Search Publications
Radial mean velocity in the solar neighbourhood
Cubarsi, R.; Alcobé, S.
A large sample with the full space motions drawn from the Hipparcos Catalogue allows us to select some nested subsamples containing an increasing number of thick disk stars. Segregated thick disk populations show a progressive decreasing vertex deviation according to a trend of axial symmetry, as well as an increasing velocity dispersion and mean …
Swift and XMM-Newton observations of the dark GRB 050326
Campana, S.; Tagliaferri, G.; Cusumano, G. +30 more
We present Swift and XMM-Newton observations of the bright gamma-ray burst GRB 050326, detected by the Swift Burst Alert Telescope. The Swift X-Ray Telescope (XRT) and XMM-Newton discovered the X-ray afterglow beginning 54 min and 8.5 h after the burst, respectively. The prompt GRB 050326 fluence was (7.7±0.9) × 10-6 erg cm-2…
Doppler redistribution of anisotropic radiation and resonance polarization in moving scattering media. Predicted results for the coronal O VI 1032 Å line
Raouafi, N. -E.; Sahal-Bréchot, S.
The present paper puts the Doppler redistribution theory of anisotropic radiation and resonance polarization in moving scattering media into a predictive application following Sahal-Bréchot et al. (1998, A&A, 340, 579; P{{II}}), using the example of the O VI 1032 Å line of the corona. Numerical results are presented for different heights over …
X-ray variability of NGC 2516 stars in the XMM-Newton observations
Micela, G.; Peres, G.; Marino, A. +1 more
We present the characteristics of the X-ray variability of stars in the cluster NGC 2516 as derived from XMM-Newton/EPIC/pn data. The X-ray variations on short (hours), medium (months), and long (years) time scales have been explored. We detected 303 distinct X-ray sources by analysing six EPIC/pn observations; 194 of them are members of the clust…
FH Leonis, the first dwarf nova member of a multiple star system?
Vogt, N.
Aims.Sudden brightenings of HD 96273 or BD+07 2411B were observed with the HIPPARCOS satellite in 1992, which still require a convincing explanation.
Methods: .A new analysis of all known data of these two stars is given, including additional information on the Balmer line equivalent widths.
Results: .The brightenings can be explained as S…
NGC 7679: an anomalous, composite Seyfert 1 galaxy whose X-ray luminous AGN vanishes at optical wavelengths
Held, E. V.; Lim, J.; Buson, L. M. +3 more
Morphological disturbances and gas kinematics of the SB0 galaxy NGC 7679 = Arp 216 are investigated to understand the history of this highly composite object, where AGN and starburst signatures dominate in the X-ray and optical/IR regime, respectively. Perturbations of the ionized gas velocity field appear quite mild within 15'' (~5 kpc) of the ce…
Multi-wavelength properties of the high-energy bright Seyfert 1 galaxy IGR J18027-1455
Chaty, S.; Combi, J. A.; Martí, J. +1 more
A new sample of hard X-ray sources in the Galactic Plane is being revealed by the regular observations performed by the INTEGRAL satellite. The full characterization of these sources is mandatory to understand the hard X-ray sky. Here we report new multifrequency radio, infrared and optical observations of the source
Probing the ionized ISM of the CSS quasar 3C 277.1. I. Observations
Fanti, R.; Cotton, W. D.; Fanti, C. +2 more
We present new multi-wavelength high resolution VLA polarimetric images of the CSS quasar 3C 277.1 and analyze them with older Merlin and HST [OIII] images. These observations were made to test the hypothesis that the [OIII] emission as well as the long wavelength radio opacity arise in shocks that the quasar jet induces in the ISM. The multi-wave…
An information-theoretical methodology for profile parameter estimation of solar coronal spectra
Nakagawa, A.
Aims.An attempt is made to establish an information-theoretical methodology for profile parameter estimation of the spectral lines of the solar corona.
Methods: .In this formalism, "description lengths" of a target line profile are defined for every possible profile model and are used to identify the optimal one among possible models. To prope…
Near-infrared observations of the carbon stars TU Geminorum and SS Virginis at milliarcsecond resolution
Chandrasekhar, T.; Richichi, A.
Aims.High-angular resolution investigations of carbon stars.
Methods. Milliarcsecond resolution observations in the near infrared K band by the method of lunar occultations are presented for the carbon stars
Results. Although a companion to