RXTE shows a transition to the high-soft state in MAXI J1659-152
ATel #2951; Nikolai Shaposhnikov (UMD/CRESST/NASA/GSFC), Kazutaka Yamaoka (Aoyama Gakuin University)
on 18 Oct 2010; 15:28 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Nikolai Shaposhnikov (nikolai.v.shaposhnikov@nasa.gov)
Subjects: X-ray, Black Hole, Transient
Referred to by ATel #: 2999
The last two RXTE observations of the new galactic black hole candidate
MAXI J1659-152 (Atels #2873,#2877,#2881) performed on October 17, 2010, 04:16 UT and
18:52 UT have clearly shown changes in the source spectral and variability
properties consistent with a transition to the high soft state.
Specifically, the power density spectrum have shown the rms variability level
of about 5% presented by the low frequency red noise only. No quasi-periodic
features are observed. Our spectral analysis have shown that
the source spectrum has softened significantly. Namely, the Comptonized
fraction has decreased sharply from 0.3 to 0.2, while the index stayed
at the value of 2.35 for both observations. The spectral hardness
(9-20 keV/ 2-9 keV flux ratio) have correspondingly decreased from 0.85 to
0.7.
The observed evolution strongly suggests that the source has completed the
transition through the soft intermediate state (Atel #2927) and has entered
the high soft state.
RXTE team plans to continue the MAXI J1659-152 monitoring
program throughout the active phase of the current outburst.
