Institute of Astronomy

Outflows from starburst and AGN

SpeakerTalk DateTalk Series
Sara Cazzoli & Stefano Carniani (Cavendish)27 March 2015Institute of Astronomy Galaxies Discussion Group

Abstract

Galactic-scale outflows are one of the major feedback mechanisms regulating the growth of galaxies. Despite the import role outflows play in galaxy evolution, the occurrence and properties of outflows are not well constrained yet. By taking advantage of the integral
field spectroscopy (IFS) technique we can unambiguously identify wind galaxies by investigating the absorption and emission line kinematics. The first part of this talk will present VIMOS-observations of neutral
outflows in nearby extreme starbursts (such as [U]LIRGs) via the optical IFS of NaD (λλ5890, 5896). The neutral gas velocity fields are generally dominated by non-circular motions, and in nearly half of the
sample (22/51) we have revealed an outflow signature. The quantitative analysis of the outflow feedback and kinematics suggest that it is relevant for both the quenching of star formation and for the recycling of gas and metals within the galaxy. The second part of this
talk is dedicated to the study of the [OIII]λ5007 line emission, which is a good tracer of outflows and ionized gas dynamics in the narrow-line regions of AGN, in a sample of high redshift quasars. More specifically, VLT-SINFONI near-IR integral field spectra of five
quasar at redshift z=2.4 are presented and discussed. The kinematical analysis of the [OIII] line shows complex gas kinematics in a region of several kpc from the location of the AGN, with blueshifted velocities of a few hundreds of km/s and line widths up to 1500 km/s.
[OIII] emission likely traces a massive outflow with a conical morphology. Meanwhile, Hα emission, tracing star formation, is strongly suppressed in the outflows regions. These observations suggests a clear evidence of AGN negative feedback.

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