Kenneth Carrell

Verified

Kenneth verified their affiliation via an institutional email.

Learn more

Verified

Kenneth verified their affiliation via an institutional email.

Learn more

• PhD
• Associate Professor & Planetarium Director at Angelo State University

New results on the behavior of the double-mode RR Lyrae V338 Boo are presented. The Transiting Exoplanet Survey Satellite (TESS) observed this star again in 2022, and an observing campaign of the American Association of Variable Star Observers (AAVSO) was completed after the TESS observations as a follow-up. We find that the first overtone pulsatio...

New results on the behavior of the double-mode RR Lyrae V338 Boo are presented. The Transiting Exoplanet Survey Satellite (TESS) observed this star again in 2022, and an observing campaign of the American Association of Variable Star Observers (AAVSO) was completed after the TESS observations as a follow-up. We find that the first overtone pulsatio...

RR Lyrae stars play a central role in tracing phase-space structures within the Milky Way because they are easy to identify, are relatively luminous, and are found in large numbers in the Galactic bulge, disk, and halo. In this work, we present a new set of spectroscopic metallicity calibrations that use the equivalent widths of the Ca II K and Bal...

We present analysis of the RR Lyrae star, LS Her, and confirm the previously reported modulation to its Blazhko cycles. We performed Fourier analysis on two sectors (Sector 24 and 25) of data from the Transiting Exoplanet Survey Satellite (TESS) spanning 53 days. We find LS Her to have a primary pulsation period of 0.2308 day and a Blazhko period o...

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 the scientific community in the definition of the LSST observing strategy. We are mainly interested in using radial variables (RR Lyrae, classical Cepheids, long-period variables) as stellar...

Two charged particle detectors were built using resources available from the Cosmic Watch program. Along with other atmospheric trends, the cosmic ray rate as a function of altitude was measured to heights above 20 km via the use of high-altitude balloon launches with the detectors as part of the payload. Atmospheric data, verification of the detec...

Using potentially variable sources flagged in value-added catalogs created by combining data from the Gaia, IPHAS, and KIS surveys, we utilized data from TESS, McDonald Observatory, and the Southern Plains Private Observatory to confirm and identify four of these potentially variable sources as eclipsing binaries. Combining large data sets and obta...

We investigated the observational properties of Triangulum-Andromeda (TriAnd), Monoceros Ring (MRi), and Anti-Center Stream (ACS) in the anticenter region using K giants, M giants, and RGB stars from LAMOST and SDSS survey. The Friends of Friends algorithm was applied to select member stars of these structures. We found a new spur of TriAnd at l ∼...

We present an analysis of the lightcurve extracted from Transiting Exoplanet Survey Satellite (TESS) Full Frame Images (FFIs) of the double-mode RR Lyrae V338 Boo. We find that the fundamental mode pulsation is changing in amplitude across the 54 days of observations. The first overtone mode pulsation also changes, but on a much smaller scale. Harm...

We present an analysis of the lightcurve extracted from Transiting Exoplanet Survey Satellite Full Frame Images of the double-mode RR Lyrae V338 Boo. We find that the fundamental mode pulsation is changing in amplitude across the 54 days of observations. The first overtone mode pulsation also changes, but on a much smaller scale. Harmonics and comb...

We have obtained a sample of ~22,000 red giant branch (RGB) stars based on stellar parameters, provided by the ninth data release of the Sloan Digital Sky Survey, and the CH(G)/MgH indices, measured from the included spectra. The Galactic rest-frame velocity of V gsr versus longitude for the sample shows the existence of several groups of stars fro...

We present distance determinations for a large and clean sample of red giant branch stars selected from the ninth data release of the Sloan Digital Sky Survey. The distances are calculated based on both observational cluster fiducials and theoretical isochrones. Distributions of distances from the two methods are very similar with peaks at about 10...

We estimate the 3D extinction law in the optical–NIR bands for a line of sight in the 2nd quadrant of the Galactic disk. Two dust lanes are identified at ~9 and ~10.25 kpc in both A V and R V , indicating that the size of the dust grains in the spiral arms is larger than that in the inter-arm regions.

We use line-of-sight velocities of more than 4000 red clump stars observed from MMT/Hectospec to derive the Galactic rotation curve between 8 and 13 kpc in Galactocentric radius to better than 10 km s-1. A three-component (bulge+disk+halo) with an additional massive ring of 1.66×1010 M☉ at about 11.6 kpc provides an excellent fit with the observati...

We analyze the radial and vertical metallicity and [alpha/Fe] gradients of the disk stars of a disk galaxy simulated in a fully cosmological setting with the chemodynamical galaxy evolution code, GCD+. We study how the radial abundance gradients vary as a function of height above the plane and find that the metallicity ([alpha/Fe]) gradient becomes...

A total of $\sim640,000$ objects from LAMOST pilot survey have been publicly released. In this work, we present a catalog of DA white dwarfs from the entire pilot survey. We outline a new algorithm for the selection of white dwarfs by fitting S\'ersic profiles to the Balmer H$\beta$, H$\gamma$ and H$\delta$ lines of the spectra, and calculating the...

The LAMOST spectroscopic survey for Galactic structure and evolution has been in operation since October 2012, following a one-year pilot survey. The pilot survey produced a data release containing over 600,000 stellar spectra. By cross-checking with a large time series photometric database of RR Lyrae stars in high Galactic latitude regions, we fo...

We have measured the CH G band (CH(G)) index for evolved stars in the globular cluster M3 based on the Sloan Digital Sky Survey (SDSS) spectroscopic survey. It is found that there is a useful way to select red giant branch (RGB) stars from the contamination of other evolved stars such as asymptotic giant branch (AGB) and red horizontal branch (RHB)...

We selected red horizontal-branch stars along the streams of the Sagittarius dwarf galaxy (Sgr) from sdss DR7 spectroscopic data using a theoretical model. We investigate the metallicity distribution of stars in the Sgr streams. The metallicity gradient is (-1.8 +/- 0.3) × 10⊃3 dex deg-1 in the first wrap of the trailing arm and (-1.5 +/- 0.4) × 10...

We examine the metallicity distribution of the Galactic thick disk using F, G, and K dwarf stars selected from the Sloan Digital Sky Survey, Data Release 8. Using the large sample of dwarf stars with proper motions and spectroscopically determined stellar parameters, metallicity gradients in the radial direction for various heights above the Galact...

We investigate the extinction together with the radial velocity dispersion and distribution of red clump stars in the anti-center direction using spectra obtained with Hectospec on the MMT. We find that extinction peaks at Galactocentric radii of about 9.5 and 12.5 kpc, right in front of the locations of the Perseus and Outer arms and in line with...

We have selelcted 556 Red Horizontal Branch (RHB) stars along the streams of the Sagittarius dwarf galaxy (Sgr) from SDSS DR7 spectroscopic data using a theoretical model. The metallicity and \alpha-elements distributions are investigated for stars in the Sgr streams and for Galactic stars at the same locations. We find that the Sgr stars have two...

Based on SDSS DR8, we have selected a sample of 1728 red horizontal branch stars with |Z|<3 kpc by using a color-metallicity relation and stellar parameters. The sample stars clearly trace a typical thick disk population with peaks at |Z|=1.26 kpc and [Fe/H]=-0.54. The vertical metallicity gradient of the thick disk is estimated in two ways. One is...

We have probed a section (l ~ 150, b ~ -60) of the trailing tidal arm of the Sagittarius dwarf spheroidal galaxy by identifying a sample of Red Clump stream stars. Red Clump stars are not generally found in the halo field, but are found in significant numbers in both the Sagittarius galaxy and its tidal streams, making them excellent probes of stre...

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of...

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of...

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in t...

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 1034 cm−2 s−1 (1027 cm−2 s−1). At the core of the CMS detector sits a hig...

Using 2MASS colors, Martin et al. (2004) uncovered evidence for a remnant dwarf galaxy in Canis Major, in the form of an over-density of M-giant stars. The spatial distribution of the M-giants indicate an extended, and likely disrupted, group of stars extending over roughly 30 degrees of the sky. Alternative explanations of the origin of this over-...

We obtained new UBV photometry and spectroscopy of Blue Plume (BP) stars in fields near the center of the Canis Major Over-Density (CMa). We combined analysis of the color-color diagrams with a new comparison of the hydrogen Balmer-line profile to the reddening-free Q parameter to improve the reddening and extinction estimates for this low-latitude...

We propose using the 4-meter Blanco telescope and the Hydra Spectrograph for three half-nights to observe blue plume stars associated with the Canis Major Over-density (CMO). Using photometry obtained on the 0.9m telescope at CTIO we have identified two fields of a size well-suited to Hydra, containing a large number of blue plume candidate stars....

We are requesting time on the WIYN 3.5m with Hydra to extend our study of the tidal tails of the Sagittarius dwarf spheroidal galaxy. At the end of August we successfully observed a section of the Southern Arm and we are now proposing to observe a portion of the Northern Arm. Our goal is to continue our program to explore the ratio of horizontal br...

Results are presented of measurements of high-energy hadronic shower profiles with a copper-based fiber calorimeter. This calorimeter was equipped with a mixture of scintillating fibers and undoped (quartz or plastic) fibers. The latter measured the spatial distribution of shower particles with velocities above the Cherenkov threshold, whereas the...

We describe a new RR Lyrae identification technique based on out-of-phase single-epoch photometric and spectroscopic observations contained in SDSS Data Release 6 (DR-6). This technique detects variability by exploiting the large disparity between the g-r color and the strength of the hydrogen Balmer lines when the two observations are made at rand...

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 the H2 beam line at CERN with particle momenta varying from 20 to 300GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics runn...

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region (3 £ |h| £ 53\leq|\eta|\leq5), and is essential for a large number of physics channels with missing transverse energy. It is also expected to play a pr...

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 the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics run...

We report on the test beam results and calibration methods using charged particles of the CMS Forward Calorimeter (HF). The HF calorimeter covers a large pseudorapidity region (3\l |\eta| \le 5), and is essential for large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of f...

The Prototype Visible Integral-Field Replicable Unit Spectrograph (VIRUS-P) is a new instrument currently in use on the 2.7 meter telescope at McDonald Observatory. This instrument is a prototype of the Integral-Field Units (IFU) planned for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The instrument has a pack of 246 fibers which ca...

Using 2MASS colors Martin et al. (2004) uncovered evidence for a remnant dwarf galaxy in Canis Major, in the form of an overdensity of M-giant stars. The spatial distribution of the M-giants indicate an extended, and likely disrupted, group of stars extending over roughly 30 degrees of the sky. We present new photometry and color magnitude diagrams...

The Sagittarius dwarf galaxy and associated streams are an important dynamical system that can be used to probe the properties of our own Milky Way galaxy as well as to shed light on how galaxies cannibalize their smaller counterparts. We have made observations of both Horizontal Branch and Red Clump stars in the Southern Arm of the Sagittarius Str...

The Large Hadron Collider at CERN is due to begin operation at the end of 2007 opening a new energy frontier in particle physics. The LHC is ultimately expected to operate at L=10E34 cm2/s and the CMS detector has been designed to cope with the high radiation and event rates expected at this luminosity. However, after several years of running at th...

CMS is a general purpose experiment, designed to study the physics of pp collisions at 14 TeV at the Large Hadron Collider ( LHC). It currently involves more than 2000 physicists from more than 150 institutes and 37 countries. The LHC will provide extraordinary opportunities for particle physics based on its unprecedented collision energy and lumin...

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies , will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of th...

New and exciting evidence for stellar substructure is being discovered in our Galactic halo. This presentation will highlight the development of a more rigorous and quantitative way to characterize some of these structures. The use of kinematic, spatial and chemical abundance data for a large sample of stars along with a novel clustering technique...

http://cds.cern.ch/record/922757

Simultaneous measurement of the scintillation and the Cherenkov light produced in hadronic shower development makes it possible to eliminate the effects of fluctuations in the electromagnetic shower fraction, which dominate and spoil the performance of non-compensating calorimeters. In this paper, we report on a study to separate the light signal p...

Results are presented of detailed measurements of high-energy electromagnetic shower profiles measured in a copper-based fiber calorimeter. The calorimeter was equipped with a mixture of scintillating fibers and undoped (quartz or clear plastic) fibers. The latter measured Cherenkov light generated in the shower development process, whereas the sci...

Hadronic shower development in a copper-based fiber calorimeter is studied by simultaneously measuring the scintillation light and the Cherenkov light generated in this process. By comparing these two signals, the electromagnetic shower fraction can be measured event by event. Fluctuations in this fraction are the dominant contribution to the hadro...

Electromagnetic shower development in a copper-based fiber calorimeter is studied by simultaneously measuring the scintillation light and the Cherenkov light generated in this process. We report on the energy resolution, the signal linearity and the dependence of the response function on the impact point and the angle of incidence.The electrons ran...

Simultaneous measurement of the scintillation and the Cherenkov light produced in hadronic shower development makes it possible to eliminate the effects of fluctuations in the electromagnetic shower fraction, which dominate and spoil the performance of non-compensating calorimeters. In this paper, we report on a study to separate the light signal p...

Muon detection in a copper-based fiber calorimeter is studied by simultaneously measuring the scintillation light and the Cherenkov light generated in the detector. We report on the calorimeter response to muons ranging in energy from 20–300 GeV. Muons penetrate the full depth of a calorimeter and therefore can pass through the readout structure (i...

We present a measurement of the mass difference m(D-s(+))- m(D+), where both the D-s(+) and D+ are reconstructed in the phipi(+) decay channel. This measurement uses 11.6 pb(-1) of data collected by CDF II using the new displaced-track trigger. The mass difference is found to be m(D-s(+))-m(D+)=99.41+/- 0.38(stat)+/-0.21(syst) MeV/c(2).

We present a measurement of the mass difference m(D-s(+))-m(D+), where both the D-s(+) and D+ are reconstructed in the phipi(+) decay channel. This measurement uses 11.6 pb(-1) of data collected by CDF II using the new displaced-track trigger. The mass difference is found to be m(D-s(+))-m(D+)=99.41+/-0.38(stat)+/-0.21(syst) MeV/c(2).

DREAM (Dual-REAdout Module) calorimeter module, built at TTU, is a unique detector prototype consisting of scintillating and clear optical fibers in a copper absorber matrix. It contains 15 km of scintillating and 30 km of clear (fused silica and clear plastic) fibers in 1600 kg of copper. I will describe the construction details of this detector a...

This is a report on the reconstruction of the charged B meson in the decay channel B^+ -> J/psi K^+ ; J/psi -> mu ^+ mu ^- with the recent CDF data at the Fermilab Tevatron.

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region (3 <= vertical bar eta vertical bar <= 5), and is essential for a large number of physics channels with missing transverse energy. It is also expected...

The online version of the original article can be found under doi:10.1140/epjc/s10052-009-0959-5. Now at: RWTH, I. Physikalisches Institut, Aachen, Germany. Now at: University of Pennsylvania, Philladelphia, PA, USA. Now at: ENEA, Casaccia Research Center, S. Maria di Galeria, Italy. At: Niğde University, Niğde, Turkey. Now at: Southern Methodist U...

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with an outer calorimeter to ensure high energy shower containment in the calorimeter. Fabrication, testing and calibratio...