Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection

Details Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection

2011-04-21

arxiv.org/abs/1104.4264v1

Astronomy and Astrophysics

Astrophysics

High Energy Astrophysical Phenomena

Accepted for publication in MNRAS (accepted 2011 April 20. Received 2011 April 20; in original form 2010 December 07); 9 pages

Scientific paper

We report results of a one-year monitoring of the low mass X-ray binary (LMXB) source (atoll type) 4U 1728-34 with INTEGRAL and RXTE. Three time intervals were covered by INTEGRAL, during which the source showed strong spectral evolution. We studied the broad-band X-ray spectra in detail by fitting several models in the different sections of the hardness-intensity diagram. The soft states are characterised by prominent blackbody emission plus a contribution from a Comptonized emission. The hard states are characterised by the presence of an excess flux with respect to the Comptonization model above 50 keV while the soft component is fainter. To obtain an acceptable fit to the data this excess is modeled either with a power law with photon index Gamma ~ 2 or a Comptonization (CompPS) spectrum implying the presence of hybrid thermal and non-thermal electrons in a corona. This makes 4U 1728-34 one of the few LMXBs of atoll type showing non-thermal emission at high energy. From our analysis, it is also apparent that the presence of the hard tail is more prominent as the overall spectrum becames harder. We discuss also alternative models which can discribe these hard states.

Affiliated with

Also associated with

No associations

Rating

Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-178537