Related papers: Modelling rapid TeV variability of PKS 2155-304
The emission mechanism of the gamma-ray binary LS5039 in energy bands of TeV, GeV, and X-ray is investigated. Observed light curves in LS5039 show that TeV and GeV fluxes anticorrelate and TeV and X-ray fluxes correlate. However, such…
M87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Cherenkov telescopes, we can now probe the variability in the gamma-ray flux at small timescales, thus…
The high-peaked BL Lac object Pks2155-304 shows high variability at multiwavelengths, i.e. from optical up to TeV energies. A giant flare of around 1 hour at X-ray and TeV energies was observed in 2006. In this context, it is essential to…
We have analyzed three XMM-Newton observations of the central part of the unidentified TeV \gamma-ray source HESS J1804-216. We focus on two X-ray sources 2XMMi J180442.0-214221 (Src 1) and 2XMMi J180432.5-214009 (Src 2), which were…
The last years have seen a revolution in ground-based gamma-ray detectors. We can now detect the spectra of nearby TeV blazars like Mrk 421 and 501 out to approximately 20 TeV, and during the strongest flares, we can now follow fluctuations…
Recent HESS observations show that microquasars in high-mass systems are sources of VHE gamma-rays. A leptonic jet model for microquasar gamma-ray emission is developed. Using the head-on approximation for the Compton cross section and…
A model independent Levy expansion method is introduced to describe nearly Levy shaped squared moduli of Fourier transforms. We apply this method to precisely characterize the most recent elastic scattering data of proton-proton collisions…
Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. The emitting region is sufficiently compact to let…
At the center of our Galaxy lies the bright {\gamma}-ray point-like source HESS J1745-290, which is compatible in position with Sgr A star, although an association between the two remains uncertain. Using data obtained between 2004 and 2019…
Aims: We investigate the one-zone SSC model of TeV blazars in the presence of electron acceleration. In this picture electrons reach a maximum energy where acceleration saturates from a combination of synchrotron and inverse Compton…
We present a new time-dependent leptonic code that we developed to model the varying multi-wavelength (MWL) emission during blazar flares. In our modeling, we assume that the blazar emission originates from a plasma blob located in the jet,…
PKS 2155-304 is a well studied BL Lac object in the southern sky. The historical optical data during different period have been collected and compiled. Light curves with a time span of 35 years have been constructed. The R-band light curve…
The extremely rapid burst of TeV photons from Mkn 421 (15 May 1996) can be reconciled with the standard properties of a relativistic gamma-ray emitting jet (bulk Lorentz factor $\approx$ 10; size $\10^{17}$ cm) if one assumes that the…
Blazars, a class of active galactic nuclei (AGN) powered by supermassive black holes, are known for their remarkable variability across multiple timescales and wavelengths. Despite significant advancements in our understanding of AGN…
Stellar variability and transient events provide critical insights into astrophysics, accelerated by missions like CoRoT, Kepler, and K2. NASA's Transiting Exoplanet Survey Satellite (TESS) adds a unique combination of long baseline and…
We present broadband spectral energy distributions (SEDs) and light curves of the gamma-ray binary 1FGL J1018.6$-$5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is…
Combined with very-long-baseline interferometry measurements, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have been detected to date, and…
The blazars 3C 454.3, PKS 0537-441 and PKS 2155-304 are traditionally known to be among the most active sources of this class. They emit at all frequencies, up to the gamma-rays, and are good probes of multiwavelength nuclear variability.…
The $\gamma$-ray flare of PKS 1222+216, observed in June 2010, is interpreted as an outcome of jet dynamics at recollimation zone. We obtained the $\gamma$-ray light-curves in three different energy bands, namely, 100--300 MeV, 300 MeV--1…
The physical mechanism behind the TeV gamma-ray source observed at the centre of the Galaxy is still unknown. One intriguing possibility is that the accretion flow onto the central supermassive black hole is responsible for accelerating…