J. Linnemann
A5084137298- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Computational Physics and Python Applications
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Radiation Detection and Scintillator Technologies
- Distributed and Parallel Computing Systems
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Radiation Therapy and Dosimetry
- Muon and positron interactions and applications
- Scientific Computing and Data Management
- Algorithms and Data Compression
- X-ray Spectroscopy and Fluorescence Analysis
- Particle accelerators and beam dynamics
- Medical Imaging Techniques and Applications
Michigan State University
2016-2025
Barnard College
2021
Center for Research and Advanced Studies of the National Polytechnic Institute
1997-2021
Colorado State University
2021
Instituto Politécnico Nacional
2012-2021
California University of Pennsylvania
2021
Universidade Federal de São Carlos
2021
Universidade de São Paulo
2021
George Mason University
2021
Georgia Institute of Technology
2021
Exotic origin for cosmic positrons Several cosmic-ray detectors have found more arriving at Earth than expected. Some researchers interpret this as a signature of exotic physics, such the annihilation dark matter particles. Others prefer mundane explanation that involves positron generation pulsars followed by diffusion to Earth. Abeysekara et al. detected extended emission gamma rays around two nearby pulsars, generated high-energy electrons and positrons. The size was used calculate how...
The Crab Nebula is the brightest TeV gamma-ray source in sky and has been used for past 25 years as a reference astronomy, calibration verification of new instruments. High Altitude Water Cherenkov Observatory (HAWC), completed early 2015, to observe at high significance across nearly full spectrum energies which HAWC sensitive. unique its wide field-of-view, 2 sr any instant, high-energy reach, up 100 TeV. HAWC's sensitivity improves with energy. Above $\sim$1 driven by best background...
We present the first catalog of TeV gamma-ray sources realized with recently completed High Altitude Water Cherenkov Observatory (HAWC). It is most sensitive wide field-of-view telescope currently in operation, a 1-year survey sensitivity ~5-10% flux Crab Nebula. With an instantaneous field view >1.5 sr and >90% duty cycle, it continuously surveys monitors sky for gamma ray energies between hundreds GeV tens TeV. HAWC located Mexico at latitude 19 degree North was March 2015. Here, we 2HWC...
Abstract We present TeV gamma-ray observations of the Crab Nebula, standard reference source in ground-based astronomy, using data from High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. In this analysis we use two independent energy estimation methods that utilize extensive air shower variables such as core position, angle, and lateral distribution. contrast, previously published HAWC spectrum roughly estimated with only number photomultipliers triggered. This new methodology...
A survey of Galactic gamma-ray sources at a median energy ~20 TeV has been performed using the Milagro Gamma-Ray Observatory. Eight candidate emission are detected with pretrial significances >4.5 σ in region longitude l ∊ [30°, 220°] and latitude b [-10°, 10°]. Four these sources, including Crab Nebula recently published MGRO J2019+37, observed >4 after accounting for trials. All four also coincident EGRET sources. Two lower significance one is Geminga. The other two candidates Cygnus...
The diffuse gamma radiation arising from the interaction of cosmic-ray particles with matter and in Galaxy is one few probes available to study origin cosmic rays. Data Milagro gamma-ray observatory—a water Cerenkov detector that continuously views ~2 sr overhead sky—shows brightest extended region entire northern sky Cygnus Galactic plane. TeV image contains at least new source, MGRO J2019+37, which 10.9 σ above isotropic background, as well correlations density region. However, flux (after...
The 7 year data set of the Milagro TeV observatory contains 2.2 x 10(11) events which most are due to hadronic cosmic rays. These searched for evidence intermediate scale structure. Excess emission on angular scales approximately 10 degrees has been found in two localized regions unknown origin with greater than 12sigma significance. Both inconsistent pure gamma-ray high confidence. One a different energy spectrum isotropic cosmic-ray flux at level 4.6sigma, and it is consistent hard protons...
We present the result of a search Milagro sky map for spatial correlations with sources from subset recent Fermi Bright Source List (BSL). The BSL consists 205 most significant detected above 100 MeV by Large Area Telescope. select based on their categorization in BSL, taking all confirmed or possible Galactic field view Milagro. Of 34 selected, 14 are observed at significance 3 standard deviations more. conduct this new analysis which employs newly optimized gamma-hadron separation and...
Results are presented of a harmonic analysis the large-scale cosmic-ray (CR) anisotropy as observed by Milagro observatory. We show two-dimensional display sidereal projections in right ascension (R.A.) generated fitting three harmonics to 18 separate declination bands. The observatory is water Cherenkov detector located Jemez mountains near Los Alamos, New Mexico. With high duty cycle and large field view, an excellent instrument for measuring this with sensitivity at TeV energies....
Abstract The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view sensitive to 500 GeV–100 TeV gamma-rays and cosmic rays. It can also perform diverse indirect searches for dark matter annihilation decay. Among the most promising targets detection are dwarf spheroidal galaxies. These objects expected have few astrophysical sources but high content, making them ideal candidates an with gamma-rays. Here we present individual limits on cross section decay lifetime...
The High-Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays and charged cosmic at TeV energies.The detector still under construction, but data acquisition with the partially deployed started in 2013.An analysis of cosmic-ray arrival direction distribution based on 4.9 × 10 events recorded between June 2013 February 2014 shows anisotropy -4 level angular scales about • .The HAWC sky map exhibits three regions significantly enhanced flux; two these were first reported by...
Abstract The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, located on the side of Sierra Negra volcano in Mexico, has been fully operational since 2015. HAWC collaboration recently significantly improved their extensive air shower reconstruction algorithms, which notably advanced observatory performance. energy resolution for primary gamma rays with energies below 1 TeV was by including a noise-suppression algorithm. Corrections have also made to systematic errors direction...
Abstract Galactic gamma-ray diffuse emission (GDE) is emitted by cosmic rays (CRs), ultra-relativistic protons, and electrons, interacting with gas electromagnetic radiation fields in the interstellar medium. Here we present analysis of teraelectronvolt from a region plane over range longitude l ∈ [43°, 73°], using data collected High Altitude Water Cherenkov (HAWC) detector. Spectral, longitudinal, latitudinal distributions are shown. The spectrum compatible arising CR population an index...
Diffuse γ-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in Galaxy can be used to probe distribution cosmic rays their sources different regions Galaxy. With its large field view long observation time, Milagro Gamma Ray Observatory is an ideal instrument for surveying northern hemisphere sky detecting diffuse at very high energies. Here spatial flux TeV energy range a median 15 Galactic longitude between 30° 110° 136° 216° latitude –10° 10° are...
Spectral lag, which is defined as the difference in time of arrival high and low energy photons, a common feature Gamma-ray Bursts (GRBs). Previous investigations have shown correlation between this lag isotropic peak luminosity for long duration bursts. However, most previous used lags extracted observer-frame only. In work (based on sample 43 Swift GRBs with known redshifts), we present an analysis lag-luminosity relation GRB source-frame. Our indicates higher degree -0.82 +/- 0.05 (chance...
The HAWC experiment reports the first ground-based measurement of all-particle cosmic-ray spectrum in 10-500 TeV energy range. This data overlaps with direct measurements made by balloon-borne detectors as well those other higher air-shower detectors. closes an important gap between these different experiments.
Abstract We present the detection of very-high-energy gamma-ray emission above 100 TeV from HAWC J2227+610 with High-Altitude Water Cherenov Gamma-Ray Observatory (HAWC) observatory. Combining our observations previously published results by Very Energetic Radiation Imaging Telescope Array System (VERTIAS), we interpret as protons a lower limit in their cutoff energy 800 TeV. The most likely source is associated supernova remnant G106.3+2.7, making it good candidate for Galactic PeVatron....
Abstract The Earth is bombarded by ultrarelativistic particles, known as cosmic rays (CRs). CRs with energies up to a few PeV (=10 15 eV), the knee in particle spectrum, are believed have Galactic origin. One or more factories of CRs, PeVatrons, must thus be active within our Galaxy. direct detection protons from their sources not possible since they deflected magnetic fields. Hundred TeV γ -rays decaying π 0 , produced when collide ambient gas, can provide decisive evidence proton...
We report the first detection of a TeV γ-ray flux from solar disk (6.3σ), based on 6.1 years data High Altitude Water Cherenkov (HAWC) observatory. The 0.5–2.6 spectrum is well fit by power law, dN/dE=A(E/1 TeV)−γ, with A=(1.6±0.3)×10−12 TeV−1 cm−2 s−1 and γ=3.62±0.14. shows strong indication anticorrelation activity. These results extend bright, hard GeV emission observed Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering nuclei in atmosphere. However, current theoretical...