Biplob Sarkar

Biplob Sarkar
Tezpur University · School of Engineering

Doctor of Philosophy

About

17
Publications
12,273
Reads
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48
Citations
Citations since 2016
12 Research Items
48 Citations
2016201720182019202020212022024681012
2016201720182019202020212022024681012
2016201720182019202020212022024681012
2016201720182019202020212022024681012
Introduction
I am an Assistant Professor (Physics) in Dept. of Applied Sciences. I am working on the theoretical aspects of Black Hole (BH) Astrophysics. My research interests are primarily to understand the role of magnetic fields in the accretion flows around BHs. I deal with the theoretical understanding of the observational aspects from BH candidates like the accretion disc luminosity and jet kinetic power and how the shocks in accretion flows may help in explaining these observational findings.
Additional affiliations
July 2011 - August 2018
Indian Institute of Technology Guwahati
Position
  • Astrophysical Flows around Compact Objects
Description
  • PhD Scholar
July 2011 - August 2018
Indian Institute of Technology Guwahati
Position
  • Research Assistant
Description
  • M.Sc. 2nd and 3rd Sem Physics Lab, B. Tech First Year General Physics Lab
Education
August 2009 - May 2011
Tezpur University
Field of study
  • Physics

Publications

Publications (17)
Preprint
Full-text available
We report the results of an observation of low mass X-ray binary GX 3+1 with {\it AstroSat}'s Large Area X-ray Proportional Counter (LAXPC) and Soft X-ray Telescope (SXT) instruments on-board for the first time. We have detected one Type-1 thermonuclear burst ($\sim$ 15 s) present in the LAXPC 20 light curve, with a double peak feature at higher en...
Poster
Full-text available
4U 1608−52 is a transient neutron star low mass X-ray binary (LMXB) which shows occasional outbursts. In this poster, we present the broadband X-ray data analysis of LMXB 4U 1608-52 using AstroSat, India's first multi-wavelength mission. We aim at performing a detailed timing and spectral study of the source using the observations made with Astro...
Poster
Full-text available
This poster discusses the X-ray transient universe very straightforwardly, starting from discovering the transient X-ray sources and explaining the various types and behavior.
Chapter
Full-text available
This paper describes the general term `curriculum' and provides an overview of college education. Here we discuss the various elements of an effective college education curriculum. Again, in recent years, activity based teaching-learning (ABTL) has proven to be an effective pedagogy for students to become actively involved in the learning process....
Preprint
Full-text available
Abstract: X-ray astronomy started in the early 1960s and since then, the X-ray range of electromagnetic radiation has produced a great deal of astronomical information about the high-energy universe. We begin this article by giving a brief introduction to X-ray astronomy. We then provide a concise explanation of the emission and detection of X-rays...
Article
We investigate the dynamical behavior of a magnetized, dissipative accretion flow around a rapidly rotating black hole. We solve the magnetohydrodynamic equations and calculate the transonic accretion solutions which may contain discontinuous shock transitions. We investigate the effect of ζ –parameter (parametrizing the radial variation of the tor...
Preprint
Full-text available
We investigate the dynamical behaviour of a magnetized, dissipative, accretion flow around a rapidly rotating black hole. We solve the magnetohydrodynamic equations and calculate the transonic accretion solutions which may contain discontinuous shock transitions. We investigate the effect of $\chi-$parameter (parametrizing the radial variation of t...
Article
Full-text available
We present the global structure of magnetized advective accretion flow around the rotating black holes in presence of dissipation. By considering accretion flow to be threaded by toroidal magnetic fields and by assuming synchrotron radiative mechanism to be the dominant cooling process, we obtain global transonic accretion solutions in terms of dis...
Preprint
Full-text available
We present the global structure of magnetized advective accretion flow around the rotating black holes in presence of dissipation. By considering accretion flow to be threaded by toroidal magnetic fields and by assuming synchrotron radiative mechanism to be the dominant cooling process, we obtain global transonic accretion solutions in terms of dis...
Article
Full-text available
We explore the global structure of the accretion flow around a Schwarzschild black hole where the accretion disc is threaded by toroidal magnetic fields. The accretion flow is optically thin and advection dominated. Synchrotron radiation is considered to be the active cooling mechanism in the flow. With this, we obtain the global transonic accretio...
Article
Full-text available
We investigate the global structure of the advection dominated accretion flow around a Schwarzschild black hole where the accretion disc is threaded by toroidal magnetic fields. We consider synchrotron radiative process as an effective cooling mechanism active in the flow. With this, we obtain the global transonic accretion solutions by exploring t...
Article
Full-text available
We study the global structure of optically thin, advection dominated, magnetized accretion flow around black holes. We consider the magnetic field to be turbulent in nature and dominated by the toroidal component. With this, we obtain the complete set of accretion solutions for dissipative flows where bremsstrahlung process is regarded as the domin...
Conference Paper
Full-text available
We investigate a single-temperature, magnetized accretion disk around a Schwarzschild black hole. The global transonic accretion solutions including Rankine-Hugoniot (RH) shocks are studied in the presence of synchrotron cooling. We study the shock properties in terms of plasma β (= p gas /p mag , where p gas and p mag represent the gas pressure an...
Article
Full-text available
We study the coupled disc-jet system around the black hole where the outflow solutions are obtained in terms of the inflow parameters. We observe that an advective accretion disc can eject outflows/jets for wide range of viscosity parameter. However, such possibility is reduced if the cooling is active as the energy dissipative process inside the d...
Conference Paper
Full-text available
We self-consistently study the properties of the dissipative standing shock waves in an accrertion flow around a stationary black hole. We use analytical method to achieve our goal and identify an effective area in the parameter space spanned by the specific energy and the specific an-gular momentum which allows accretion flow to pass through shock...
Data
In this report we shall discuss a number of models of the accretion disks including the advective disk paradigm which comprises the most complete solution presented so far. It incorporates accretion and outflows within the same framework, and takes into account angular momentum, viscosity, heating/cooling etc.
Thesis
This paper presents a brief summary of the field of X­ray astronomy with special focus on Active Galactic Nuclei (AGN) studies. The paper begins with an overview of X­ray astronomy and deals with its history, importance and different X­ray satellites. The paper then discusses the X­ray emission processes and the various astrophysical X­ray sour...

Questions

Questions (15)
Question
Suppose, in a particular X-ray observation data set for a particular low-mass X-ray binary neutron star source, we find no QPO features, thermonuclear burst features or strong X-ray pulsations.
If neither of these features ( QPO, thermonuclear bursts or strong X-ray pulsations) are present in a given X-ray observation, then what other interesting features can be explored from the data set with the aim to get a suitable refereed publication?
Question
Does the New Astronomy Journal charge fees for publishing accepted papers? Are there any page charges?
Or is it totally free like Research in Astronomy and Astrophysics Journal of IOP or Journal of Astrophysics and Astronomy of Springer?
Question
Hi All!! I have recently completed my PhD in theoretical astrophysics with work on accretion flow around black holes. Now I want to venture into some observational studies. I would like to know how I can make use of the VIRTUAL OBSERVATORIES to start some good quality research work in observations. I would be very glad if you could share some useful links or documents. Thanking you all...
Question
A human being is such a complex organism, he has his emotions, various thoughts rise in his mind. Society again is an aggregate of individual human beings. So much of complexity just can't be grasped by studying the laws at the atomic or even deeper at the quark level.
Are there statistical physical laws which can explain our thoughts or the way we behave as members of a society?
Question
Supermongo and IDL are also very popular among astrophysicists. Are Matlab, Mathematica, Xmgrace, Gnuplot also popular among some groups?
Question
In the literature we find that relativistic e- - e+ jets are not possible. For truly relativistic jests, we need to have e- - p pairs.
Question
The above relation has been used in the synchrotron cooling expression in the paper "Behaviour of dissipative accretion flows around black holes" 2007MNRAS.376.1659D.
We know that the electron thermal velocity is v_e = (k T_e/m_e)^0.5 and ion thermal velocity is v_i = (k T_i/m_i)^0.5. If we say that ions and electrons have same kinetic energy then...m_e (v_e^2) = m_i (v_i^2)...and we arrive at the ralation...
T_e = (m_e/m_i)T_i
But under what assumptions can we arrive at the relation T_e = (m_e/m_i)^0.5 T_i ??
Question
Why does the outward increase of angular momentum in an accretion disk make the disk Rayleigh stable? Since the density profile in an accretion disk increases inward in the case of constant accretion rate, there should not be an instability in between consecutive rings. Is that the reason why they are Rayleigh stable?

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Projects

Project (1)
Archived project
Investigation of magnetized dissipative accretion flow around Black Holes