Heavily reddened z ∼ 2 type 1 quasars - II. H α star formation constraints from SINFONI IFU observations
Heavily reddened z ∼ 2 type 1 quasars - II. H α star formation constraints from SINFONI IFU observations
We use near-infrared integral field unit spectroscopy to search for H α emission associated with star formation in a sample of 28 heavily reddened (E(B - V) ≃ 0.5-1.9), hyperluminous (log(Lbol/erg s-1)≃ 47-48) broad-line quasars at z ≃ 1.4-2.7. 16 of the 28 quasars show evidence for star formation with an average extinction-corrected star formation rate (SFR) of 320 ± 70 M⊙ yr-1. A stacked spectrum of the detections shows weak [N II], consistent with star formation as the origin of the narrow H α emission. The star-forming regions are spatially unresolved in 11 of the 16 detections and constrained to lie within ∼6 kpc of the quasar emission. In the five resolved detections we find the star-forming regions are extended on scales of ∼8 kpc around the quasar emission. The prevalence of high SFRs is consistent with the identification of the heavily reddened quasar population as representing a transitional phase from apparent `starburst galaxies' to optically luminous quasars. Upper limits are determined for 10 quasars in which star formation is undetected. In two of the quasars the SFR is constrained to be relatively modest, <50 M⊙ yr−1, but significantly higher levels of star formation could be present in the other eight quasars. The combination of the 16 strong star formation detections and the eight high SFR limits means that high levels of star formation may be present in the majority of the sample. Higher spatial resolution data, of multiple emission lines, will allow us to better understand the interplay between star formation and active galactic nucleus activity in these transitioning quasars.
galaxies: active, quasars: emission lines, quasars: general
999-1017
Alaghband-Zadeh, S.
7d36b464-4547-4900-8739-06bb1c759932
Banerji, Manda
ce0a04bf-70a4-4b64-9027-b1a01def7325
Hewett, Paul C.
a4763f70-9f9a-4a4e-85ed-10694a66e5c9
McMahon, Richard G.
43b8802d-36da-4b74-a7e4-66155c0e1a87
1 June 2016
Alaghband-Zadeh, S.
7d36b464-4547-4900-8739-06bb1c759932
Banerji, Manda
ce0a04bf-70a4-4b64-9027-b1a01def7325
Hewett, Paul C.
a4763f70-9f9a-4a4e-85ed-10694a66e5c9
McMahon, Richard G.
43b8802d-36da-4b74-a7e4-66155c0e1a87
Alaghband-Zadeh, S., Banerji, Manda, Hewett, Paul C. and McMahon, Richard G.
(2016)
Heavily reddened z ∼ 2 type 1 quasars - II. H α star formation constraints from SINFONI IFU observations.
Monthly Notices Of The Royal Astronomical Society, 459 (1), .
(doi:10.1093/mnras/stw682).
Abstract
We use near-infrared integral field unit spectroscopy to search for H α emission associated with star formation in a sample of 28 heavily reddened (E(B - V) ≃ 0.5-1.9), hyperluminous (log(Lbol/erg s-1)≃ 47-48) broad-line quasars at z ≃ 1.4-2.7. 16 of the 28 quasars show evidence for star formation with an average extinction-corrected star formation rate (SFR) of 320 ± 70 M⊙ yr-1. A stacked spectrum of the detections shows weak [N II], consistent with star formation as the origin of the narrow H α emission. The star-forming regions are spatially unresolved in 11 of the 16 detections and constrained to lie within ∼6 kpc of the quasar emission. In the five resolved detections we find the star-forming regions are extended on scales of ∼8 kpc around the quasar emission. The prevalence of high SFRs is consistent with the identification of the heavily reddened quasar population as representing a transitional phase from apparent `starburst galaxies' to optically luminous quasars. Upper limits are determined for 10 quasars in which star formation is undetected. In two of the quasars the SFR is constrained to be relatively modest, <50 M⊙ yr−1, but significantly higher levels of star formation could be present in the other eight quasars. The combination of the 16 strong star formation detections and the eight high SFR limits means that high levels of star formation may be present in the majority of the sample. Higher spatial resolution data, of multiple emission lines, will allow us to better understand the interplay between star formation and active galactic nucleus activity in these transitioning quasars.
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stw682
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Accepted/In Press date: 21 March 2016
e-pub ahead of print date: 23 March 2016
Published date: 1 June 2016
Keywords:
galaxies: active, quasars: emission lines, quasars: general
Identifiers
Local EPrints ID: 489944
URI: http://eprints.soton.ac.uk/id/eprint/489944
ISSN: 1365-2966
PURE UUID: 07926117-1fa3-4771-9727-460fde9f58be
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Date deposited: 08 May 2024 16:30
Last modified: 09 May 2024 01:57
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Author:
S. Alaghband-Zadeh
Author:
Paul C. Hewett
Author:
Richard G. McMahon
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