My Research

The gif shows the evolution of a magnetized tori in presence of a uniform vertical magnetic field. The color bar shows the density profile variation.

Magnetic fields are ubiquitous in all astrophysical environments and play a crucial role in driving the accretion flows around black holes (BHs). Recently, the Event Horizon Telescope collaboration (EHTC) presented a detailed analysis on the linear polarization of M87, providing the first-ever visual evidence of the magnetic field structures nearby its supermassive black hole (SMBH) located in the central region. It is well known that the accretion onto SMBHs and the consequent jet formation power the observed emission from the active galactic nuclei (AGNs).

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                           However, the underlying mechanisms that govern accretion flow are not well understood. Hence, our research focuses on the theoretical understanding of magnetohydrodynamics (MHD) accretion flows around such compact objects to explain their observational findings. But in reality, the universe is evolving with time, so the realistic feeling can only be observed through numerical simulations. 

                 General relativistic magneto-hydrodynamical (GRMHD) simulations have been an extremely useful tool for modeling accretion flow around the black hole. Additionally, these GRMHD codes have incorporated the radiative transfer processes to study the emission spectrum from the accreting matter. As a consequence, we can post-process the simulation results, and finally using ray-tracing codes we will be able to generate BH images similar to EHTC. Currently, I am working on GRMHD simulation using a code called Athena++.  

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Further details are mentioned in the research statements.

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Publications

1. Santabrata Das, Anuj Nandi, C. S. Stalin, Suvendu Rakshit, Indu Kalpa Dihingia, Swapnil Singh, Ramiz Aktar, Samik Mitra, ​On the origin of core radio emissions from black hole sources in the realm of relativistic shocked accretion flow , Accepted for publication in MNRAS 2022.

2. Samik Mitra, Debaprasad Maity, Indu Kalpa Dihingia, Santabrata Das, ​Study of general relativistic magnetodydrodynamics accretion flows around black holes , Accepted for publication in MNRAS 2022.

3. Samik Mitra, S. M. ghoreyshi, A. Mosallanezhad, S. Abbasi, S. Das, Global Transonic Solution of Hot Accretion Flow with Thermal Conduction , Under review in MNRAS 2023.

4. Samik Mitra, S. Das, Global structure of shock-induced GRMHD Flows , Manuscript under preparation 2023.

Workshop / Conferences (Attended)

1. International workshop on NUMERICAL ASTROPHYSICS, organized by Ferdowsi University of Mashhad, Mashhad, Iran, July 27-31th, 2020.

2. North-East Meet of Astronomers (NEMA) - VI, IIT Guwahati, Assam, India 10 - 13 November, 2020.

3. Prof. S. M. Chitre Memorial Symposium on Frontiers in Astrophysics and Fluid Dynamics, Organized by UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, India, 6 - 8 May, 2021 .

4. NEEM seminar, IUCAA, 13th July, Pune.

5. Online Workshop on HPC in Astrophysics and Astronomy, September 20-23, 2021, NCRA-TIFR and IIT Kharagpur under the aegis of National Supercomputing Mission.

6. International Online Conference Black Holes Inside and Out (BHIO 2021) from September 27th to October 1st 2021.

7. Regular black holes in quantum gravity and beyond: from theory to shadow observations, 18-21 October

8. Participate on the “Chandra's Contribution in Plasma Astrophysics”, from 19-20 October, 2021, School of Physical Sciences, JNU, Neew Delhi.

9. PMRF talk at IIT Guwahati, on 15-16 November, 2021 (oral).

10. Participate on the “XII-Biennial National conference of PANE: Physics Academy of North East”, from 15-17 December, 2021 (oral). (Received PANE Young Researcher Award in Astrophysics & Cosmology section)

11. Attended the “School on Black Holes and Gravitational Waves”, from 17-22 January, 2022, IIT Madras, India.

12. Participated on Research and Industrial Conclave 2022 (RIC2022), from 10-23 January, 2022, IIT Guwahati, Assam(oral & 3-minute Thesis presentation (Second Prize for 3-minute thesis presentation)).

13. Participated on North-East Meet of Astronomers (NEMA) - VII, from 27-29 January, 2022, Rajib Gandhi University, Arunachal Pradesh(oral).

14. Participated on Black Hole Astrophysics with VLBI 2022, from 7-9 February, 2022, Institute of Cosmic Ray Research, the University of Tokyo (Kashiwa/On-line).

15. Attended (online) on Testing Aspects of General Relativity, from 11-14 March, 2022, IIT Gandhinagar, India.

16. Participated on 40th meeting of the Astronomical Society of India (ASI) 2022, from 25-29 March, 2022, hosted jointly by IIT Roorkee and ARIES Nainital (On-line). Poster presentation (​presentation Link )

17. Attended (online) the IAGRG School 2022, from 16-28, May, 2022, IIT Gandhinagar

18. Presented (offline) on the 44th COSPAR 2022, from 16-24 July, 2022, Athens, Greece. Abstract is accepted for Oral presentation.

19. Attended (online) the International School for Space Simulations, from 12-16 September, 2022.

20. Presented (offline) on the Young Astronomers Meet 2022, from 9-13 November, 2022, Aries, Nainital. Abstract is accepted for Oral presentation.

21. Attended (online) the Challenges and Innovations in Computational Astrophysics IV, from 21-23 November, 2022.

22. Presented (offline) on the REcent Trends in the study of Compact Objects (RETCO-V): Theory and Observation, from 3-5 April, 2023, Kodaikanal Solar Observatory (KSO), IIA. Abstract is accepted for Oral presentation.

Teaching

Institue Teaching Assistantship (TA)

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PH 110 - Advanced B.Tech. Laboratory Course

PH 403 - Classical Mechanics (M.Sc.)

PH 417 - Advanced Physics Laboratory

PH 101 - B.Tech. Advanced Physics Theory - Completed

PH 516 - Advanced Physics Laborary (M.Sc.);Completed

PH 101 - Advanced Physics Theory (B.Tech.);Completed

PH 102 - Advanced Physics Theory (B.Tech.);Completed

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Proctoring Duties

Outside Institue (1.5 hrs / week)

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North Gauhati College

College Nagar, Guwhati – 781031,
Assam, India

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PHY-HC-1026 - Mechanics (Completed)

PHY-HC-4016 - Mathematical Physics III (Completed)

PHY-HC-3016 -  Mathematical Physics II (Completed)

PHY-HC-4016 -  Mathematical Physics II (Completed)

PHY-HC-6056 -  Classical Dynamics (Completed)