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Article

Study of Accretion Flow Dynamics of V404 Cygni during Its 2015 Outburst

1
Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India
2
Indian Centre for Space Physics, Garia Station Road, Kolkata 700084, India
3
Institute of Astronomy, National Tsing Hua University, Hsinchu 30013, Taiwan
4
Indian Institute of Astrophysics, Koramangala, Bangalore 560034, India
5
Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
*
Author to whom correspondence should be addressed.
Academic Editors: Yosuke Mizuno and Emilio Elizalde
Galaxies 2021, 9(2), 39; https://doi.org/10.3390/galaxies9020039
Received: 10 April 2021 / Revised: 9 May 2021 / Accepted: 21 May 2021 / Published: 25 May 2021
(This article belongs to the Special Issue Global Understanding of Accretion and Ejection around Black Holes)
The 2015 Outburst of V404 Cygni is an unusual one with several X-ray and radio flares and rapid variation in the spectral and timing properties. The outburst occurred after 26 years of inactivity of the black hole. We study the accretion flow properties of the source during its initial phase of the outburst using Swift/XRT and Swift/BAT data in the energy range of 0.5–150 keV. We have done spectral analysis with the two component advective flow (TCAF) model fits file. Several flow parameters such as two types of accretion rates (Keplerian disk and sub-Keplerian halo), shock parameters (location and compression ratio) are extracted to understand the accretion flow dynamics. We calculated equipartition magnetic field Beq for the outburst and found that the highest Beq900 Gauss. Power density spectra (PDS) showed no break, which indicates no or very less contribution of the Keplerian disk component, which is also seen from the result of the spectral analysis. No signature of prominent quasi-periodic oscillations (QPOs) is observed in the PDS. This is due to the non-satisfaction of the condition for the resonance shock oscillation as we observed mismatch between the cooling timescale and infall timescale of the post-shock matter. View Full-Text
Keywords: X-rays: binaries—stars individual: (V404 Cygni)—stars:black holes—accretion; accretion disks—shock waves—radiation:dynamics X-rays: binaries—stars individual: (V404 Cygni)—stars:black holes—accretion; accretion disks—shock waves—radiation:dynamics
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MDPI and ACS Style

Jana, A.; Shang, J.-R.; Debnath, D.; Chakrabarti, S.K.; Chatterjee, D.; Chang, H.-K. Study of Accretion Flow Dynamics of V404 Cygni during Its 2015 Outburst. Galaxies 2021, 9, 39. https://doi.org/10.3390/galaxies9020039

AMA Style

Jana A, Shang J-R, Debnath D, Chakrabarti SK, Chatterjee D, Chang H-K. Study of Accretion Flow Dynamics of V404 Cygni during Its 2015 Outburst. Galaxies. 2021; 9(2):39. https://doi.org/10.3390/galaxies9020039

Chicago/Turabian Style

Jana, Arghajit, Jie-Rou Shang, Dipak Debnath, Sandip K. Chakrabarti, Debjit Chatterjee, and Hsiang-Kuang Chang. 2021. "Study of Accretion Flow Dynamics of V404 Cygni during Its 2015 Outburst" Galaxies 9, no. 2: 39. https://doi.org/10.3390/galaxies9020039

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