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Evolution of the quasi-periodic oscillation frequency in GRO J1655-40 -- Implications for accretion disk dynamics
Sandip K. Chakrabarti, Dipak Debnath, Anuj Nandi +1
Low and intermediate frequency quasi-periodic oscillations (QPOs) are thought to be due to oscillations of Comptonizing regions or hot blobs embedded in Keplerian disks. Any moveme…
Photometric Evidence of Bullets in SS433 Jet
Sandip K. Chakrabarti, A. Nandi, S. Pal +2
We report the photometric evidence of bullet like features in SS433 in X-rays, Infra-red and Radio bands through a multi-wavelength campaign.
Spectral Signatures of Winds from Accretion Disks Around Black Holes
Sandip K. Chakrabarti, A. Nandi, A. R. Rao
We show that with the wind/jet activity, the spectral index of hard X-ray is changed in galactic microquasars. When mass loss takes place, the spectrum becomes softer and when mass…
SS 433: Results of a Recent Multi-wavelength Campaign
Sandip K. Chakrabarti, B. G. Anandarao, S. Pal +8
We conducted a multi-wavelength campaign in September-October, 2002, to observe SS 433. We used 45 meter sized 30 dishes of Giant Meter Radio Telescope (GMRT) for radio observation…
Evidence of Class Transitions in GRS 1915+105 from IXAE Data
Sandip K. Chakrabarti, A. Nandi, Asit Choudhury +1
GRS 1915+105 shows at least twelve distinct classes of light curves. By analysing the data obtained from Indian X-ray Astronomy Experiment (IXAE) instrument aboard IRS-P3 satellite…
Class Transitions and Two Component Accretion Flow in GRS 1915+105
Sandip K. Chakrabarti, Anuj Nandi, A. K. Chatterjee +2
The light curve of the galactic micro-quasar GRS 1915+105 changes in at least thirteen different ways which are called classes. We present examples of the transitions from one clas…
X-ray Observation of SS 433 with RXTE
A. Nandi, Sandip K. Chakrabarti, Tomaso Belloni +1
Apart from regular monitoring by ASM, the compact object SS 433 was observed with RXTE several times last two/three years. We present the first analysis of these observations. We a…
Possible Photometric Evidence of Ejection of Bullet Like Features in the Relativistic Jet source SS433
Sandip K. Chakrabarti, S. Pal, A. Nandi +2
SS433 is well-known for its precessing twin jets having optical bullets inferred through {\it spectroscopic} observation of lines. Recently, Chakrabarti et al. (2002) describ…
Computation of outflow rates from accretion disks around black holes
Santabrata Das, Indranil Chattopadhyay, A. Nandi +1
We self-consistently estimate the outflow rate from the accretion rates of an accretion disk around a black hole in which both the Keplerian and the sub-Keplerian matter flows simu…
Ejection of the inner accretion disk in GRS 1915+105: the magnetic rubber-band effect
A. Nandi, S. K. Chakrabarti, S. V. Vadawale +1
We examine theoretically the behaviour of the inner accretion disk in GRS 1915+105 when soft X-ray dips are present in the X-ray light curve. We assume the presence of a radial sho…
On the Ejection Mechanism of Bullets in SS 433
Sandip K. Chakrabarti, P. Goldoni, P. J. Wiita +2
We discuss plausible mechanisms to produce bullet-like ejecta from the precessing disk in the SS 433 system. We show that non-steady shocks in the sub-Keplerian accretion flow can…
Observational evidence for mass ejection during soft X-ray dips in GRS1915+105
S. V. Vadawale, A. R. Rao, A. Nandi +1
We investigate the connection between the X-ray and radio properties of the Galactic microquasar GRS1915+105, by analyzing the X-ray data observed with RXTE, during the presence of…
Relation of Light Curve Behaviour with Accretion Rates in Black Hole Candidate GRS1915+105
Sandip K. Chakrabarti, A. Nandi, S. G. Manickam
We report some properties of the light curves of GRS 1915+105 and present their interpretation using the variation of net accretion rate.
On the source of QPO of the black hole candidate GRS1915+105: some new observations and their interpretation
Anuj Nandi, Sivakumar G. Manickam, A. R. Rao +1
A few classes of the light curve of the black hole candidate GRS 1915+105 have been analyzed in detail. We discover that unlike the previous findings, QPOs occasionally occur even…
Fundamental States of Accretion/Jet Configuration and the Black Hole Candidate GRS1915+105
Sandip K. Chakrabarti, Anuj Nandi
Advective disk paradigm of black hole accretion includes self-consistent formation of shocks and outflows from post-shock region. We apply this paradigm to understand rich variatio…
Understanding Galactic Black Hole Candidate GRS 1915+105
Sandip K. Chakrabarti, S. G. Manickam, A. Nandi +1
We interpret observed features of the black hole candidate GRS1915+105 in the light of the advective flow paradigm. The light curve of this black hole is seen to be of four classes…
Classification of Light curves of the Black Hole Candidate GRS1915+105
Anuj Nandi, Sivakumar G. Manickam, Sandip K. Chakrabarti
The black hole candidate GRS 1915+105 exhibits a rich variety of variability. Assuming that the earlier paradigm of black hole accretion which includes a shock is applicable for th…
Spectral Signature of Wind Generation From The Post-Shock Region in GRS1915+105 Accretion Disk
Sandip K. Chakrabarti, Sivakumar G. Manickam, Anuj K. Nandi +1
Accretion and outflows are common in systems which include black holes. Especially important is the case of the well known micro-quasar GRS1915+105 in our own galaxy, where super-l…