Maria Diaz Trigo

XMM-Newton   ESA


I have started to work in ESAC in May 2006 for the XMM-Newton Users
Support Group after two years in ESTEC as a Research Fellow. 

My main research interest is the study of low mass X-ray binaries
(LMXBs) observed at high inclination. A number of these LMXBs show
dips in their X-ray intensity which recur at the orbital period of
the system and are thought to be caused by obscuration by material
located in a thickened outer region of the accretion disk due to
its interaction with the inflowing gas stream from the companion.

With the discovery of Fe XXV and Fe XXVI absorption features in
several binaries close to the disk plane, XMM and Chandra have
revealed the existence of a highly-ionized atmosphere above the
accretion disk. My collaborators and myself have further 
demonstrated that the spectral changes during dips, both in the
lines and in the continuum of such binaries can be explained by a
decrease in the ionization level of this plasma. 

Lately we have studied a black hole candidate (BHC) LMXB in
outburst and demonstrated that both absorption from a highly
photoionized plasma and a relativistically broadened Fe line are
necessary to explain its spectrum. This is an important result
since other authors have claimed that a proper self-consistent
modelling of the absorption could reduce the need for relativistic
broadening of the Fe emission lines common in active galactic
nuclei and galactic BHCs.