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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…
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
Deep X-ray survey of the young open cluster NGC 2516 with XMM-Newton
Micela, G.; Sciortino, S.; Pillitteri, I. +1 more
Aims.We report a deep X-ray survey of the young (~140 Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite.
Methods: .By combining data from six observations, a high sensitivity, greater than a factor of 5 with respect to recent Chandra observations, has been achieved. Kaplan-Meier estimators of the …
High spatial resolution mid-infrared spectroscopy of the starburst galaxies NGC 3256, II Zw 40 and Henize 2-10
Schaerer, D.; Sauvage, M.; Tielens, A. G. G. M. +2 more
Aims.In order to show the importance of high spatial resolution observations of extra-galactic sources when compared to observations obtained with larger apertures such as ISO, we present N-band spectra (8-13 µm) of some locations in three starburst galaxies. In particular, we show the two galactic nuclei of the spiral galaxy NGC 3256, the c…
A statistical study of the characteristics of type II doublet radio bursts
Subramanian, K. R.; Ebenezer, E.
Aims.We study the characteristics of doublet type II radio bursts in which two type II bursts occur in sequence and investigate their drivers.
Methods: .37 type II bursts reported by the Culgoora radio observatory in the Solar Geophysical data for the period September 1994-July 2004 were used to determine their time and frequency characterist…
On the complex X-ray structure tracing the motion of Geminga
Caraveo, P. A.; Bignami, G. F.; de Luca, A. +2 more
A deep (100 ks) XMM-Newton observation of Geminga has shown two faint tails of diffuse X-ray emission, extending for ~2' behind the pulsar, well aligned with the proper motion (PM) direction. We report here on a recent ~20 ks Chandra observation, which unveils a new structure, ~25'' long and ~5'' thick, starting at the pulsar position and perfectl…
Comments on the amplitude-phase relationship of asteroid lightcurves. Effects of topography, surface scattering properties, and obliquity
Rodrigo, R.; Gutiérrez, P. J.; Ortiz, J. L. +2 more
Aims.We present a theoretical study on the amplitude-phase relationship (APR) for lightcurves of simulated asteroids.
Methods: .In support of the Rosetta (ESA) mission, we developed a numerical model for the investigation of the light reflectance properties of asteroidal bodies. The code is able to deal with irregular and chemically inhomogene…
Unveiling the nature of the highly absorbed X-ray source SAX J1748.2-2808 with XMM-Newton
Mereghetti, S.; Parmar, A. N.; Sidoli, L. +2 more
We report on the results of an EPIC XMM-Newton observation of the faint source SAX J1748.2-2808 and the surrounding field. This source was discovered during the BeppoSAX Galactic center survey performed in 1997-1998. A spatial analysis resulted in the detection of 31 sources within the EPIC field of view. SAX J1748.2-2808 is clearly resolved into …
The old globular cluster system of the dIrr galaxy NGC 1427A in the Fornax cluster
Infante, L.; Hilker, M.; Georgiev, I. Y. +5 more
We present a study of the old globular cluster (GC) population of the dwarf irregular galaxy NGC 1427A using multi-wavelength VLT observations in U,B,V,I, Hα and J bands under excellent observing conditions. We applied color and size selection criteria to select old GC candidates and made use of archival ACS images taken with the Hubble Space Tele…
Surface-brightness fluctuations in stellar populations. IAC-star models for the optical and near-IR wavelengths
Marín-Franch, A.; Aparicio, A.
Aims.A new theoretical calibration of surface-brightness fluctuations (SBF) for single age, single metallicity stellar populations is presented for the optical and near-IR broad-band filters, as well as for the HST WFPC2 and ACS filters.
Methods: .The IAC-star code is used. Two Padua and the Teramo stellar evolution libraries have been conside…