Search Publications

XMM-Newton spectroscopy of stars in open clusters and star forming regions

Pallavicini, R.; Franciosini, E.; Sanz-Forcada, J. +2 more

We discuss observations of open clusters and star forming regions obtained with the RGS and EPIC instruments on board XMM-Newton. These observations provide a powerful tool to investigate the temperature structure, emission measure distribution and elemental abundances of stars from the pre-main sequence phase to post-main sequence evolution. We r…

Ordered Fine Structure in the Radio Emission Observed by Cassini Cluster and Polar

Kurth, W. S.; Menietti, J. D.

Cassini has observed ordered fine structure in the Saturn kilometric radiation (SKR) data that bears a strong resemblance to similar features observed by Polar and Cluster in the terrestrial auroral kilometric radiation (AKR) data. We investigate the possible role of electromagnetic ion cyclotron (EMIC) waves in stimulating the growth of AKR and p…

Solar flares with and without SOHO/LASCO coronal mass ejections and type II shocks

Hillaris, A.; Preka-Papadema, P.; Moussas, X. +10 more

We analyse of a set of radio rich (accompanied by type IV or II bursts) solar flares and their association with SOHO/LASCO Coronal Mass Ejections in the period 1998 2000. The intensity, impulsiveness and energetics of these events are investigated. We find that, on the average, flares associated both with type IIs and CMEs are more impulsive and m…

Relativistic Fe line emission and highly photoionized absorption in GRO J1655-40

Díaz Trigo, M.; Miller, J. M.; Kuulkers, E. +1 more

We report on two XMM-Newton and simultaneous INTEGRAL observations of the microquasar GRO J1655-40 during its 2005 outburst. The source was most probably in its high-soft state during both observations. There is evidence for the presence of both a relativistically broadened Fe line providing strong support for the existence of a spinning black hol…

Host galaxy evolution in radio-loud AGN

Urry, C. Megan; O'Dowd, Matt

We investigate the luminosity evolution of the host galaxies of radio-loud AGN through Hubble Space Telescope imaging of 72 BL Lac objects. This sample has enabled us to avoid the biases implicit in quasar studies. We find that the host galaxies of BL Lacs evolve strongly, consistent with that observed in the hosts of other radio-loud AGN, and inc…

Magnetars' Giant Flares: the Case of SGR 1806 20

Mereghetti, Sandro; Turolla, Roberto; Tiengo, Andrea +4 more

We report on the properties of the SGR 1806 20's Giant Flare occurred on 2004 December 27th, with particular interest on the pre and post flare intensity/hardness correlated variability. We show that these findings are consistent with the picture of a twisted internal magnetic field which stresses the star solid crust, until the latter is not able…

Precessional correction and the proper-motion systems of FK5 and Hipparcos

Zhu, Z.

Comparing proper motions of the FK5 and Hipparcos, several authors declared that the two proper-motion systems are inconsistent with the value of the precessional correction obtained from VLBI and LLR observations. Based on the proper-motion data from the PPM and ACRS catalogues which are constructed on the FK5 system, the discrepant values of the…

Introduction to the Venus Express special issue

Taylor, Fredric W.

Cluster observations of a magnetic field cavity in the plasma sheet

Davies, J. A.; Wild, J. A.; Fazakerley, A. N. +6 more

During the recovery phase of a substorm occurring on 1 September 2002 the four Cluster spacecraft crossed from the northern tail lobe into the plasma sheet. While the spacecraft were located in the plasma sheet boundary layer, the magnetic field data from the four spacecraft detected a cavity of close to zero magnetic field. The plasma in this cav…

Search for Dark Matter with GLAST

Morselli, Aldo

The detection of gamma-rays, antiprotons and positrons due to pair annihilation of dark matter particles in the Milky Way halo is a viable techniques to search for supersymmetric dark matter candidates. In particular the EGRET team has seen a convincing signal for a strong excess of emission from the Galactic center that has no simple explanation …