A5056938388- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Oxidative Organic Chemistry Reactions
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Chemical Synthesis and Reactions
- Synthetic Organic Chemistry Methods
- Calibration and Measurement Techniques
- Astrophysics and Cosmic Phenomena
- Radical Photochemical Reactions
- Organic Chemistry Synthesis Methods
- Synthesis of Organic Compounds
- Vanadium and Halogenation Chemistry
- CCD and CMOS Imaging Sensors
- Inorganic and Organometallic Chemistry
- Chemical Synthesis and Analysis
- Metal complexes synthesis and properties
- Optical Systems and Laser Technology
- Coal and Its By-products
- Synthesis and biological activity
- Solar and Space Plasma Dynamics
Purdue University West Lafayette
2014-2024
Wilford Hall Ambulatory Surgical Center
2010
Stanford University
2004-2007
Kavli Institute for Particle Astrophysics and Cosmology
2004-2007
Columbia University
1999-2006
Social Science Research Council
2005
El Colegio de la Frontera Norte
2005
The University of Texas Medical Branch at Galveston
1988-2005
Universidad Autónoma de Ciudad Juárez
2005
University of Tennessee at Knoxville
1971-2003
The ESA X-ray Multi Mirror mission, XMM-Newton, carries two identical Reflection Grating Spectrometers (RGS) behind of its three nested sets Wolter I type mirrors. instrument allows high-resolution ( to 500) measurements in the soft range (6 38 Åor 2.1 0.3 keV) with a maximum effective area about 140 cm2 at 15 Å. Its design is optimized for detection K-shell transitions carbon, nitrogen, oxygen, neon, magnesium, and silicon, as well L shell iron. present paper gives full description RGS...
We present detailed spatially-resolved spectroscopy results of the observation Abell 1835 using European Photon Imaging Cameras (EPIC) and Reflection Grating Spectrometers (RGS) on XMM-Newton observatory. is a luminous (1046 ergs ), medium redshift (), X-ray emitting cluster galaxies. The observations support interpretation that large amounts cool gas are in multi-phase surrounded by hot ( keV) outer envelope. detect O VIII Lyα two Fe XXIV complexes RGS spectrum. emission measure below keV...
We present high-resolution X-ray spectra of 14 putative cooling-flow clusters galaxies obtained with the Reflection Grating Spectrometer on XMM-Newton. The in sample span a large range temperatures and mass deposition rates. Various these exhibit line emission from O VIII, Ne X, Mg XII XI, Al XIII XII, Si XIV XIII, N VII, C VI as well all Fe L ions. strong cool plasma at just below ambient temperature, T0, down to T0/2, but also severe deficit relative predictions isobaric model lower...
The initial results from XMM-Newton observations of the rich cluster galaxies Abell 1795 are presented. spatially-resolved X-ray spectra taken by European Photon Imaging Cameras (EPIC) show a temperature drop at radius $\sim 200$ kpc center, indicating that ICM is cooling. Both EPIC and Reflection Grating Spectrometers (RGS) extracted center can be described an isothermal model with 4$ keV. volume emission measure any cool component ($<1$ keV) less than few % hot center. A strong OVIII...
Tumour necrosis factor alpha (TNF alpha) antagonists are effective for the treatment of rheumatoid arthritis (RA), but concerns remain about safety these agents in presence chronic infections, including hepatitis C virus (HCV) infection.To examine influence with TNF on levels HCV viraemia and serum transaminases patients RA HCV.In a retrospective survey course 16 infected who had received etanercept or infliximab was analysed. Eight additional were also enrolled into three month prospective...
We present spatially resolved X-ray spectra taken with the EPIC cameras of XMM-Newton a sample 17 cooling clusters and three non-cooling for comparison. The deprojected are analyzed multi-temperature model, independent any priori assumptions about physics behind heating mechanisms. All show central decrement average temperature, most them factor . Three (Sérsic 159-3, MKW 3s Hydra A) only weak temperature decrement, while two others (A 399 A 2052) have very strong decrement. pressure...
We present the first high spectral resolution X-ray observation of giant elliptical galaxy NGC 4636, obtained with Reflection Grating Spectrometer on-board XMM-Newton Observatory. The resulting spectrum contains a wealth emission lines from various charge states oxygen, neon, magnesium, and iron. Examination cross-dispersion profiles several these provides clear, unambiguous evidence resonance scattering by highest oscillator strength lines, as well weak temperature gradient in inner regions...
Future weak lensing surveys potentially hold the highest statistical power for constraining cosmological parameters compared to other probes. The of a survey is determined by sky coverage, inverse noise in shear measurements and galaxy number density. combination latter two factors often expressed terms neff – 'effective density galaxies used measurements'. In this work, we estimate Large Synoptic Survey Telescope (LSST) project, most powerful ground-based planned next decades. We...
The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with goal testing and facilitating development methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation very small galaxy shape distortions, presence far larger intrinsic shapes distortions due blurring kernel caused by atmosphere, telescope optics, instrumental effects. GREAT3...
The RS CVn binary system HR 1099 was extensively observed by the XMM-Newton observatory in February 2000 as its first-light target. A total of 570 ks exposure time accumulated with Reflection Grating Spectrometers (RGS). integrated X-ray spectrum between 5-35 Åis unprecedented quality and shows numerous features attributed to transitions elements C, N, O, Ne, Mg, Si, S, Fe, Ni. We perform an in-depth study elemental composition average corona this system, find that abundances strongly depend...
The cluster of galaxies Sérsic 159-03 was observed with the XMM-Newton X-ray observatory as part Guaranteed Time program. spectra taken EPIC and RGS instruments show no evidence for strong cooling flow derived from previous observations. There is a significant lack cool gas below 1.5 keV compared to standard isobaric models. While oxygen distributed more or less uniformly over cluster, iron shows concentration in center slightly offset brightness but within central cD galaxy. This points...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTManganese(III)-mediated .gamma.-lactone annulationWilliam E. Fristad and John R. PetersonCite this: J. Org. Chem. 1985, 50, 1, 10–18Publication Date (Print):January 1985Publication History Published online1 May 2002Published inissue 1 January 1985https://pubs.acs.org/doi/10.1021/jo00201a003https://doi.org/10.1021/jo00201a003research-articleACS PublicationsRequest reuse permissionsArticle Views1580Altmetric-Citations132LEARN ABOUT THESE...
ABSTRACT: The Soil and Water Assessment Tool (SWAT) model, designed for use on rural ungaged basins incorporating a GRASS GIS interface, was used to model the hydrologic response of Ariel Creek watershed northeastern Pennsylvania. Model evaluation daily flow prior calibration revealed deviation runoff volumes (D v ) 68.3 percent Nash‐Sutcliffe coefficient of‐0.03. performance affected by unusually large observed snowmelt events inability accurately simulate baseflow, which influenced...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConversion of alkenes to 1,2-diazides and 1,2-diaminesWilliam E. Fristad, Timothy A. Brandvold, John R. Peterson, Scott ThompsonCite this: J. Org. Chem. 1985, 50, 19, 3647–3649Publication Date (Print):September 1, 1985Publication History Published online1 May 2002Published inissue 1 September 1985https://pubs.acs.org/doi/10.1021/jo00219a049https://doi.org/10.1021/jo00219a049research-articleACS PublicationsRequest reuse permissionsArticle...
ABSTRACT We apply a new deep learning technique to detect, classify, and deblend sources in multiband astronomical images. train evaluate the performance of an artificial neural network built on Mask Region-based Convolutional Neural Network image processing framework, general code for efficient object detection, classification, instance segmentation. After evaluating our against simulated ground truth images star galaxy classes, we find precision 92 per cent at 80 recall stars 98 galaxies...
We present Chandra high-energy transmission grating spectra of seven cataclysmic variables. find that they divide unambiguously into two distinct types. Spectra the first type are remarkably well fitted by a simple cooling flow model, which assumes only steady-state isobaric radiative cooling. The maximum temperature, kTmax, and normalization, provides highly precise measurement accretion rate, free parameters this model. second grossly inconsistent with They instead exhibit hard continuum...
Strong evidence for cooling flows has been found in low-resolution X-ray imaging and spectra of many clusters galaxies. However, high-resolution several from the Reflection Grating Spectrometer on XMM-Newton now show a soft spectrum inconsistent with simple flow. The main problem is lack emission lines expected gas below 1–2 keV. Lines at about 2–3 keV are observed, even high-temperature cluster such as A1835, indicating that down to keV, but not lower temperatures. Here we discuss solutions...
XMM-Newton observations of 19 galaxy clusters are used to measure the elemental abundances and their spatial distributions in intracluster medium. The sample mainly consists X-ray bright relaxed with a cD galaxy. Along detailed Si, S Fe radial abundance within 300–700 kpc radius, O accurately derived central region clusters. maxima towards cluster center, possibly due metals from galaxy, spatially resolved. Si also exhibit increases general, resulting uniform Fe-Si-S ratios cluster. In...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTManganese(III) .gamma.-lactone annulation with substituted acidsWilliam E. Fristad, John R. Peterson, and Andreas B. ErnstCite this: J. Org. Chem. 1985, 50, 17, 3143–3148Publication Date (Print):August 1, 1985Publication History Published online1 May 2002Published inissue 1 August 1985https://pubs.acs.org/doi/10.1021/jo00217a025https://doi.org/10.1021/jo00217a025research-articleACS PublicationsRequest reuse permissionsArticle...
We examine deep XMM-Newton Reflection Grating Spectrometer (RGS) spectra from the cores of three X-ray bright cool core galaxy clusters, Abell 262, 3581 and HCG 62. Each RGS show Fe XVII emission lines indicating presence gas around 0.5 keV. There is no evidence for O VII which would imply at still cooler temperatures. The range in detected temperature these objects a factor 3.7, 5.6 2 62, respectively. coolest only has volume filling fraction 6 3 per cent 262 3581, but likely to be Chandra...
Several A- and B-ring-substituted sampangines were synthesized evaluated for antifungal antimycobacterial activity against AIDS-related opportunistic infection pathogens. Electrophilic halogenation provided a channel structural elaboration of the sampangine B-ring at position 4, while synthesis A-ring 3-substituted benzo[4,5]sampangine (24) achieved from corresponding functionalized cleistopholines. Two-dimensional NMR spectroscopy was used to rigorously characterize substituent patterns....
We examine deep XMM-Newton Reflection Grating Spectrometer (RGS) observations of the X-ray luminous galaxy cluster A1835. For first time in a we place direct limits on turbulent broadening emission lines. This is possible because coolest emitting gas cluster, which responsible for lines, occupies small region within core. The most conservative determination 90 per cent upper limit line-of-sight, non-thermal, velocity 274 km/s, measured from lines originating 30 kpc radius. ratio to thermal...