Continuum and Emission-Line Properties of Broad Absorption Line Quasars

Reichard, Timothy A.; Richards, Gordon T.; Hall, Patrick B.; Schneider, Donald P.; Berk, D. E. vanden; Fan, Xiaohui; York, Donald G.; Knapp, G. R.; Brinkmann, Jonathan

doi:10.1086/379293

Cited by 265 publications

(381 citation statements)

References 43 publications

(82 reference statements)

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“…Willott et al (2003) observed 30 BAL quasars with 2 ≤ z ≤ 2.6 using the SCUBA camera at the JCMT. This sample was drawn from the SDSS Early DR BAL sample of Reichard et al (2003). Priddey et al (2003) performed SCUBA observations of 57 non-BAL quasars from the Large Bright Quasar Survey (LBQS; Hewett, Foltz & Chaffee 1995) in the redshift range 1.5 ≤ z ≤ 3; and Priddey et al (2007) observed 15 LBQS BAL QSOs with SCUBA.…”

Section: Discussionmentioning

confidence: 99%

“…Sanders et al 1988a), and much of the focus has been on the broad absorption line (BAL) class of QSOs. BAL QSOs exhibit broad troughs (∼2000-20 000 km s −1 wide) in their UV and optical spectra arising from resonance-line absorption in gas with high outflowing velocities up to 66 000 km s −1 (Lynds 1967;Foltz et al 1983;Weymann et al 1991;Hall et al 2002;Reichard et al 2003), comprising 26 per cent of QSOs (Trump et al 2006), and they come in three sub-types according to the visible absorption features: (1) high ionization BAL QSOs (HiBALs) show absorption in N V, Si IV and C IV; (2) low ionization BAL QSOs (LoBALs) contain all of the HiBAL absorption features plus absorption in Mg II and other low ionization species (Voit, Weymann & Korista 1993); and finally (3) the rarer FeLoBALs, which are LoBALs also exhibiting absorption from excited fine-structure levels or excited atomic terms of Fe II or Fe III (e.g. Hazard et al 1987;Becker et al 1997Becker et al , 2000.…”

Section: Introductionmentioning

confidence: 99%

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A SCUBA-2 survey of FeLoBAL QSOs. Are FeLoBALs in a ‘transition phase’ between ULIRGs and QSOs?

Violino¹,

Coppin²,

Stevens³

et al. 2016

Mon. Not. R. Astron. Soc.

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It is thought that a class of broad absorption line (BAL) QSOs, characterised by Fe absorption features in their UV spectra (called 'FeLoBALs'), could mark a transition stage between the end of an obscured starburst event and a youthful QSO beginning to shed its dust cocoon, where Fe has been injected into the interstellar medium by the starburst. To test this hypothesis we have undertaken deep SCUBA-2 850 µm observations of a sample of 17 FeLoBAL QSOs with 0.89 z 2.78 and -23.31 M B -28.50 to directly detect an excess in the thermal emission of the dust which would probe enhanced star-formation activity. We find that FeLoBALs are not luminous sources in the submillimetre, none of them are individually detected at 850 µm, nor as a population through stacking (F s = 1.14 ± 0.58 mJy). Statistical and survival analyses reveal that FeLoBALs have sub-mm properties consistent with BAL and non-BAL QSOs with matched redshifts and magnitudes. An SED fitting analysis shows that the FIR emission is dominated by AGN activity, and a starburst component is required only in 6/17 sources of our sample; moreover the integrated total luminosity of 16/17 sources is L 10 12 L , high enough to classify FeLoBALs as infrared luminous.In conclusion, we do not find any evidence in support of FeLoBAL QSOs being a transition population between a ULIRG and an unobscured QSO; in particular, FeLoBALs are not characterized by a cold starburst which would support this hypothesis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A SCUBA-2 survey of FeLoBAL QSOs. Are FeLoBALs in a ‘transition phase’ between ULIRGs and QSOs?

Violino¹,

Coppin²,

Stevens³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…Elvis 2000). LoBALQs are observed to have a redder continuum than HiBALQs (Weymann et al 1991;Boroson & Meyers 1992;Sprayberry & Foltz 1992;Reichard et al 2003;Gibson et al 2009), and are likely predominantly located at the parameter-space of the lowest He ii EW and the reddest αUV (BLH13). The increase in the CF of C iv BAL with decreasing He ii EW and redder αUV (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The intrinsic fraction of quasars that are BALQs is estimated to be typically ∼20 per cent (Hewett & Foltz 2003;Reichard et al 2003;Knigge et al 2008;Gibson et al 2009;cf. Allen et al 2011), and ranges from ∼4 per cent in blue, strong He ii emission quasars, to ∼30 per cent in red, weak He ii emission quasars (Baskin, Laor & Hamann 2013, hereafter BLH13).…”

Section: Introductionmentioning

confidence: 99%

“…Allen et al 2011), and ranges from ∼4 per cent in blue, strong He ii emission quasars, to ∼30 per cent in red, weak He ii emission quasars (Baskin, Laor & Hamann 2013, hereafter BLH13). Although there are several differences in emission properties between BALQs and non-BALQs, the two subtypes appear to be drawn from the same population (Weymann et al 1991;Hamann, Korista & Morris 1993;Reichard et al 2003). The C iv broad absorption line (BAL) spans a large range in depth, width and the velocity shift (v shift ) of maximum absorption depth (v md ) among different BALQs.…”

Section: Introductionmentioning

confidence: 99%

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On the origins of C iv absorption profile diversity in broad absorption line quasars

Baskin

Laor

Hamann

2015

Monthly Notices of the Royal Astronomical Society

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There is a large diversity in the C iv broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the C iv BAL properties, FWHM, maximum depth of absorption and its velocity shift (v md ), using the SDSS DR7 quasar catalogue. We find the following: (i) Although the median C iv BAL profile in the quasar rest-frame becomes broader and shallower as the UV continuum slope (α UV at 1700-3000Å) gets bluer, the median individual profile in the absorber rest-frame remains identical, and is narrow (FWHM = 3500 km s −1 ) and deep. Only 4 per cent of BALs have FWHM > 10, 000 km s −1 . (ii) As the He ii emission equivalent-width (EW) decreases, the distributions of FWHM and v md extend to larger values, and the median maximum depth increases. These trends are consistent with theoretical models in which softer ionizing continua reduce overionization, and allow radiative acceleration of faster BAL outflows. (iii) As α UV becomes bluer, the distribution of v md extends to larger values. This trend may imply faster outflows at higher latitudes above the accretion disc plane. (iv) For non-BALQs, the C iv emission line decreases with decreasing He ii EW, and becomes more asymmetric and blueshifted. This suggests an increasing relative contribution of emission from the BAL outflow to the C iv emission line as the ionizing spectral energy distribution (SED) gets softer, which is consistent with the increasing fraction of BALQs as the ionizing SED gets softer.

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Are radio‐loud Broad Absorption Line Quasars young sources?

et al. 2009

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Studying Broad Absorption Line Quasars (BAL QSOs) is interesting because they probe the physics of the AGN environment, and because AGN outflows are important ingredients in many recent astrophysical puzzles. In the last decade, a substantial population of radio BAL QSOs was discovered and we have started a characterisation of the radio-loud BAL QSO population studying their radio spectra, radio morphology and polarisation properties. Our high-resolution radio maps show that BAL QSOs are compact radio sources with projected linear sizes below 1 kpc. Most BAL QSOs in our sample are unpolarised or weakly polarised at 8.4 GHz. They display convex radio spectra which typically flatten at low frequencies and become steeper at high frequencies, i.e. above 20 GHz. Many of these characteristics are common to the population of young radio sources, like Compact Steep Spectrum (CSS) or Gigahertz-Peaked Spectrum (GPS) sources. The above supports the hypothesis that BAL QSOs might be related to the initial stages in the AGN evolution.

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Continuum and Emission-Line Properties of Broad Absorption Line Quasars

Abstract: We investigate the continuum and emission-line properties of 224 broad absorption line quasars (BALQSOs) with 0.9 Show more

Cited by 265 publications

References 43 publications

A SCUBA-2 survey of FeLoBAL QSOs. Are FeLoBALs in a ‘transition phase’ between ULIRGs and QSOs?

A SCUBA-2 survey of FeLoBAL QSOs. Are FeLoBALs in a ‘transition phase’ between ULIRGs and QSOs?

On the origins of C iv absorption profile diversity in broad absorption line quasars

Are radio‐loud Broad Absorption Line Quasars young sources?

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