A5007623886- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Stellar, planetary, and galactic studies
- Particle Detector Development and Performance
- Meteorological Phenomena and Simulations
- Radio Wave Propagation Studies
- Wind and Air Flow Studies
- Particle Accelerators and Free-Electron Lasers
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Fluid Dynamics and Turbulent Flows
- Atmospheric aerosols and clouds
- Photocathodes and Microchannel Plates
- Air Traffic Management and Optimization
- Aerospace and Aviation Technology
- Particle accelerators and beam dynamics
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Calibration and Measurement Techniques
- Precipitation Measurement and Analysis
Deutsches Elektronen-Synchrotron DESY
2014-2022
Bureau Veritas (France)
2020
DePauw University
2019
German Institute for Adult Education – Leibniz Centre for Lifelong Learning
2019
University of Oxford
2019
Max Planck Society
2012-2018
Max Planck Institute for Extraterrestrial Physics
2012-2018
Washington University in St. Louis
2017
Radboud University Nijmegen
2013-2016
RTX (United States)
1982-1984
We present coordinated multiwavelength observations of the bright, nearby BL Lac object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations instruments, providing data from radio to very-high-energy (VHE) gamma-ray bands. NuSTAR yielded previously unattainable sensitivity 3-79 keV range, revealing that spectrum softens when source is dimmer until X-ray spectral shape saturates into a steep power law with photon index...
We present constraints on the annihilation cross section of weakly interacting massive particles dark matter based joint statistical analysis four dwarf galaxies with VERITAS. These results are derived from an optimized photon weighting technique that improves standard imaging atmospheric Cherenkov telescope (IACT) analyses by utilizing spectral and spatial properties individual events. report $\ensuremath{\sim}230$ hours observations five galaxies. find no evidence gamma-ray emission any...
We present LOFAR measurements of radio emission from extensive air showers. find that this is strongly polarized, with a median degree polarization nearly $99\%$, and the angle between direction electric field Lorentz force acting on particles, depends observer location in shower plane. This can be understood as superposition radially polarized charge-excess mechanism, first proposed by Askaryan geomagnetic mechanism Kahn Lerche. calculate relative strengths both contributions, quantified...
The low frequency array (LOFAR), is the first radio telescope designed with capability to measure emission from cosmic-ray induced air showers in parallel interferometric observations. In $\sim 2\,\mathrm{years}$ of observing, 405 events energy range $10^{16} - 10^{18}\,\mathrm{eV}$ have been detected band $30 80\,\mathrm{MHz}$. Each these registered up $\sim1000$ independent antennas resulting measurements unprecedented detail. This article describes dataset, as well analysis pipeline, and...
Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints diffuse radiation fields that fill universe. The detection significant emission above 100 GeV a distant quasar would show some radiated gamma-rays escape pair-production interactions with low-energy photons, be it extragalactic background light (EBL), or near supermassive black hole lying at jet's base. VERITAS detected up to ∼200 PKS 1441+25 (z = 0.939) during 2015 April,...
High-energy gamma-ray emission from supernova remnants (SNRs) has provided a unique perspective for studies of Galactic cosmic-ray acceleration. Tycho's SNR is particularly good target because it young, type Ia that well-studied over wide range energies and located in relatively clean environment. Since the detection by VERITAS Fermi-LAT, there have been several theoretical models proposed to explain its broadband high-energy morphology. We report on an update measurements with 147 hours 84...
A coherent Doppler lidar has been used in an aircraft to measure the 2-dimensional wind field a number of different atmospheric situations. The lidar, pulsed CO2 system, was installed NASA Convair 990, Galileo II, and flown summer program that included flights California, Oklahoma at National Severe Storms Laboratory, Montana Cooperative Convective Precipitation Experiment (CCOPE). This paper provides brief description instrumentation summarizes research flights. Examples some results are...
We report on observations of the pulsar / Be star binary system PSR J2032+4127 MT91 213 in energy range between 100 GeV and 20 TeV with VERITAS MAGIC imaging atmospheric Cherenkov telescope arrays. The orbit has a period approximately 50 years, most recent periastron occurring 2017 November 13. Our span from 18 months prior to one month after. A new, point-like, gamma-ray source is detected, coincident location 213. light curve spectrum are well-characterized over passage. flux variable at...
We present a search for magnetically broadened gamma-ray emission around active galactic nuclei (AGNs), using VERITAS observations of seven hard-spectrum blazars. A cascade process occurs when multi-TeV gamma-rays from an AGN interact with extragalactic background light (EBL) photons to produce electron–positron pairs, which then cosmic microwave via inverse-Compton scattering gamma-rays. Due the deflection non-zero intergalactic magnetic field (IGMF) would potentially detectable effects on...
We present results from deep observations towards the Cygnus region using 300 hours of very-high-energy (VHE) $\gamma$-ray data taken with VERITAS Cherenkov telescope array and over seven years high-energy Fermi satellite at an energy above 1 GeV. As brightest diffuse emission in northern sky, provides a promising area to probe origins cosmic rays. report identification potential Fermi-LAT counterpart VER J2031+415 (TeV J2032+4130), resolve extended VHE source J2019+368 into two candidates...
We present a study of $\gamma$-ray emission from the core-collapse supernova remnant Cas~A in energy range 0.1GeV to 10TeV. used 65 hours VERITAS data cover 200 GeV - 10 TeV, and 10.8 years \textit{Fermi}-LAT 0.1-500 GeV. The spectral analysis shows significant curvature around $1.3 \pm 0.4_{stat}$ that is consistent with expected spectrum pion decay. Above this energy, joint deviates significantly simple power-law, best described by power-law index $2.17\pm 0.02_{stat}$ cut-off $2.3...
Air showers induced by cosmic rays create nanosecond pulses detectable at radio frequencies. These have been measured successfully in the past few years LOw Frequency ARray (LOFAR) and are used to study properties of rays. For a complete understanding this phenomenon underlying physical processes, an absolute calibration detecting antenna system is needed. We present three approaches that were check improve model LOFAR provide whole for air shower measurements. Two methods based on...
Abstract On 2017 September 22, the IceCube Neutrino Observatory reported detection of high-energy neutrino event IC 170922A, potential astrophysical origin. It was soon determined that direction consistent with location gamma-ray blazar TXS 0506+056 (3FGL J0509.4+0541), which in an elevated emission state as measured by Fermi satellite. Very Energetic Radiation Imaging Telescope Array System (VERITAS) observations neutrino/blazar region started on 23 response to alert and continued through...
We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during month February, 2010 when an extraordinary flare reaching a level $\sim$27~Crab Units above 1~TeV was measured in very-high-energy (VHE) $\gamma$-rays with VERITAS observatory. This is highest flux state for ever observed VHE $\gamma$-rays. Data are analyzed from coordinated campaign across multiple instruments including $\gamma$-ray (VERITAS, MAGIC), high-energy (HE) (Fermi-LAT),...
During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHEs, GeV) are constrained since the photomultiplier tubes (PMTs) in telescope camera extremely sensitive to background moonlight. Observations VERITAS standard configuration performed only a moon illumination less than 35% of full moon. Since 2012, collaboration has implemented new observing mode under bright moonlight, by either reducing voltage applied PMTs (reduced-high-voltage; RHV...
Between the beginning of its full-scale scientific operations in 2007 and 2012, VERITAS Cherenkov telescope array observed more than 130 blazars; these, 26 were detected as very-high-energy (VHE; E>100 GeV) {\gamma}-ray sources. In this work, we present analysis results a sample 114 undetected objects. The observations constitute total live-time ~570 hours. includes several unidentified Fermi-Large Area Telescope (LAT) sources (located at high Galactic latitude) well all from second...
ABSTRACT The F-type star KIC 8462852 has recently been identified as an exceptional target for search extraterrestrial intelligence (SETI) observations. We describe analysis methodology optical SETI, which we have used to analyze nine hours of serendipitous archival observations made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence pulsed beacons, above a pulse intensity at Earth approximately , is found. also discuss potential use imaging atmospheric Cherenkov...
Este trabalho tem como objetivo examinar as principais utilizações da Inteligência Artificial (IA) dentro do campo Engenharia Civil. Serão abordadas inovações mais significativas, os efeitos dessas tecnologias nas práticas profissionais e previsões para o futuro seu uso na área. A pesquisa examinará casos de sucesso, obstáculos encontrados implementação soluções inteligência artificial impacto revolucionário no setor. Além disso, irá destacar direções específicas a evolução Civil próximas...
The very high energy (VHE; E $>$ 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54938--54956), 2009, as part of an extensive multi-wavelength campaign from radio to VHE. Strong VHE $\gamma$-ray activity detected on 1st with Whipple VERITAS, when the flux (E 400 increased 10 times pre-flare baseline ($3.9{\times 10^{-11}}~{\rm ph~cm^{-2}~s^{-1}}$), reaching five Crab Nebula. This coincided a decrease in optical polarization rotation angle by 15$^{\circ}$. flare...
ABSTRACT The Galactic Center ridge has been observed extensively in the past by both GeV and TeV gamma-ray instruments revealing a wealth of structure, including diffuse component point sources G0.9+0.1 (a composite supernova remnant) Sgr A* (believed to be associated with supermassive black hole located at center our Galaxy). Previous very high energy (VHE) observations H.E.S.S. experiment have also detected an extended along plane >300 regime. Here we report on from 2010 2014 VERITAS...
ABSTRACT The TeV binary system LS I +61° 303 is known for its regular, non-thermal emission pattern that traces the orbital period of compact object in 26.5 day orbit around B0 Ve star companion. typically presents elevated apastron passage with flux levels between 5% and 15% steady from Crab Nebula (>300 GeV). In this article, VERITAS observations taken late 2014 are presented, during which bright flares at peaking above 30% were detected. This brightest such activity source ever seen...