17,388 research outputs found
Valuing the attributes of renewable energy investments in Scotland
This study was funded by a grant from the Scottish Economic Policy Network (SEPN) with funding assistance provided by the University of Glasgow, Department of Economics (Professor Nick Hanley) and the University of Sterling (Robert Wright). The goal of the project was to determine the value of differing types of renewable energy projects by how they would effect environmental and community quality of life factors. The key issues examined include; air quality, landscape, wildlife, and long term local employment. Stated preference methods were employed through the use of a discrete choice experiment survey approach. Willingness-to-pay for different types of renewable energy projects was estimated, i.e., moderate onshore windmill farms, large onshore windmill farms, offshore windmill farms, and biomass fueled power plants. The most significant findings were that rural areas likely to be most highly impacted by the new energy projects were willing to accept low or moderate environmental damage in exchange for commercial development gains. Urban respondents on the other hand were more likely to oppose any disturbance to the landscape or wildlife and had no value placed on the economics development gains for the rural areas; income level of households showed no significant difference in environmental values
OUTLINE OF A GENERALLY COVARIANT QUANTUM FIELD THEORY AND A QUANTUM THEORY OF GRAVITY
We study a tentative generally covariant quantum field theory, denoted the
T-Theory, as a tool to investigate the consistency of quantum general
relativity. The theory describes the gravitational field and a minimally
coupled scalar field; it is based on the loop representation, and on a certain
number of quantization choices. Four-dimensional diffeomorphism-invariant
quantum transition probabilities can be computed from the theory. We present
the explicit calculation of the transition probability between two volume
eigenstates as an example. We discuss the choices on which the T-theory relies,
and the possibilities of modifying them.Comment: Latex file, 33 page
Feeding Versus Feedback in AGNs from Near-Infrared IFU Observations: The Case of Mrk79
We have mapped the gaseous kinematics and the emission-line flux
distributions and ratios from the inner ~680pc radius of the Seyfert 1 galaxy
Mrk79, using two-dimensional (2D) near-IR J- and Kl-band spectra obtained with
the Gemini instrument NIFS at a spatial resolution of ~100pc and velocity
resolution of ~40km/s. The molecular hydrogen flux distribution presents two
spiral arms extending by ~700pc, one to the north and another to the south of
the nucleus, with an excitation indicating heating by X-rays from the central
source. The low velocity dispersion (sigma~50km/s) and rotation pattern
supports a location of the H2 gas in the disk of the galaxy. Blueshifts
observed along the spiral arm in the far side of the galaxy and redshifts in
the spiral arm in the near side, suggest that the spiral arms are feeding
channels of H2 to the inner 200pc. From channel maps along the H2 l2.1218um
emission-line profile we estimate a mass inflow rate of ~4E-3 M_Sun/year, which
is one order of magnitude smaller than the mass accretion rate necessary to
power the AGN of Mrk79. The emission from the ionized gas (traced by Pabeta and
[FeII]l1.2570um emission lines) is correlated with the radio jet and with the
narrow-band [OIII] flux distribution. Its kinematics shows both rotation and
outflows to the north and south of the nucleus. The ionized gas mass outflow
rate through a cross section with radius ~320pc located at a distance of ~455pc
from the nucleus is 3.5 MSun/year, which is much larger than the AGN mass
accretion rate, indicating that most of the outflowing gas originates in the
interstellar medium surrounding the galaxy nucleus, which is pushed away by a
nuclear jet.Comment: Accepted by MNRA
An outflow perpendicular to the radio jet in the Seyfert nucleus of NGC5929
We report the observation of an outflow perpendicular to the radio jet in
near-infrared integral field spectra of the inner 250 pc of the Seyfert 2
galaxy NGC 5929. The observations were obtained with the Gemini Near infrared
Integral Field Spectrograph at a spatial resolution of ~20 pc and spectral
resolution R~5300 and reveal a region 50 pc wide crossing the nucleus and
extending by 300 pc perpendicularly to the known radio jet in this galaxy.
Along this structure - which we call SE-NW strip - the emission-line profiles
show two velocity components, one blueshifted and the other redshifted by -150
km/s and 150 km/s, respectively, relative to the systemic velocity. We
interpret these two components as due to an outflow perpendicular to the radio
jet, what is supported by low frequency radio emission observed along the same
region. We attribute this feature to the interaction of ambient gas with an
"equatorial outflow" predicted in recent accretion disk and torus wind models.
Perpendicularly to the SE-NW strip, thus approximately along the radio jet,
single component profiles show blueshifts of ~-150 km/s to the north-east and
similar redshifts to the south-west, which can be attributed to gas
counter-rotating relative to the stellar kinematics. More double-peaked
profiles are observed in association with the two radio hot-spots, attributed
to interaction of the radio jet with surrounding gas.Comment: Accepted for publication in ApJL; 5 page
Feeding Versus Feedback in AGNs from Near-Infrared IFU Observations: The Case of Mrk 766
We have mapped the emission-line flux distributions and ratios as well as the
gaseous kinematics of the inner 450 pc radius of the Seyfert 1 galaxy Mrk 766
using integral field near-IR J- and Kl-band spectra obtained with the Gemini
nifs at a spatial resolution of 60 pc and velocity resolution of 40 km/s.
Emission-line flux distributions in ionized and molecular gas extend up to ~
300 pc from the nucleus. Coronal [S IX]{\lambda}1.2523{\mu}m line emission is
resolved, being extended up to 150 pc from the nucleus. At the highest flux
levels, the [Fe II]{\lambda}1.257{\mu}m line emission is most extended to the
south-east, where a radio jet has been observed.The emission-line ratios [Fe
II]{\lambda}1.2570{\mu}m/Pa{\beta} and {\lambda}2.1218{\mu}m/Br{\gamma}
show a mixture of Starburst and Seyfert excitation; the Seyfert excitation
dominates at the nucleus, to the north-west and in an arc-shaped region between
0.2" and 0.6" to the south-east at the location of the radio jet. A
contribution from shocks at this location is supported by enhanced [Fe II]/[P
II] line ratios and increased [Fe II] velocity dispersion. The gas velocity
field is dominated by rotation that is more compact for than for
Pa{\beta}, indicating that the molecular gas has a colder kinematics and is
located in the galaxy plane. There is about solar masses of hot ,
implying ~ solar masses of cold molecular gas. At the location of the
radio jet, we observe an increase in the [Fe II] velocity dispersion (150
km/s), as well as both blueshift and redshifts in the channel maps, supporting
the presence of an outflow there. The ionized gas mass outflow rate is
estimated to be ~ 10 solar masses/yr, and the power of the outflow ~ 0.08
Extended Gas in Seyfert Galaxies: Near Infrared Observations of NGC 2110 and Circinus
We present results of near--IR long-slit spectroscopy in the J and K bands of
the Seyfert 2 galaxies NGC 2110 and Circinus, investigating the gaseous
distribution, excitation, reddening and kinematics. In NGC 2110, the emission
line ratio [FeII]/Pa beta increases towards the nucleus (to ~ 7). The nuclear
[Fe II]1.257 (microns) and Pa beta lines are broader (FWHM ~ 500 km/s) than the
H2 (2.121) line (FWHM ~ 300 km/s). Both these results suggest that shocks,
driven by the radio jet, are an important source of excitation of [Fe II]. The
H2 excitation appears to be dominated by X-rays from the nucleus. In Circinus,
both [FeII]/Pa beta and H2/Br gamma decrease from ~ 2 at 4 arcsec from the
nucleus to nuclear values of ~ 0.6 and ~ 1, respectively, suggesting that the
starburst dominates the nuclear excitation, while the AGN dominates the
excitation further out (r > 2 arcsec). For both galaxies, the gaseous
kinematics are consistent with circular rotation in the plane of the disk. Our
rotation curves suggest that the nucleus (identified with the peak of the IR
continuum) is displaced from the kinematic centre of the galaxies. This effect
has been observed previously in NGC 2110 based on the kinematics of optical
emission lines, but the displacement is smaller in the infrared, suggesting the
effect is related to obscuration. The continuum J-K colours of the nuclear
region indicate a red stellar population in NGC 2110 and a reddened young
stellar population in Circinus. Right at the nucleus of both galaxies, the
colours are redder, apparently a result of hot dust emission from the inner
edge of a circumnuclear torus.Comment: 11 pages, 14 figures, accepted for publication in MNRA
The Spectral Energy Distribution of Normal, Starburst and Active Galaxies
We present the results of an extensive literature search of multiwavelength
data for a sample of 59 galaxies, consisting of 26 Starbursts, 15 Seyfert 2's,
5 LINER's, 6 normal spirals and 7 normal elliptical galaxies. The data include
soft X-ray fluxes, ultraviolet and optical spectra, near, mid/far infrared
photometry and radio measurements, selected to match as closely as possible the
IUE aperture (10" X 20"). The galaxies are separated into 6 groups with similar
characteristics, namely, Ellipticals, Spirals, LINER's, Seyfert 2's, Starbursts
of Low and High reddening, for which we create average spectral energy
distributions (SED). The individual groups SED's are normalized to the
7000\AA flux and compared, looking for similarities and differences
among them.The bolometric fluxes of different types of galaxies were calculated
integrating their SED's. These values are compared with individual waveband
flux densities, in order to determine the wavebands which contribute most to
the bolometric flux. Linear regressions were performed between the bolometric
and individual band fluxes for each kind of galaxy. These fits can be used in
the calculation of the bolometric flux for other objects of similar activity
type, but with reduced waveband information. We have also collected
multiwavelength data for 4 HII regions, a thermal supernova remnant, and a
non-thermal supernova remnant (SNR), which are compared with the Starburst
SED's.Comment: 29 pages, 13 postscript figures and 10 tables. To appear in The
Astronomical Journa
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