Related papers: Periodic morphological changes in gamma-ray binari…
We are leading a comprehensive multi-waveband monitoring program of 34 gamma-ray bright blazars designed to locate the emission regions of blazars from radio to gamma-ray frequencies. The "maps" are anchored by sequences of images in both…
Compact object binaries formed from dynamics interactions will generically have non-zero orbital eccentricity. The gravitational waves from such binaries can change drastically depending on how large the eccentricity is, ranging from…
The high-mass X-ray binary LS I +61{\deg}303 is also cataloged as a gamma-ray binary as a result of frequent outbursts at TeV photon energies. The system has released two soft-gamma flares in the past, suggesting a magnetar interpretation…
Violent multi-wavelength variabilities are observed in gamma-ray-selected blazars. We present an analysis of long-term light curves for eight bright blazars to explore the co-variation pattern in the gamma-ray and radio bands. We extract…
LS I +61303 is a gamma-ray binary with periodic radio outbursts coincident with the orbital period of P=26.5 d. The origin of the radio emission is unclear,it could be due either to a jet, as in microquasars, or to the shock boundary…
In this paper we give the first attempt to model the evolution of the spectrum of PSR B1259$-$63 radio emission while the pulsar orbits the companion Be star. As suggested by Kijak et al. (Mon. Not. R. Astron. Soc. 418:L114, 2011a) this…
Guillemot et al. recently reported the discovery of $\gamma$-ray pulsations from the 22.7ms pulsar (pulsar A) in the famous double pulsar system J0737-3039A/B. The $\gamma$-ray light curve (LC) of pulsar A has two peaks separated by…
LS I +61 303 is a puzzling object detected from radio up to high-energy gamma-rays. Variability has recently been observed in its high-energy emission. The object is a binary system, with a compact object and a Be star as primary. The…
Fast radio bursts (FRBs) are short, intense extragalactic radio bursts of unknown origin. Recent polarimetric studies have shown that a noticeable fraction of the repeating FRBs display irregular, short-time variations of the Faraday…
A rare group of high mass X-ray binaries (HMXBs) are known that also exhibit MeV, GeV, and/or TeV emission ("gamma-ray binaries"). Expanding the sample of gamma-ray binaries and identifying unknown Fermi sources are currently of great…
Blazars display variable emission across the entire electromagnetic spectrum, with timescales that can range from a few minutes to several years. Our recent work has shown that a sample of five blazars exhibit hints of periodicity with a…
After initial claims and a long hiatus, it is now established that several binary stars emit high (0.1-100 GeV) and very high energy (>100 GeV) gamma rays. A new class has emerged called 'gamma-ray binaries', since most of their radiated…
We report the detection of pulsed gamma-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850 and J1718-3825 using the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST).…
PKS 1155+251 is a radio-loud quasar source at z=0.203. Observations using very long baseline interferometry (VLBI) at ~2, 5, 8 and 15 GHz show that the structure of the radio source is quite complicated on parsec scales and that the outer…
The gamma-ray binary 1FGL J1018.6-5856 consists of an O6V((f)) type star and an unknown compact object, and shows orbitally modulated emission from radio to very high energy gamma rays. The X-ray light curve shows a maximum around the same…
Supermassive binary black holes (SBBHs) are a natural outcome of galaxy mergers. Here we show that low-frequency ($f \leq 10^{-6}$ Hz) quasi-periodic variability observed from cosmic blazar sources can provide substantial inductive support…
A 2.1-year periodic oscillation of the gamma-ray flux from the blazar PG 1553+113 has previously been tentatively identified in almost 7 year of data from the Fermi Large Area Telescope. After 15 years of Fermi sky-survey observations,…
We report on orbital modulation of the 100-600 MeV gamma-ray emission of the $P_{\rm B}=4.6$ hr millisecond pulsar binary PSR J2339$-$0533 using 11 yr of Fermi Large Area Telescope data. The modulation has high significance (chance…
The binary status of gamma-Cas stars has been discussed while theoretically examining the origin of their peculiar X-ray emission. However, except in two cases, no systematic radial velocity monitoring of these stars had been undertaken yet…
The results of gamma-ray observations of the binary system HESS J0632+057 collected during 450 hours over 15 years, between 2004 and 2019, are presented. Data taken with the atmospheric Cherenkov telescopes H.E.S.S., MAGIC, and VERITAS at…