Abstract for Proposal 094016

The Underlying X-ray Spectrum of the X-ray Transient NLS1 WPVS 007

The goal of this re-submitted, previously approved, but not triggered proposal is to obtain the underlying X-ray spectrum of the X-ray transient Narrow Line Seyfert 1 galaxy WPVS 007 during one of its {\bf rare X-ray high states}. While WPVS 007 is typically in extremely low X-ray flux states which are caused primarily by absorption, it has shown episodes of very violent X-ray activity. In order to understand the real nature of the X-ray absorber, a good knowledge of the underlying X-ray spectrum is crucial. This, however, can only be done when it is in a higher flux state. We therefore propose a {\bf 35 ks triggered observation} of WPVS 007 (includes 40\% overhead)



Details on Observing Strategy and Trigger Criteria
We will trigger XMM when Swift will find WPVS 007 in a high state that exceeds a flux of 5e-16 Wm?2 (equal to 0.01 counts/s in the Swift XRT). Considering that we have seen WPVS 007 over the last decade only twice above this level and that the XMM observing windows only cover four month a year, we can roughly estimate that our trigger probability is of the order of roughly 10% in a year. Although the chance of triggering WPVS 007 is low, it is crucial that we can trigger in a fast turn-around time.