Journal article
Kinematics of CIV and [OIII] emission in luminous high-redshift quasars
30 Apr 2019
Abstract
We characterise ionised gas outflows using a large sample of ~330
high-luminosity (45.5 < log(L_bol/erg s^-1) < 49.0), high-redshift (1.5 < z <
4.0) quasars via their [OIII]4960,5008 emission. The median velocity width of
the [OIII] emission line is 1540 kms^-1, increasing with increasing quasar
luminosity. Broad, blue-shifted wings are seen in the [OIII] profiles of 42 per
cent of the sample. Rest-frame ultraviolet spectra with well-characterised CIV
1550 emission line properties are available for more than 210 quasars, allowing
an investigation of the relationship between the Broad Line Region (BLR) and
Narrow Line Region (NLR) emission properties. The [OIII] blueshift is
correlated with CIV blueshift, even when the dependence of both quantities on
quasar luminosity has been taken into account. A strong anti-correlation
between the [OIII] equivalent width (EW) and CIV blueshift also exists.
Furthermore, [OIII] is very weak, with EW<1A, in ~10 per cent of the sample, a
factor of 10 higher compared to quasars at lower luminosities and redshifts. If
the [OIII] emission originates in an extended NLR, the observations suggest
that quasar-driven winds are capable of influencing the host-galaxy environment
out to kilo-parsec scales. The mean kinetic power of the ionised gas outflows
is then 10^44.7 erg s^-1, which is ~0.15 per cent of the bolometric luminosity
of the quasar. These outflow efficiencies are broadly consistent with those
invoked in current active galactic nuclei feedback models.
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Details
- Title
- Kinematics of CIV and [OIII] emission in luminous high-redshift quasars
- Creators
- Liam CoatmanPaul C HewettManda BanerjiGordon T RichardsJoeseph F HennawiJ. Xavier Prochaska
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Identifiers
- 991019201363104721