Related papers: Radio/X-ray correlations and variability in the X-…
The high-mass X-ray binary LS I +61{\deg}303 is composed of a Be-type star and a compact object. The emission is variable and periodic across the electromagnetic spectrum, from radio to very high-energy gamma rays. The orbital period is…
The stellar binary system LS I +61303, composed of a compact object in an eccentric orbit around a B0 Ve star, emits from radio up to gamma-ray energies. The orbital modulation of radio spectral index, X-ray, and GeV gamma-ray data suggests…
We studied a solar flare with pronounced quasi-periodic pulsations detected in the microwave, X-ray, and radio bands. We used the methods of correlation, Fourier, and wavelet analyses to examine the temporal fine structures and…
We report the discovery of a systematic constant time lag between the X-ray and radio flares of the gamma-ray binary LSI +61 303, persistent over long, multi-year, time scale. Using the data of monitoring of the system by RXTE we show that…
Space-VLBI observations of stellar sources represent a challenge since there are few sources with sufficiently high brightness temperature for detection on space-ground baselines. X-ray binaries (XRB) are among the few types of stellar…
The gamma-ray emitting binary stellar system LS I +61 303 was observed with the Imaging X-ray Polarimetry Explorer (IXPE) on two successive orbits over orbital phases of 0.74 to 1.05. Polarization is detected at a significance of…
We present the first simultaneous, multi-wavelength observations of an L dwarf, the L3.5 candidate brown dwarf 2MASS J00361617+1821104, conducted with the Very Large Array, the Chandra X-ray Observatory, and the Kitt Peak 4-m telescope. We…
LS I +61 303 is an exceptionally rare example of a high mass X-ray binary (HMXB) that also exhibits MeV-TeV emission, making it one of only a handful of "gamma-ray binaries". Here we present H-alpha spectra that show strong variability…
We present a comprehensive study of (quasi-)simultaneous radio:X-ray observations of stellar black hole binaries during the spectrally hard X-ray state, finding evidence for a strong correlation between these two bands over more than three…
We have identified a likely radio counterpart to the low-mass X-ray binary MXB 1730-335 (the Rapid Burster). The counterpart has shown 8.4 GHz radio on/off behavior correlated with the X-ray on/off behavior as observed by the RXTE/ASM…
Young stellar objects are known to exhibit strong radio variability on timescales of weeks to months, and a few reports have documented extreme radio flares, with at least an order of magnitude change in flux density on timescales of hours…
The most peculiar radio characteristics of the TeV emitting high-mass X-ray binary LS I +61{\deg}303 are two periodicities: A large periodic outburst which exhibits the same period as the orbit (phase \Phi) and a second periodicity of 1667…
We present quasi-simultaneous radio and X-ray observations of the black hole X-ray binary GRS 1739--278 of its 2015-2016 mini-outbursts, i.e. between 2015 June 10 and 2016 October 31, with the X-ray-to-radio time interval being less than…
Recently a correlation between the radio and X-ray luminosities is found, $L_{\rm R}\propto L_{\rm X}^{0.7}$, in black hole sources including black hole candidates in our galaxy and active galactic nuclei. We first show that the correlation…
We review some of the ways that X-ray observations provide unique information on radio galaxies. Thermal bremsstrahlung X-ray emission provides detailed data on ambient densities and temperatures. These parameters in turn can be used for…
We present the results of a ~ 3 year campaign to monitor the low luminosity active galactic nucleus (LLAGN) NGC 7213 in the radio (4.8 and 8.4 GHz) and X-ray bands (2-10 keV). With a reported X-ray Eddington ratio of 7 x 10^-4 L_Edd, NGC…
LS I + 61$^\circ$303 is a high-mass X-ray binary system comprising a massive Be star and a rapidly rotating neutron star. Its spectral energy distribution across multi-wavelengths categorizes it as a $\gamma$-ray binary system. In our…
Using simultaneous X-ray and radio observations from solar flares, we investigate the link between the type III radio burst starting frequency and hard X-ray spectral index. For a proportion of events the relation derived between the…
It has long been known that X-ray and optical/UV variability in active X-ray binaries is sometimes correlated. The expectation has been that this arises from rapid reprocessing of X-rays into longer wavelength photons, and hence that the…
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…