1,229 research outputs found
The Intermediate Line Region and the Baldwin Effect
Statistical investigations of samples of quasars have established that
clusters of properties are correlated. The strongest trends among the
ultraviolet emission-line properties are characterized by the object-to-object
variation of emission from low-velocity gas, the so-called ``intermediate-line
region'' or ILR. The strongest trends among the optical emission-line
properties are characterized by the object-to-object variation of the line
intensity ratio of [O III] 5007 to optical Fe II. Additionally, the strength of
ILR emission correlates with [O III]/Fe II, as well as with radio and X-ray
properties. The fundamental physical parameter driving these related
correlations is not yet identified. Because the variation in the ILR dominates
the variation in the equivalent widths of lines showing the Baldwin effect, it
is important to understand whether the physical parameter underlying this
variation also drives the Baldwin effect or is a primary source of scatter in
the Baldwin effect.Comment: 11 pages, to appear in the proceedings of the meeting on "Quasars as
Standard Candles for Cosmology" held on May 18-22, 1998, at La Serena, Chile.
To be published by ASP, editor G. Ferlan
2D stellar population and gas kinematics of the inner kiloparsec of the post-starburst quasar SDSS J0330-0532
We have used optical Integral Field Spectroscopy in order to map the star
formation history of the inner kiloparsec of the Post-Starburst Quasar (PSQ)
J0330--0532 and to map its gas and stellar kinematics as well as the gas
excitation. PSQs are hypothesized to represent a stage in the evolution of
galaxies in which the star formation has been recently quenched due to the
feedback of the nuclear activity, as suggested by the presence of the
post-starburst population at the nucleus. We have found that the old stellar
population (age 2.5 Gyr) dominates the flux at 5100 \AA\ in the inner
0.26 kpc, while both the post-starburst (100 Myr age 2.5 Gyr) and
starburst (age 100 Myr) components dominate the flux in a circumnuclear
ring at 0.5 kpc from the nucleus. With our spatially resolved study we
do not have found any post-starburst stellar population in the inner 0.26\,kpc.
On the other hand, we do see the signature of AGN feedback in this region,
which does not reach the circumnuclear ring where the post-starburst population
is observed. We thus do not support the quenching scenario for the J0330-0532.
In addition, we have concluded that the strong signature of the post-starburst
population in larger aperture spectra (e.g. from Sloan Digital Sky Survey) is
partially due to the combination of the young and old age components. Based on
the M relationship and the stellar kinematics we
have estimated a mass for the supermassive black hole of 1.48 0.66
10 M.Comment: 16 pages, 11 figures. arXiv admin note: text overlap with
arXiv:1210.120
2D stellar population and gas kinematics of the inner 1.5 kpc of the post-starburst quasar SDSS J0210-0903
Post-Starburst Quasars (PSQs) are hypothesized to represent a stage in the
evolution of massive galaxies in which the star formation has been recently
quenched due to the feedback of the nuclear activity. In this paper our goal is
to test this scenario with a resolved stellar population study of the PSQ
J0210-0903, as well as of its emitting gas kinematics and excitation. We have
used optical Integral Field Spectroscopy obtained with the Gemini GMOS
instrument at a velocity resolution of ~120 km/s and spatial resolution of ~0.5
kpc. We find that old stars dominate the luminosity (at 4700 \AA) in the inner
0.3 kpc (radius), while beyond this region (at ~0.8 kpc) the stellar population
is dominated by both intermediate age and young ionizing stars. The gas
emission-line ratios are typical of Seyfert nuclei in the inner 0.3 kpc, where
an outflow is observed. Beyond this region the line ratios are typical of
LINERs and may result from the combination of diluted radiation from the
nucleus and ionization from young stars. The gas kinematics show a combination
of rotation in the plane of the galaxy and outflows, observed with a maximum
blueshift of -670 km/s. We have estimated a mass outflow rate in ionized gas in
the range 0.3--1.1 M_sun/yr and a kinetic power for the outflow of dE/dt ~
1.4--5.0 x 10^40 erg/s ~0.03% - 0.1% x L_bol. This outflow rate is two orders
of magnitude higher than the nuclear accretion rate of ~8.7 x 10^-3 M_sun/yr,
thus being the result of mass loading of the nuclear outflow by circumnuclear
galactic gas. Our observations support an evolutionary scenario in which the
feeding of gas to the nuclear region has triggered a circumnuclear starburst
100's Myr ago, followed by the triggering of the nuclear activity, producing
the observed gas outflow which may have quenched further star formation in the
inner 0.3 kpc.Comment: 17 pages, 9 Figures, 2 Table
Spectropolarimetry of PKS 0040-005 and the Orientation of Broad Absorption Line Quasars
We have used the Very Large Telescope (VLT) to obtain spectropolarimetry of
the radio-loud, double-lobed broad absorption line (BAL) quasar PKS 0040-005.
We find that the optical continuum of PKS 0040-005 is intrinsically polarized
at 0.7% with an electric vector position angle nearly parallel to that of the
large-scale radio axis. This result is naturally explained in terms of an
equatorial scattering region seen at a small inclination, building a strong
case that the BAL outflow is not equatorial. In conjunction with other recent
results concerning radio-loud BAL quasars, the era of simply characterizing
these sources as ``edge-on'' is over.Comment: 5 Pages, including 2 PostScript figures. Accepted for publication in
MNRAS letter
Outflows and the Physical Properties of Quasars
We have investigated a sample of 5088 quasars from the Sloan Digital Sky
Survey Second Data Release in order to determine how the frequency and
properties of broad absorptions lines (BALs) depend on black hole mass,
bolometric luminosity, Eddington fraction (L/L_Edd), and spectral slope. We
focus only on high-ionization BALs and find a number of significant results.
While quasars accreting near the Eddington limit are more likely to show BALs
than lower systems, BALs are present in quasars accreting at only a
few percent Eddington. We find a stronger effect with bolometric luminosity,
such that the most luminous quasars are more likely to show BALs. There is an
additional effect, previously known, that BAL quasars are redder on average
than unabsorbed quasars. The strongest effects involving the quasar physical
properties and BAL properties are related to terminal outflow velocity. Maximum
observed outflow velocities increase with both the bolometric luminosity and
the blueness of the spectral slope, suggesting that the ultraviolet luminosity
to a great extent determines the acceleration. These results support the idea
of outflow acceleration via ultraviolet line scattering.Comment: Uses emulateapj.cls, 14 pages including 7 tables and 7 figures.
Accepted for publication in the Astrophysical Journal, Unabridged version of
Table 4 can be downloaded from http://physics.uwyo.edu/agn
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