R. C. Smith
A5107343945- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Ionosphere and magnetosphere dynamics
- Meteorological Phenomena and Simulations
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- History and Developments in Astronomy
- Dark Matter and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Remote Sensing in Agriculture
- Scientific Research and Discoveries
- CCD and CMOS Imaging Sensors
- Tropical and Extratropical Cyclones Research
University of Sussex
1988-2023
Boeing (United States)
1995-2023
University of Alberta
2023
Cerro Tololo Inter-American Observatory
2010-2020
Max Planck Institute for Astrophysics
2013-2019
Jet Propulsion Laboratory
2019
Federal Center for Technological Education Celso Suckow da Fonseca
2018
Laboratório Interinstitucional de e-Astronomia
2018
University of Liverpool
2015-2016
Texas A&M University
2016
We present the results of a large library cosmological N-body simulations, using power-law initial spectra. The nonlinear evolution matter power spectra is compared with predictions existing analytic scaling formulae based on work Hamilton et al. approach has assumed that highly structures obey `stable clustering' and are frozen in proper coordinates. Our show that, when transformed under self-similarity scaling, scale-free define locus clearly shallower than would be required stable...
We propose a heuristic model that displays the main features of realistic theories for galaxy bias. show low-order clustering statistics dark-matter distribution depend almost entirely on locations and density profiles haloes. A hypothetical catalogue depends (i) efficiency formation, as manifested by halo occupation number -- galaxies brighter than some sample limit contained in given mass; (ii) location these within their halo. The first factor is constrained empirical luminosity function...
We present constraints on the dark energy equation-of-state parameter, w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from ESSENCE supernova survey. derive a set of nature assuming flat Universe. By including (Omega_M, w) baryon acoustic oscillations, we obtain value for static parameter w=-1.05^{+0.13}_{-0.12} (stat; 1 sigma) +- 0.11 (sys) and Omega_M=0.274^{+0.033}_{-0.020} with best-fit chi^2/DoF 0.96. These results are consistent those reported by SuperNova Legacy Survey in similar...
We have coordinated Hubble Space Telescope (HST) photometry with ground-based discovery for three supernovae: Type Ia supernovae near z ≈ 0.5 (SN 1997ce, SN 1997cj) and a third event at = 0.97 1997ck). The superb spatial resolution of HST separates each supernova from its host galaxy leads to good precision in the light curves. use these curves relations between luminosity, light-curve shape, color calibrated low-z samples derive relative luminosity distances that are accurate 10% 20% 1....
The first cosmological results from the ESSENCE supernova survey (Wood-Vasey and coworkers) are extended to a wider range of models including dynamical dark energy nonstandard models. We fold in greater number external data sets such as recent Higher-z release high-redshift supernovae (Riess coworkers), well several complementary probes. Model comparison statistics Bayesian Akaike information criteria applied gauge worth These favor that give good fit with fewer parameters. Based on this...
In this, the first in a series of three papers concerning SuperCOSMOS Sky Survey (SSS), we give an introduction and user guide to survey programme. We briefly describe other wide-field surveys compare them with our own. examples data, make comparison accuracies various image parameters available those from providing similar data; show that SSS data base interface offer advantages over these surveys. Some science applications are also described some limitations discussed. The constitutes...
We report the discovery of eight new Milky Way companions in optical imaging data collected during first year Dark Energy Survey (DES). Each system is identified as a statistically significant over-density individual stars consistent with expected isochrone and luminosity function an old metal-poor stellar population. The objects span wide range absolute magnitudes (MV from to ), physical sizes (), heliocentric distances (). Based on low surface brightnesses, large sizes, and/or...
ABSTRACT We search for excess γ -ray emission coincident with the positions of confirmed and candidate Milky Way satellite galaxies using six years data from Fermi Large Area Telescope (LAT). Our sample 45 stellar systems includes 28 kinematically dark-matter-dominated dwarf spheroidal (dSphs) 17 recently discovered that have photometric characteristics consistent population known dSphs. For each these targets, relative predicted flux due to dark matter annihilation is taken kinematic...
ABSTRACT We describe updates to the redMaPPer algorithm, a photometric red-sequence cluster finder specifically designed for large surveys. The updated algorithm is applied of Science Verification (SV) data from Dark Energy Survey (DES), and Sloan Digital Sky (SDSS) DR8 set. DES SV catalog locally volume limited contains 786 clusters with richness (roughly equivalent ) . consists 26,311 , sharply increasing threshold as function redshift performance both catalogs shown be excellent,...
Recent studies have shown that the cross-correlation coefficient between galaxies and dark matter is very close to unity on scales outside a few virial radii of galaxy haloes, independent details how populate haloes. This finding makes it possible determine clustering from measurements galaxy–galaxy weak lensing clustering. We present new cosmological parameter constraints based large-scale spectroscopic samples Sloan Digital Sky Survey (SDSS) data release 7. generalize approach Baldauf et...
The dark energy dominated warm matter (WDM) model is a promising alternative cosmological scenario. We explore large-scale structure formation in this paradigm. do two different ways: with the halo approach and help of an ensemble high-resolution N-body simulations. Combining these quasi-independent approaches leads to physical understanding important processes which shape structures. take detailed look at mass function, concentrations linear bias WDM. In all cases we find interesting...
We combine Dark Energy Survey Year 1 clustering and weak lensing data with Baryon Acoustic Oscillations (BAO) Big Bang Nucleosynthesis (BBN) experiments to constrain the Hubble constant. Assuming a flat $\Lambda$CDM model minimal neutrino mass ($\sum m_\nu = 0.06$ eV) we find $H_0=67.2^{+1.2}_{-1.0}$ km/s/Mpc (68% CL). This result is completely independent of constant measurements based on distance ladder, Cosmic Microwave Background (CMB) anisotropies (both temperature polarization), strong...
We describe the creation, content, and validation of Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support upcoming cosmological analyses. The GOLD set is assembled from multiple epochs DES imaging consists calibrated photometric zeropoints, object catalogs, ancillary products - e.g., maps survey depth observing conditions, star-galaxy classification, redshift estimates that are necessary for accurate wide-area catalog ~137 million objects detected coadded...
We constrain the mass–richness scaling relation of redMaPPer galaxy clusters identified in Dark Energy Survey Year 1 data using weak gravitational lensing. split into 4 × 3 bins richness λ and redshift |$z$| for ≥ 20 0.2 ≤ 0.65 measure mean masses these their stacked lensing signal. By modelling as 〈M200m|λ, |$z$|〉 = M0(λ/40)F((1 + |$z$|)/1.35)G, we normalization at 5.0 per cent level, finding M0 [3.081 ± 0.075(stat) 0.133(sys)] · 1014 M⊙ 40 0.35. The recovered index is F 1.356 0.051 (stat)...
We present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 square degrees with a median redshift of $0.59$. The cover main fields: Stripe 82, and an area overlapping South Pole Telescope survey region. describe our analysis process in particular measurement using independent shear pipelines, METACALIBRATION IM3SHAPE. catalogue uses Gaussian model innovative internal calibration scheme, was applied to $riz$-bands, yielding 34.8M objects. IM3SHAPE...
We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The was specifically developed to minimize photometric redshift uncertainties in large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary produce a luminosity-thresholded LRG sample of constant comoving density. demonstrate that photozs are very nearly as accurate best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer...
Future galaxy surveys require one percent precision in the theoretical knowledge of power spectrum over a large range including very nonlinear scales. While this level accuracy is easily obtained linear regime with perturbation theory, it represents serious challenge for small scales where numerical simulations are required. In paper we quantify present-day $N$-body methods, identifying main potential error sources from set-up initial conditions to measurement final spectrum. We directly...
We present weak lensing shear catalogues for 139 square degrees of data taken during the Science Verification (SV) time new Dark Energy Camera (DECam) being used Survey (DES). describe our object selection, point spread function estimation and measurement procedures using two independent pipelines, im3shape ngmix, which produce 2.12 million 3.44 galaxies, respectively. detail a set null tests measurements find that they pass requirements systematic errors at level necessary science...
ABSTRACT We present angular diameter distance measurements obtained by locating the baryon acoustic oscillations (BAO) scale in distribution of galaxies selected from first year Dark Energy Survey data. consider a sample over 1.3 million distributed footprint 1336 deg2 with 0.6 < $z$photo 1 and typical redshift uncertainty 0.03(1 + $z$). This was selected, as fully described companion paper, using colour/magnitude selection that optimizes trade-offs between number density uncertainty....
We present UBVRI photometry obtained from Mosaic images of M31 and M33 using the KPNO 4-m telescope. The survey covers 2.2 sq degrees M31, 0.8 M33, chosen so as to include all regions currently active in forming massive stars. catalog contains 371,781 146,622 stars respectively, where every star has a counterpart (at least) B, V, R. compare our previous studies. provide cross references confirmed members by spectroscopy, location these complete set color-magnitude diagrams. While follow-up...
We present UBVRIz lightcurves of the Type Ia SN 1999ee and Ib/c 1999ex, both located in galaxy IC 5179. has an extremely well sampled lightcurve spanning from 10 days before Bmax through 53 after peak. Near maximum we find systematic differences ~0.05 mag photometry measured with two different telescopes, even though is reduced to same local standards around supernova using specific color terms for each instrumental system. use models our bandpasses spectrophotometry derive magnitude...
Many results in modern astrophysics rest on the notion that Initial Mass Function (IMF) is universal. Our observations of HI selected galaxies light H-alpha and far-ultraviolet (FUV) challenge this notion. The flux ratio H-alpha/FUV from these two star formation tracers shows strong correlations with surface-brightness R band: Low Surface Brightness (LSB) have lower ratios compared to High expectations equilibrium models using commonly favored IMF parameters. Weaker but significant...
We present optical and infrared spectroscopy of the first 2 months evolution Type II supernova SN 1999em. combine these data with high-quality optical/infrared photometry beginning only 3 days after shock breakout, in order to study performance "expanding photosphere method" (EPM) determination distances. With this purpose, we develop a technique measure accurate photospheric velocities by cross-correlating observed model spectra. The application 1999em shows that can reach an average...