Search Publications
A photometric study of two neglected eclipsing binaries
Fedurco, M.; Parimucha, Š.; Kudak, V. +1 more
We present the first BVR photometry, period variation and photometric light curve analysis of two poorly studied eclipsing binaries, V1321 Cyg and CR Tau. Observations were carried out from November 2017 to January 2020 at the observatory of Uzhhorod National University. Period variations were studied using all available early published as well as…
High amplitude δ Scuti star BO Lyn with evidence of a late A-type companion in an elliptical orbit
Li, Lin-Jia; Qian, Sheng-Bang; Zhu, Li-Ying +2 more
We present 145 times of light maximum for high amplitude δ Scuti star BO Lyn based on several sky surveys (CRTS, DASCH, NSVS, OMC and SuperWASP) and our photometric observations. Combining with the data in literature, a total of 179 times of light maximum are used to analyze the O - C diagram of BO Lyn. We find that it can be described by an upwar…
Understanding the X-ray spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters
Liu, Yuan; Guo, Yan-Jun; Tong, Hao +3 more
Hard X-rays above 10 keV are detected from several anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), and different models have been proposed to explain the physical origin within the frame of either a magnetar model or a fallback disk system. Using data from Suzaku and INTEGRAL, we study the soft and hard X-ray spectra of four AX…
Hard X-ray emission cutoff in the anomalous X-ray pulsar 4U 0142+61 detected by INTEGRAL
Wang, Wei; Guo, Yan-Jun; Tong, Hao
The anomalous X-ray pulsar 4U 0142+61 has been studied with observations from INTEGRAL. The hard X-ray spectrum in the range 18-500 keV for 4U 0142+61 was derived using nearly nine years of INTEGRAL/IBIS data. We obtained the average hard X-ray spectrum of 4U 0142+61 with all available data. The spectrum of 4U 0142+61 can be fitted with a power la…
Photometric investigation of the K-type extremely shallow contact binary V1799 Orion
Qian, Sheng-Bang; Liao, Wen-Ping; He, Jia-Jia +3 more
New multi-color light curves of the very short period K-type eclipsing binary V1799 Ori were obtained and analyzed with the Wilson-Devinney code. The photometric solutions reveal that the system is a W-type shallow-contact binary with a mass ratio of q = 1.335(±0.005) and a degree of contact of about f = 3.5(±1.1)%. In general, the results are in …
Temporal variations and spectral properties of the Be/X-ray pulsar GRO J1008—57 studied by INTEGRAL
Wang, Wei
The spin period variations and hard X-ray spectral properties of the Be/X-ray pulsar GRO J1008—57 are studied with INTEGRAL observations during two outbursts in 2004 June and 2009 March. The pulsation periods of ~ 93.66 s in 2004 and ~ 93.73 s in 2009 are determined. Pulse profiles of GRO J1008—57 during outbursts are strongly energy dependent wit…
High energy neutron and pion-decay gamma-ray emissions from solar flares
Chupp, Edward L.; Ryan, James M.
Solar flare gamma-ray emissions from energetic ions and electrons have been detected and measured to GeV energies since 1980. In addition, neutrons produced in solar flares with 100 MeV to GeV energies have been observed at the Earth. These emissions are produced by the highest energy ions and electrons accelerated at the Sun and they provide our …
Orbital X-ray modulation study of three supergiant HMXBs
Paul, Biswajit; Jain, Chetana; Dutta, Anjan
We present the orbital X-ray modulation study of three high mass X-ray binary systems, IGR J18027-2016, IGR J18483-0311 and IGR J16318-4848, using data obtained with RXTE-ASM, Swift-BAT and INTEGRAL-ISGRI. Using the long term light curves of the eclipsing HMXB IGR J18027-2016, obtained with Swift-BAT in the energy range 15-50 keV and INTEGRAL-ISGR…
Detectability of rotation-powered pulsars in future hard X-ray surveys
Wang, Wei
Recent INTEGRAL/IBIS hard X-ray surveys have detected about 10 young pulsars. We show hard X-ray properties of these 10 young pulsars, which have a luminosity of 1033-1037 erg s-1 and a photon index of 1.6-2.1 in the energy range of 20-100 keV. The correlation between X-ray luminosity and spin-down power of LX…