Strong Broad Absorption Lines Research Articles

Deep absorption in SDSS J110511.15+530806.5

Aims. We study the origin of the anomalous deep absorption in a spectrum of the SDSS J110511.15+530806.5 distant quasar (z = 1.929) obtained by the Sloan Digital Sky Survey in Data Release 14 of the optical catalog. We aim to estimate the velocity of absorbing material, and we show that this material considerably affects our measurements of the black hole (BH) mass in massive quasars with the use of common virial mass estimators. Methods. The spectral shape of the quasar was modeled assuming that the accretion disk emission is influenced by a hot corona, warm skin, and absorbing material located close to the nucleus. The whole analysis was undertaken with XSPEC models and tools. The overall spectral shape was represented with the AGNSED model, while the deep absorption is well described by two Gaussians. Results. The observed spectrum and the fitting procedure allowed us to estimate the BH mass in the quasar as 3.52 ± 0.01 × 109 M⊙, the nonzero BH spin is a* = 0.32 ± 0.04, and the accretion rate is ṁ = 0.274 ± 0.001. The velocities of the detected absorbers lie in the range of 6330–108 135 km s−1. When we consider that absorption is caused by the C IV ion, one absorber is folding toward the nucleus with a velocity of 73 887 km s−1. We derived a BI index of about 20 300 km s−1 and a mass outflow rate up to 38.5% of the source accretion rate. Conclusions. The high absorption observed in SDSS J110511.15+530806.5 is evidence of fast winds that place the source in the group of objects on the border with UFO (ultra-fast outflows), strong broad absorption line, and fast failed radiatively accelerated dusty outflow (FRADO). This absorption affects the BH mass measurement by two orders of magnitude as compared to virial mass estimation.

Probing Early Supermassive Black Hole Growth and Quasar Evolution with Near-infrared Spectroscopy of 37 Reionization-era Quasars at 6.3 < z ≤ 7.64

Abstract We report the results of near-infrared spectroscopic observations of 37 quasars in the redshift range 6.3 < z ≤ 7.64, including 32 quasars at z > 6.5, forming the largest quasar near-infrared spectral sample at this redshift. The spectra, taken with Keck, Gemini, VLT, and Magellan, allow investigations of central black hole mass and quasar rest-frame ultraviolet spectral properties. The black hole masses derived from the Mg ii emission lines are in the range (0.3–3.6) × 109 M ⊙, which requires massive seed black holes with masses ≳103–104 M ⊙, assuming Eddington accretion since z = 30. The Eddington ratio distribution peaks at λ Edd ∼ 0.8 and has a mean of 1.08, suggesting high accretion rates for these quasars. The C iv–Mg ii emission-line velocity differences in our sample show an increase of C iv blueshift toward higher redshift, but the evolutionary trend observed from this sample is weaker than the previous results from smaller samples at similar redshift. The Fe ii/Mg ii flux ratios derived for these quasars up to z = 7.6, compared with previous measurements at different redshifts, do not show any evidence of strong redshift evolution, suggesting metal-enriched environments in these quasars. Using this quasar sample, we create a quasar composite spectrum for z > 6.5 quasars and find no significant redshift evolution of quasar broad emission lines and continuum slope, except for a blueshift of the C iv line. Our sample yields a strong broad absorption line quasar fraction of ∼24%, higher than the fractions in lower-redshift quasar samples, although this could be affected by small sample statistics and selection effects.

A Luminous Quasar at Redshift 7.642

Abstract Distant quasars are unique tracers to study the formation of the earliest supermassive black holes (SMBHs) and the history of cosmic reionization. Despite extensive efforts, only two quasars have been found at z ≥ 7.5, due to a combination of their low spatial density and the high contamination rate in quasar selection. We report the discovery of a luminous quasar at z = 7.642, J0313−1806, the most distant quasar yet known. This quasar has a bolometric luminosity of 3.6 × 1013 L ⊙. Deep spectroscopic observations reveal a SMBH with a mass of (1.6 ± 0.4) × 109 M ⊙ in this quasar. The existence of such a massive SMBH just ∼670 million years after the big bang challenges significantly theoretical models of SMBH growth. In addition, the quasar spectrum exhibits strong broad absorption line (BAL) features in C iv and Si iv, with a maximum velocity close to 20% of the speed of light. The relativistic BAL features, combined with a strongly blueshifted C iv emission line, indicate that there is a strong active galactic nucleus (AGN)-driven outflow in this system. Atacama Large Millimeter/submillimeter Array observations detect the dust continuum and [C ii] emission from the quasar host galaxy, yielding an accurate redshift of 7.6423 ± 0.0013 and suggesting that the quasar is hosted by an intensely star-forming galaxy, with a star formation rate of ∼200 M ⊙ yr−1 and a dust mass of ∼7 × 107 M ⊙. Follow-up observations of this reionization-era BAL quasar will provide a powerful probe of the effects of AGN feedback on the growth of the earliest massive galaxies.

On the structure and energetics of quasar broad absorption-line outflows

Quasar accretion-disk outflows might play an important role in galaxy evolution, but they are notoriously difficult to study due to line saturation and blending problems in the Ly-alpha forest. We circumvent these problems by constructing median composite spectra of diverse broad absorption lines (BALs) and `mini-BALs' in SDSS-III BOSS quasars at redshifts 2.3 < z < 3.5. Sorting by CIV 1549,1551 absorption-line strength with AlIII 1855,1863 as an additional indicator of low ionisations (LoBALs) we find the following: (1) Deeper and broader BALs are accompanied by weaker HeII 1640 emission lines, consistent with softer ionising spectra producing more effective radiative acceleration. (2) PV 1118,1128 absorption is present with resolved ~1:1 depth ratios in all composites from mini-BALs to strong BALs indicating that line saturation, large total column densities log N_H(cm^-2) > 22.7, and large ionisation parameters log U > -0.5 are common. (3) Different observed depths in saturated lines identify inhomogeneous partial covering on spatial scales <0.006 pc, where weak/low-abundance transitions like PV form in small high-column density clumps while stronger/broader lines like CIV form in larger volumes. (4) Excited-state SiIV* 1073 and CIII* 1176 lines in BAL outflows indicate typical densities n_e > 3 x 10^5 cm^-3 and maximum radial distances R < 23pc from the quasars. (5) For reasonable actual distances, the median BAL outflow has minimum kinetic energy L_K/L > 0.005(R/1.2pc) sufficient (by some estimates) for feedback to galaxy evolution. (6) LoBAL quasars have the largest median outflow column densities, highest velocities, and weakest HeII 1640 emission in our study; they appear to be at one extreme in a distribution of quasar properties where softer ionising spectra drive more powerful outflows.

The Carbon and Nitrogen Abundance Ratio in the Broad Line Region of Tidal Disruption Events

Abstract The rest-frame UV spectra of three recent tidal disruption events (TDEs), ASASSN-14li, PTF15af, and iPTF16fnl, display strong nitrogen emission lines but weak or undetectable carbon lines. In these three objects, the upper limits of the C iii] /N iii] ratio are about two orders of magnitude lower than those of quasars, suggesting a high abundance ratio of [N/C]. With detailed photoionization simulations, we demonstrate that and are formed in the same zone, so the Ciii]/N iii] ratio depends only moderately on the physical conditions in the gas and weakly on the shape of the ionizing continuum. There are smaller than 0.5 dex variations in the line ratio over wide ranges of gas densities and ionization parameters at a given metallicity. This allows a robust estimate of the relative abundance ratio of nitrogen to carbon. We derive a relative abundance ratio of [N/C] &gt; 1.5 for ASASSN-14li, and an even higher one for PTF15af and iPTF16fnl. This suggests that the broad line region in those TDE sources is made of nitrogen-enhanced core material that falls back at later times. Based on stellar evolution models, the lower limit of the disrupted star should be larger than . The chemical abundance of the line-emitting gas provides convincing evidence that the flares originate from stellar tidal disruptions. The coincidence of the weakness of the X-ray emission with the strong broad absorption lines in PTF15af and iPTF16fnl, and the strong X-ray emission without such lines in ASASSN-li14, are analogous to quasars with and without broad absorption lines.

STRONG VARIABILITY OF OVERLAPPING IRON BROAD ABSORPTION LINES IN FIVE RADIO-SELECTED QUASARS

We present the variability study of broad absorption lines (BALs) in a uniformly radio-selected sample of 28 BAL quasars using the archival data from the FIRST Bright Quasar Survey (FBQS) and the Sloan Digital Sky Survey (SDSS), as well as those obtained by ourselves, covering time scales $\sim 1-10$ years in the quasar's rest-frame. To our surprise, 5 quasars showing strong variations are all belong to a special subclass of overlapping iron low ionization BAL (OFeLoBAL) quasars, however, other 4 non-overlapping FeLoBALs (non-OFeLoBALs) are invariable except one case with weak optical depth change. Meanwhile, we also find 6 typical variations of high-ionization and low-ionization BALs in this BAL quasar sample. Photoionization models suggest that OFeLoBALs are formed in a relative dense ($n_e>10^6$ cm$^{-3}$) outflows at a distance from the subparsec to the dozens of parsecs from the continuum source. They differ from those of non-OFeLoBALs, which are likely produced by low-density gas, locating at a distance of hundreds to thousands parsecs. Thus, OFeLoBALs and non-OFeLoBALs, i.e., FeLoBALs with/without strong BAL variations, perhaps represent the bimodality of Fe II absorption, the former is located in the active galactic nucleus environment rather than the host galaxy. We suggest that high density and small distance are the necessary conditions that cause OFeLoBALs. As suggested in the literature, strong BAL variability is possibly due to variability of the covering factor of BAL regions caused by clouds transiting across the line of sight rather than ionization variations.

Unusual quasars from the Sloan Digital Sky Survey selected by means of Kohonen self-organising maps

We exploit the spectral archive of the Sloan Digital Sky Survey (SDSS) Data Release 7 to select unusual quasar spectra. The selection method is based on a combination of the power of self-organising maps and the visual inspection of a huge number of spectra. Self-organising maps were applied to nearly 10^5 spectra classified as quasars by the SDSS pipeline. Particular attention was paid to minimise possible contamination by rare peculiar stellar spectral types. We present a catalogue of 1005 quasars with unusual spectra. This large sample provides a useful resource for both studying properties and relations of/between different types of unusual quasars and selecting particularly interesting objects. The spectra are grouped into six types. All these types turn out to be on average more luminous than comparison samples of normal quasars after a statistical correction is made for intrinsic reddening. Both the unusual broad absorption line (BAL) quasars and the strong iron emitters have significantly lower radio luminosities than normal quasars. We also confirm that strong BALs avoid the most radio-luminous quasars. Finally, we create a sample of quasars similar to the two "mysterious" objects discovered by Hall et al. (2002) and briefly discuss the quasar properties and possible explanations of their highly peculiar spectra. (Abstract modified to match the arXiv format)

Quasar Broad Absorption Line Variability on Multiyear Timescales

We use quantitative metrics to characterize the variation of C IV λ1549 broad absorption lines (BALs) over 3-6 (rest-frame) years in a sample of 13 quasars at 1.7 ≤ z≤ 2.8 and compare the results to previous studies of BAL variability on shorter timescales. The strong BALs in our study change in complex ways over 3-6 yr. Variation occurs in discrete regions only a few thousand kilometers per second wide, and the distribution of the change in absorption equivalent width broadens over time. We constrain the typical C IV BAL lifetime to be at least a few decades. While we do not find evidence to support a scenario in which the variation is primarily driven by photoionization on multiyear timescales, there is some indication that the variation is produced by changes in outflow geometry. We do not observe significant changes in the BAL onset velocity, indicating that the absorber is either far from the source or is being continually replenished and is azimuthally symmetric. It is not possible in a human lifetime to expand the timescales in our study by more than a factor of a few using optical spectroscopy. However, the strong variation we have observed in some BALs indicates that future studies of large numbers of BAL QSOs will be valuable to constrain BAL lifetimes and the physics of variation.

Evolutionary unification in composite active galactic nuclei

In this paper, we present an evolutionary unification scenario, involving supermassive black holes (SMBHs) and starbursts (SBs) with outflow (OF), that seems capable of explaining most of the observational properties (of at least part) of active galactic nuclei (AGN). The scenario includes a nuclear/circumnuclear SB closely associated with the AGN where the narrow-line region (NLR), broad-line region (BLR) and broad absorption line (BAL) region are produced in part by the OF process with shells and in compact supernova remnants (cSNRs). The OF process in BAL quasi-stellar objects (QSOs) with extreme infrared (IR) and Fe II emission is studied. In addition, the Fe II problem regarding the BLR of AGN is analysed. The correlations between the BAL, IR emission, Fe II intensity and the intrinsic properties of the AGN are not clearly understood. We suggest here that the behaviour of the BAL, IR and Fe II emission in AGN can be understood within an evolutionary and composite model for AGN. In our model, strong BAL systems and Fe II emission are present (and intense) in young IR objects. Parameters like the BALs, IR emission, Fe II/Hβ intensity ratio, Fe II equivalent width (EW), broad-line width, [O III] λ5007-A intensity and width, NLR size, X-ray spectral slope in radio quiet (RQ) AGN plus lobe separation, and lobe to core intensity ratio in radio loud (RL) AGN are proposed to be fundamentally time-dependent variables inside time-scales of the order of 10 8 yr. Orientation/obscuration effects take the role of a second parameter providing the segregation between Seyfert 1/Seyfert 2 galaxies (Sy1/Sy2) and broad-/narrow-line radio galaxies (BLRG/NLRG).

LBQS 0103−2753: A 0[farcs]3 Binary Quasar

Imaging and spectroscopy with the Hubble Space Telescope show that LBQS 0103-2753 (V = 17.8, z = 0.848) is a binary quasar with a separation of 03, or 2.3 kpc. This is by far the smallest separation binary quasar reported to date. The two components have very different spectra, including the presence of strong broad absorption lines (BALs) in component A only. The emission-line redshifts, based on the broad high-ionization C IV lines, are zA = 0.834 and zB = 0.858; their difference is 3900 km s-1 in velocity units. The broad C IV lines, however, are probably not a good indicator of systemic redshift; and LBQS 0103-2753A and B could have a much smaller systemic redshift difference, like the other known binary quasars. If the systemic redshift difference is small, then LBQS 0103-2753 would most likely be a galaxy merger that has led to a binary supermassive black hole. There is now one known 03 binary among roughly 500 QSOs that have been observed in a way that would reveal such a close binary. This suggests that QSO activity is substantially more likely for black hole binaries at spacings ~2 kpc than at ~15 to 60 kpc. Between 1987 and 1998, the observed Mg II BAL disappeared.

Quasar candidates near 1057 + 01

Positions and magnitudes are given for 143 quasar candidates and three white dwarf candidates discovered with the CFHT blue grens in a 2.7 square degree area in the direction 1057 + 01. The goal of this survey is to provide complete samples of quasars to study the large scale distribution of matter at moderate to high (z less than 3.4) redshifts. Part of the region surveyed in this paper was previously studied by Crampton and Parmar (1983), allowing a comparison of the search and measurements accuracies. Redshifts, derived from MMT spectroscopy, for 27 of the candidates are also presented. One quasar, 1058.1 + 0052, displays strong broad absorption lines characteristic of BAL quasars. 5 refs.

Morphology and nuclear spectroscopy of Markarian 231

Deep optical imaging of Mkn 231 reveals twin (tidal?) tails, a linear nuclear feature at green wavelengths, and a very blue region 4 arcsec south of the nucleus. Much of the central part of the galaxy is red, but there are complex areas of blue luminosity outside this, and a sharp edge to the luminosity at a distance of about 16 arcsec from the center. Overall, the host galaxy appears to have a normal optical luminosity and blue color (B-R = about 0.7) despite being one of the most luminous galaxies known in the IR. Radio emission in the system is extended on one side on a scale similar to the optical tails, but shows no detailed correspondence with optical structure; in particular, there is no radio counterpart to the optical 'jet'. Examination of IUE archival data indicates that the UV flux is very weak and the UV spectrum is peculiar for a Seyfert galaxy. The UV observations provide evidence for considerable nuclear extinction in the system, in accordance with previously published optical and IR work, but the UV extinction is unlike Galactic absorption and may be more similar to that seen in the LMC. Recent optical spectra of Mkn 231 show changes in both the emission-line spectrum and in the strong broad absorption lines (BAL), compared with previously published observations. It is suggested that Mkn 231 may be a recently merged system which is currently undergoing star formation. The connection with BAL QSOs is also discussed.

Morphology and Spectroscopy of Markarian 231

Deep optical imaging of Mkn 231 reveals twin (tidal?) tails, a linear nuclear feature at green wavelengths, and a very blue region 4 arcsec south of the nucleus. Much of the central part of the galaxy is red, but there are complex areas of blue luminosity outside this, and a sharp edge to the luminosity at a distance of ~16 arcsec from the centre. Overall, the host galaxy appears to have a normal optical luminosity and blue colour (B-R ~0.7) despite being one of the most luminous galaxies known in the infrared. Radio emission in the system is extended on one side on a similar scale to the optical tails, but shows no detailed correspondence with optical structure; in particular there is no radio counterpart to the optical ‘jet’. Examination of IUE archival data indicate that the UV flux is very weak and the UV spectrum is peculiar for a Seyfert galaxy. The UV observations provide evidence for considerable nuclear extinction in the system, in accordance with previously published optical and infrared work, but the UV extinction is unlike Galactic absorption and may be more similar to that seen in the LMC. Recent optical spectra of Mkn 231 show changes in both the emission line spectrum and in the strong broad absorption lines (BAL), compared with previously published observations. This places strong limitations on the size of the nuclear continuum source. We suggest that Mkn 221 is a recently merged system which is currently undergoing star-formation, and discuss the connection with BAL QSOs.

The emission-line regions in broad absorption line quasars

view Abstract Citations (89) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Emission-Line Regions in Broad Absorption Line Quasars Hartig, G. F. ; Baldwin, J. A. Abstract The properties of the emission-line regions in 16 broad absorption line (BAL) quasars are compared to those of non-BAL quasars. It is found that about half the BAL quasars, those having detached BALs, are significantly different from the comparison samples of normal quasars. They have large Al III/semiforbidden C III intensity ratios, strong Fe II emission, and unusually weak C IV emission lines whose profiles do not agree well with those of the lower ionization emission lines. New spectra of the Mg II 2798 A region in 13 of these BAL quasars show a few cases of possible weak Mg II BAL absorption, but no unambiguously strong cases. Thus, it is concluded that strong BAL absorption in Mg II is rare. The quasar H0335 -336 has very narrow emission lines (1000 km/s), and thus may offer a rare opportunity to measure many weak or normally blended emission lines which can give information about physical conditions in the emission-line gas. Publication: The Astrophysical Journal Pub Date: March 1986 DOI: 10.1086/163974 Bibcode: 1986ApJ...302...64H Keywords: Astronomical Spectroscopy; Emission Spectra; Quasars; Spectral Energy Distribution; Spectral Line Width; Abundance; Aluminum; Carbon; Iron; Spectrum Analysis; Astrophysics; QUASARS full text sources ADS | data products SIMBAD (18) NED (17)