Issue |
A&A
Volume 390, Number 1, July IV 2002
|
|
---|---|---|
Page(s) | 199 - 204 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20020703 | |
Published online | 05 July 2002 |
A low/hard state outburst of XTE J1550-564
1
INAF – Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate (LC), Italy e-mail: colombo@merate.mi.astro.it; homan@merate.mi.astro.it; campana@merate.mi.astro.it
2
Dipartimento di Scienze, Università dell'Insubria, Via Valleggio 11, 22100 Como, Italy
3
Astronomical Institute “A. Pannekoek” and Center for High-Energy Astrophysics, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands e-mail: michiel@astro.uva.nl
Corresponding author: T. Belloni, belloni@merate.mi.astro.it
Received:
4
March
2002
Accepted:
6
May
2002
We present the results of the analysis of 11 RXTE/PCA observations
of the January 2002 outburst of the black-hole transient
XTE J1550-564. The outburst was rather short, with an e-folding
time of ~11 days in the PCA band 3–25 keV.
The source was seen in an extreme low/hard state. The energy spectra
could be fitted with a power law slightly steepening ( to ~1.5) in time, with a high-energy cutoff decreasing from ~300 keV
to ~100 keV and some additional
features between 6 and 7 keV, while the 3–150 keV flux
decreased by a factor of 17.
The power spectra were fitted with two broad Lorentzian
components, whose characteristic frequencies decreased with
the source flux, and whose fractional rms contribution was
rather constant.
The timing parameters derived can be identified with those
observed in other systems.
These results show that, although during previous, more luminous,
outbursts, a very complex behavior was observed,
at low luminosities XTE J1550-564 behaves in a
way comparable to most Black-Hole Candidates.
Key words: accretion: accretion disks / stars: binaries / X-rays: stars
© ESO, 2002
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