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An XMM-Newton observation of the flare star AU MIC
Mewe, R.; Audard, M.; Güdel, M. +1 more
Preliminary results from an XMM- Newton observation of the active flare star AU Mic are presented. During the observation six flares were observed, along with numerous smaller-scale events. Coronal densities have been obtained using the density-sensitive He-like line triplet of O VII, for both the full observation and the final four flares. High b…
Modeling solar and stellar flares
Reale, F.
The thermal phase of solar X-ray flares has been described as heating-triggered evolution of plasma confined in coronal loops. This paper describes how the modeling of the thermal phase of spatially resolved solar X-ray flares has been extended to investigate spatially unresolved stellar X-ray flares with different scopes, aims and perspectives. H…
Coronal densities and temperatures for cool stars in different stages of activity
Schmitt, J. H. M. M.; Audard, M.; Güdel, M. +1 more
With the advent of the new X-ray missions Chandra and XMM-Newton, high-resolution spectroscopy has become available for studies of stellar coronae. Individual lines can be used as diagnostic tools for measuring densities and temperatures in coronal plasma. In addition to the overall X-ray luminosity, spectroscopic properties can be used for a clas…
Pile-up on X-ray CCD instruments
Ballet, J.
Pile-up occurs on X-ray CCDs when several photons hit the detector at the same place between two readouts. In that case they are counted as one (or not at all) and their energies are summed. Pile-up thus affects both flux measurements and spectral characterisation of bright sources. Here I extend a previous work on flux loss, and present a simple …
XMM- Newton observations of open clusters
Pallavicini, R.; Franciosini, E.; Randich, S.
We present observations of stellar clusters obtained with XMM- Newton as part of the Guaranteed Time program. We have obtained EPIC observations of the open clusters Praesepe, a Per, o Ori and Hyades and of the Taurus-Auriga star-forming region. The results of the analysis are presented and discussed, with emphasis on the imaging data. In all clus…
High-resolution XMM-Newton X-ray spectra of τ SCORPII
Raassen, A. J. J.; Mewe, R.; Güdel, M. +3 more
The first high-resolution X-ray spectra of the B0.2V star τ Scorpii obtained during 22.5ks on Aug. 20, 2001 with the RGS GRATING and the EPIC-MOS CCD spectrometers on board XMM-Newton exhibit bright emission lines of the H- and He-like ions of C, N, O, Ne, Mg, and Si, as well as Fe XVII and Fe XVIII lines. The emission line and continuum spectra h…
Chasing coronaij x-ray emission to the end of the pleiades main sequence … and beyond?
Briggs, K. R.; Pye, J. P.
We have used a 40-ks XMM-Newton observation to examine the X-ray emission of 33 proposed M-type members in. the core of the Pleiades. We reach a limiting X-ray luminosity of LX ≈ × 10 27 erg s -1 in the field centre and detect 17 of 19 members with MIc < 10.5 (where MIc
XMM-Newton high-resolution x-ray spectroscopy of the Wolf-Rayet object WR25 (WN6HA+04F)
Schmutz, W.; Raassen, A. J. J.; Mewe, R. +5 more
We report the analysis of the X-ray spectrum of the Wolf-Rayet star WR 25, observed by RGS and EPIC-MOS on board XMM-Newton. Temperatures up to 40 MK have been determined. Strong absorption, exceeding the value due to the Inter Stellar Medium (ISM) has been detected and assigned to the dense stellar wind.
AD Leonis, (dM3:l5V): Analysis of the x-ray spectrum
Raassen, A. J. J.; Mewe, R.; Audard, M. +3 more
We report the analysis of the X-ray spectrum of AD Leo (dM3.5 V), observed by RGS and EPIC-MOS on board XMM-Newton and by LETGS on board Chandra. From the lightcurve the presence of flaring states and a quiescent part is noticed. Temperatures up to 20 MIA have been determined. A significant increase of the emission measure (EM) at high temperature…