147 citations · 1.7k across the 59 of their papers we have counts for
44 papers · 1 filter
Influences of dynamical disruptions on the evolution of pulsars in globular clusters
Kwangmin Oh, C. Y. Hui, Jongsuk Hong +5
By comparing the physical properties of pulsars hosted by core-collapsed (CCed) and non-core-collapsed (Non-CCed) globular clusters (GCs), we find that pulsars in CCed GCs rotate s…
A non-thermal pulsed X-ray emission of AR~Scorpii
J. Takata, C. -P. Hu, L. C. C. Lin +5
We report the analysis result of UV/X-ray emission from AR~Scorpii, which is an intermediate polar (IP) composed of a magnetic white dwarf and a M-type star, with the XMM-Newton da…
Cosmic Ray (Stochastic) Acceleration from a Background Plasma
V. A. Dogiel, K. S. Cheng, D. O. Chernyshov +3
We give a short review of processes of stochastic acceleration in the Galaxy. We discuss: how to estimate correctly the number of accelerated particles, and at which condition the…
Differences between radio-loud and radio-quiet gamma-ray pulsars as revealed by Fermi
C. Y. Hui, Jongsu Lee, J. Takata +2
By comparing the properties of non-recycled radio-loud ray pulsars and radio-quiet ray pulsars, we have searched for the differences between these two populations. We found…
Observing two dark accelerators around the Galactic Centre with Fermi Large Area Telescope
C. Y. Hui, P. K. H. Yeung, C. W. Ng +6
We report the results from a detailed ray investigation in the field of two "dark accelerators", HESS J1745-303 and HESS J1741-302, with years of data obtained by the Fer…
X-Ray afterglow of SWIFT J1644+57: a Compton echo?
K. S. Cheng, D. O. Chernyshov, V. A. Dogiel +2
Swift, Chandra and XMM have found a weak but nearly constant X-ray component from Swift J1644+57 that appeared at ~500 days and was visible at least until ~ 1400 days after the ste…
Probing gamma-ray emissions of Fermi-LAT pulsars with a non-stationary outer gap model
J. Takata, C. W. Ng, K. S. Cheng
We explore a non-stationary outer gap scenario for gamma-ray emission process in pulsar magnetosphere. Electrons/positrons that migrate along the magnetic field line and enter the…
Measuring dark energy with the correlation of gamma-ray bursts using model-independent methods
J. S. Wang, F. Y. Wang, K. S. Cheng +1
In this paper, we use two model-independent methods to standardize long gamma-ray bursts (GRBs) using the correlation, where is the isotropic-…
Searches for millisecond pulsar candidates among the unidentified Fermi objects
C. Y. Hui, S. M. Park, C. P. Hu +9
Here we report the results of searching millisecond pulsar (MSP) candidates from the Fermi LAT second source catalog (2FGL). Seven unassociated ray sources in this catalog are…
Spectrum of Relativistic and Subrelativistic Cosmic Rays in the 100 pc Central Region
V. A. Dogiel, D. O. Chernyshov, A. M. Kiselev +6
From the rate of hydrogen ionization and the gamma ray flux, we derived the spectrum of relativistic and subrelativistic cosmic rays (CRs) nearby and inside the molecular cloud Sgr…
Constraining the bulk Lorentz factor from the photosphere emission
Yuan-Chuan Zou, K. S. Cheng, F. Y. Wang
We propose a direct and model-independent method to constrain the Lorentz factor of a relativistically expanding object, like gamma-ray bursts. Only the measurements, such as therm…
A detailed X-ray investigation of PSR J2021+4026 and -Cygni supernova remnant
C. Y. Hui, K. A. Seo, L. C. C. Lin +9
We have investigated the field around the radio-quiet -ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and a ~56 ks archival Chandra data. Through analyzing th…
Fermi-LAT Detection of Pulsed Gamma-rays Above 50 GeV from the Vela Pulsar
Gene C. K. Leung, J. Takata, C. W. Ng +4
The First \fermi-LAT Catalog of Sources Above 10 GeV reported evidence of pulsed emission above 25 GeV from 12 pulsars, including the Vela pulsar, which showed evidence of pulsatio…
NuSTAR observations and broadband spectral energy distribution modeling of the millisecond pulsar binary PSR J1023+0038
K. L. Li, A. K. H. Kong, J. Takata +4
We report the first hard X-ray (3-79 keV) observations of the millisecond pulsar (MSP) binary PSR J1023+0038 using NuSTAR. This system has been shown transiting between a low-mass…
Discovery of an ultracompact gamma-ray millisecond pulsar binary candidate
A. K. H. Kong, R. Jin, T. -C. Yen +8
We report multi-wavelength observations of the unidentified Fermi object 2FGL J1653.6-0159. With the help of high-resolution X-ray observation, we have identified an X-ray and opti…
Emission mechanism of GeV-quiet soft gamma-ray pulsars; A case for peculiar geometry?
Y. Wang, C. W. Ng, J. Takata +2
There is a growing new class of young spin-down powered pulsars called GeV-quiet soft gamma-ray pulsar; (1) spectral turnover appears around~10MeV, (2) the X-ray spectra of below 2…
Chandra detection of a new diffuse X-ray component from the globular cluster 47 Tucanae
E. M. H. Wu, C. Y. Hui, A. K. H. Kong +3
In re-analyzing the archival Chandra data of the globular cluster 47 Tucanae, we have detected a new diffuse X-ray emission feature within the half-mass radius of the cluster. The…
High-Energy Emission of the First Millisecond Pulsar
C. -Y. Ng, J. Takata, G. C. K. Leung +2
We report on X-ray and gamma-ray observations of the millisecond pulsar B1937+21 taken with the Chandra X-ray Observatory, XMM-Newton, and the Fermi Large Area Telescope. The pulsa…
Exploring the X-ray and gamma-ray properties of the redback millisecond pulsar PSR J1723-2837
C. Y. Hui, P. H. T. Tam, J. Takata +5
We have investigated the X-ray and -ray properties of the redback millisecond pulsar PSR J1723-2837 with XMM-Newton, Chandra and Fermi. We have discovered the X-ray orbital modu…
Discovery of X-ray Pulsation from the Geminga-like Pulsar PSR J2021+4026
L. C. C. Lin, C. Y. Hui, C. P. Hu +8
We report the discovery of X-ray periodicity of ~265.3 ms from a deep XMM-Newton observation of the radio-quiet gamma-ray pulsar, PSR J2021+4026, located at the edge of the superno…
Search for pulsed gamma-ray emission from globular cluster M28
J. H. K. Wu, C. Y. Hui, E. M. H. Wu +5
Using the data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope, we have searched for the gamma-ray pulsations from the direction of globular cluster M28…
Orbital Phase Dependent Gamma-ray emissions from the Black Widow Pulsar
E. M. H. Wu, J. Takata, K. S. Cheng +5
We report on evidence for orbital phase-dependence of the gamma-ray emission from PSR B1957+20 black widow system by using the data of the Fermi Large Area Telescope. We divide an…
Pulsed γ-ray emission from magnetar 1E 2259+586
J. H. K. Wu, C. Y. Hui, R. H. H. Huang +6
Anomalous x-ray pulsars (AXPs) are thought to be magnetars which are young isolated neutron stars with extremely strong magnetic fields of > 10^14Gauss. Their tremendous magnetic f…
X-ray studies of the Black Widow Pulsar PSR B1957+20
R. H. H. Huang, A. K. H. Kong, J. Takata +3
We report on Chandra observations of the black widow pulsar, PSR B1957+20. Evidence for a binary-phase dependence of the X-ray emission from the pulsar is found with a deep observa…