168 research outputs found
The bond scheme
Under the bond scheme, a pre-determined series of payments would compensate farmers for lost revenues resulting from policy change. Unlike the Single Payment Scheme, payments would be fully decoupled: recipients would not have to retain farmland, or remain in agriculture. If vested in a paper asset, the guaranteed, unencumbered, income stream would be similar to that from a government bond.
Recipients could exchange this for a capital sum reflecting the net present value of future payments, and reinvest in other business ventures, either on- or offfarm.With a finite, declining flow of payments, budget expenditure would reduce, releasing funds for other uses
Decoupling EU Farm Support: Does the New Single Payment Scheme Fit within the Green Box?
Recent reform of the EU's Common Agricultural Policy (CAP) has led to a further decoupling of farm support. The EU believes that the new Single Payment Scheme, which replaces the former system of area and headage payments to farmers, tied to production, will qualify for green-box status in the WTO. We examine this contention, particularly in light of the recent WTO panel report on upland cotton.decoupling, EU, green box, Single Payment Scheme, WTO, Agricultural and Food Policy,
The A2667 Giant Arc at z=1.03: Evidence for Large-scale Shocks at High Redshift
We present the spatially resolved emission line ratio properties of a ~10^10
M_sun star-forming galaxy at redshift z=1.03. This galaxy is gravitationally
lensed as a triple-image giant arc behind the massive lensing cluster Abell
2667. The main image of the galaxy has magnification factors of 14+/-2.1 in
flux and ~ 2 by 7 in area, yielding an intrinsic spatial resolution of 115-405
pc after AO correction with OSIRIS at KECK II. The HST morphology shows a
clumpy structure and the H\alpha\ kinematics indicates a large velocity
dispersion with V_{max} sin(i)/\sigma ~ 0.73, consistent with high redshift
disk galaxies of similar masses. From the [NII]/H\alpha\ line ratios, we find
that the central 350 parsec of the galaxy is dominated by star formation. The
[NII]/H\alpha\ line ratios are higher in the outer-disk than in the central
regions. Most noticeably, we find a blue-shifted region of strong
[NII]/H\alpha\ emission in the outer disk. Applying our recent HII region and
slow-shock models, we propose that this elevated [NII]/H\alpha\ ratio region is
contaminated by a significant fraction of shock excitation due to galactic
outflows. Our analysis suggests that shocked regions may mimic flat or inverted
metallicity gradients at high redshift.Comment: 11 pages, 9 figures, ApJ accepte
The Emission Line Properties of Gravitationally-lensed 1.5 < z < 5 Galaxies
We present and analyse near-infrared spectroscopy for a sample of 28
gravitationally- lensed star-forming galaxies in the redshift range 1.5 < z <
5, observed mostly with the Keck II telescope. With typical magnifications of
~1.5-4 magnitudes, our survey provides a valuable census of star formation
rates, gas-phase metallicities and dynamical masses for a representative sample
of low luminosity galaxies seen at a formative period in cosmic history. We
find less evolution in the mass-metallicity relation compared to earlier work
that focused on more luminous systems with z - 2-3, especially in the low mass
(- 10^9 Msol) where our sample is - 0.25 dex more metal-rich. We interpret this
offset as a result of the lower star formation rates (typically a factor of -10
lower) for a given stellar mass in our sub-luminous systems. Taking this effect
into account, we conclude our objects are consistent with a fundamental
metallicity relation recently proposed from unlensed observations.Comment: 22 pages, 12 figures, MNRAS, version including proof correction
Resolved Spectroscopy of Gravitationally-Lensed Galaxies: Recovering Coherent Velocity Fields in Sub-Luminous z~2-3 Galaxies
We present spatially-resolved dynamics for six strongly lensed star-forming
galaxies at z=1.7-3.1, each enlarged by a linear magnification factor ~8. Using
the Keck laser guide star AO system and the OSIRIS integral field unit
spectrograph we resolve kinematic and morphological detail in our sample with
an unprecedented fidelity, in some cases achieving spatial resolutions of ~100
pc. With one exception our sources have diameters ranging from 1-7 kpc, star
formation rates of 2-40 Msun/yr (uncorrected for extinction) and dynamical
masses of 10^(9.7-10.3) Msun. With this exquisite resolution we find that four
of the six galaxies display coherent velocity fields consistent with a simple
rotating disk model, which can only be recovered with the considerably improved
spatial resolution and sampling from the combination of adaptive optics and
strong gravitational lensing. Our model fits imply ratios for the systemic to
random motion, V sin(i)/sigma, ranging from 0.5-1.3 and Toomre disk parameters
Q<1. The large fraction of well-ordered velocity fields in our sample is
consistent with data analyzed for larger, more luminous sources at this
redshift. Our high resolution data further reveal that all six galaxies contain
multiple giant star-forming HII regions whose resolved diameters are in the
range 300 pc - 1.0 kpc, consistent with the Jeans length expected in the case
of dispersion support. The density of star formation in these regions is ~100
times higher than observed in local spirals; such high values are only seen in
the most luminous local starbursts. The global dynamics and demographics of
star formation in these HII regions suggest that vigorous star formation is
primarily governed by gravitational instability in primitive rotating disks.Comment: 18 pages, 8 figures, submitted to MNRA
Nebular and global properties of the gravitationally lensed galaxy "the 8 o'clock arc"
We present the analysis of new NIR, intermediate-resolution spectra of the
gravitationally lensed galaxy "the 8 o'clock arc" at z_sys = 2.7350 obtained
with VLT/X-shooter. These rest-frame optical data, combined with HST and
Spitzer images, provide very valuable information, which nicely complement our
previous detailed rest-frame UV spectral analysis. From high-resolution HST
images, we reconstruct the morphology of the arc in the source plane, and
identify that the source is formed of two majors parts, the main galaxy
component and a smaller blob separated by 1.2 kpc in projected distance. The
blob, with a twice larger magnification factor, is resolved in the spectra. The
multi-Gaussian fitting of detected nebular emission lines and the spectral
energy distribution modeling of the available multi-wavelength photometry
provide the census of gaseous and stellar dust extinctions, gas-phase
metallicities, star-formation rates (SFRs), and stellar, gas, and dynamical
masses for both the main galaxy and the blob. As a result, the 8 o'clock arc
shows a marginal trend for a more attenuated ionized gas than stars, and
supports a dependence of the dust properties on the SFR. With a high specific
star-formation rate, SSFR = 33+/-19 Gyr^{-1}, this lensed Lyman-break galaxy
deviates from the mass-SFR relation, and is characterized by a young age of
40^{+25}_{-20} Myr and a high gas fraction of about 72%. The 8 o'clock arc
satisfies the fundamental mass, SFR, and metallicity relation, and favors that
it holds up beyond z~2.5. We believe that the blob, with a gas mass M_gas =
(2.2+/-0.9)x10^{9} Msun (one order of magnitude lower than the mass of the
galaxy), a half-light radius r1/2 = 0.53+/-0.05 kpc, a star-formation rate
SFR_Halpha = 33+/-19 Msun yr^{-1}, and in rotation around the main core of the
galaxy, is one of these star-forming clumps commonly observed in z>1
star-forming galaxies. (Abridged)Comment: 15 pages, 5 figures, published in Astronomy and Astrophysic
The behaviour of dark matter associated with 4 bright cluster galaxies in the 10kpc core of Abell 3827
Galaxy cluster Abell 3827 hosts the stellar remnants of four almost equally
bright elliptical galaxies within a core of radius 10kpc. Such corrugation of
the stellar distribution is very rare, and suggests recent formation by several
simultaneous mergers. We map the distribution of associated dark matter, using
new Hubble Space Telescope imaging and VLT/MUSE integral field spectroscopy of
a gravitationally lensed system threaded through the cluster core. We find that
each of the central galaxies retains a dark matter halo, but that (at least)
one of these is spatially offset from its stars. The best-constrained offset is
1.62+/-0.48kpc, where the 68% confidence limit includes both statistical error
and systematic biases in mass modelling. Such offsets are not seen in field
galaxies, but are predicted during the long infall to a cluster, if dark matter
self-interactions generate an extra drag force. With such a small physical
separation, it is difficult to definitively rule out astrophysical effects
operating exclusively in dense cluster core environments - but if interpreted
solely as evidence for self-interacting dark matter, this offset implies a
cross-section sigma/m=(1.7+/-0.7)x10^{-4}cm^2/g x (t/10^9yrs)^{-2}, where t is
the infall duration.Comment: 15 pages, 9 figure
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