40 research outputs found
The Integrated Sachs-Wolfe Signal from BOSS Super-Structures
Cosmic structures leave an imprint on the microwave background radiation
through the integrated Sachs-Wolfe effect. We construct a template map of the
linear signal using the SDSS-III Baryon Acoustic Oscillation Survey at redshift
0.43 < z < 0.65. We verify the imprint of this map on the Planck CMB
temperature map at the 97% confidence level and show consistency with the
density-temperature cross-correlation measurement. Using this ISW
reconstruction as a template we investigate the presence of ISW sources and
further examine the properties of the Granett-Neyrinck-Szapudi supervoid and
supercluster catalogue. We characterise the three-dimensional density profiles
of these structures for the first time and demonstrate that they are
significant structures. Model fits demonstrate that the supervoids are
elongated along the line-of-sight and we suggest that this special orientation
may be picked out by the void-finding algorithm in photometric redshift space.
We measure the mean temperature profiles in Planck maps from public void and
cluster catalogues. In an attempt to maximise the stacked ISW signal we
construct a new catalogue of super-structures based upon local peaks and
troughs of the gravitational potential. However, we do not find a significant
correlation between these structures and the CMB temperature.Comment: Updated to match journal articl
The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Growth rate of structure measurement from cosmic voids
We present a void clustering analysis in configuration-space using the
completed Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon Oscillation
Spectroscopic Survey (eBOSS) DR16 samples. These samples consist of Luminous
Red Galaxies (LRG) combined with the high redshift tail of the SDSS-III Baryon
Oscillation Spectroscopic Survey (BOSS) DR12 CMASS galaxies (called as
LRG+CMASS sample), Emission Line Galaxies (ELG) and quasars (QSO). We build
void catalogues from the three eBOSS DR16 samples using a ZOBOV-based
algorithm, providing 2,814 voids, 1,801 voids and 4,347 voids in the LRG+CMASS,
ELG and QSO samples, respectively, spanning the redshift range . We
measure the redshift space distortions (RSD) around voids using the anisotropic
void-galaxy cross-correlation function and we extract the distortion parameter
. We test the methodology on realistic simulations before applying it to
the data, and we investigate all our systematic errors on these mocks. We find
, and , for
the LRG+CMASS, ELG and QSO sample, respectively. The quoted errors include
systematic and statistical contributions. In order to convert our measurements
in terms of the growth rate , we use consensus values of linear bias
from the eBOSS DR16 companion papers~\citep{eBOSScosmo}, resulting in the
following constraints: ,
and . Our
measurements are consistent with other measurements from eBOSS DR16 using
conventional clustering techniques.Comment: 17 pages, 8 figure
Calibrating the BAO scale using the CMB: Lifting the degeneracy between geometric and dynamic distortions using the sound horizon from the CMB
The degeneracy between geometric (Alcock-Paczynski) and dynamic (redshift
space) distortions in the pattern of the galaxy distribution has been a long
standing problem in the study of the large scale structure of the universe. We
examine the possibility of lifting this degeneracy and constraining
cosmological parameters by using the Baryon Acoustic Oscillation (BAO) scale as
a feature of known physical size, the sound horizon r_s ~ 150 Mpc. We
callibrate this scale with the equivalent feature in the Cosmic Microwave
Background (CMB). First, we construct a toy model of a power spectrum which
includes the BAO as well as geometric and dynamic distortions. By adding a
prior onto the sound horizon of ~1% we show, using a Fisher matrix analysis,
that error ellipses for line of sight and tangential distortion parameters
shrink by a factor of two for a 20(Gpc/h)^3 `DESpec/BigBOSS'-like galaxy survey
including shot noise. This improvement is even more marked in smaller surveys.
We also carry out a Monte Carlo Nested Sampling analysis on our parameter
space. We find that Monte Carlo and Fisher methods can agree reasonably well
for surveys with large volume but differ greatly for small volume surveys.Comment: 10 pages, 7 figures, submitted to MNRA
Adam Smith’s Green Thumb and Malthus’ Three Horsemen: Cautionary tales from classical political economy
This essay identifies a contradiction between the flourishing interest in the environmental economics of the classical period and a lack of critical parsing of the works of its leading representatives. Its focus is the work of Adam Smith and Thomas Malthus. It offers a critical analysis of their contribution to environmental thought and surveys the work of their contemporary devotees. It scrutinizes Smith's contribution to what Karl Polanyi termed the "economistic fallacy," as well as his defenses of class hierarchy, the "growth imperative" and consumerism. It subjects to critical appraisal Malthus's enthusiasm for private property and the market system, and his opposition to market regulation. While Malthus's principal attraction to ecological economists lies in his having allegedly broadened the scope of economics, and in his narrative of scarcity, this article shows that he, in fact, narrowed the scope of the discipline and conceptualized scarcity in a reified and pseudo-scientific way
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Inflation and Dark Energy from spectroscopy at z > 2
The expansion of the Universe is understood to have accelerated during two
epochs: in its very first moments during a period of Inflation and much more
recently, at z < 1, when Dark Energy is hypothesized to drive cosmic
acceleration. The undiscovered mechanisms behind these two epochs represent
some of the most important open problems in fundamental physics. The large
cosmological volume at 2 < z < 5, together with the ability to efficiently
target high- galaxies with known techniques, enables large gains in the
study of Inflation and Dark Energy. A future spectroscopic survey can test the
Gaussianity of the initial conditions up to a factor of ~50 better than our
current bounds, crossing the crucial theoretical threshold of
of order unity that separates single field and
multi-field models. Simultaneously, it can measure the fraction of Dark Energy
at the percent level up to , thus serving as an unprecedented test of
the standard model and opening up a tremendous discovery space