Ionised outflows in z $\sim$ 2.4 quasar host galaxies

By S. Carniani, A. Marconi, R. Maiolino, B. Balmaverde, M. Brusa, M. Cano-d'iaz, C. Cicone, A. Comastri, G. Cresci, Fabrizio Fiore and 10 more. 2015

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AGN-driven outflows 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. This work aims to detect the presence of extended ionised outflows in luminous quasars where we expect the maximum 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, $z>2$. We analyse a sample of six luminous (${\rm L>10^{47} \ erg/s}$) quasars at $z\sim2.4$, observed in H-band using the near-IR integral field spectrometer SINFONI at VLT. We perform a kinematic analysis of the [OIII] emission line at $\lambda = 5007A$. [OIII] has a complex gas kinematic, with blue-shifted velocities of a few hundreds of km/s and line widths up to 1500 km/s. Using the spectroastrometric method we infer size of the ionised outflows of up to $\sim$2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows driven by radiation pressure, which depends on the emitted luminosity. We derive mass outflow rates of about 6-700 M$_{\odot}$/yr for our sample, which are lower than those observed in molecular outflows. Indeed physical properties of ionised outflows show dependences on AGN luminosity which are similar to those of molecular outflows but indicating that the mass of ionised gas is smaller than that of the molecular one. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/794643d9f2100500012fb9abf9cb8402ee597aab

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Citations in the corpus

AGN wind scaling relations and the co-evolution of black holes and galaxies (2017, background): “For ionised winds, the mass of the outflowing gas is calculated by using the following equations (Osterbrock & Ferland 2006; Carniani et al. 2015): M[OIII] = 4.0 × 107 M ( C 10O/H ) (L[OIII] 1044 ) ( 〈ne〉 103 )−1 (B.3) and MHβ = 7.8 × 108C ( LHβ 1044 ) ( 〈ne〉 103 )−1 (B.4) assuming that the…”
Discovery of extreme [O III] λ5007 Å outflows in high-redshift red quasars (2015, background): “…of strong cosmological surface brightness dimming, resolving the sizes of extended line regions at high redshifts is very difficult, but existing measurements also suggest [O III]-emitting sizes of a few kpc (Alexander et al. 2010; Cano-Dı́az et al. 2012; Carniani et al. 2015; Brusa et al. 2016).”