TY - JOUR
T1 - Radio Continuum Variability and Molecular Gas Reservoirs in the Type-Transitioning Seyfert Galaxy Mrk 590
AU - Koay, Jun Yi
AU - Vestergaard, Marianne
AU - Casasola, Viviana
AU - Peterson, Bradley M.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - Sometime between 2006 and 2012, the broad Hβ emission line of Mrk
590, once classified as a bona-fide Seyfert 1 galaxy, has completely
disappeared! The optical-UV continuum emission has decreased to the
point where it can be fully accounted for by stellar population models
of the host galaxy. As such, Mrk 590 would now be classified as a
Seyfert 1.9 or 2 galaxy, which goes against the prevailing scheme of AGN
classification and unification where the presence of broad emission
lines depends only on source orientation. Similar decreases in X-ray and
radio continuum fluxes show that the central engine of Mrk 590 may be
turning off or transitioning into a radiatively inefficient mode of
accretion. We discuss the origin of the compact, unresolved radio
emission in Mrk 590 and the physics of its variability in relation to
the variability observed at other wavelengths, based on archival radio
data and new VLBI observations. We also present recent ALMA observations
of the CO(3-2) spectral line and sub-mm continuum emission; these
provide the strongest limits to date on the molecular gas mass in the
central ~100 pc, plus reveal the gas distribution and kinematics in the
central kpc, to determine if this intriguing AGN is indeed running out
of fuel.
AB - Sometime between 2006 and 2012, the broad Hβ emission line of Mrk
590, once classified as a bona-fide Seyfert 1 galaxy, has completely
disappeared! The optical-UV continuum emission has decreased to the
point where it can be fully accounted for by stellar population models
of the host galaxy. As such, Mrk 590 would now be classified as a
Seyfert 1.9 or 2 galaxy, which goes against the prevailing scheme of AGN
classification and unification where the presence of broad emission
lines depends only on source orientation. Similar decreases in X-ray and
radio continuum fluxes show that the central engine of Mrk 590 may be
turning off or transitioning into a radiatively inefficient mode of
accretion. We discuss the origin of the compact, unresolved radio
emission in Mrk 590 and the physics of its variability in relation to
the variability observed at other wavelengths, based on archival radio
data and new VLBI observations. We also present recent ALMA observations
of the CO(3-2) spectral line and sub-mm continuum emission; these
provide the strongest limits to date on the molecular gas mass in the
central ~100 pc, plus reveal the gas distribution and kinematics in the
central kpc, to determine if this intriguing AGN is indeed running out
of fuel.
M3 - Journal article
VL - 22
SP - 2255682
JO - IAU General Assembly, Meeting #29
JF - IAU General Assembly, Meeting #29
ER -