Search Publications
X-ray properties of active M dwarfs as observed by XMM-Newton
Schmitt, J. H. M. M.; Robrade, J.
We present a comparative study of X-ray emission from a sample of active M dwarfs with spectral types using XMM-Newton observations of two single stars, AD Leonis and EV Lacertae, and two unresolved binary systems, AT Microscopii and EQ Pegasi. The light curves reveal frequent flaring during all four observations. We perform a uniform spectral ana…
A search for changing-look AGN in the Grossan catalog
Maiolino, R.; Fiore, F.; Bianchi, S. +4 more
We observed with XMM-Newton 4 objects selected from the Grossan (1992, Ph.D. Thesis) catalog, with the aim to search for new "changing-look" AGN. The sample includes all the sources which showed in subsequent observations a flux much lower than the one measured with HEAO A-1: NGC 7674, NGC 4968, IRAS 13218+0552 and NGC 1667. None of the sources wa…
The WEBT campaign to observe AO 0235+16 in the 2003-2004 observing season. Results from radio-to-optical monitoring and XMM-Newton observations
Lähteenmäki, A.; Papadakis, I. E.; Smith, N. +64 more
A multiwavelength campaign to observe the BL Lac object
X-ray quasi-periodic pulsations in solar flares as magnetohydrodynamic oscillations
Fletcher, L.; Foullon, C.; Nakariakov, V. M. +1 more
We report the first observation at high spatial resolution of long-period quasi-periodic pulsations (QPP) of X-ray radiation during solar flares, made possible with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), supported by complementary data at other wavelengths from space-based and ground-based telescopes. Evidence for the p…
Three XMM-Newton observations of the anomalous X-ray pulsar 1E 1048.1-5937: Long term variations in spectrum and pulsed fraction
Tiengo, A.; Mereghetti, S.; Stella, L. +4 more
We report the results of a recent (July 2004) XMM-Newton Target of Opportunity observation of the Anomalous X-ray Pulsar 1E 1048.1-5937 together with a detailed re-analysis of previous observations carried out in 2000 and 2003. In July 2004 the source had a 2-10 keV flux of 6.2 × 10-12 erg cm-2 s-1 and a pulsed fra…
Spectral properties and origin of the radio halo in A3562
Finoguenov, A.; Brunetti, G.; Giacintucci, S. +6 more
We present a new detailed multiband study of the merging cluster A3562, in the core of the Shapley Concentration Supercluster. We analyzed new, low frequency radio data performed at 240 MHz, 332 MHz and 610 MHz with the Giant Metrewave Radio Telescope (GMRT). The new GMRT data allowed us to carry out a detailed study of the radio halo at the centr…
Coronal phenomena at the release of solar energetic electron events
Krucker, S.; Klein, K. -L.; Hoang, S. +1 more
We investigate dynamical processes in the solar corona at the release of electrons (~30-500 keV) detected by the Wind/3DP experiment, with the aim to clarify the relationship between coronal acceleration and the escape of electrons to interplanetary space. Energetic electrons and plasma in the corona are traced using radio, EUV and X-ray observati…
Footpoint excitation of standing acoustic waves in coronal loops
Doyle, J. G.; Erdélyi, R.; Bradshaw, S. J. +1 more
A new theoretical model for the study of slow standing sausage mode oscillations in hot (T > 6 MK) active region coronal loops is presented. These oscillations are observed by the SUMER spectrometer on board the SoHO satellite. The model contains the transition region and the upper chromosphere which enables us to study the entire process of ho…
Slow wind and magnetic topology in the solar minimum corona in 1996-1997
Abbo, L.; Antonucci, E.; Dodero, M. A.
This study examines the physical conditions of the outer solar corona in order to identify the regions where the slow solar wind is accelerated and to investigate the latitudinal transition from slow to fast wind during the minimum of the solar cycle. The analysis is based on observations of six streamers obtained during the years of solar minimum…
The mass loss of C-rich giants
Bergeat, J.; Chevallier, L.
The mass loss rates, expansion velocities and dust-to-gas density ratios from millimetric observations of 119 carbon-rich giants are compared, as functions of stellar parameters, to the predictions of recent hydrodynamical models. Distances and luminosities previously estimated from HIPPARCOS data, masses from pulsations and C/O abundance ratios f…