J/MNRAS/455/4191 Radio emission from radio-quiet quasars (Zakamska+, 2016)
Star formation in quasar hosts and the origin of radio emission in
radio-quiet quasars.
Zakamska N.L., Lampayan K., Petric A., Dicken D., Greene J.E.,
Heckman T.M., Hickox R.C., Ho L.C., Krolik J.H., Nesvadba N.P.H.,
Strauss M.A., Geach J.E., Oguri M., Strateva I.V.
<Mon. Not. R. Astron. Soc., 455, 4191-4211 (2016)>
=2016MNRAS.455.4191Z 2016MNRAS.455.4191Z (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Radio sources ; Infrared sources
Keywords: quasars: general - galaxies: star formation -
radio continuum: galaxies
Abstract:
Radio emission from radio-quiet quasars may be due to star formation
in the quasar host galaxy, to a jet launched by the supermassive black
hole, or to relativistic particles accelerated in a wide-angle
radiatively driven outflow. In this paper, we examine whether radio
emission from radio-quiet quasars is a byproduct of star formation in
their hosts. To this end, we use infrared spectroscopy and photometry
from Spitzer and Herschel to estimate or place upper
limits on star formation rates in hosts of ∼300 obscured and
unobscured quasars at z<1. We find that low-ionization
forbidden emission lines such as [NeII] and [NeIII] are likely
dominated by quasar ionization and do not provide reliable star
formation diagnostics in quasar hosts, while polycyclic aromatic
hydrocarbon (PAH) emission features may be suppressed due to the
destruction of PAH molecules by the quasar radiation field. While the
bolometric luminosities of our sources are dominated by the quasars,
the 160µm fluxes are likely dominated by star formation, but they
too should be used with caution. We estimate median star formation
rates to be 6-29M☉/yr, with obscured quasars at the high end of
this range. This star formation rate is insufficient to explain the
observed radio emission from quasars by an order of magnitude, with
log(Lradio,obs/Lradio,SF)=0.6-1.3 depending on quasar
type and star formation estimator. Although radio-quiet quasars in our
sample lie close to the 8-1000µm infrared/radio correlation
characteristic of the star-forming galaxies, both their infrared
emission and their radio emission are dominated by the quasar
activity, not by the host galaxy.
Description:
Our goal is to assemble a large sample of quasars (whether optically
obscured or unobscured) for which the host star formation rates can be
usefully constrained with existing archival data.
Our first sample consists of Spitzer and Herschel follow-up of
obscured (type 2) quasars from Reyes et al. (2008, Cat. J/AJ/136/2373)
at z≲0.8.
For this sample, we collect archival Spitzer photometry and analyse
new Herschel photometry for a total of 136 objects.
Our second sample is comprised of 115 type 1 quasars at z,∼0.5 studied
with Spitzer spectroscopy by Shi et al. (2007ApJ...669..841S 2007ApJ...669..841S). Out of
115 type 1 quasars, all but one have complete 4-band photometry from
Wide-field Infrared Survey Explorer (WISE, Cat. II/311).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 126 83 160 micron photometry and photometric
constraints on star formation
table2.dat 122 46 IRS spectroscopy of type 2 quasars
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See also:
J/AJ/133/303 : Optical microvariability in radio-quiet QSOs (Carini+, 2007)
J/ApJ/657/116 : X-ray & UV parameters of radio-quiet quasars (Kelly+, 2007)
J/MNRAS/383/1513 : 2MASS, SDSS and FIRST fluxes of QSOs (Labita+, 2008)
J/ApJ/696/924 : UV and X-Ray radio-quiet QSOs (Gibson+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 25 A25 --- Name SDSS or 2MASS name (JHHMMSS.ss+DDMMSS.s)
27- 31 A5 --- Subsample [T2 T1red] subsample object type (1)
34- 39 F6.4 --- z Redshift
41- 47 F7.2 [10-7W] logL12um ?=-100.00 Log of nu Lnu at rest-frame 12um
49 A1 --- l_F160um 5 sigma upper limit flag on F160um
50- 54 F5.1 mJy F160um Observed flux at 160 micron
57- 59 I3 Msun/yr SFR Upper limit on star formation rate from
160um flux
63- 67 F5.2 [10-7W] L1.4GHzSF Upper limit on the radio luminosity nuLnu
due to star formation at rest-frame 1.4GHz
70 A1 --- l_L1.4GHzobs 5 sigma upper limit flag on L1.4GHzobs
71- 75 F5.2 [10-7W] L1.4GHzobs Observed radio luminosity nuLnu,
k-corrected to rest-frame 1.4GHz
77-126 A50 --- Com Comment on how the object was targeted for
observations
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Note (1): Subsample object type as follows:
T2 = type 2 quasar
T1red = red 2MASS quasar
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name SDSS name (JHHMMSS.ss+DDMMSS.s)
27- 32 F6.4 --- z Redshift
35- 39 F5.2 --- S[9.7um] Strength of the silicate feature at 9.7um
42- 46 F5.3 --- SLfactor Order stitching factor (1)
49 A1 --- l_logL1.4GHz 5 sigma upper limit flag on lognuLnu
51- 55 F5.2 [10-7W] logL1.4GHz Observed radio luminosity nu Lnu,
k-corrected to rest-frame 1.4GHz
59 A1 --- l_L[NeII] 3 sigma upper limit flag on LNeII
60- 64 F5.2 10+35W L[NeII] Luminosity of [NeII]12.8um emission line
68 A1 --- l_L[NeIII] 3 sigma upper limit flag on LNeIII
69- 73 F5.2 10+35W L[NeIII] ?=- Luminosity of [NeIII]15.6um emission
line
77 A1 --- l_LPAH6.2um 3 sigma upper limit flag on LPAH6.2um
78- 82 F5.2 10+35W LPAH6.2um Luminosity of PAH 6.2um emission line
86 A1 --- l_LPAH11.3um 3 sigma upper limit flag on LPAH11.3um
87- 91 F5.2 10+35W LPAH11.3um Luminosity of PAH 11.3um emission line
94-122 A29 --- Com Comment on how the object was targeted
for observations
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Note (1): a multiplicative factor applied to SL data to bring its flux
normalization into agreement with LL data.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 29-Jul-2016