Skip to main content

Research Repository

Advanced Search

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

Violino, G.; Coppin, K.E.K.; Stevens, J.A.; Farrah, D.; Geach, J.E.; Alexander, D.M.; Hickox, R.; Smith, D.J.B.; Wardlow, J.L.

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


G. Violino

K.E.K. Coppin

J.A. Stevens

D. Farrah

J.E. Geach

R. Hickox

D.J.B. Smith

J.L. Wardlow


It is thought that a class of broad absorption line (BAL) QSOs, characterized 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 Submillimetre Common-User Bolometer Array 2 (SCUBA-2) 850 μm observations of a sample of 17 FeLoBAL QSOs with 0.89 ≤ z ≤ 2.78 and −23.31 ≤ MB ≤ −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 sub-mm, none of them are individually detected at 850 μm, nor as a population through stacking (Fs = 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 Spectral Energy Distribution fitting analysis shows that the far-infrared emission is dominated by active galactic nuclei 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 ≥ 1012 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 an ultraluminous infrared galaxy (ULIRG) and an unobscured QSO; in particular, FeLoBALs are not characterized by a cold starburst which would support this hypothesis.


Violino, G., Coppin, K., Stevens, J., Farrah, D., Geach, J., Alexander, D., …Wardlow, J. (2016). A SCUBA-2 survey of FeLoBAL QSOs. Are FeLoBALs in a ‘transition phase’ between ULIRGs and QSOs?. Monthly Notices of the Royal Astronomical Society, 457(2), 1371-1384.

Journal Article Type Article
Acceptance Date Dec 15, 2015
Online Publication Date Feb 4, 2016
Publication Date Apr 1, 2016
Deposit Date May 31, 2016
Publicly Available Date Jun 15, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 457
Issue 2
Pages 1371-1384
Public URL
Related Public URLs


Published Journal Article (2.5 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

You might also like

Downloadable Citations