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A Connection between Obscuration and Star Formation in Luminous Quasars

Chen, C.-T.J.; Hickox, R.C.; Alberts, S.; Harrison, C.M.; Alexander, D.M.; Assef, R.; Brodwin, M.; Brown, M.J.I.; Del Moro, A.; Forman, W.R.; Gorjian, V.; Goulding, A.D.; Hainline, K.N.; Jones, C.; Kochanek, C.S.; Murray, S.S.; Pope, A.; Rovilos, E.; Stern, D.

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C.-T.J. Chen

R.C. Hickox

S. Alberts

C.M. Harrison

R. Assef

M. Brodwin

M.J.I. Brown

A. Del Moro

W.R. Forman

V. Gorjian

A.D. Goulding

K.N. Hainline

C. Jones

C.S. Kochanek

S.S. Murray

A. Pope

E. Rovilos

D. Stern


We present a measurement of the star formation properties of a uniform sample of mid-IR-selected, optically unobscured, and obscured quasars (QSO1s and QSO2s) in the Boötes survey region. We use a spectral energy distribution analysis for photometric data spanning optical to far-IR wavelengths to separate the active galactic nucleus (AGN) and host galaxy components. We find that when compared to a matched sample of QSO1s, the QSO2s have roughly twice the far-IR detection fractions, far-IR fluxes, and infrared star formation luminosities ($L_{{\rm IR}}^{{\rm SF}}$). Correspondingly, we show that the AGN obscured fraction rises from 0.3 to 0.7 between (4–40) × ${{10}^{11}}{{L}_{\odot }}$. We also find evidence associating X-ray absorption with the presence of far-IR-emitting dust. Overall, these results are consistent with galaxy evolution models in which quasar obscuration is associated with dust-enshrouded starburst galaxies.


Chen, C., Hickox, R., Alberts, S., Harrison, C., Alexander, D., Assef, R., …Stern, D. (2015). A Connection between Obscuration and Star Formation in Luminous Quasars. Astrophysical Journal, 802(1), Article 50.

Journal Article Type Article
Acceptance Date Jan 20, 2015
Publication Date Mar 20, 2015
Deposit Date May 15, 2015
Publicly Available Date May 21, 2015
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 802
Issue 1
Article Number 50
Keywords Galaxies: active, Galaxies: starburst, Infrared: galaxies, Quasars: general, X-rays: galaxies.
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Copyright Statement
© 2015. The American Astronomical Society. All rights reserved.

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