A5076172126- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Particle physics theoretical and experimental studies
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Neutrino Physics Research
- Pulsars and Gravitational Waves Research
- Radiation Therapy and Dosimetry
- Energy Harvesting in Wireless Networks
- Astrophysical Phenomena and Observations
- Wireless Power Transfer Systems
- Radio Frequency Integrated Circuit Design
- Radiation Detection and Scintillator Technologies
- Ionosphere and magnetosphere dynamics
- High-Energy Particle Collisions Research
- Noncommutative and Quantum Gravity Theories
- Advanced DC-DC Converters
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Microwave Engineering and Waveguides
- Advanced Antenna and Metasurface Technologies
- Innovative Energy Harvesting Technologies
Tibet University
2016-2025
University of Liverpool
2024-2025
Institute of High Energy Physics
2017
Chinese Academy of Sciences
2017
We report, for the first time, long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in Galactic disk. Particularly, all above 398 are observed apart from known gamma-ray sources compatible expectations hadronic emission scenario which originate decay $π^0$'s produced through interaction protons interstellar medium Galaxy. This is strong evidence that cosmic accelerated beyond our Galaxy spread over
The events recorded by ARGO-YBJ in more than five years of data collection have been analyzed to determine the diffuse gamma-ray emission Galactic plane at longitudes 25° < l 100° and latitudes . energy range covered this analysis, from ∼350 GeV ∼2 TeV, allows connection region explored Fermi with multi-TeV measurements carried out Milagro. Our analysis has focused on two selected regions plane, i.e., 40° 65° 85° (the Cygnus region), where Milagro observed an excess respect predictions...
The ARGO-YBJ detector is an extensive air shower array that has been used to monitor the northern $\gamma$-ray sky at energies above 0.3 TeV from 2007 November 2013 January. In this paper, we present results of a survey in declination band $-10^{\circ}$ $70^{\circ}$, using data recorded over past five years. With integrated sensitivity ranging 0.24 $\sim$1 Crab units depending on declination, six sources have detected with statistical significance greater than 5 standard deviations. Several...
Abstract We report on the analysis of 10–1000 TeV large-scale sidereal anisotropy Galactic cosmic rays (GCRs) with data collected by Tibet Air Shower Array from 1995 October to 2010 February. In this analysis, we improve energy estimate and extend decl. range down −30°. find that maps above 100 are distinct at a multi-TeV band. The so-called tail-in loss-cone features identified low energies get less significant, new component appears ∼100 TeV. spatial distribution GCR intensity an excess...
This paper reports on the measurement of large-scale anisotropy in distribution cosmic-ray arrival directions using data collected by air shower detector ARGO-YBJ from 2008 January to 2009 December, during minimum solar activity between cycles 23 and 24. In this period, more than 2 × 1011 showers were recorded with energies ∼1 30 TeV. The observed two-dimensional cosmic rays is characterized two wide regions excess deficit, respectively, both relative intensity ∼10−3 respect a uniform flux,...
ARGO-YBJ is an air shower detector array with a fully covered layer of resistive plate chambers. It operated high duty cycle and large field view. continuously monitors the northern sky at energies above 0.3 TeV. In this paper, we report long-term monitoring Mrk 421 over period from 2007 November to 2010 February. This source was observed by satellite-borne experiments Rossi X-ray Timing Explorer Swift in band. especially active first half 2008. Many flares are both γ-ray bands...
As one of the brightest active blazars in both X-ray and very high energy $\gamma$-ray bands, Mrk 501 is useful for physics associated with jets from AGNs. The ARGO-YBJ experiment monitoring it $\gamma$-rays above 0.3 TeV since November 2007. Starting October 2011 largest flare 2005 observed, which lasts to about April 2012. In this paper, a detailed analysis reported. During flaring episodes 17 22, 2011, an excess event rate over 6 $\sigma$ detected by direction 501, corresponding increase...
The ARGO-YBJ air shower detector monitored the Crab Nebula gamma ray emission from 2007 November to 2013 February. integrated signal, consisting of $\sim$3.3 $\times$ 10$^5$ events,reached statistical significance 21.1 standard deviations. obtained energy spectrum in range 0.3-20 TeV can be described by a power law function dN/dE = I$_0$ (E / 2 TeV)$^{-\alpha}$, with flux normalization (5.2 $\pm$ 0.2) 10$^{-12}$ photons cm$^{-2}$ s$^{-1}$ TeV$^{-1}$ and $\alpha$ 2.63 0.05, corresponding an...
The extended gamma-ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for ∼4 years ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. peak signal is found position consistent pulsar PSR J1907+0602. Parameterizing shape two-dimensional Gauss function, we estimate an extension σext = 049 ± 022, which previous measurement Cherenkov Array H.E.S.S. energy spectrum dN/dE 6.1 1.4 × 10−13 (E/4 TeV)−2.54...
Abstract This paper reports on the observation of sidereal large-scale anisotropy cosmic rays using data collected by ARGO-YBJ experiment over 5 years (2008–2012). analysis extends previous work limited to period from 2008 January 2009 December, near minimum solar activity between cycles 23 and 24. With new sample, cycle 24 maximum is investigated. A method used improve energy reconstruction, allowing us cover a much wider range, 4 520 TeV. Below 100 TeV, dominated two wide regions,...
We report on the extensive multi-wavelength observations of blazar Markarian 421 (Mrk 421) covering radio to gamma-rays, during 4.5 year period ARGO-YBJ and Fermi common operation time, from August 2008 February 2013. In particular, thanks data, whole energy range 100 MeV 10 TeV is covered without any gap. observation period, Mrk showed both low high activity states at all wavebands. The correlations among flux variations in different wavebands were analyzed. Seven large flares, including...
The energy spectrum of cosmic Hydrogen and Helium nuclei has been measured, below the so-called "knee", by using a hybrid experiment with wide field-of-view Cherenkov telescope Resistive Plate Chamber (RPC) array ARGO-YBJ at 4300 m above sea level. have well separated from other ray components multi-parameter technique. A highly uniform resolution about 25% is achieved throughout whole range (100 TeV - 700 TeV). observed compatible single power law index gamma=-2.63+/-0.06.
We report the observation of a very high energy γ-ray source whose position is coincident with HESS J1841−055. This has been observed for 4.5 years by ARGO-YBJ experiment from 2007 November to 2012 July. Its emission detected statistical significance 5.3 standard deviations. Parameterizing shape two-dimensional Gaussian function, we estimate an extension , which consistent measurement. The spectrum dN/dE = (9.0 ± 1.6) × 10−13(E/5 TeV)−2.32 0.23 photons cm−2 s−1 TeV−1, in range 0.9–50 TeV....
A 100 m2 muon detector (MD) was successfully constructed under the existing Tibet air shower (AS) array in late fall of 2007. The sensitivity AS to cosmic gamma rays can be improved by selecting muon-poor events with MD. Our MC simulation MD response reasonably agrees experimental data terms charge distribution for one-muon and background rejection power. Using collected taken from 2008 March 2010 February, we search continuous gamma-ray emission Crab Nebula above ∼100 TeV. No significant...
Rectifier plays a pivotal role in wireless power transfer systems. While numerous studies have concentrated on enhancing efficiency and bandwidth at specific high-power levels, practical scenarios often involve unpredictable inputs. Consequently, distinct need arises for rectifier that demonstrates superior across broad range of input levels. This paper introduces RF-to-DC designed WPT applications, featuring an ultrawide dynamic power. The rectification process leverages GaN (gallium...
Abstract Gamma rays from HESS J1849−000, a middle-aged TeV pulsar wind nebula (PWN), are observed by the Tibet air shower array and muon detector array. The detection significance of gamma reaches 4.0 σ 4.4 levels above 25 100 TeV, respectively, in units Gaussian standard deviation . energy spectrum measured between 40 < E 320 for first time is described with simple power-law function <?CDATA ${dN}/{dE}={(2.86\pm 1.44)\times {10}^{-16}(E/40\,\mathrm{TeV})}^{-2.24\pm...
The hadronic interaction of cosmic rays with solar atmosphere can produce high energy gamma rays. gamma-ray luminosity is correlated both the flux primary and intensity magnetic field. below 200 GeV have been observed by $Fermi$ without any evident cutoff. bright above 100 has detected only during minimum. available data in TeV range come from HAWC observations, however outside ARGO-YBJ dataset used to search for sub-TeV/TeV Sun minimum 2008 2010, same time period covered Fermi data. A...
Abstract HESS J1843–033 is a very high energy gamma-ray source whose origin remains unidentified. This work presents, for the first time, spectrum of gamma rays beyond 100 TeV from region using data recorded by Tibet air shower array and its underground muon detector array. A with an extension 0.°34 ± 0.°12 successfully detected above 25 at ( α , δ ) = (281.°09 0.°10, −3.°76 0.°09) near statistical significance 6.2 σ named TASG J1844–038. The position J1844–038 consistent those J1843–033,...
A high-power RF-to-DC rectifier applied to wireless power transfer (WPT) with ultra-wide input dynamic range is proposed in this paper. GaN (gallium nitride) HEMT (high electron mobility transistor) utilized realize rectification at high up 12 W and a Schottky diode used for lower-power rectification. Excellent switching between the two circuits' modes achieved by adding circulator. The has 30 dB an efficiency of over 50% 2.4 GHz.
A wide field of view (FOV) is an important feature a detector in the gamma ray observation sporadic, extended, and transient sources. In this work, we discuss atmospheric Cherenkov telescope (ACT) with refractive water convex lens as its light collector, test feasibility new approach. We determine optical properties diameter 0.9 m, such focal length, spot size, transmittance. The first detection cosmic rays (CRs) observed coincidence scintillator extensive air shower (EAS) array presented discussed.
We have upgraded the new Tibet ASgamma experiment in China since 2014 to measure chemical composition of cosmic rays around knee. This hybrid consist an air-shower-core detector array (YAC-II) detect high energy electromagnetic component, air-shower (Tibet-III) and a large underground water-Cherenkov muon-detector (MD). carried out detailed Monte Carlo (MC) simulation study performance detectors by using CORSIKA (version 7.5000), which includes EPOS-LHC, QGSJETII-04, SIBYLL2.1 SIBYLL2.3...