Douglas Applegate
A5071010767- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Adaptive optics and wavefront sensing
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Liver Disease Diagnosis and Treatment
- Advanced NMR Techniques and Applications
- Astrophysics and Star Formation Studies
- Lipid metabolism and disorders
- Astronomical Observations and Instrumentation
- Liver Diseases and Immunity
- Calibration and Measurement Techniques
- Liver Disease and Transplantation
- Proteoglycans and glycosaminoglycans research
- Advanced Fluorescence Microscopy Techniques
- Evolutionary Algorithms and Applications
- Radio Astronomy Observations and Technology
- X-ray Diffraction in Crystallography
Novartis (United States)
2024
Novartis (Switzerland)
2024
University of Bonn
2013-2021
University of Chicago
2017-2021
Kavli Institute for Particle Astrophysics and Cosmology
2008-2014
Stanford University
2008-2014
SLAC National Accelerator Laboratory
2010-2014
Oklahoma State University
2013
Carnegie Mellon University
2006-2009
We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500 deg$^2$ South Pole Telescope (SPT) data. This work represents the complete sample detected at high significance in 2500-square-degree SPT-SZ survey, which was completed 2011. A total 677 (409) cluster candidates are identified above signal-to-noise threshold $\xi$ =4.5 (5.0). Ground- and space-based optical near-infrared (NIR) imaging confirms overdensities similarly colored galaxies...
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 report weak-lensing masses for 51 of the most X-ray luminous galaxy clusters known. This cluster sample, introduced earlier in this series papers, spans redshifts 0.15 < z_cl 0.7, and is well suited to calibrate mass proxies current cosmology experiments. Cluster are measured with a standard `color-cut' lensing method from three-filter photometry each field. Additionally, 27 fields at least five-filter photometry, we measure high-accuracy using new that exploits all information available...
This is the first in a series of papers which we measure accurate weak-lensing masses for 51 most X-ray luminous galaxy clusters known at redshifts 0.15<z<0.7, order to calibrate and other mass proxies cosmological cluster experiments. The primary aim improve absolute calibration observables, currently dominant systematic uncertainty count Key elements this work are rigorous quantification uncertainties, high-quality data reduction photometric calibration, "blind" nature analysis avoid...
(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...
In light of the tension in cosmological constraints reported by Planck team between their Sunyaev–Zel'dovich-selected cluster counts and Cosmic Microwave Background (CMB) temperature anisotropies, we compare mass estimates with robust, weak-lensing measurements from Weighing Giants (WtG) project. For 22 clusters common cosmology sample WtG, find an overall ratio 〈MPlanck/MWtG〉 = 0.688 ± 0.072. Extending to not used analysis yields a consistent value 0.698 0.062 38 common. Identifying masses...
We constrain the physical nature of dark matter using newly identified massive merging galaxy cluster MACSJ0025.4-1222. As was previously shown by example Bullet Cluster (1E0657-56), such systems are ideal laboratories for detecting isolated matter, and distinguishing between cold (CDM) other scenarios (e.g. self-interacting alternative gravity theories). MACSJ0025.4-1222 consists two subclusters similar richness at z=0.586. measure distribution X-ray emitting gas from Chandra data find it...
We present constraints on the scaling relations of galaxy cluster X-ray luminosity, temperature and gas mass (and derived quantities) with redshift, employing masses from robust weak gravitational lensing measurements. These are first such results obtained an analysis that simultaneously accounts for selection effects underlying function, directly incorporates data to constrain total masses. Our their intrinsic scatters in good agreement previous studies, reinforce a picture which departures...
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...
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...
We present an HST/ACS weak gravitational lensing analysis of 13 massive high-redshift (z_median=0.88) galaxy clusters discovered in the South Pole Telescope (SPT) Sunyaev-Zel'dovich Survey. This study is part a larger campaign that aims to robustly calibrate mass-observable scaling relations over wide range redshift enable improved cosmological constraints from SPT cluster sample. introduce new strategies ensure systematics do not degrade on significantly. First, we efficiently remove...
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...
The gravitational potential of clusters galaxies acts as a cosmic telescope allowing us to find and study at fainter limits than otherwise possible thus probe closer the epoch formation first galaxies. We use Bullet Cluster 1E0657-56 (z = 0.296) case study, because its high mass merging configuration makes it one most efficient telescopes we know. develop new algorithm reconstruct Cluster, based on non-uniform adaptive grid, combining strong weak lensing data derived from deep HST/ACS...
High-statistics differential cross sections for the reactions $\ensuremath{\gamma}p\ensuremath{\rightarrow}p\ensuremath{\eta}$ and $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\eta}}^{'}$ have been measured using CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab center-of-mass energies from near threshold up to 2.84 GeV. The ${\ensuremath{\eta}}^{'}$ results are most precise date provide largest energy angular coverage. $\ensuremath{\eta}$ measurements extend range of...
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%...
We present improved methods for using stars found in astronomical exposures to calibrate both star and galaxy colors as well adjust the instrument flat field. By developing a spectroscopic model SDSS stellar locus color-color space, synthesizing an expected locus, simultaneously solving all unknown zeropoints when fitting instrumental we increase calibration accuracy of matching. also use new combined technique estimate flat-field models Subaru SuprimeCam camera, forming `star flats' based...
We present new ultraviolet, optical, and X-ray data on the Phoenix galaxy cluster (SPT-CLJ2344-4243). Deep optical imaging reveals previously undetected filaments of star formation, extending to radii ∼50–100 kpc in multiple directions. Combined UV-optical spectroscopy central a massive (2 × 109 M⊙), young (∼4.5 Myr) population stars, consistent with time-averaged formation rate 610 ± 50 M⊙ yr−1. report strong detection O vi λλ1032,1038, which appears originate primarily shock-heated gas,...
We present a multi-wavelength study of 90 brightest cluster galaxies (BCGs) in sample galaxy clusters selected via the Sunyaev Zel'dovich effect by South Pole Telescope, utilizing data from various ground- and space-based facilities. infer star formation rate (SFR) for BCG each cluster, based on UV IR continuum luminosity, as well [O II] emission line luminosity cases where spectroscopy is available, finding 7 systems with SFR > 100 Msun/yr. find that exceeds 10 Msun/yr 31 (34%) at 0.25 < z...
Aims Metabolic dysfunction Associated Steatotic Liver Disease (MASLD) outcomes such as MASH (metabolic associated steatohepatitis), fibrosis and cirrhosis are ordinarily determined by resource-intensive invasive biopsies. We aim to show that routine clinical tests offer sufficient information predict these endpoints. Methods Using the LITMUS Metacohort derived from European NAFLD Registry, largest MASLD dataset in Europe, we create three combinations of features which vary degree procurement...
High-statistics differential cross sections and spin density matrix elements for the reaction gamma p -> omega have been measured using CLAS at Jefferson Lab center-of-mass (CM) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide CM energy bins, each subdivided into cos(theta_CM) bins of width 0.1. These most precise extensive photoproduction measurements date. A number prominent structures clearly present data. Many these not previously observed due limited...
We report on a deep, multiwavelength study of the galaxy cluster MACS J1931.8−2634 using Chandra X-ray, Subaru optical and Very Large Array 1.4-GHz radio data. This (z= 0.352) harbours one most X-ray luminous cool cores yet discovered, with an equivalent mass, cooling rate within central is ∼700 M⊙ yr−1. Unique features observed in core hint to wealth past activity that has greatly disrupted original core. The data suggest oscillatory motion along roughly north–south direction. also observe...
We present a measurement of the fraction cluster galaxies hosting X-ray bright active galactic nuclei (AGN) as function clustercentric distance scaled in units r500. Our analysis employs high-quality Chandra and Subaru optical imaging for 42 massive X-ray-selected galaxy fields spanning redshift range 0.2 < z 0.7. In total, our study involves 176 AGN with (R 23) counterparts above 0.5–8.0 keV flux limit 10-14 erg cm-2 s-1. When excluding central dominant from calculation, we measure regions...
We present the results of SPT-GMOS, a spectroscopic survey with Gemini Multi-Object Spectrograph (GMOS) on South. The targets SPT-GMOS are galaxy clusters identified in SPT-SZ survey, millimeter-wave 2500 squ. deg. southern sky using South Pole Telescope (SPT). Multi-object observations 62 SPT-selected were performed between January 2011 and December 2015, yielding spectra radial velocity measurements for 2595 sources. identify 2243 these sources as galaxies, 352 stars. Of we 1579 members...