Ionised outflows in z ~ 2.4 quasar host galaxies
Journal
Date Issued
2015
Author(s)
Carniani, S.
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Maiolino, R.
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Brusa, M.
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CICONE, CLAUDIA
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La Franca, F.
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Mainieri, V.
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Nagao, T.
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Netzer, H.
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Risaliti, G.
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Shemmer, O.
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Cano-Díaz, M.
Description
We thank the anonymous referee for comments and suggestions that improved the paper. We acknowledge financial support from INAF under the contracts PRIN-INAF-2011 (“Black Hole growth and AGN feedback through cosmic time”) and PRIN MIUR 2010-2011 (“The dark Universe and the cosmic evolution of baryons”). M.B. acknowledges support from the FP7 Career Integration Grant “eEASy” (CIG 321913). C.F. gratefully acknowledges financial support from PRIN MIUR 2010-2011, project “The Chemical and Dynamical Evolution of the Milky Way and Local Group Galaxies”, prot. 2010LY5N2T. E.P. acknowledges financial support from INAF under the contract PRIN-INAF-2012. Funding for this work has also been provided by the Israel Science Foundation grant 284/13.
Abstract
Aims. Outflows driven by active galactic nuclei (AGN) are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super-massive black holes and their host galaxies. We here aim to detect extended ionised outflows in luminous quasars, where we expect the highest activity both in star formation and in black-hole accretion. Currently, there are only a few studies based on spatially resolved observations of outflows at high redshift, z > 2.
Methods. We analysed a sample of six luminous (L > 10^47 erg/s) quasars at z ∼ 2.4, observed in H-band using the near-IR integral field spectrometer SINFONI at the VLT. We performed a kinematic analysis of the [OIII] emission line at λ = 5007Å.
Results. We detect fast, spatially extended outflows in five out of six targets. [OIII]λ5007 has a complex gas kinematic, with blue- shifted velocities of a few hundreds of km s−1 and line widths up to 1500 km s−1 . Using the spectroastrometric method, we infer a size of the ionised outflows of up to ∼2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate, and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows that are driven by radiation pressure, which depends on the emitted luminosity.
Conclusions: We derive mass outflow rates of about 6-700 M☉ yr-1 for our sample, which are lower than those observed in molecular outflows. The physical properties of ionised outflows show dependences on AGN luminosity that are similar to those of molecular outflows, but indicate that the mass of ionised gas is lower than that of molecular outflows. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms.
Volume
580
Start page
A102
Issn Identifier
0004-6361
Ads BibCode
2015A&A...580A.102C
Rights
open.access
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