Search Publications
Swift BAT Survey of AGNs
Gehrels, N.; Mushotzky, R. F.; Barthelmy, S. +5 more
We present the results of the analysis of the first 9 months of data of the Swift BAT survey of AGNs in the 14-195 keV band. Using archival X-ray data or follow-up Swift XRT observations, we have identified 129 (103 AGNs) of 130 objects detected at | b| > 15° and with significance >4.8 σ. One source remains unidentified. These same X-ray dat…
The first XMM-Newton slew survey catalogue: XMMSL1
Altieri, B.; Read, A. M.; Esquej, P. +3 more
Aims:We report on the production of a large area, shallow, sky survey, from XMM-Newton slews. The great collecting area of the mirrors coupled with the high quantum efficiency of the EPIC detectors have made XMM-Newton the most sensitive X-ray observatory flown to date. We use data taken with the EPIC-pn camera during slewing manoeuvres to perform…
The broad-lined Type Ic supernova 2003jd
Pian, E.; Frontera, F.; Gal-Yam, A. +28 more
The results of a worldwide coordinated observational campaign on the broad-lined Type Ic supernova (SN Ic) 2003jd are presented. In total, 74 photometric data points and 26 spectra were collected using 11 different telescopes. SN 2003jd is one of the most luminous SN Ic ever observed. A comparison with other Type Ic supernovae (SNe Ic) confirms th…
Inverse Compton Origin of the Hard X-Ray and Soft Gamma-Ray Emission from the Galactic Ridge
Bouchet, L.; Porter, Troy A.; Strong, Andrew W. +2 more
A recent redetermination of the nonthermal component of the hard X-ray to soft γ-ray emission from the Galactic ridge, using the SPI instrument on the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), is shown to be well reproduced as inverse Compton emission from the interstellar medium. Both cosmic-ray primary electrons and secondary e…
HESS very-high-energy gamma-ray sources without identified counterparts
Santangelo, A.; Ripken, J.; Carrigan, S. +141 more
Context: The detection of gamma rays in the very-high-energy (VHE) energy range (100 GeV-100 TeV) provides a direct view of the parent population of ultra-relativistic particles found in astrophysical sources. For this reason, VHE gamma rays are useful for understanding the underlying astrophysical processes in non-thermal sources.
Aims: We in…
Cosmic X-Ray Background and Earth Albedo Spectra with Swift BAT
Greiner, J.; Strong, A. W.; Ajello, M. +8 more
We use Swift BAT Earth occultation data at different geomagnetic latitudes to derive a sensitive measurement of the cosmic X-ray background (CXB) and of the Earth albedo emission in the 15-200 keV band. We compare our CXB spectrum with recent (INTEGRAL, BeppoSAX) and past results (HEAO-1) and find good agreement. Using an independent measurement o…
An asymmetric distribution of positrons in the Galactic disk revealed by γ-rays
Knödlseder, Jürgen; Winkler, Christoph; Diehl, Roland +8 more
Gamma-ray line radiation at 511keV is the signature of electron-positron annihilation. Such radiation has been known for 30years to come from the general direction of the Galactic Centre, but the origin of the positrons has remained a mystery. Stellar nucleosynthesis, accreting compact objects, and even the annihilation of exotic dark-matter parti…
Polarized Gamma-Ray Emission from the Crab
Hill, A. B.; Bird, A. J.; Ubertini, P. +7 more
Pulsar systems accelerate particles to immense energies. The detailed functioning of these engines is still poorly understood, but polarization measurements of high-energy radiation may allow us to locate where the particles are accelerated. We have detected polarized gamma rays from the vicinity of the Crab pulsar using data from the spectrometer…
Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. II. The environment of the companion star
Pantin, E.; Chaty, S.; Rahoui, F. +1 more
Context: The INTEGRAL mission has led to the discovery of a new type of supergiant X-ray binaries (SGXBs), whose physical properties differ from those of previously known SGXBs. Those sources are in the course of being unveiled by means of multi-wavelength X-rays, optical, near- and mid-infrared observations, and two classes are appearing. The fir…
Polarization of the Crab Pulsar and Nebula as Observed by the INTEGRAL/IBIS Telescope
Grenier, I. A.; Laurent, P.; Lebrun, F. +2 more
Neutron stars generate powerful winds of relativistic particles that form bright synchrotron nebulae around them. Polarimetry provides a unique insight into the geometry and magnetic configuration of the wind, but high-energy measurements have failed until recently. The INTEGRAL/IBIS telescope has been used in its Compton mode to search for linear…