384 research outputs found
Redshift-space distortions with split densities
Accurate modelling of redshift-space distortions (RSD) is challenging in the
non-linear regime for two-point statistics e.g. the two-point correlation
function (2PCF). We take a different perspective to split the galaxy density
field according to the local density, and cross-correlate those densities with
the entire galaxy field. Using mock galaxies, we demonstrate that combining a
series of cross-correlation functions (CCFs) offers improvements over the 2PCF
as follows: 1. The distribution of peculiar velocities in each split density is
nearly Gaussian. This allows the Gaussian streaming model for RSD to perform
accurately within the statistical errors of a (Gpc) volume for
almost all scales and all split densities. 2. The PDF of the density field at
small scales is non-Gaussian, but the CCFs of split densities capture the
non-Gaussianity, leading to improved cosmological constraints over the 2PCF. We
can obtain unbiased constraints on the growth parameter at the
per-cent level, and Alcock-Paczynski (AP) parameters at the sub-per-cent level
with the minimal scale of . This is a 30 per cent
and 6 times improvement over the 2PCF, respectively. The diverse and
steep slopes of the CCFs at small scales are likely to be responsible for the
improved constraints of AP parameters. 3. Baryon acoustic oscillations (BAO)
are contained in all CCFs of split densities. Including BAO scales helps to
break the degeneracy between the line-of-sight and transverse AP parameters,
allowing independent constraints on them. We discuss and compare models for RSD
around spherical densities.Comment: 23 pages, 16 figures, MNRAS accepted version after peer review, minor
comment
Association of Bacteroides acidifaciens relative abundance with high-fibre diet-associated radiosensitisation
Funding Information: This work was funded by Cancer Research UK Programme grant C5255/ A23755 and Wellcome Trust Investigator Award 209397/Z/17/Z. The funding body had no role in the design of the study; in the collection, analysis, and interpretation of data; or in the writing of the manuscript. Acknowledgements We thank Professor Simon Kroll and Dr. Anderson Ryan for their very helpful comments. We thank Dr. Jia-Yu Ke at Research Diets, Inc. for formulation of the mouse diets, Dr. Lisa Folkes for assistance with the faecal butyrate quantification, and Omega Bioservices (Georgia, USA) for the 16S rRNA gene sequencing on a MiSeq platform.Peer reviewedPublisher PD
Revealing the properties of void galaxies and their assembly using the EAGLE simulation
We explore the properties of central galaxies living in voids using the EAGLE
cosmological hydrodynamic simulations. Based on the minimum void-centric
distance, we define four galaxy samples: inner void, outer void, wall, and
skeleton. We find that inner void galaxies with host halo masses
have lower stellar mass and stellar mass fractions than those
in denser environments, and the fraction of galaxies with star formation (SF)
activity and atomic hydrogen (HI) gas decreases with increasing void-centric
distance, in agreement with observations. To mitigate the influence of stellar
(halo) mass, we compare inner void galaxies to subsamples of fixed stellar
(halo) mass. Compared to denser environments, inner void galaxies with have comparable SF activity and HI gas fractions, but
the lowest quenched galaxy fraction. Inner void galaxies with have the lowest HI gas fraction, the highest quenched
fraction and the lowest gas metallicities. On the other hand, inner void
galaxies with have comparable SF activity and HI gas
fractions to their analogues in denser environments. They retain the highest
metallicity gas that might be linked to physical processes that act with lower
efficiency in underdense regions, such as AGN feedback. Furthermore, inner void
galaxies have the lowest fraction of positive gas-phase metallicity gradients,
which are typically associated with external processes or feedback events,
suggesting they have more quiet merger histories than galaxies in denser
environments. Our findings shed light on how galaxies are influenced by their
large-scale environment.Comment: 20 pages,16 figures, revised version with a discussion section and
edition in the text. Accepted to MNRA
Constraining modified gravity with weak-lensing peaks
\ua9 2024 The Author(s)It is well established that maximizing the information extracted from upcoming and ongoing stage-IV weak-lensing surveys requires higher order summary statistics that complement the standard two-point statistics. In this work, we focus on weak-lensing peak statistics to test two popular modified gravity models, f(R) and nDGP, using the FORGE and BRIDGE weak-lensing simulations, respectively. From these simulations, we measure the peak statistics as a function of both cosmological and modified gravity parameters simultaneously. Our findings indicate that the peak abundance is sensitive to the strength of modified gravity, while the peak two-point correlation function is sensitive to the nature of the screening mechanism in a modified gravity model. We combine these simulated statistics with a Gaussian Process Regression emulator and a Gaussian likelihood to generate stage-IV forecast posterior distributions for the modified gravity models. We demonstrate that, assuming small scales can be correctly modelled, peak statistics can be used to distinguish general relativity from f(R) and nDGP models at the 2σ level with a stage-IV survey area of 300 and 1000 deg2, respectively. Finally, we show that peak statistics can constrain log10 (|fR0|) = −6 per cent to 2 per cent precision, and log10(H0rc) = 0.5 per cent to 25 per cent precision
The Histone Deacetylase Inhibitor Romidepsin Spares Normal Tissues While Acting as an Effective Radiosensitizer in Bladder Tumors in Vivo
Funding Information: This work was funded by Cancer Research UK (CRUK; C5255/A23755). J.L.R. was funded by CRUK (project grant C15140/A19817). C.K.T. was funded by a CRUK DPhil Research Training and Support Grant, the Balliol College Alfred Douglas Stone Scholarship, and the University of Oxford Clarendon Fund. S.K. was funded by a CRUK/MRC Oxford Institute of Radiation Oncology CRUK studentship.Peer reviewedPublisher PD
Cosmological measurements from void-galaxy and galaxy-galaxy clustering in the Sloan Digital Sky Survey
We present the cosmological implications of measurements of void-galaxy and
galaxy-galaxy clustering from the Sloan Digital Sky Survey (SDSS) Main Galaxy
Sample (MGS), Baryon Oscillation Spectroscopic Survey (BOSS), and extended BOSS
(eBOSS) luminous red galaxy catalogues from SDSS Data Release 7, 12, and 16,
covering the redshift range . We fit a standard CDM
cosmological model as well as various extensions including a constant dark
energy equation of state not equal to , a time-varying dark energy equation
of state, and these same models allowing for spatial curvature. Results on key
parameters of these models are reported for void-galaxy and galaxy-galaxy
clustering alone, both of these combined, and all these combined with
measurements from the cosmic microwave background (CMB) and supernovae (SN).
For the combination of void-galaxy and galaxy-galaxy clustering plus CMB and
SN, we find tight constraints of for a
base CDM cosmology, additionally allowing the dark energy equation of state to
vary, and further extending to
non-flat models.Comment: 11 pages, 9 figures. Submitted to MNRA
Constraining CDM with density-split clustering
The dependence of galaxy clustering on local density provides an effective
method for extracting non-Gaussian information from galaxy surveys. The
two-point correlation function (2PCF) provides a complete statistical
description of a Gaussian density field. However, the late-time density field
becomes non-Gaussian due to non-linear gravitational evolution and higher-order
summary statistics are required to capture all of its cosmological information.
Using a Fisher formalism based on halo catalogues from the Quijote simulations,
we explore the possibility of retrieving this information using the
density-split clustering (DS) method, which combines clustering statistics from
regions of different environmental density. We show that DS provides more
precise constraints on the parameters of the CDM model compared to
the 2PCF, and we provide suggestions for where the extra information may come
from. DS improves the constraints on the sum of neutrino masses by a factor of
and by factors of 5, 3, 4, 6, and 6 for , , , ,
and , respectively. We compare DS statistics when the local density
environment is estimated from the real or redshift-space positions of haloes.
The inclusion of DS autocorrelation functions, in addition to the
cross-correlation functions between DS environments and haloes, recovers most
of the information that is lost when using the redshift-space halo positions to
estimate the environment. We discuss the possibility of constructing
simulation-based methods to model DS clustering statistics in different
scenarios.Comment: Submitted to MNRAS. Source code for all figures in the paper is
provided in the caption
SN 2009ib: A Type II-P supernova with an unusually long plateau
We present optical and near-infrared photometry and spectroscopy of SN 2009ib, a Type II-P supernova in NGC 1559. This object has moderate brightness, similar to those of the intermediate-luminosity SNe 2008in and 2009N. Its plateau phase is unusually long, lasting for about 130 days after explosion. The spectra are similar to those of the subluminous SN 2002gd, with moderate expansion velocities. We es- timate the 56Ni mass produced as 0.046 ± 0.015 M⊙. We determine the distance to SN 2009ib using both the expanding photosphere method (EPM) and the standard candle method. We also apply EPM to SN 1986L, a type II-P SN that exploded in the same galaxy. Combining the results of different methods, we conclude the distance to NGC 1559 as D = 19.8 ± 3.0 Mpc. We examine archival, pre-explosion images of the field taken with the Hubble Space Telescope, and find a faint source at the position of the SN, which has a yellow colour ((V − I)0 = 0.85 mag). Assuming it is a single star, we estimate its initial mass as MZAMS = 20 M⊙. We also examine the possibility, that instead of the yellow source the progenitor of SN 2009ib is a red supergiant star too faint to be detected. In this case we estimate the upper limit for the initial zero-age main sequence mass of the progenitor to be ∼ 14 − 17 M⊙. In addition, we infer the physical properties of the progenitor at the explosion via hydrodynamical modelling of the observables, and estimate the total energy as ∼ 0.55 × 1051 erg, the pre-explosion radius as ∼ 400 R⊙, and the ejected envelope mass as ∼ 15 M⊙, which implies that the mass of the progenitor before explosion was ∼ 16.5 − 17 M
p97/VCP inhibition causes excessive MRE11-dependent DNA end resection promoting cell killing after ionizing radiation
Funding Information: This work was funded by Cancer Research UK (CRUK) program grant C5255/A23755 to A.E.K. Medical Research Council UK (MRC) program grant MC_PC 12001/1 (MC_UU_00001/1) and Breast Cancer Now (Grant No. 2019DecPR1406) to K.R. S.K. was supported by the MRC Oxford Institute of Radiation Oncology (OIRO) CRUK studentship. We thank Dr. Sovan Sarkar (Department of Oncology, University of Oxford) for generously providing DR-GFP U2OS cells. We thank Diogo Dias (Ludwig Cancer Research Institute, University of Oxford) for his technical advice on HR and SSA assays and assistance with the analysis. We thank Dr. Lisa Folkes and Alix Hampson for the high-performance liquid chromatography (HPLC) analysis of CB-5083 concentration in tissue extracts from CD-1 nude mice bearing subcutaneous RT112 tumors. We also thank the Oxford Radcliffe Biobank for providing us with human tissue sections.Peer reviewedPublisher PD
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