This letter presents the first results of an observational campaign to study the Galactic Centre with INTEGRAL. The mosaicked images obtained with the IBIS/ISGRI coded aperture instrument in the energy ranges 20–40 and 40–100 keV, give a yet unseen view of the high-energy sources of this region in hard X-and gamma-rays with an angular resolution of 12 ′ (FWHM). We report on the discovery of a s...

This letter presents the first results of an observational campaign to study the Galactic Centre with INTEGRAL. The mosaicked images obtained with the IBIS/ISGRI coded aperture instrument in the energy ranges 20–40 and 40–100 keV, give a yet unseen view of the high-energy sources of this region in hard X-and gamma-rays with an angular resolution of 12 ′ (FWHM). We report on the discovery of a s...

In spite of increasing evidences of the presence of a massive Black Hole at the Galactic Center, its radio counterpart, Sgr A, shows little activity at high energies, and recent models involving energy advection (ADAF) have been proposed to explain this difficulty. We present results on the hard X-ray emission from the galactic central square degree obtained from the SIGMA/GRANAT 1990-1997 surv...

We first present a self-consistent dynamical model in which ω Cen is formed from an ancient nucleated dwarf galaxy merging with the first generation of the Galactic thin disc in a retrograde manner with respect to the Galactic rotation. Our numerical simulations demonstrate that during merging between the Galaxy and the ω Cen’s host dwarf with MB ≃ −14 mag and its nucleus mass of 10 7 M⊙, the o...

Received ; accepted – 2 – ABSTRACT We find that a non-axisymmetric bow shock model, with an appropriate choice of parameters, could fit the line splitting velocity field of the cone-like Hα nebula in NGC 4945 better than a canonical cone model. Meanwhile, the bow shock model could also reproduce the morphology of the Hα nebula. The bow shock results from the interaction of the galactic superwin...

We report on the detection in the combined Gaia-DR1/RAVE data of a lack of disk stars in the solar neighbourhood with velocities close to zero angular momentum. We propose that this may be caused by the scattering of stars with very low angular momentum onto chaotic, halo-type orbits when they pass through the Galactic nucleus. We model the effect in a Milky-Way like potential and fit the resul...

The first coded-aperture images of the Galactic center region at energies above 30 keV have revealed two strong y-ray sources. One source has been identified with the X-ray source 1E 1740.7-2942, located 0~8 away from the nucleus. If this source is at the distance of the Galactic center, it is one of the most luminous objects in the galaxy at energies from 35 to 200 keV. The second source is co...