Search Publications
Detection of X-ray emission from β Pictoris with XMM-Newton: a cool corona, a boundary layer or what?
Schmitt, J. H. M. M.; Ness, J. -U.; Robrade, J. +1 more
β Pictoris (
Simultaneous X-ray and optical spectroscopy of the Seyfert galaxy Mrk 993
Barcons, X.; Carrera, F. J.; Mateos, S. +2 more
We present the results of simultaneous XMM-Newton X-ray and 3.5 m/CAHA optical spectroscopic observations of the Seyfert galaxy Mrk 993. This galaxy exhibited in the past significant variations of its broad emission lines which classified it as Sy1, Sy1.5 and Sy1.9 in different epochs. In order to test the X-ray/optical consistency of the unified …
The soft X-ray counterpart of the newly discovered INTEGRAL source IGR J16195-4945
Mereghetti, S.; Sidoli, L.; Vercellone, S. +1 more
The INTEGRAL satellite, during its regular scanning observations of the Galactic plane, has discovered several new X-ray sources emitting above 20 keV. The nature of the great majority of them is still unknown. Here we report on the likely low energy counterpart, observed with ASCA in 1994 and 1997, of one of these sources, IGR J16195-4945. The AS…
Cascades of shocks in active galactic nuclei and their radiation
Courvoisier, T. J. -L.; Türler, M.
We discuss accretion flows on massive black holes in which different elements of the flow (clumps) have velocities that may differ substantially. We estimate the consequence of collisions between these clumps as they come close to the central object and calculate the resulting radiation. We show that this radiation is similar to that observed in t…
INTEGRAL and XMM-Newton observations of GRB 040106
Tiengo, A.; Götz, D.; McGlynn, S. +10 more
On January 6th 2004, the IBAS burst alert system triggered the 8th gamma-ray burst (GRB) to be located by the INTEGRAL satellite. The position was determined and publicly distributed within 12 s, prompting ESA's XMM-Newton to execute a ToO observation just 5 h later, during which an X-ray afterglow was detected. The GRB had a duration ~52 s with t…
Influence of random magnetic field on solar global oscillations: The incompressible f-mode
Erdélyi, R.; Kerekes, A.; Mole, N.
The discrepancies between theoretically predicted and observed frequencies of solar global oscillations (e.g. p- and f-modes) have attracted major attention in the past decades. The f-mode is essentially a surface wave hence the mode frequencies are less likely to be influenced by the solar stratification. Most probably then the discrepancies are …
A large spin-up rate measured with INTEGRAL in the high mass X-ray binary pulsar SAX J2103.5+4545
Mereghetti, S.; Santangelo, A.; Sidoli, L. +7 more
The High Mass X-ray Binary Pulsar SAX J2103.5+4545 has been observed with INTEGRAL several times during the last outburst in 2002-2004. We report a comprehensive study of all INTEGRAL observations, allowing a study of the pulse period evolution during the recent outburst. We measured a very rapid spin-up episode, lasting 130 days, which decreased …
Kinematics of nearby subdwarf stars
Wielen, R.; Jahreiß, H.; Fuchs, B. +1 more
We present an analysis of the space motions of 742 subdwarf stars based on the sample of Carney et al. (1994, AJ, 107, 22 40). Hipparcos parallaxes, TYC2+HIP proper motions and Tycho 2 proper motions were combined with radial velocities and metallicities from CLLA. The kinematical behavior is discussed in particular in relation to their metallicit…
Exceptional H2 emission in the Antennae galaxies: Pre-starburst shocks from the galaxy collision
Klaas, U.; Haas, M.; Chini, R.
The collision of gas-rich galaxies is believed to produce strong shocks between their gas clouds which cause the onset of the observed bursts of extended star formation. However, the so far observed shock signatures in colliding galaxies can be explained essentially by winds from already existing massive stars and supernovae and thus do not give a…
X-ray properties of NGC 300. I. Global properties of X-ray point sources and their optical counterparts
Schirmer, M.; Wilms, J.; Kendziorra, E. +1 more
We present X-ray properties of NGC 300 point sources, extracted from 66 ks of XMM-Newton data taken in 2000 December and 2001 January. A total of 163 sources were detected in the energy range of 0.3-6 keV. We report on the global properties of the sources detected inside the D25 optical disk, such as the hardness ratio and X-ray fluxes,…