Observations of supergiant fast X-ray transients with LOFT

Supergiant fast X-ray transients are a subclass of high mass X-ray binaries displaying a peculiar and still poorly understood extreme variability in the X-ray domain. These sources undergo short sporadic outbursts (L-x similar to 10(36)-10(37) erg s(-1)), lasting few ks at the most, and spend a large fraction of their time in an intermediate luminosity state at about L-x similar to 10(33)-10(34) erg s(-1). The sporadic and hardly predictable outbursts of supergiant fast X-ray transients were so far best discovered by large field of view (FOV) coded-mask instruments; their lower luminosity states require, instead, higher sensitivity focusing instruments to be studied in sufficient details. In this contribution, we provide a summary of the current knowledge on supergiant fast X-ray transients and explore the contribution that the new space mission concept LOFT, the Large Observatory for X-ray Timing, will be able to provide in the field of research of these objects. (C) 2012 COSPAR. Published by Elsevier Ltd. All rights reserved.