Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2009-11-19
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
10 pages, 7 figures, 3 tables, accepted for publication in ApJ
Scientific paper
We present the long-term monitoring of the High Mass X-ray Binary GX 301-2 performed with the SuperAGILE instrument on-board the AGILE mission. The source was monitored in the 20-60 keV energy band during the first year of the mission from 2007 July 17 to 2008 August 31, covering about one whole orbital period and three more pre-periastron passages for a total net observation time of about 3.7 Ms. The SuperAGILE dataset represents one of the most continuous and complete monitoring at hard X-ray energies of the 41.5 day long binary period available to date. The source behavior was characterized at all orbital phases in terms of hard X-ray flux, spectral hardness, spin period history, pulsed fraction and pulse shape profile. We also complemented the SuperAGILE observations with the soft X-ray data of the RossiXTE/ASM. Our analysis shows a clear orbital modulation of the spectral hardness, with peaks in correspondence with the pre-periastron flare and near phase 0.25. The hardness peaks we found could be related with the wind-plus-stream accretion model proposed in order to explain the orbital light curve modulation of GX 301-2. Timing analysis of the pulsar spin period shows that the secular trend of the about 680 s pulse period is consistent with the previous observations, although there is evidence of a slight decrease in the spin-down rate. The analysis of the hard X-ray pulsed emission also showed a variable pulse shape profile as a function of the orbital phase, with substructures detected near the passage at the periastron, and a clear modulation of the pulsed fraction, which appears in turn strongly anti-correlated with the source intensity.
Antonelli Lucio Angelo
Argan Andrea
Barbiellini Guido
Boffelli F.
Bulgarelli Andrea
No associations
LandOfFree
Temporal properties of GX 301-2 over a year-long observation with SuperAGILE 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 Temporal properties of GX 301-2 over a year-long observation with SuperAGILE, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Temporal properties of GX 301-2 over a year-long observation with SuperAGILE will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-452845