Related papers: High Energy Sources Observed with OMC
The X-ray source IGR J16318-4848 was the first source discovered by INTEGRAL. The high energy spectrum exhibits such a high column density that the source is undetectable in X-rays below 2 keV. We used the NTT telescope of ESO to obtain…
The X-ray source IGR J16318-4848 was the first source discovered by INTEGRAL on 2003, January 29. We carried out optical and near-infrared (NIR) observations at the European Southern Observatory (ESO La Silla) in the course of a Target of…
Using 8 telescopes in the northern and southern hemispheres, plus archival data from two on-line sky surveys, we performed a systematic optical spectroscopic study of 39 putative counterparts of unidentified or poorly studied INTEGRAL…
The recent detection of optical emission lines from the circumgalactic medium (CGM) in combined, large samples of low-redshift, normal galaxy spectra hints at the potential to map the cool ($\sim$ 10$^4$ K) CGM in individual, representative…
Parameters from the literature, such as positions, photoelectric absorption (nH), spin and orbital periods, and distances or redshifts, were collected for all ~500 sources detected by INTEGRAL-ISGRI so far. We investigate where new and…
Within the framework of our program of assessment of the nature of unidentified or poorly known INTEGRAL sources, we present here spectroscopy of optical objects, selected through positional cross-correlation with soft X-ray detections…
The nature of most of the ~300 high-energy gamma-ray sources discovered by the EGRET instrument aboard the Gamma-ray Observatory (GRO) between 1991 and 1999 is one of the greatest enigmas in high-energy astrophysics. While about half of the…
We present results of an all-sky hard X-ray survey based on almost four years of observations with the IBIS telescope on board the INTEGRAL observatory. The dead time-corrected exposure of the survey is ~33 Ms. Approximately 12% and 80% of…
Here we report on X-ray observations of ten 17-60 keV sources discovered by the INTEGRAL satellite. The primary new information is sub-arcsecond positions obtained by the Chandra X-ray Observatory. In six cases (IGR J17040-4305, IGR…
INTEGRAL is the first gamma-ray astronomy mission with a sufficient sensitivity and angular resolution combination appropriate to the detection and identification of considerable numbers of gamma-ray emitting sources. The large field of…
H.E.S.S. results from the first three years of nominal operation are presented. Among the many exciting measurements that have been made, most gamma-ray sources are of Galactic origin. I will concentrate here on an overview of Galactic…
A large fraction of the recently discovered Galactic Very High Energy (VHE) source population remains unidentified to date. VHE gamma-ray emission traces high energy particles in these sources, but for example in case of hadronic processes…
Using the Chandra ACIS-I instruments, we have carried out a deep X-ray observation on the Galactic plane region at (l,b) ~ (28.5, 0.0), where no discrete X-ray sources have been known previously. We have detected, as well as strong diffuse…
The nature of the soft gamma-ray (20-200 keV) Galactic emission has been a matter of debate for a long time. Previous experiments have tried to separate the point source contribution from the real interstellar emission, but with a rather…
Of the 21 new sources that INTEGRAL discovered up to Feb. 1, 2004, five were detected with the BeppoSAX Wide Field Cameras at earlier times. IGR J16320-4751 appears to be a persistently active X-ray source which hints at a supergiant…
The observational progress in the $\gamma$-ray astronomy in the last few years has led to the discovery of more than a thousand sources at GeV energies and more than a hundred sources at TeV energies. A few different classes of compact…
In this paper we report on the fourth soft gamma-ray source catalog obtained with the IBIS gamma-ray imager on board the INTEGRAL satellite. The scientific dataset is based on more than 70Ms of high quality observations performed during the…
Recent progress in pushing the sensitivity of the Imaging Atmospheric Cherenkov Technique into the 10 mCrab regime has enabled first sensitive observations of the innermost few 100 pc of the Milky Way in Very High Energy (VHE; >100 GeV)…
We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov (HAWC) Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV.…
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is discovering a large number of new hard X-ray sources, many of them being HMXBs. The identification and spectral characterization of their optical/infrared counterparts is a…