Search Publications
Analysis of Ulysses data: Radiation pressure effects on dust particles
Krüger, H.; Grün, E.; Wehry, A.
The objective of this paper is to illustrate the influence of the radiation pressure and the electromagnetic force on dust particles in interplanetary space. Between 1990 and 2001 62 so-called β-meteoroids (β describes the ratio of the radiation pressure force to gravity) were detected as dust particles coming from the inner solar system on hyperb…
The August 11th, 1999 CME
Koutchmy, S.; Baudin, F.; Bocchialini, K. +5 more
We present here a set of observations, space borne and ground based, at different wavelengths, of the solar corona at and after the time of the total solar eclipse of August 11{th}. It is used to consider some unusual features of the coronal dynamics related to a limb Coronal Mass Ejection (CME) observed after the total eclipse. The complementary …
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…
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…
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 …
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…
On the age and mass function of the globular cluster M 4: A different interpretation of recent deep HST observations
Prada Moroni, P. G.; Paresce, F.; De Marchi, G. +1 more
Very deep images of the Galactic globular cluster M 4 (NGC 6121) through the F606W and F814W filters were taken in 2001 with the WFPC2 on board the HST. A first published analysis of this data set (Richer et al. \cite{Richer2002}) produced the result that the age of M 4 is 12.7± 0.7 Gyr (Hansen et al. \cite{Hansen2002}), thus setting a robust lowe…
Modeling the wind structure of AG Peg by fitting of C IV and N V resonance doublets
Wahlgren, G. M.; Johansson, S.; Eriksson, M.
The latest outburst of AG Peg has lasted for 150 years, which makes it the slowest nova eruption ever recorded. During the time of IUE observations (1978-1995) line profiles and intensity ratios of the N V and C IV doublet components changed remarkably, and we discuss plausible reasons. One of them is radiative pumping of Fe II which is investigat…
Number counts of bright extremely red objects: Evolved massive galaxies at z ∼1
Väisänen, P.; Johansson, P. H.
We present results on number counts of Extremely Red Objects (EROs) in a 2850 arcmin2 near-infrared survey performed in European Large Area ISO Survey (ELAIS) fields at K<17.5. Counts of EROs are extended to brighter levels than available previously, giving 0.002 ± 0.001 arcmin-2 at K<16.5 and consistent numbers with li…