Abstract for Proposal 084523
Revealing Accreting Millisecond X-ray Pulsars with XMM-Newton
We propose ToO observations of Galactic X-ray transients aimed at
discovering accreting millisecond X-ray pulsars. XMM-Newton represents
an ideal observatory capable of fulfilling such goal, which will help
to increase the knowledge of the evolutionary paths followed by NS, and
possibly lead to breakthrough discoveries of extremely quickly rotating
objects. We propose up to 3x30 ks observations of newly discovered X-ray
transients. Criteria set to maximise the probability of discovering
new sources of this class, based on the X-ray flux (> 7 and >10 mCrab,
in 2-10 and 20-40 keV energy bands, respectively), the spectral shape (a
power law with index from 1.5 to 2.5), and the absence of an alternative
identification, will be used to trigger the proposed observations.
Details on Observing Strategy and Trigger Criteria
The proposed ToO would be triggered by:
a flux larger than 7 and 10 mCrab in 2-10 and 20-40 keV energy bands,
(equivalent to 2E-10 and 8E-11 erg/cm2/s), to observe sources
bright enough to detect signals with amplitudes >5%;
an energy spectrum described by a power-law with index ranging from
1.5 to 2.5;
no alternative identification driven by, e.g. a bright O/B optical
counterpart, long period ( > 1 s) pulsations, or very short ( < 1 s)
bursts typical of soft gamma-ray repeaters.