Kenneth Carrell
A5015796528- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- Astronomical Observations and Instrumentation
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Quantum Chromodynamics and Particle Interactions
- Galaxies: Formation, Evolution, Phenomena
- History and Developments in Astronomy
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Space Exploration and Technology
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Distributed and Parallel Computing Systems
- Image Processing and 3D Reconstruction
- Radiation Therapy and Dosimetry
- thermodynamics and calorimetric analyses
Angelo State University
2016-2025
National Astronomical Observatories
2011-2014
Chinese Academy of Sciences
2011-2014
Texas Tech University
2003-2012
Association of Universities For Research In Astronomy
2012
We report on the test beam results and calibration methods using high energy electrons, pions muons with CMS forward calorimeter (HF). The HF covers a large pseudorapidity region ( $3\leq|\eta|\leq5$ ), is essential for number of physics channels missing transverse energy. It also expected to play prominent role in measurement tagging jets weak boson fusion Higgs production. based steel absorber embedded fused-silica-core optical fibers where Cherenkov radiation forms basis signal...
Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in H2 beam line at CERN particle momenta varying from 20 to 300 GeV/c. The time structure events was measured full chain preproduction front-end electronics running 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers HB. energy dependent slewing effect tuned optimal performance.
Based on SDSS DR8, we have selected a sample of 1728 red horizontal branch stars with |Z|<3 kpc by using color-metallicity relation and stellar parameters. The clearly trace typical thick disk population peaks at |Z|=1.26 [Fe/H]=-0.54. vertical metallicity gradient the is estimated in two ways. One fit to Gaussian histograms subtracting minor contributions from thin inner halo based Besancon Galaxy model. resulting -0.12+-0.01 dex/kpc for 0.5 <|Z| <3 kpc. other method linearly data 1 being...
The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 350 GeV/c has been measured. To our knowledge, this is widest momenta in which any system studied. These tests, carried out at H2 beam-line CERN, provide wealth information, especially low energies. analysis differences charged pions, kaons, protons antiprotons detailed discussion underlying phenomena are presented. We also show techniques that apply...
We examine the metallicity distribution of Galactic thick disk using F, G, and K dwarf stars selected from Sloan Digital Sky Survey, Data Release 8. Using large sample with proper motions spectroscopically determined stellar parameters, gradients in radial direction for various heights above plane vertical distances Galaxy center have been found. In particular, we find a gradient −0.113 ± 0.010 (−0.125 0.008) dex kpc−1 an isochrone (photometric) distance determination range 1 kpc <|Z| < 3...
Abstract This investigation is mainly focused on the LSST Survey Strategy Optimization process, a bottom-up approach that turned out to be quite effective in involving scientific community definition of observing strategy. We are interested using radial variables (RR Lyrae, classical Cepheids, long-period variables) as stellar tracers and distance indicators, we developed new tool called PulsationStarRecovery quantify recovery light-curve period amplitude from an LSST-simulated time series....
A total of ∼640, 000 objects from the LAMOST pilot survey have been publicly released. In this work, we present a catalog DA white dwarfs (DAWDs) entire survey. We outline new algorithm for selection (WDs) by fitting Sérsic profiles to Balmer Hβ, Hγ, and Hδ lines spectra, calculating equivalent width Ca ii K line. Two thousand nine hundred sixty-four candidates are selected constraining parameters All spectra visually inspected. identify 230 DAWDs (59 which already included in Villanova SDSS...
We have obtained a sample of ∼22,000 red giant branch (RGB) stars based on stellar parameters, provided by the ninth data release Sloan Digital Sky Survey, and CH(G)/MgH indices, measured from included spectra. The Galactic rest-frame velocity Vgsr versus longitude for shows existence several groups globular clusters known streams. Excluding these substructures, ∼16,000 RGB general field is used to investigate properties thick disk, inner halo, outer halo our Galaxy. metallicity rotational...
We investigate the extinction together with radial velocity dispersion and distribution of red clump stars in anti-center direction using spectra obtained Hectospec on MMT. find that peaks at Galactocentric radii about 9.5 12.5 kpc, right front locations Perseus Outer arms line relative position dust external spiral galaxies. The around 10kpc, which coincides location arm, yields an estimated arm-interarm density contrast 1.3-1.5 is agreement previous studies. Finally, we discover bifurcates...
We have selected 556 red horizontal branch stars along the streams of Sagittarius (Sgr) dwarf galaxy from Sloan Digital Sky Survey DR7 spectroscopic data using a theoretical model. The metallicity and α-element distributions are investigated for in Sgr Galactic at same locations. find that two peaks distribution while more prominent metal-poor peak. Meanwhile, [α/Fe] ratios lower than those stars. Among stars, we difference between leading trailing arms tidal tails. arm is similar to Galaxy....
We analyze the radial and vertical metallicity [alpha/Fe] gradients of disk stars a galaxy simulated in fully cosmological setting with chemodynamical evolution code, GCD+. study how abundance vary as function height above plane find that ([alpha/Fe]) gradient becomes more positive (negative) increasing height, changing sign around 1.5 kpc plane. At largest (2 < |z| 3 kpc), our shows gradient. is caused by age-metallicity age-velocity dispersion relation, where younger have higher lower...
Abstract New results on the behavior of double-mode RR Lyrae V338 Boo are presented. The Transiting Exoplanet Survey Satellite (TESS) observed this star again in 2022, and an observing campaign American Association Variable Star Observers (AAVSO) was completed after TESS observations as a follow-up. We find that first overtone pulsation mode completely disappears during window. This reappears at end observations, AAVSO shows months followed, not only present but dominant pulsation. star,...
The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure energy that not contained by barrel HB) and electromagnetic (ECAL EB) calorimeters. Due space limitation calorimeters do contain completely hadronic shower an outer calorimeter (HO) was designed, constructed inserted in muon system leakage. Testing calibration HO carried out a 300 GeV/c test beam improved linearity resolution. will provide net improvement missing E T measurements at LHC energies. Information...
The LAMOST pilot survey has produced a data release containing over 600,000 stellar spectra. By cross-checking with large time series photometric database of RR Lyrae stars in high Galactic latitude regions, we found total number 157 that have been observed LAMOST. In this sample, successfully captured three the fast expansion phase, all them showing hypersonic shock wave features Balmer line region. We fit shape Hα region and determine emission feature seen within broadened absorption...
We present a measurement of the mass difference m(Ds+)−m(D+), where both Ds+ and D+ are reconstructed in φπ+ decay channel. This uses 11.6 pb−1 data collected by CDF II using new displaced-track trigger. The is found to be m(Ds+)−m(D+)=99.41±0.38(stat)±0.21(syst)MeV/c2. Received 19 March 2003DOI:https://doi.org/10.1103/PhysRevD.68.072004©2003 American Physical Society
We present distance determinations for a large and clean sample of red giant branch stars selected from the ninth data release Sloan Digital Sky Survey. The distances are calculated based on both observational cluster fiducials theoretical isochrones. Distributions two methods very similar with peaks at about 10 kpc tails extending to more than 70 kpc. find that agree well majority stars; though, average, isochrones 10% higher those fiducials. test accuracy our using 332 Galactic globular...