV and X-ray analysis, using photoionization calculations, to determine the nature of the absorbing gas. The UV and X-ray data sets were not obtained simultaneously. Nonetheless, our analysis suggests that the X-ray absorption occurs at high velocities in the same general region as the UV absorber. There are not enough constraints to rule out multizone models. In fact, the distinct broad and narrow UV line profiles clearly indicate that multiple zones are present. Our preferred estimates of the ionization and total column density in the X-ray absorber (log U ¼ 1:6, N H ¼ 10 22:4 cm À2 ) overpredict the O vi 1032, 1038 absorption unless the X-ray absorber is also outflowing at $56,000 km s À1 , but they overpredict the Ne viii 770, 780 absorption at all velocities. If we assume that the X-ray-absorbing gas is outflowing at the same velocity as the UVabsorbing wind and that the wind is radiatively accelerated, then the outflow must be launched at a radius of 10 15 cm from the central continuum source. The smallness of this radius casts doubts on the assumption of radiative acceleration.

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“…Are they a subset (small or moderate) of all QSOs (a) because only some QSOs blow out such clouds, (b) because the absorbing clouds are little things that might or might not happen to cover the nucleus along our particular line of sight, or (c) because the obscuring gas is part of some large torus or disk whose plane we are in for some QSOs and not for others? The answer is yes (Turnshek et al 1997;Hamann et al 1997b). That is, one or more of these choices is probably correct, but we are not sure which, nor whether it is the same for all BAL versus non-BAL QSOs.…”

Section: Qsos With Broad Absorption Linesmentioning

confidence: 97%

“…Next the absorption z was supposed to be pretty close to the emission z, since, after all, how vigorously can even a QSO kick out gas? One case where and , nevertheless, z ϭ 2.51 z ϭ 2.24 e a has been claimed as an example of ejected gas producing lines 400 km s Ϫ1 wide (Hamann et al 1997a). In addition, there was supposed to be a fairly clean line between BAL QSO and other classes.…”

Section: Qsos With Broad Absorption Linesmentioning

confidence: 99%

Astrophysics in 1997

Trimble¹,

McFadden²

1998

PUBL ASTRON SOC PAC

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ABSTRACT. Martian marvels, a gamma-ray burster with a redshift, Galileo converses with Ganymede, a record galactic redshift of 4.92, and much else. Fiscal 1997 was definitely an exciting year for astronomers. We have tried hard to hit all the obvious highlights, but also to report more gradual progress on traditional problems of understanding planets, stars, galaxies, and the universe. Though the year was saddened by the loss of many valued colleagues, we nevertheless indulge in occasional soupçons of frivolity.

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High‐Resolution Spectra of Intrinsic Absorption Lines in the Quasi‐stellar Object UM 675

Cited by 178 publications

References 18 publications

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

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

The Nature of the Ultraviolet/X‐Ray Absorber in PG 2302+029

Astrophysics in 1997

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