A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Third Data Release

Trump, Jonathan R.; Hall, Patrick B.; Reichard, Timothy A.; Richards, Gordon T.; Schneider, Donald P.; Berk, D. E. vanden; Knapp, G. R.; Anderson, Scott F.; Fan, Xiaohui; Brinkman, J.; Kleinman, S. J.; Nitta, A.

doi:10.1086/503834

Cited by 379 publications

(344 citation statements)

References 52 publications

Supporting

Mentioning

321

Contrasting

Order By: Relevance

“…A rare subclass of the LoBAL quasars are the FeLoBALs with absorption from metastable excited states of Fe ii and Fe iii (Hazard et al 1987;Becker et al 2000). The BAL quasars are thought to account for between 10% and ∼40% of all quasars (Hewett & Foltz 2003;Reichard et al 2003;Carballo et al 2006;Trump et al 2006;Dai et al 2008;Gibson et al 2009;Allen et al 2011). We note that the exact BAL fraction is not trivial to determine because of differential selection effects between BAL quasars and non-BAL quasars.…”

Section: Introductionmentioning

confidence: 91%

See 1 more Smart Citation

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

Meusinger¹,

Schalldach²,

Scholz³

et al. 2012

A&A

View full text Add to dashboard Cite

Context. Large spectroscopic surveys have discovered very peculiar and hitherto unknown types of active galactic nuclei (AGN). Such rare objects may hold clues to the accretion history of the supermassive black holes at the centres of galaxies. Aims. We aim to create a sizeable sample of unusual quasars from the unprecedented spectroscopic database of the Sloan Digital Sky Survey (SDSS). Methods. We exploit the spectral archive of the 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 at redshifts from z = 0.6 to 4.3 by the SDSS pipeline. Particular attention was paid to minimise possible contamination by rare peculiar stellar spectral types. All selected quasar spectra were individually studied to determine the object type and the redshift.Results. We present a catalogue of 1005 quasars with unusual spectra. These spectra are dominated by either broad absorption lines (BALs; 42%), unusual red continua (27%), weak emission lines (18%), or conspicuously strong optical and/or UV iron emission (11%). 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, even though the compilation is not aimed at completeness in a quantifiable sense. The spectra are grouped into six types for which composite spectra are constructed and mean properties are computed. Remarkably, 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 (E(B − V) ≈ 0 to 0.4 for SMC-like extinction). Both the unusual BAL quasars and the strong iron emitters have significantly lower radio luminosities than normal quasars. We also confirm that strong BALs avoid the most radioluminous quasars. For 32 particularly interesting objects, individual spectra are presented. Among these objects are quasars with many narrow BAL troughs and one quasar where the continuum is strongly suppressed by overlapping BAL troughs across nearly the whole SDSS spectrum. Finally, we create a sample of quasars similar to the two "mysterious" objects discovered by Hall et al. (2002, ApJS, 141, 267) and briefly discuss the quasar properties and possible explanations of their highly peculiar spectra.

show abstract

Section: Introductionmentioning

confidence: 91%

“…In addition, different definitions of BAL quasars have been used in different studies. According to the criteria applied by Trump et al (2006), BAL quasars comprise 26% of quasars, LoBALs about 1.3%, and FeLoBALs about 0.3% (these being the raw fractions without correction for the additional reddening of BAL quasars compared to non-BALs).…”

Section: Introductionmentioning

confidence: 99%

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

Meusinger¹,

Schalldach²,

Scholz³

et al. 2012

A&A

View full text Add to dashboard Cite

show abstract

“…C0366 has been classified as a broad absorption-line quasar by Trump et al (2006) and Scaringi et al (2009) and has a spectroscopic redshift of 2.94 (Trump et al 2009). It is a faint radio source with an integrated VLA radio flux density of 362 µJy at 1.4 GHz.…”

Section: C0366mentioning

confidence: 99%

Unveiling the origin of the radio emission in radio-quiet quasars

Ruiz

Middelberg

Norris

et al. 2016

A&A

View full text Add to dashboard Cite

The origin of the radio emission in radio-quiet quasars (RQQs) has been a matter of debate for a long time. It is not well understood whether the emission is caused by star formation in the host galaxy or by black hole activity of the active galactic nuclei (AGN). We shed some light on these questions using the Very Long Baseline Interferometry (VLBI) technique to search for RQQs in the field of the Cosmological Evolution Survey (COSMOS). The extensive multi-wavelength coverage of the field (from radio to X-rays) was used to classify RQQs, and the milli-arcsecond resolution of VLBI provides a direct way to identify AGNs. In a sample of 18 RQQs we detected 3 using the Very Long Baseline Array (VLBA) at 1.4 GHz. In this Letter we report for the first time on a sample of RQQs with a measured lower limit on the fraction of radio emission coming from the AGN, thus demonstrating that the radio emission of at least some RQQs is dominated by an AGN.

show abstract

“…but with the change that the parameter C is unity over contiguous troughs of at least 1000 km s −1 (as in Trump et al 2006), and we considered as genuine BAL QSOs only objects with an AI > 100. To perform this calculation, we integrated the spectral region between the peaks of the C iv and Si iv emission lines to up to 25 000 km s −1 from the former.…”

Section: Optically Bright Samplementioning

confidence: 99%

Investigating the radio-loud phase of broad absorption line quasars

Bruni

González‐Serrano

Pedani

et al. 2014

A&A

View full text Add to dashboard Cite

Context. Broad absorption lines (BALs) are present in the spectra of ∼20% of quasars (QSOs); this indicates fast outflows (up to 0.2c) that intercept the observer's line of sight. These QSOs can be distinguished again into radio-loud (RL) BAL QSOs and radio-quiet (RQ) BAL QSOs. The first are very rare, even four times less common than RQ BAL QSOs. The reason for this is still unclear and leaves open questions about the nature of the BAL-producing outflows and their connection with the radio jet. Aims. We explored the spectroscopic characteristics of RL and RQ BAL QSOs with the aim to find a possible explanation for the rarity of RL BAL QSOs. Methods. We identified two samples of genuine BAL QSOs from SDSS optical spectra, one RL and one RQ, in a suitable redshift interval (2.5 < z < 3.5) that allowed us to observe the Mg ii and Hβ emission lines in the adjacent near-infrared (NIR) band. We collected NIR spectra of the two samples using the Telescopio Nazionale Galileo (TNG, Canary Islands). By using relations known in the literature, we estimated the black-hole mass, the broad-line region radius, and the Eddington ratio of our objects and compared the two samples. Results. We found no statistically significant differences from comparing the distributions of the cited physical quantities. This indicates that they have similar geometries, accretion rates, and central black-hole masses, regardless of whether the radio-emitting jet is present or not. Conclusions. These results show that the central engine of BAL QSOs has the same physical properties with and without a radio jet. The reasons for the rarity of RL BAL QSOs must reside in different environmental or evolutionary variables.

show abstract

A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Third Data Release

Cited by 379 publications

References 52 publications

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

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

Unveiling the origin of the radio emission in radio-quiet quasars

Investigating the radio-loud phase of broad absorption line quasars

Contact Info

Product

Resources

About