Search Publications
Pulsar Wind Nebulae in Egret Error Boxes
Hessels, Jason W. T.; Ng, C. -Y.; Gaensler, Bryan M. +3 more
A remarkable number of pulsar wind nebulae (PWN) are coincident with EGRET γ-ray sources. X-ray and radio imaging studies of unidentified EGRET sources have resulted in the discovery of at least six new pulsar wind nebulae (PWN). Stationary PWN (SPWN) appear to be associated with steady EGRET sources with hard spectra, typical for γ-ray pulsars. T…
Accretion in Strong Gravity: from Galactic to Supermassive Black Holes
Done, Chris; Gierliński, Marek
The galactic black hole binary systems give an observational template showing how the accretion flow changes as a function of increasing mass accretion rate, or L/LEdd. These data can be synthesised with theoretical models of the accretion flow to give a coherent picture of accretion in strong gravity, in which the major hard-soft spect…
Rapid X-Ray Variability of Seyfert 1 Galaxies
Iwasawa, K.; Vaughan, S.; Fabian, A. C.
The rapid and seemingly random fluctuations in X-ray luminosity of Seyfert galaxies provided early support for the standard model in which Seyferts are powered by a supermassive black hole fed from an accretion disc. However, since EXOSAT there has been little opportunity to advance our understanding of the most rapid X-ray variability. Observatio…
The Seyfert-Liner Galaxy NGC 7213: An XMM-Newton Observation
Page, M. J.; Branduardi-Raymont, G.; Soria, R. +3 more
We examine the XMM X-ray spectrum of the low-ionisation nuclear emission-line region (LINER)-AGN NGC 7213, which is best fit with a power law, Kα emission lines from Fe I, Fe XXV and Fe XXVI and a soft X-ray collisionally ionised thermal plasma with kT = 0.18+0.03‑0.01 keV. We find a luminosity of 7× 10‑4 LEdd…
Optical and X-Ray Observations of the Symbiotic System Ag Draconis During Quiescence and Outburst
Friedjung, Michael; González-Riestra, Rosario; Greiner, Jochen +6 more
We review the main characteristics of the symbiotic system AG Draconis, with special emphasis on its optical and X-ray variations. We also discuss the X-ray to visual energy distribution during quiescence and outburst and describe our spectroscopic and X-ray observations during the 2003 outburst.
Periodicity Search in the X-ray Data of RX J0007.0+7302
Lin, Lupin C. -C.; Chang, Hsiang-Kuang
Some unidentified EGRET sources have been reported to have probable X-ray counterparts. Periodicities in the X-ray data of those sources, if found, may help to strengthen the identification and to reveal their nature. We performed a detailed search of periodicities with a photon-counting method, the H-test, in the XMM and ASCA data of RX J0007.0+7…
Multiwavelength Study of two Unidentified γ-ray Sources
Caraveo, Patrizia; La Palombara, Nicola; Bignami, Giovanni F. +3 more
Most counterparts of the identified low-latitude γ-ray sources are isolated neutron stars (INSs). Since INSs are characterized by an extremely high value of f X/f opt, a systematic X-ray/optical coverage of the fields of unidentified low-latitude γ-ray sources is the best way to unveil INS counterparts of unidentified sources…