XTE J1752-223 seen by RXTE in Black Hole Intermediate State
ATel #2391; N. Shaposhnikov (U. Maryland & NASA/GSFC)
on 20 Jan 2010; 18:20 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Jean Swank (swank@milkyway.gsfc.nasa.gov)
Subjects: X-ray, Binary, Black Hole, Transient
The first pointed RXTE observation of a new Galactic black hole candidate
XTE J1752-223 (Atel #2258) after a two month period of invisibility due to
Sun constrains showed that the source has changed its spectral
state from a long stable extreme hard state (Atel #2269). Both thermal
and a power-law component are present in the energy spectrum. The photon index
of the non-thermal part is 1.9. The variability shows a broad band-limited noise with a
break at 0.5 Hz accompanied by a strong low frequency quasi-periodic oscillation (QPO) at 2.2 Hz.
This picture is consistent with the hard intermediate spectral state of
black hole binaries, confirming the anticipated hard-to-soft transition lately
indicated by Swift and MAXI data (Atel #2387). RXTE monitoring will continue
daily to follow the source evolution. Radio observations to look for a
possible ejection event, as well as observations at other wavelengths, are
highly recommended.
