Talk detail

Participant	DUTTA, BROJA GOPAL
Institution	Y. S. Palpara College (Vidyasagar University) & Indian Centre for Space Physics - Palpara - Palpara, Purba-Medinipur - West Bengal - India

Session	SO1	Accepted		Order	Time
Talk	Poster abstract	Title	Behaviour of accretion flows around the Galactic black hole candidates during their outbursts
Co-authors
Abstract	We have studied the timing and spectral properties to explain the accretion flow behavior of a few Galactic black hole candidates (such as XTE J1550-564, GRO J1655-40, GX 339-4 etc.) during their outburst. We find that the spectral features of these black hole candidates could be clearly understood by a two component (Keplerian and sub-Keplerian) advective flow (TCAF). We choose the spectral data (PCA) from of the RXTE satellite and fit them quite satisfactorily using TCAF model and also calculate the disc parameters (Keplerian rate, the sub-Keplerian rate, shock location, inner edge of the Keplerian disc). From the timing analysis we find a systematic drifts (onset and in decline phase) in Quasi-Periodic Oscillations (QPOs) frequency during the outburst. This type of evolutions in QPO frequency was seen in the various black hole candidates such as GRO J1655-40, XTE J1550-564, GX 339-4 etc. We model the frequency drift with a propagatory oscillating shock solution where the post-shock region behaves as the Comptonized region. The smoothness of the variation of the QPO frequency over a period of weeks directly supports the view that it is due to the drifting of the Comptonizing region rather than the movements of a blob inside a differentially rotating disk. We conclude the presence of two independent component in the accretion flow.

Session	SO1	Accepted		Order	Time
Talk	Poster abstract	Title	Systematic evolution of timing properties in GX 339-4 during outbursts
Co-authors
Abstract	The transient black hole binary GX 339-4 exhibited four outbursts phases at a 2-3 years of interval. The complex outburst phase begins and ends in the low/hard state. We analyzed RXTE/PCA data of this black hole source and studied the behaviour of Low Frequency Quasi Periodic Oscillations (QPOs) frequency with time during the rising phases of four outbursts (2002, 2004, 2007, 2010). We find a systematic variation in QPO frequency during the 2002, 2007 and 2010 outbursts. These frequency evolutions could be clearly interpreted with the propagatory shock oscillations solution where the post-shock region behaves as the Comptonized region and in which an oscillating shock produces geometrical variation of Comptonising region which reprocesses the soft photon into higher energy photon and also responsible for generating the modulated photon count. The smoothness of the variation of the QPO frequency over a period of weeks directly supports the view that it is due to the drifting of the Comptonizing region

Session	SO2	Accepted		Order	Time
Talk	Oral abstract	Title	The evolution of timing properties in GX 339-4 during outbursts
Co-authors
Abstract	The transient black hole binary GX 339-4 exhibited four outbursts phases at a 2-3 years of interval. The complex outburst phase begins and ends in the low/hard state. We analyzed RXTE/PCA data of this black hole source and studied the behaviour of Low Frequency Quasi Periodic Oscillations (QPOs) frequency with time during the rising phases of four outbursts (2002, 2004, 2007, 2010). We find a systematic variation in QPO frequency during the 2002, 2007 and 2010 outbursts. These frequency evolutions could be clearly interpreted with the propagatory shock oscillations solution where the post-shock region behaves as the Comptonized region and in which an oscillating shock produces geometrical variation of Comptonising region which reprocesses the soft photon into higher energy photon and also responsible for generating the modulated photon count. The smoothness of the variation of the QPO frequency over a period of weeks directly supports the view that it is due to the drifting of the Comptonizing region.