* Astronomy

Blobrana · L

NGC 2110

Blobrana · L

Title: Young Star Clusters In The Circumnuclear Region Of NGC 2110
Author: Mark Durré, Jeremy Mould

High-resolution observations in the near infrared show star clusters around the active galactic nucleus (AGN) of the Seyfert 1 NGC2110, along with a 90 x 35 pc bar of shocked gas material around its nucleus. These are seen for the first time in our imaging and gas kinematics of the central 100pc with the Keck OSIRIS instrument with adaptive optics. Each of these clusters is 2-3 times brighter than the Arches cluster close to the centre of the Milky Way. The core star formation rate (SFR) is 0.3 solar masses/yr. The photoionized gas (He I) dynamics imply an enclosed mass of 3-4 x 10^8 solar masses. These observations demonstrate the physical linkage between AGN feedback, which triggers star formation in massive clusters, and the resulting stellar (and SNe) winds, which cause the observed [Fe II] emission and feed the black hole.

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Blobrana · L

Title: The Nuclear Outflow in NGC 2110
Authors: D.J. Rosario (UCO/Lick), M. Whittle (UVa.), C.H. Nelson (Drake), A.S. Wilson (UMd.)

We present a HST/STIS spectroscopic and optical/radio imaging study of the Seyfert NGC 2110 aiming to measure the dynamics and understand the nature of the nuclear outflow in the galaxy. Previous HST studies have revealed the presence of a linear structure in the Narrow-Line Region (NLR) aligned with the radio jet. We show that this structure is strongly accelerated, probably by the jet, but is unlikely to be entrained in the jet flow. The ionisation properties of this structure are consistent with photoionisation of dusty, dense gas by the active nucleus. We present a plausible geometrical model for the NLR, bringing together various components of the nuclear environment of the galaxy. We highlight the importance of the circum-nuclear disc in determining the appearance of the emission line gas and the morphology of the jet. From the dynamics of the emission line gas, we place constraints on the accelerating mechanism of the outflow and discuss the relative importance of radio source synchrotron pressure, radio jet ram pressure and nuclear radiation pressure in accelerating the gas. While all three mechanisms can account for the energetics of the emission line gas, gravitational arguments support radio jet ram pressure as the most likely source of the outflow.

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