Search Publications
Variability of the Fe K line relativistic component in a sample of Seyfert 1 galaxies
Cappi, M.; Dadina, M.; De Marco, B. +1 more
We present the analysis of X-ray spectral variability made on a sample of 7 Seyfert 1 bright galaxies, using XMM-Newton data. From the ``XMM-Newton Science Archive'' we selected those bright Seyfert 1 showing one or more prominent flares in their 2-10 keV light curves. For each of them we extracted spectra in 3 different time intervals: before, du…
Millisecond Pulsar Population in the Galactic Center and High Energy Contributions
Wang, Wei
We propose that there possibly exists a population of millisecond pulsars in the Galactic center region. Millisecond pulsars (MSPs) could emit GeV gamma-rays through synchrotron-curvature radiation as predicted by outer gap models. In the same time, the compact wind nebulae around millisecond pulsars can emit X-rays though synchrotron radiation an…
XMM-Newton observations of low luminosity Be/X-ray candidates
Haberl, F.; Motch, C.; Janot-Pacheco, E. +2 more
A small number of early Be stars exhibit X-ray luminosities intermediate between those typical of early type stars and those radiated by Be/X-ray binaries in the quiescent state. We report on XMM-Newton observations of two such Be stars, HD 161103 and SAO 49725 which were originally discovered in a systematic cross-correlation between the ROSAT al…
FUV and X-ray grating spectra of novae and supersoft X-ray sources
Orio, M.
I review recent FUV and X-ray observations of classical and recurrent novae and supersoft X-ray sources, among them potential type Ia supernova progenitors. FUSE spectra show emission lines of O VI, which appear to be produced very close to the white dwarf of the binary system. In one case, these lines have allowed a measurement of the white dwarf…
Search for narrow energy-shifted lines in AGN spectra in the XMM-Newton archive
Bianchi, S.; Guainazzi, M.; Santos-Lleo, M. +2 more
Thanks to the large effective area and the spectral resolution of current X-ray satellites, the detection of X-ray narrow spectral features in the 5-7 keV band is becoming commonplace in many AGN observations. Such lines, both in emission and in absorption, are mostly interpreted as arising from Iron atoms. When observed with some displacement fro…
XMM-Newton and Chandra observations of SHEEP sources
Georgakakis, A.; Nandra, K.; Papadakis, I. E. +3 more
We present Chandra and XMM-Newton observations of 12 bright [f(2-10keV) > 10-13ergcm-2s-1] sources from the ASCA search for the High Energy Extragalactic Population (SHEEP) survey. Most of these have been either not observed or not detected previously with the ROSAT mission, and therefore they constitute a sampl…
Modelling the large particle environment of comet 67P/Churyumov Gerasimenko
Agarwal, J.; Grün, E.; Müller, M. +1 more
A method is presented to simulate images of a cometary dust trail in consistency with observed gas and dust production rates. It is also applicable to dust tails including neckline and antitail phenomena. Our main objective is to analyse the amount of mm-sized and larger particles within a given image. These are interesting to us because their emi…
Apsidal Motion and Photometric Elements of the Eccentric Eclipsing Binary V401 Lacertae
Demircan, Osman; Bulut, Ibrahim
New (UBV) photometric observations of the recently discovered eccentric orbit binary V401 Lacertae were analyzed by using the Wilson-Devinney program. Seven new minimum times were estimated by using new observations. The analysis of the light curves and all available minimum times has revealed that the system is detached, with the orbital eccentri…
KET Ulysses Observations of SEP in and out of the Ecliptic
Heber, Bernd; Struminsky, Alexei
Observations of eight solar energetic particle (SEP) events in the polar heliospheric regions and six events near the Jupiter orbit and their implications for the current paradigm of particle acceleration and propagation in the heliosphere are discussed. These events are easily identified with well-known episodes of the solar activity in 1992, 199…
Relations Between Bursty Bulk Flows in the Magnetotail and Substorms
Dandouras, I.; Reme, H.; Cao, Jin-Bin +3 more
By using the data of three satellites of Cluster from 2001 to 2002, we study BBFs in the magnetotail and its relation to substorms. It is found that sometimes one or two of three satellites have already observed the BBF, and however the rest haven't. The reasons are as follows: (1) while the bulk flows satisfy the selection criterion of BBFs, the …