Search Publications
Classical and MgII-selected damped Lyman α absorbers: impact on ΩHI at z < 1.7
Deharveng, Jean-Michel; Péroux, Céline; Cristiani, Stefano +1 more
The damped Lyα systems (DLAs), seen in absorption in the spectrum of background quasars, are believed to contain a large fraction of the neutral gas in the Universe. Paradoxically, these systems are more difficult to observe at zabs < 1.7, since they are rare and their HI feature then falls in UV spectra, thus requiring the use of sp…
Variations of the hard X-ray footpoint asymmetry in a solar flare
Siarkowski, M.; Falewicz, R.
We analysed hard and soft X-ray observations from the SXT and HXT instruments on the Yohkoh satellite of an X5.3 class flare of 25 August 2001. The most prominent features of this flare are: a fast (450 km s-1), hard (up to 90 keV) and compact X-ray moving feature, two clear footpoint sources, and loop-top emission between them. The Yoh…
Reanalysis of Copernicus Measurements of Interstellar Carbon Monoxide
Federman, S. R.; Crenny, T.
We used archival data acquired with Copernicus to reexamine CO column densities, as self-consistent oscillator strengths are now available. Our focus is on lines of sight containing modest amounts of molecular species. Our resulting column densities are small enough that self-shielding from photodissociation does not occur in the clouds probed by …
Multiwavelength study of the very long GRB 020410
Piro, L.; Pian, E.; Costa, E. +12 more
GRB 020410 is by far the longest γ-ray burst (with a duration of about 1600 s) to have been followed up from the X-ray through the radio regime. Afterglow emission was detected in X-rays and at optical wavelengths whereas no emission was detected at 8 GHz brighter than 120 µJy. The decaying X-ray afterglow, back-extrapolated to 11 h after th…
Infrared mergers and infrared quasi-stellar objects with galactic winds - I. NGC 2623: nuclear outflow in a proto-elliptical candidate
Terlevich, R.; Lípari, S.; Díaz, R. J. +4 more
We present the first results of a study of the morphology, kinematics and ionization structure of infrared (IR) mergers/quasi-stellar objects (QSOs) with galactic winds. This study is based mainly on INTEGRAL two-dimensional (2D) fibre spectroscopy [obtained on the 4.2-m William Herschel Telescope (WHT), La Palma] combined with high-resolution Hub…
Classification of Spectra from the Infrared Space Observatory PHT-S Database
Kraemer, Kathleen E.; Price, Stephan D.; Walker, Helen J. +1 more
We have classified over 1500 infrared spectra obtained with the PHT-S spectrometer aboard the Infrared Space Observatory according to the system developed for the Short Wavelength Spectrometer (SWS) spectra by Kraemer et al. The majority of these spectra contribute to subclasses that are either underrepresented in the SWS spectral database or cont…
Hard X-ray emission clumps in the γ-Cygni supernova remnant: An INTEGRAL-ISGRI view
Chevalier, R. A.; Terrier, R.; Rauw, G. +12 more
Spatially resolved images of the galactic supernova remnant G78.2+2.1 (γ-Cygni) in hard X-ray energy bands from 25 keV to 120 keV are obtained with the IBIS-ISGRI imager aboard the International Gamma-Ray Astrophysics Laboratory INTEGRAL. The images are dominated by localized clumps of about ten arcmin in size. The flux of the most prominent North…
Highly ionized Fe Kα emission lines from the LINER galaxy M 81
Page, M. J.; Zane, S.; Soria, R. +2 more
We present spectral and timing results from a long (130 ks) {XMM-Newton EPIC observation of the nucleus of the Seyfert/LINER galaxy M 81. During the observation the X-ray flux varied by 20%, but there was no significant change in spectral shape. The 2-10 keV spectrum is well described by a power law continuum and three narrow Fe Kα emission lines …
Mars Express and MARSIS
Nielsen, Erling
The Mars Express mission to be launched in 2003 will provide high resolution measurements of the Martian atmosphere and ionosphere. The neutral density, temperature, and composition will be measured, and MARSIS, a low frequency radar experiment, will probe the Martian plasma environment for electron densities in the range from 100 to 3 × 105<…
Broadband X-ray spectrum of GRS 1734-292, a luminous Seyfert 1 galaxy behind the Galactic Center
Sunyaev, R. A.; Sazonov, S. Yu.; Lutovinov, A. A. +2 more
Based on a deep survey of the Galactic Center region performed with the INTEGRAL observatory, we measured for the first time the hard X-ray (20-200 keV) spectrum of the Seyfert 1 galaxy GRS 1734-292 located in the direction of the Galactic Center. We extended the spectrum to lower energies using archival GRANAT and ASCA observations. The broadband…