384 research outputs found

    Redshift-space distortions with split densities

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    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 (1.5h11.5\,h^{-1}Gpc)3^3 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 fσ12f\sigma_{12} at the per-cent level, and Alcock-Paczynski (AP) parameters at the sub-per-cent level with the minimal scale of 15h1Mpc15\,h^{-1}{\rm Mpc}. This is a \sim30 per cent and \sim6 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

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    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

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    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 <1012M<10^{12}M_\odot 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 M=10[9.09.5]MM_{*}= 10^{[9.0-9.5]}M_\odot have comparable SF activity and HI gas fractions, but the lowest quenched galaxy fraction. Inner void galaxies with M=10[9.510.5]MM_{*}= 10^{[9.5-10.5]}M_\odot have the lowest HI gas fraction, the highest quenched fraction and the lowest gas metallicities. On the other hand, inner void galaxies with M>1010.5MM_{*}>10^{10.5}M_\odot 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

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    \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

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    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

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    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 0.07<z<1.00.07 < z < 1.0. We fit a standard Λ\LambdaCDM cosmological model as well as various extensions including a constant dark energy equation of state not equal to 1-1, 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 Ωm=0.3127±0.0055\Omega_\mathrm{m} = 0.3127\pm 0.0055 for a base Λ\LambdaCDM cosmology, Ωm=0.3172±0.0061,w=0.930±0.039\Omega_\mathrm{m} = 0.3172\pm 0.0061, w = -0.930\pm 0.039 additionally allowing the dark energy equation of state ww to vary, and Ωm=0.3239±0.0085,w=0.889±0.052,and Ωk=0.0031±0.0028\Omega_\mathrm{m} = 0.3239\pm 0.0085, w = -0.889\pm 0.052, \mathrm{and}\ \Omega_\mathrm{k} = -0.0031\pm 0.0028 further extending to non-flat models.Comment: 11 pages, 9 figures. Submitted to MNRA

    Constraining νΛ\nu \LambdaCDM with density-split clustering

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    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 νΛ\nu \LambdaCDM 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 88 and by factors of 5, 3, 4, 6, and 6 for Ωm\Omega_m, Ωb\Omega_b, hh, nsn_s, and σ8\sigma_8, 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

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    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

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    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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