TY - JOUR
T1 - The Atlas3D project - XXXI. Nuclear radio emission in nearby early-type galaxies
AU - Nyland, Kristina
AU - Young, Lisa M.
AU - Wrobel, Joan M.
AU - Sarzi, Marc
AU - Morganti, Raffaella
AU - Alatalo, Katherine
AU - Blitz, Leo
AU - Bournaud, Frederic
AU - Bureau, Martin
AU - Cappellari, Michele
AU - Crocker, Alison F.
AU - Davies, Roger L.
AU - Davis, Timothy A.
AU - de Zeeuw, P. T.
AU - Duc, Pierre-Alain
AU - Emsellem, Eric
AU - Khochfar, Sadegh
AU - Krajnovic, Davor
AU - Kuntschner, Harald
AU - McDermid, Richard M.
AU - Naab, Thorsten
AU - Oosterloo, Tom
AU - Scott, Nicholas
AU - Serra, Paolo
AU - Weijmans, Anne-Marie
N1 - The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Advanced Grant RADIOLIFE-320745. MC acknowledges support from a Royal Society University Research Fellowship. This work was supported by the rolling grants `Astrophysics at Oxford' PP/E001114/1 and ST/H002456/1 and visitor grants PPA/V/S/2002/00553, PP/E001564/1 and ST/H504862/1 from the UK Research Councils. RLD acknowledges travel and computer grants from Christ Church, Oxford and support from the Royal Society in the form of a Wolfson Merit Award 502011.K502/jd. TN acknowledges support from the DFG Cluster of Excellence Origin and Structure of the Universe. MS acknowledges support from a STFC Advanced Fellowship ST/F009186/1. TAD acknowledges the support provided by an ESO fellowship. The research leading to these results has received funding from the European Community's Seventh Framework Programme (/FP7/2007-2013/) under grant agreement No 229517. The authors acknowledge financial support from ESO. SK acknowledges support from the Royal Society Joint Projects Grant JP0869822. NS acknowledges support of Australian Research Council grant DP110103509. AW acknowledges support of a Leverhulme Trust Early Career Fellowship.
PY - 2016/5/11
Y1 - 2016/5/11
N2 - We present the results of a high-resolution, 5 GHz, Karl G. Jansky Very Large Array study of the nuclear radio emission in a representative subset of the ATLAS3D survey of early-type galaxies (ETGs). We find that 51 ± 4% of the ETGs in our sample contain nuclear radio emission with luminosities as low as 1018 W Hz−1. Most of the nuclear radio sources have compact (≲ 25 − 110 pc) morphologies, although ∼10% display multi-component core+jet or extended jet/lobe structures. Based on the radio continuum properties, as well as optical emission line diagnostics and the nuclear X-ray properties, we conclude that the majority of the central 5 GHz sources detected in the ATLAS3D galaxies are associated with the presence of an active galactic nucleus (AGN). However, even at sub-arcsecond spatial resolution, the nuclear radio emission in some cases appears to arise from low-level nuclear star formation rather than an AGN, particularly when molecular gas and a young central stellar population is present. This is in contrast to popular assumptions in the literature that the presence of a compact, unresolved, nuclear radio continuum source universally signifies the presence of an AGN. Additionally, we examine the relationships between the 5 GHz luminosity and various galaxy properties including the molecular gas mass and - for the first time - the global kinematic state. We discuss implications for the growth, triggering, and fueling of radio AGNs, as well as AGN-driven feedback in the continued evolution of nearby ETGs.
AB - We present the results of a high-resolution, 5 GHz, Karl G. Jansky Very Large Array study of the nuclear radio emission in a representative subset of the ATLAS3D survey of early-type galaxies (ETGs). We find that 51 ± 4% of the ETGs in our sample contain nuclear radio emission with luminosities as low as 1018 W Hz−1. Most of the nuclear radio sources have compact (≲ 25 − 110 pc) morphologies, although ∼10% display multi-component core+jet or extended jet/lobe structures. Based on the radio continuum properties, as well as optical emission line diagnostics and the nuclear X-ray properties, we conclude that the majority of the central 5 GHz sources detected in the ATLAS3D galaxies are associated with the presence of an active galactic nucleus (AGN). However, even at sub-arcsecond spatial resolution, the nuclear radio emission in some cases appears to arise from low-level nuclear star formation rather than an AGN, particularly when molecular gas and a young central stellar population is present. This is in contrast to popular assumptions in the literature that the presence of a compact, unresolved, nuclear radio continuum source universally signifies the presence of an AGN. Additionally, we examine the relationships between the 5 GHz luminosity and various galaxy properties including the molecular gas mass and - for the first time - the global kinematic state. We discuss implications for the growth, triggering, and fueling of radio AGNs, as well as AGN-driven feedback in the continued evolution of nearby ETGs.
KW - Galaxies: elliptical and lenticular
KW - Galaxies: active
KW - Galaxies: nuclei
KW - Radio continuum: galaxies
UR - http://adsabs.harvard.edu/abs/2016arXiv160205579N
U2 - 10.1093/mnras/stw391
DO - 10.1093/mnras/stw391
M3 - Article
SN - 0035-8711
VL - 458
SP - 2221
EP - 2268
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -