Search Publications
Diffuse light and building history of the galaxy cluster Abell 2667
Kneib, J. -P.; Adami, C.; Slezak, E. +3 more
Aims.We searched for diffuse intracluster light in the galaxy cluster Abell 2667 (z=0.233) from HST images in three broad band-filters.
Methods: .We applied an iterative multi-scale wavelet analysis and reconstruction technique to these images, which allows to subtract stars and galaxies from the original images.
Results: .We detect a zone…
Strong and Weak Damping of Slow MHD Standing Waves in Hot Coronal Loops
Dwivedi, B. N.; Pandey, V. S.
Slow magnetohydrodynamic (MHD) standing wave oscillations in hot coronal loops for both strong (i.e. τd/P∼ 1) and weak (i.e. τd/P≥ 2) damping are investigated taking account of viscosity, thermal conductivity and optically thin radiation. The individual effect of the dissipative terms is not sufficient to explain the observed…
Coma revealed as an extended hard X-rays source by INTEGRAL IBIS/ISGRI
Terrier, R.; Bélanger, G.; Renaud, M. +2 more
Aims.We report the INTEGRAL/IBISobservations of the Coma Clusterin the hard X-ray/soft γ-raydomain.
Methods: .Since the Coma Clusterappears as an extended source, its global intensity and significance cannot be directly extracted with standard coded mask analysis. We used the method of imaging the extended sources with a coded mask telescope d…
Discovery of Hard X-Ray Delays in the X-Ray Emission of the Seyfert 1 Galaxy Markarian 110: Possible Evidence of Comptonization
Rao, A. R.; Dasgupta, Surajit
We report the discovery of hard X-ray delays in the X-ray emission of the Seyfert 1 galaxy Mrk 110, based on a long XMM-Newton observation. Cross-correlation between the X-ray light curves of different energy bands reveals an energy-dependent delay ranging from a few minutes to an hour. We find that the energy spectrum can be modeled by Comptoniza…
Astrometric observations of Phobos and Deimos with the SRC on Mars Express
Oberst, J.; Neukum, G.; Hoffmann, H. +4 more
Observations of Phobos and Deimos, carried out by the SRC (Super Resolution Channel) on the Mars Express spacecraft between May 2004-April 2005, were used to determine the center-of-figure positions of the two Satellites with accuracies of 0.5-5 km (Phobos) and 1.0 km (Deimos). We find that the Phobos and Deimos orbit predictions from NASA-JPL (Je…
Titan: Preliminary results on surface properties and photometry from VIMS observations of the early flybys
Sotin, C.; Brown, R. H.; Baines, K. H. +10 more
Cassini observations of the surface of Titan offer unprecedented views of its surface through atmospheric windows in the 1-5 µm region. Images obtained in windows for which the haze opacity is low can be used to derive quantitative photometric parameters such as albedo and albedo distribution, and physical properties such as roughness and pa…
X-Rays from Radio Millisecond Pulsars: Comptonized Thermal Radiation
Bogdanov, Slavko; Grindlay, Jonathan E.; Rybicki, George B.
X-ray emission from many rotation-powered millisecond pulsars (MSPs) is observed to be of predominantly thermal nature. In PSR J0437-4715, the nearest MSP known, an additional faint power-law tail is observed above 2.5 keV, commonly attributed to nonthermal magnetospheric radiation. We propose that the hard emission in this and other similar MSPs …
XMM-Newton X-ray and optical observations of the globular clusters M 55 and NGC 3201
Wheatley, P. J.; Webb, N. A.; Barret, D.
We have observed two low concentration Galactic globular clusters with the X-ray observatory XMM-Newton. We detect 47 faint X-ray sources in the direction of
Proper Motion of the Crab Pulsar Revisited
Ng, C. -Y.; Romani, Roger W.
It has been suggested that the Crab pulsar's proper motion is aligned with the symmetry axis of the pulsar wind nebula. We have revisited this question, examining >6 years of F547M WFPC2 chip 3 images to obtain a best-fit value of µ*=14.9+/-0.8 mas yr-1 at P.A. 278deg+/-3deg. At 26deg…
Discovery of a Metal-Line Absorber Associated with a Local Dwarf Starburst Galaxy
York, Donald G.; Stocke, John T.; Keeney, Brian A. +2 more
We present optical and near-infrared images, H I 21 cm emission maps, optical spectroscopy, and Hubble Space Telescope Space Telescope Imaging Spectrograph ultraviolet spectroscopy of the QSO/galaxy pair SBS 1122+594/IC 691. The QSO sight line lies at a position angle of 27° from the minor axis of the nearby dwarf starburst galaxy IC 691 (czg…