Search Publications
Dynamics of the Lyα and C IV Emitting Gas in 3C 273
Paltani, Stéphane; Türler, Marc
In this paper we study the variability properties of the Lyα and C IV emission lines in 3C 273 using archival International Ultraviolet Explorer observations. Our data show for the first time the existence of variability on timescales of several years. We study the spatial distribution and the velocity field of the emitting gas by performing detai…
Stellar Motions in the Polar Ring Galaxy NGC 4650A
Swaters, Rob A.; Rubin, Vera C.
We present the first measurement of the stellar kinematics in the polar ring of NGC 4650A. There is well-defined rotation, with the stars and gas rotating in the same direction, and with similar amplitude. The gaseous and stellar kinematics suggest an approximately flat rotation curve, providing further support for the hypothesis that the polar ma…
GRB 030227 : The first multiwavelength afterglow of an INTEGRAL GRB
Pian, E.; Palazzi, E.; Greiner, J. +39 more
We present multiwavelength observations of a gamma-ray burst detected by INTEGRAL (
Maximum Entropy imaging with INTEGRAL/SPI data
Strong, A. W.
The application of the Maximum Entropy method for sky imaging with the SPI instrument on INTEGRAL is described. While intended primarily for extended emission, point sources are also mapped by this method. The technique is implemented as the program spiskymax in the data analysis distribution provided by the INTEGRAL Science Data Centre. We briefl…
Impact of aerosols present in Titan's atmosphere on the CASSINI radar experiment
Rodriguez, S.; Encrenaz, P.; Dobrijevic, M. +4 more
Simulations of Titan's atmospheric transmission and surface reflectivity have been developed in order to estimate how Titan's atmosphere and surface properties could affect performances of the Cassini radar experiment. In this paper we present a selection of models for Titan's haze, vertical rain distribution, and surface composition implemented i…
Multisite observations of the PMS delta Scuti star V351 Ori
Ripepi, V.; Palla, F.; Marconi, M. +12 more
We present the results of multisite observations spanning two years on the pre-main-sequence (PMS) star V351 Ori. A total of around 180 hours of observations over 29 nights have been collected, allowing us to measure five different periodicities, most likely related to the delta Scuti variability of V351 Ori. Comparison with the predictions of lin…
Near-Infrared Observations of BL Lacertae Host Galaxies
Giavalisco, Mauro; Cheung, C. C.; Urry, C. Megan +1 more
Multiband near-infrared images of 12 BL Lacertae objects were obtained with the 2.5 m telescope at the Las Campanas Observatory in order to determine the properties of their underlying host galaxies. Resolved emission was clearly detected in eight of the lowest redshift targets (up to z~0.3) and was modeled with a de Vaucouleurs r1/4 su…
Oxirane: An Exotic Oxygenated Organic Compound on Titan?
Raulin, François; Coll, Patrice; Bernard, Jean-Michel +1 more
After the discovery of CO, CO2, and more recently H2O in Titan's atmosphere, the chemistry of oxygenated organic compounds in this environment has been limited to theoretical studies only. Both kinetic and thermochemical models predict the formation of methanol and formaldehyde as the main O-organic products. Here we show tha…
Bursty energetic electrons confined in flux ropes in the cusp region
Balogh, A.; Zong, Q. -G.; Daly, P. W. +6 more
Bursty energetic electron events with energies of about 20- 400 keV have been observed in the cusp region when the CLUSTER S/C were travelling outbound on 5 April 2001. These electron events are characterized by strong impulsive increases in the flux whereas energetic ions (>30 keV) show no obvious changes. The enhanced energetic electron flux …
Rotation and outflow in the central kiloparsec of the water-megamaser galaxies IC 2560, NGC 1386, NGC 1052, and Mrk 1210
Henkel, C.; Schulz, H.
Optical emission-line profiles were evaluated in order to explore the structure of galactic nuclei containing H2O megamaser sources. Long-slit spectra of IC 2560, NGC 1386, NGC 1052 and Mrk 1210 were obtained at ~ 100 km s-1 spectral and ~ 2arcsec x 2 arcsec spatial resolution. The following individual properties of the objec…