Abstract for Proposal 088088
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 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.