David Rapetti
A5059923075- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Planetary Science and Exploration
- Dark Matter and Cosmic Phenomena
- Superconducting and THz Device Technology
- History and Developments in Astronomy
- Scientific Research and Discoveries
- Antenna Design and Optimization
- Soil Moisture and Remote Sensing
- Radio Wave Propagation Studies
- Astronomical Observations and Instrumentation
- Millimeter-Wave Propagation and Modeling
- Scientific Computing and Data Management
- Space Exploration and Technology
- Big Data and Business Intelligence
Ames Research Center
2016-2025
University of Colorado Boulder
2016-2024
Laboratory for Atmospheric and Space Physics
2016-2024
Universities Space Research Association
2019-2024
Research Institute for Advanced Computer Science
2020-2024
University of Colorado System
2021
Ludwig-Maximilians-Universität München
2015-2019
Excellence Cluster Universe
2016-2019
Massachusetts Institute of Technology
2018
Royal Observatory
2018
We present constraints on the mean matter density, Ω m , dark energy DE and equation of state parameter, w, using Chandra measurements X-ray gas mass fraction (f ) in 42 hot (kT > 5keV), luminous, dynamically relaxed galaxy clusters spanning redshift range 0.05 < z 1.1.Using only f data for six lowest at 0.15, which has a negligible effect measurements, we measure = 0.28 ± 0.06 (68 per cent confidence limits, standard priors Hubble Constant, H 0 baryon b h 2 ).Analyzing all clusters,...
(Abridged) This is the first of a series papers in which we derive simultaneous constraints on cosmological parameters and X-ray scaling relations using observations growth massive, flux-selected galaxy clusters. Our data set consists 238 clusters drawn from ROSAT All-Sky Survey, incorporates extensive follow-up Chandra Observatory. Here describe implement new statistical framework required to self-consistently produce cosmology such data, present results models dark energy. In spatially...
(Abridged) This is the second in a series of papers which we derive simultaneous constraints on cosmology and X-ray scaling relations using observations massive, flux-selected galaxy clusters. The data set consists 238 clusters drawn from ROSAT All-Sky Survey with 0.1-2.4 keV luminosities >2.5e44 erg/second, incorporates extensive follow-up Chandra Observatory. Our analysis accounts self-consistently for all selection effects, covariances systematic uncertainties. Here describe reduction...
We employ robust weak gravitational lensing measurements to improve cosmological constraints from of the galaxy cluster mass function and its evolution, using X-ray selected clusters detected in ROSAT All-Sky Survey. Our analysis constrains absolute scale such at 8 per cent level, including both statistical systematic uncertainties. Combining it with survey data follow-up observations, we find a tight constraint on combination mean matter density late-time normalization power spectrum,...
We present the XXL Survey, largest XMM programme totaling some 6.9 Ms to date and involving an international consortium of roughly 100 members. The Survey covers two extragalactic areas 25 deg2 each at a point-source sensitivity ~ 5E-15 erg/sec/cm2 in [0.5-2] keV band (completeness limit). survey's main goals are provide constraints on dark energy equation state from space-time distribution clusters galaxies serve as pathfinder for future, wide-area X-ray missions. review science objectives,...
(abridged) We present cosmological constraints obtained from galaxy clusters identified by their Sunyaev-Zel'dovich effect signature in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich survey. consider 377 cluster candidates at z>0.25 with a detection significance greater than five, corresponding to 95% purity threshold for compute on models using measured abundance as function of mass and redshift. include additional multi-wavelength observations, including Chandra X-ray data...
This is the second in a series of papers studying astrophysics and cosmology massive, dynamically relaxed galaxy clusters. The data set employed here consists Chandra observations 40 such clusters, identified comprehensive search archive for hot (kT ≳ 5舁keV), morphologically systems, as well high-quality weak gravitational lensing subset these Here we present cosmological constraints from measurements gas mass fraction,舁 fgas, this cluster sample. By incorporating robust calibration X-ray...
We present and employ a new kinematical approach to cosmological ‘dark energy’ studies. construct models in terms of the dimensionless second third derivatives scalefactor a(t) with respect cosmic time t, namely present-day value deceleration parameter q0 jerk parameter, j(t). An elegant feature this parametrization is that all Λ cold dark matter (ΛCDM) have j(t) = 1 (constant), which facilitates simple tests for departures from ΛCDM paradigm. Applying our model three best available sets...
We present constraints on the mean matter density, Omega_m, normalization of density fluctuation power spectrum, sigma_8, and dark-energy equation-of-state parameter, w, obtained from measurements X-ray luminosity function largest known galaxy clusters at redshifts z<0.7, as compiled in Massive Cluster Survey (MACS) local BCS REFLEX cluster samples. Our analysis employs an observed mass-luminosity relation, calibrated by hydrodynamical simulations, including corrections for non-thermal...
The abundance of massive galaxy clusters is a powerful probe departures from General Relativity (GR) on cosmic scales. Despite current stringent constraints placed by stellar and galactic tests, larger scales alternative theories gravity such as $f(R)$ can still work effective theories. Here we present two popular models $f(R)$, Hu-Sawicki "designer", derived fully self-consistent analysis samples X-ray selected accounting for all the covariances between cosmological astrophysical...
Abstract Most of the current Global 21 cm experiments include ground screens that help moderate effects from Earth. In this paper, we report on a possible systematic artifact within plane may produce broad absorption features in spectra observed by these experiments. Using analytical approximations and numerical modeling, origin its impact sky-averaged spectrum are described. The publicly released EDGES data set, which 78 MHz feature was recently suggested, is used to probe for potential...
We derive cosmological constraints using a galaxy cluster sample selected from the 2500~deg$^2$ SPT-SZ survey. The spans redshift range $0.25< z<1.75$ and contains 343 clusters with SZ detection significance $\xi>5$. is supplemented optical weak gravitational lensing measurements of 32 $0.29<z<1.13$ (from Magellan HST) X-ray 89 $0.25<z<1.75$ Chandra). rely on minimal modeling assumptions: i) provides an accurate means measuring halo masses, ii) mean observables are related to true mass...
In the currently debated context of using clusters galaxies as cosmological probes, need for well-defined cluster samples is critical. The XXL Survey has been specifically designed to provide a well characterised sample some 500 X-ray detected suitable studies. main goal present article make public and describe properties catalogue in its state, associated catalogues super-clusters fossil groups. We release containing 365 total. give details follow-up observations explain procedure adopted...
We detect the kinematic Sunyaev-Zel'dovich (kSZ) effect with a statistical significance of 4.2σ by combining cluster catalogue derived from first year data Dark Energy Survey cosmic microwave background temperature maps South Pole Telescope Survey. This measurement is performed differential statistic that isolates pairwise kSZ signal, providing detection large-scale, motion clusters using redshifts photometric data. By fitting signal to theoretical template, we measure average central...
We estimate total mass (M500), intracluster medium (ICM) (MICM), and stellar (M⋆) in a Sunyaev–Zel'dovich effect (SZE) selected sample of 91 galaxy clusters with masses M500 ≳ 2.5 × 1014 M⊙ redshift 0.2 < z 1.25 from the 2500 |$\deg ^2$| South Pole Telescope SPT-SZ survey. The are estimatedfrom SZE observable, ICM MICM obtained analysis Chandra X-ray observations, M⋆ derived by fitting spectral energy distribution templates to Dark Energy Survey griz optical photometry WISE or Spitzer...
Uncertainty in mass–observable scaling relations is currently the limiting factor for galaxy-cluster-based cosmology. Weak gravitational lensing can provide direct mass calibration and reduce uncertainty. We present new ground-based weak observations of 19 South Pole Telescope (SPT) selected clusters at redshifts 0.29 ≤ |$z$| 0.61 combine them with previously reported space-based 13 galaxy 0.576 1.132 to constrain cluster Sunyaev–Zel'dovich effect (SZE), gas Mgas YX, product X-ray...
We perform a joint analysis of the counts redMaPPer clusters selected from Dark Energy Survey (DES) Y1 data and multi-wavelength follow-up collected within 2500 deg$^2$ South Pole Telescope (SPT) SZ survey. The SPT data, calibrating richness--mass relation optically catalog, enable cosmological exploitation DES cluster abundance data. To explore possible systematics related to modeling projection effects, we consider two calibrations observational scatter on richness estimates: simple...
Context. The XXL Survey is the largest survey carried out by XMM-Newton satellite and covers a total area of 50 square degrees distributed over two fields. It primarily aims at investigating large-scale structures Universe using distribution galaxy clusters active galactic nuclei as tracers matter distribution. will ultimately uncover several hundreds to redshift ~2 sensitivity ~10-14 erg s-1 cm-2 in [0.5–2] keV band.
This is the fourth in a series of papers studying astrophysics and cosmology massive, dynamically relaxed galaxy clusters. Here, we use measurements weak gravitational lensing from Weighing Giants project to calibrate Chandra X-ray total mass that rely on assumption hydrostatic equilibrium. comparison masses provides measurement combined bias due both astrophysical instrumental sources. Assuming fixed cosmology, within characteristic radius (r_2500) determined data, measure ratio 0.96 +/- 9%...
ABSTRACT We present a detection of the splashback feature around galaxy clusters selected using Sunyaev–Zel’dovich (SZ) signal. Recent measurements optically have found that radius, rsp, is smaller than predicted by N-body simulations. A possible explanation for this discrepancy rsp inferred from observed radial distribution galaxies affected selection effects related to optical cluster-finding algorithms. test possibility measuring in via SZ effect data South Pole Telescope survey and...
We present a weak-lensing analysis of X-ray galaxy groups and clusters selected from the XMM-XXL survey using first-year data Hyper Suprime-Cam (HSC) Subaru Strategic Program. Our joint focuses on 136 spectroscopically confirmed X-ray-selected systems at 0.031 < z 1.033 detected in 25sqdeg XXL-N region. characterize mass distributions individual establish concentration-mass (c-M) relation for XXL sample, by accounting selection bias statistical effects, marginalizing over remaining...
We present updated cosmological constraints from measurements of the gas mass fractions ($f_{gas}$) massive, dynamically relaxed galaxy clusters. Our new data set has greater leverage on models dark energy, thanks to addition Perseus Cluster at low redshifts, two clusters redshifts $z>0.97$, and significantly longer observations four $0.6<z<0.9$. low-redshift ($z<0.16$) $f_{gas}$ data, combined with cosmic baryon fraction measured microwave background (CMB), imply a Hubble constant $h =...
Abstract We present the discovery of TOI-7041 b (TIC 201175570 b), a hot Saturn transiting red giant star with measurable stellar oscillations. observe solar-like oscillations in frequency maximum power <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mi mathvariant="normal">max</mml:mi> </mml:msub> <mml:mspace width="0.25em"/> <mml:mo>=</mml:mo> </mml:math> 218.50 ± 2.23 μ Hz and large separation Δ ν =...
We present new constraints on the evolution of dark energy from an analysis cosmic microwave background, supernova and X-ray galaxy cluster data. Our employs a minimum priors exploits complementary nature these data sets. examine series models with up to three free parameters: current equation state w0, early-time wet, scalefactor at transition at. From combined all sets, assuming constant that Universe is flat, we measure w0=−1.05+0.10−0.12. Including wet as parameter allowing vary over...