Highly extinguished emission line outflows in the young radio source PKS 1345+12

Abstract

We present intermediate resolution, large wavelength coverage spectra for the compact radio source PKS 1345+12 (4C 12.50, z = 0.122) that were taken with the aim of investigating the impact of the nuclear activity on the circumnuclear interstellar medium (ISM). Our spectra show extended line emission up to ∼20 kpc from the nucleus, consistent with the asymmetric halo of diffuse emission observed in optical and infrared images. At the position of the nucleus we observe complex emission line profiles and Gaussian fits to the [O III] emission lines require three components (narrow, intermediate and broad), the broadest of which has width ∼2000 km s −1 (FWHM) and is blueshifted by ∼2000 km s −1 with respect to the halo of the galaxy and H I absorption. We interpret this latter component as material in outflow. We also find evidence for large reddening [0.92 < E(B − V ) < 2.00] and high densities (n e > 4200 cm −3 ) for the most kinematically disturbed component. The corresponding total mass of line-emitting gas in the kinematically disturbed components is M gas < 10 6 M . Not all emission line profiles can be reproduced by the same model: [O I]λλ6300, 6363 and [S II]λλ6716, 6731 require separate, unique models. We argue that PKS 1345+12 is a young radio source with nuclear regions that are enshrouded in a dense cocoon of gas and dust. The radio jets are expanding through this cocoon, sweeping material out of the nuclear regions. Emission originates from three kinematically distinct regions, though gradients (e.g. in density, ionization potential, velocity) must exist across the regions responsible for the emission of the intermediate and broad components. C 2003 RAS 1 H 0 = 75 km s −1 , q 0 = 0.0 assumed throughout, resulting in a scale of 2.37 kpc arcsec −1 at z = 0.122. 2 S ∝ ν −α assumed throughout.

Turbulent and fast motions of H2gas in active galactic nuclei

“…observed to be moving faster than ±250 km s −1 from V sys along the line of sight (Holt et al 2003;Rodríguez Zaurín et al 2007). A scenario that agrees better with existing observations is that the H 2 gas is moving toward us driven by feedback mechanisms (e.g., Alatalo et al 2011).…”

X‐ray emission from GPS and CSS sources

“…It is dominated by the unresolved core. Holt, Tadhunter & Morganti (2003). The X-ray emission is also stretched towards the South-West similarly to the optical emission and is aligned also agrees with the VLBI jet axis (Stanghellini et al 2001) suggesting that it may be related to the expanding GPS source.…”

Cold and warm molecular gas in the outflow of 4C 12.50

“…The rapid molecular gas motions that we detected provide direct evidence of an outflow in 4C 12.50 because none of its merging components (Axon et al 2000) is moving faster than ±250 km s −1 from its systemic velocity (Holt et al 2003;Rodríguez Zaurín et al 2007). The maximum gas velocity reaches −1500 km s −1 , which is atypical of supernova-driven outflows (e.g., Heckman et al 2000;Rupke et al 2005), but characteristic of AGN-driven outflows (e.g., Rupke & Veilleux 2011;Sturm et al 2011).…”