About me

Hello! This is my homepage. I hail from Kolkata, the eastern metropolitan city of India. Currently, a resident of Nainital, a north Indian hill station. Although, a non-resident of Kolkata for the last fifteen years, but I still maintain a strong connection with my birthplace.

I am a scientist whose main expertise is investigations in fluid mechanics (non-magnetic, as well as magnetic) in special and general relativistic scenario. My work involves theoretical modeling and numerical simulations. Most of my work has astrophysical applications, especially in the neighbourhood of compact objects like black holes and neutron stars. On 21 December 2015, Ananda Bazar Patrika (ABP)--- the most widely circulated Bengali daily, did a feature on scientists working on various aspects of general relativity and recognised my reasearch in the area of strong gravity.

I work in ARIES (Aryabhatta Research Institute of Observational Sciences) situated in Nainital. ARIES is predominantly an observational institute, with major expertise in optical observation. It has three optical telescopes, one solar telescope.

Faculty position

Joined Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, India on 27 November 2007. Present position: Scientist E

Visiting position

Visiting Scientist: S. N. Bose National Centre for Basic Sciences; September - November, 2007

Post Doctoral positions

1. Chungnam National University, Daejeon, South Korea; Post Doctoral Fellow: November, 2004 - August, 2007

2. Katholieke University of Leuven, Leuven, Belgium; Post Doctoral Fellow: October, 2002 -September, 2004

University Education

Degree	Subjects	Year	Institute/University
B. Sc.	Physics (major), Mathematics, Chemistry	1994	A. J. C. Bose College/University of Calcutta
M. Sc.	Physics	1996	Rajabazar Science College/University of Calcutta
Ph. D.	Thesis Title: Studies of the Hydrodynamic and Radiative Acceleration Processes of Cosmic Radio Jets and Bipolar Outflows from Compact Objects; Supervisor - Prof. Sandip K. Chakrabarti;	Thesis submitted 23/9/2002; Awarded 2003	S. N. Bose National Centre for Basic Sciences/Jadavpur University

Research

My research career started with the theoretical studies of the physics of fluid flow around compact objects like black holes. Though I still continue my research on fluid flow around compact objects, but I have worked in other branches of astrophysics too. I have done numerical simulation of fluid flow around our Sun, particularly in the context of how solar outflows may or may not affect the space weather around our Earth. My second postdoc was about developing relativistic hydrodynamic code to study relativistic astrophysical jets with Prof. Dongsu Ryu. We also developed a new Lagrangian-TVD code to do numerical simulation of accretion onto black hole. Currently, I am involved in developing numerical codes to study relativistic fluid flow with relativistic equation of state and flow composition, with an intention of studying extremely energetic events in the universe like (i) Gamma Ray Bursts, (ii) to investigate how extragalactic jets `shape' the extra-galactic environment. As an offshoot of such a study is to recalculate the Riemann problem with the relativistic equation of state where the adiabatic index is itself varying, which makes the Riemann invariant non-integrable! I am currently working on it. Furthermore, recasting the relativistic MHD in a flow with relativistic equation of state is extremely challenging, and currently we are doing that. Particle acceleration processes in relativistic fluids is challenging enough,we are also working on this problem with relativistic equation of state. Astrophysical fluids are mostly composed of bare ions, therefore, a fluid description warrants a coupling term between the positive ions (protons) and the negative one (electrons). However, in most spectrum generating codes this coupling term is only correct for Newtonian description. We are trying to address these issues. And finally I am open to any interesting problem, I can lay my hands on.

Teaching

Along with research in theoretical astrophysics, teaching is my other major interest. The ARIES course work is divided in five terms, and in the first four terms teaching is involved and the fifth term is project work for the students. I am teaching from 2008 on wards. Every year I have given 20-25 lectures (i.e., 20-25 contact hours each year) from 2008 to 2016 on `Introduction to plasma physics and astrophysical fluids' --- an introductory course on basics of magnetized and non-magnetized fluids and its application in astronomy. Only 2013, I taught only the magneto-hydrodynamic part of the course. Moreover, I have started teaching general relativity from the batch of 2010-11. I am giving around 10-15 lectures (10-15 contact hours) on Introduction to General Relativity. I also taught Cosmology in 2013. I also taught Introduction to general relativity and Cosmology, which is a part of M. Sc. physics course for Pt Ravishankar Shukla University (Raipur) in Nov-Dec 2015 and March 2017.

Publications

(A) Journal

1. Accretion flow dynamics during 1999 outburst of XTE J1859+226—modeling of broadband spectra and constraining the source mass: Nandi et. al., including (I. Chattopadhyay); Ap&SS, 363, 90 (2018)

2. Study of magnetized accretion flow with variable Γ equation of state: Kuldeep Singh, Indranil Chattopadhyay; MNRAS, 476, 4123 (2018)

3. Radiatively driven relativistic jets in Schwarzschild space-time: Mukesh K. Vyas, Indranil Chattopadhyay; A&A, in press (2018)

4. Study of Magnetized accretion flow with cooling processes: Kuldeep Singh, Indranil Chattopadhyay; JAA, 39, 10 (2018).

5. Radiatively driven general relativistic jets: Mukesh K. Vyas, Indranil Chattopadhyay; JAA, 39, 12 (2018).

6. Estimation of bipolar jets from accretion discs around Kerr black holes: R. Kumar, Indranil Chattopadhyay; MNRAS, 469, 4221 (2017).

7. General relativistic study of astrophysical jets with internal shocks: M. K. Vyas, Indranil Chattopadhyay; MNRAS, 469, 3270 (2017).

8. Simulations Of Viscous Accretion Flow Around Black Holes In Two-Dimensional Cylindrical Geometry: S. J. Lee, Indranil Chattopadhyay, R. Kumar, S. Hyung, D. Ryu; ApJ, 831, 33 (2016).

9. Estimation of mass outflow rates from viscous relativistic accretion discs around black holes: Indranil Chattopadhyay, R. Kumar; MNRAS, 459, 3792 (2016).

10. Radiatively driven relativistic jets with variable adiabatic index equation of state: M. K. Vyas, R. Kumar, S. Mandal, Indranil Chattopadhyay; MNRAS, 453, 2992 (2015).

11. Dissipative advective accretion disc solutions with variable adiabatic index around black holes: R. Kumar, Indranil Chattopadhyay; MNRAS, 443, 3444 (2014).

12. On the possibilities of massloss from an advective accretion disc around the stationary black holes: S. Das, I. Chattopadhyay, A. Nandi, B. Sarkar; BASI, 42, 39 (2014).

13. Periodic mass loss from viscous accretion flows around black holes: S. Das, Indranil Chattopadhyay, A. Nandi, D. Molteni; MNRAS, 442, 251 (2014).

14. Interaction of galactic wind with halo gas and the origin of multiphase extraplanar material: M. Sharma, B. Nath, I. Chattopadhyay, Y. Schekinov; MNRAS, 441, 431 (2014).

15. Radiatively and thermally driven self-consistent bipolar outflows from accretion discs around compact objects: R. Kumar, I. Chattopadhyay, S. Mandal; MNRAS, 437, 2992 (2014).

16. Effect of the fluid composition on outflow rates from accretion discs around black holes: R. Kumar, C. B. Singh, Indranil Chattopadhyay, S. K. Chakrabarti; MNRAS, 436, 2864 (2013).

17. Estimation of the mass outflow rates from viscous accretion discs: R. Kumar, Indranil Chattopadhyay; MNRAS, 430, 386 (2013).

18. Simulation of radiation driven wind from disc galaxies: Indranil Chattopadhyay, M. Sharma, B. Nath, D. Ryu; MNRAS, 423, 2153 (2012).

19. Quasi-Spherical Time-Dependent Viscous Accretion Flow: One-Dimensional Results: S. J. Lee, D. Ryu, Indranil Chattopadhyay, ApJ: 728, 142 (2011).

20. Effects of the composition on transonic properties of accretion flows around black holes: Indranil Chattopadhyay, S. K. Chakrabarti; IJMPD, 20(9), 1597 (2011).

21. Effect of fluid composition on spherical flows around black holes: Indranil Chattopadhyay, D. Ryu; ApJ, 694, 492 (2009).

22. Computation of mass outflow rates from viscous accretion disc in presence of cooling: S. Das, Indranil Chattopadhyay; New A, 13, 549 (2008).

23. Mass loss from viscous advective disc: Indranil Chattopadhyay, S. Das, New A, 12, 454 (2007).

24. Equation of state in Numerical Relativistic Hydrodynamics: D. Ryu, Indranil Chattopadhyay, E. Choi; ApJS, 166, 410-420 (2006).

25. Radiative collimation of Jets: Indranil Chattopadhyay; Journ. Kor. Phys. Soc., 49(4), 1731 (2006)

26. A New Relativistic Hydrodynamic Code for Astrophysics: D. Ryu, Indranil Chattopadhyay, E. Choi; Journ. Kor. Phys. Soc, 49(4), 1842 (2006).

27. Acceleration and collimation of pair plasma jets by radiation pressure: Indranil Chattopadhyay; Journ. Kor. Phys. Soc., 49(2), 808 (2006).

28. Radiatively driven rotating pair-plasma jets from two component accretion flows: Indranil Chattopadhyay; MNRAS, 356, 145 (2005).

29. Radiatively driven electron-positron jets from two component accretion flows: Indranil Chattopadhyay, S. Das, S. K. Chakrabarti; MNRAS, 348, 846 (2004).

30. Radiatively Driven Plasma Jets around Compact Objects: Indranil Chattopadhyay, S. K. Chakrabarti; MNRAS, 333, 454 (2002).

31. Shocks in Winds from Accretion Disks and the Formation of High Energy Particles: Indranil Chattopadhyay, S. K. Chakrabarti; BASI, 30, 313 (2002).

32. Radiatively Driven Winds from Effective Boundary Layer around Black Holes: Indranil Chattopadhyay, S. K. Chakrabarti; JAA, 23, 149 (2002).

33. Computation of Outflow Rates from Accretion Disks Around Black Holes: S. Das, I. Chattopadhyay, A. Nandi, S. K. Chakrabarti; A&A, 379, 683 (2001).

34. Standing Shocks around Black Holes - An Analytical Study: S. Das, Indranil Chattopadhyay, S. K. Chakrabarti; ApJ, 557, 983 (2001).

35. A Comparative Study of Bondi type and Radiative Outflows around Compact Objects: Indranil Chattopadhyay, S. K. Chakrabarti; Int. Journ. Mod. Phys. D, 9(6), 717 (2000).

36. Investigation of Radiative Outflows Around Compact Objects: Indranil Chattopadhyay, S. K. Chakrabarti; Int. Journ. Mod. Phys. D, 9(1), 57 (2000).

37. Theoretical Investigation and Numerical Simulation of Radiative Outflows Around Compact Objects: Indranil Chattopadhyay; Ind. Journ. Phys. B, 73, 881 (1999).

(B) Conference Proceedings

1. Simulations of relativistic astrophysical jets: Indranil Chattopadhyay; Proceedings of RETCO-II held in ARIES, Nainital; Recent Trends in the Study of Compact Objects: Theory and Observations - II, Edited by I. Chattopadhyay, A. Nandi, S. Das and S. Mandal; ASInC, Vol. 12, p.131 (2015).

2. Study of radiatively driven outflows around black holes under hydrodynamic and relativistic regime: M. Vyas, R. Kumar, S. Mandal, Indranil Chattopadhyay; Proceedings of RETCO-II held in ARIES, Nainital; Recent Trends in the Study of Compact Objects: Theory and Observations - II, Edited by I. Chattopadhyay, A. Nandi, S. Das and S. Mandal; ASInC, Vol. 12, p. 109 (2015).

3. Self-consistent accretion-ejection solutions from general relativistic viscous discs: R. Kumar, Indranil Chattopadhyay: Proceedings of RETCO-II held in ARIES, Nainital; Recent Trends in the Study of Compact Objects: Theory and Observations - II, Edited by I. Chattopadhyay, A. Nandi, S. Das and S. Mandal; ASInC, Vol. 12, p. 93 (2015).

4. 'Q' factors in Galactic Black Hole Sources -- A case study of 1999 outburst of XTE J1859+226: A. Nandi, S. Mandal, S. Das and I. Chattopadhyay; Proceedings of RETCO-II held in ARIES, Nainital; Recent Trends in the Study of Compact Objects: Theory and Observations - II, Edited by I. Chattopadhyay, A. Nandi, S. Das and S. Mandal; ASInC, Vol. 12, p. 69 (2015).

5. Numerical Simulation of astrophysical plasma with relativistic equation of state: Indranil Chattopadhyay, D. Ryu, H. Jang; Proceedings of 30-th ASI meeting held in Trivandrum, Kerala between 19-22 February, 2013; Edited by P. Khare and C. H. Ishwara-Chandra; ASInc, Vol. 9, p. 13 (2013).

6. Study of jet properties around compact objects with change in accretion disc parameters: R. Kumar, Indranil Chattopadhyay, S. Mandal: Proceedings of RETCO held in IIT-Guwahati; Recent Trends in the Study of Compact Objects: Theory and Observations, Edited by S. Das, A. Nandi, and I. Chattopadhyay}; ASInC, Vol. 8, p. 147 (2013).

7. Viscous accretion disc around compact objects with variable adiabatic index: Indranil Chattopadhyay, R. Kumar; Proceedings of RETCO-13 held in IIT-Guwahati; Recent Trends in the Study of Compact Objects: Theory and Observations, Edited by S. Das, A. Nandi, and I. Chattopadhyay; ASInC, Vol. 8, p. 19 (2013).

8. Formation of non-steady outflows and QPOs around black hole: S. Das, Indranil Chattopadhyay, A. Nandi; Proceedings of RETCO-13 held in IIT-Guwahati; Recent Trends in the Study of Compact Objects: Theory and Observations, Edited by S. Das, A. Nandi, and I. Chattopadhyay; ASInC, Vol. 8, p. 31 (2013).

9. Accretion disc spectrum in presence of mass outflow around black holes: S. Mandal, R. Kumar, Indranil Chattopadhyay; Proceedings of RETCO-13 held in IIT-Guwahati; Recent Trends in the Study of Compact Objects: Theory and Observations, Edited by S. Das, A. Nandi, and I. Chattopadhyay; ASInC, Vol. 8, p. 45 (2013).

10. How Plasma Composition affects the relativistic flows and the emergent spectra: I. Chattopadhyay, S. Garain, H. Ghosh; presented in International Conference on Astrophysics and Cosmology 2012 (ICAC2012). (arXiv:1310.0138)

11. Effect of equation of state and composition on relativistic flows: I. Chattopadhyay, S. Mandal, H. Ghosh, S. Garain, R. Kumar and D. Ryu; An Indo-Russian conference on Gamma Ray Bursts,evolution of massive stars and star formation at high red shift; 2011 held in ARIES, Edited by S. B. Pandey, V. V. Sokolov, and Yu A. Schekinov; ASInC, Vol. 5, p. 81 (2012).

12. Accretion of multi-species plasma onto the black hole: Indranil Chattopadhyay; Proceedings of Marcel Grossman Meeting 2009, Paris; Eds. Damour T., Jantsen R., Ruffini R.; p. 982 (2012). (13) Relativistic Hydrodynamic Codes for Adiabatic and Isothermal Flows: D. Ryu, Indranil Chattopadhyay, H. Jang; 5th International conference of numerical modeling of space plasma flows, San Diego, California, USA, 13-18 June 2010, ASPC, Vol. 444, p. 248 (2011).

13. Effect of plasma composition on accretion on to black holes: Indranil Chattopadhyay; Proceedings of Observational Evidence for Black Holes in the Universe - II, February 10-15, 2008, Kolkata, India, AIPC, Vol. 1053, p. 353 (2008). (15) Mass loss from a viscous accretion disc in presence of cooling: Indranil Chattopadhyay, S. Das; 2006, Proceedings of VI Microquasar Workshop: Microquasars and Beyond, September 18-22 2006, in Proceedings of Science; PoS(MQW6)034; (2006).

14. Radiative acceleration and collimation of jets from TCAF disc: Indranil Chattopadhyay; 2007, Relativistic Astrophysics and Cosmology --- Einstein's, ESO Astrophysics Symposia, Vol. ISBN 978-3-540-74712-3., 7-11 Nov 2005, Munich Germany, Springer -Verlag Berlin Heidelberg, p. 428 (2007).

15. Modeling CMEs: B. Van der Holst, S. Poedts, C. Jacobs, I. Chattopadhyay, D. Banerjee, D. Shapakidze, E. Chane, 35th COSPAR Scientific Assembly, 18 - 25 July 2004, in Paris, France, p.4394 (2005).

16. CMEs and CME Shock Evolution on Different Background Winds: B. Van der Holst, S. Poedts, C. Jacobs, E. Chane, I. Chattopadhyay, D. Shapakidze, D. Banerjee; American Astronomical Society Meeting, Vol. 36, p. 784 (2004).

17. Simulation of shock waves in the interplanetary medium: S. Poedts, B. Van der Holst, I. Chattopadhyay, D. Banerjee, T. Van Lier, R. Keppens; Proceedings ISCS 2003 Symposium, `Solar Variability as an Input to the Earth's Environment', Tatranska Lomnica, Slovak Republic, 23-28 June 2003, ed. Wilson A., ESA SP-535, Noordwijk: ESA Publications Division, p. 603 (2003).

18. Radiatively Driven Jets around Black Holes: Indranil Chattopadhyay, S. K. Chakrabarti; Proceedings of the 4th Microquasar Workshop, 2002, eds. Durouchoux P., Fuchs Y., Rodriguez J., published by the Center for Space Physics:Kolkata, p 118, (2003).

19. Radiative Acceleration of Jets and Outflows from Advective disks: Indranil Chattopadhyay, S. K. Chakrabarti; Proceeding: Heidelberg Gamma-Ray Symposium, 28-30, June, 2000, MPI (Heidelberg), Germany, eds. Aharonian F. A., Heinz J. V., p 835, (2001).

20. Generation and Acceleration of Jets from Effective Boundary Layer around Black Holes: Indranil Chattopadhyay, S. K. Chakrabarti; Proceedings: Marcel Grossman Meeting-IX, 2000, Rome, Eds. Damour T., Jantsen R., Ruffini R.; p. 2289 (2002).

21. Bulk Motion Comptonization - A sure sign of Black Holes: S. K. Chakrabarti, Indranil Chattopadhyay; Proceeding: Marcel Grossman Meeting-IX, 2000, Rome, Eds. Damour T., Jantsen R., Ruffini R.; p. 1689 (2002).

22. Role of Radiative Momentum Deposition on Acceleration of Winds and Outflows around Compact Objects: Indranil Chattopadhyay; Proceeding: Mini-Workshop of Appl. Math. ; 1-3, September, 1998, Shahjalal University of Science and Technology (SUST), Sylhet, Bangladesh (1998).

Ph. D. Students under my supervision

1. Mukesh K. Vyas: Mukesh is 5th year student, working under my supervision. His thesis is on hydrodynamic and radiative acceleration of relativistic jets around black holes. In his thesis, he is investigating whether jet internal shocks are possible under the influence of radiation, or whether the geometry of the jet affects the dynamics of the jet. Currently he has four first author publications in scientific journals.

2. Kuldeep Singh: Kuldeep is a 4th year student, working under my supervision. His thesis is on magneto hydrodynamic studies of matter flow around compact objects with hard surface, like a neutron star. He is has two first author publications in scientific journals.

3. Shilpa Sarkar: Shilpa is a 3rd year student. She is working on two temperature solution of matter flow around black holes in full general relativity. She already has very interesting results and we should be communicating soon.

Student who has already obtained Ph. D. under my supervision

1. Rajiv Kumar: Rajiv completed his PhD under my supervision. He obtained hi PhD in 2016, although submitted his thesis on 2015. His thesis topic was accretion-ejection phenomena around black holes. He has co-authored eight journal papers with me. He is now a post-doctoral fellow in Xiemin University, China.

Short term projects/visiting students under my supervision

1. Ms. Haritma Gaur (2009), Mr. Rajiv Kumar (2010), Mr. Abhishek Paswan (2012), Mr. Mukesh K. Vyas (2014), Mr. Kuldeep Singh (2015) and Ms. Shilpa Sarkar (2016 )all completed three month project under my supervision within the pre-PhD course work of ARIES. Mr. Mohan Singh (2018), has joined three month project under my supervision.

2. M. Sc Thesis of Mr. Atul Chhotray was done under my guidance who has completed MSc. Physics from BITS, Pilani. The Topic was, Theoretical studies on relativistic flows around black holes.

3. Ms. Monika Dash from IISER Pune completed her summer project (2011) on relativistic blast waves under my joint supervision, entitled `Theoretical and semi-analytical investigation of cosmic explosive events'.

4. Mr. Ramiz Ahmed from IIST, Trivandrum completed his summer project (2011) under my supervision entitled `Solar Wind: Application of fluid approximation on astrophysical plasma'.

5. Mr. Chandra Bahadur Singh a student from Nepal did project during June-July 2012, on the topic of regeneration of multi-species fluid with Pacz\'ynski Wiita Potential.

6. Ms. Enakshi Gorai from ISM, Dhanbad did her summer project from May-June 2012, on the topic of radiative hydrodynamics.

7. Mr. Kishalay De from IISc Bangalore did his summer project from May-July 2013, titled `Photometric Study of Eclipsing Binary System SS433', under me and Dr. Jeewan Pandey.

8. Mr. Golam Mahfuz from IIT-Kharagpur has completed a project under my guidance in the summer of 2013.

9. Ms. Sananda Raichaudhuri from Bose Institute, Kolkata did an one month project on numerical simulations on March-April 2015 under my guidance and again visited me for a month during 2016. She is doing a part of her doctoral research work under my guidance.

Administrative Responsibilities in ARIES

1. Presently chairman of a committee to suggest science problem with 3.6 m DOT.

2. Presently, I am also the incharge of seminars, colloquium etc in ARIES.

3. Previously I was chairman of Academic Committee for close to six years (middle of 2009 to 31st March 2015). I also was chairman of computer user committee for two terms, was also chairman of the purchase committee for close to two years. Moreover, I have been in PhD students selection committees from 2008-2016. I have been in various selection and evalutation committees for various computer engineers and other technical staffs in the past.

Organizing Meetings/conferences

1. Member of the National Scientific Advisory Committee of the National conference `Recent trends in the study of compact objects: Theory and Observation' (RETCO), held in IIT Guwahati in March 11-13, 2013. Also co-editor of the conference proceedings (www.astron-soc.in/bulletin/asics_vol008/).

2. Convener and main organizer of `Recent trends in the study of compact objects: Theory and Observation - II' (RETCO-II), organized and funded by ARIES from May 6-8, 2015. Also the editor of the proceedings (www.astron-soc.in/bulletin/asics_vol012/).

3. Organized In-house meeting of ARIES for the first time in April 20, 2012 and then again on March 18-20, 2013. ARIES In house meeting acronym as AIM, is intended to be the academic festival of ARIES, where each and every member exchange their academic work with each other.

4. Member of SOC in RETCO-III, June 5-7, 2017 organized by IIST, Trivendrum. Also one of the guest editor of the proceedings to be published in JAA as a special issue.

5. Member of the National Advisory Body of the International conference `Observational Evidence for Black Holes in the Universe', held in Kolkata 10-15 Feb 2008.

6. Member of the LOC of the National workshop `Need for Large Indian Optical Astronomy Facilities' held in ARIES, December 16-18, 2010.

7. Co-organized the Summer School 2008, in ARIES. Gave lecture on fundamentals of fluid (magneto) mechanics in the school.

Invited Talks

• Delivered a talk in Astronomical Society of India Meeting, held in Trivandrum February 20-22, 2013, entitled `Numerical Simulation with relativistic equation of state of astrophysical plasma'.

• Delivered a talk in a National conference `Recent trends in the study of compact objects: Theory and Observation', held in IIT Guwahati in March 11-13, 2013. The talk title was `Relativistic Equation of state and fluid flow around black holes'.

• Delivered a talk in the scientific conference ``Accretion onto Black Holes'' at the International Centre, Goa, September 5-7, 2013. The talk title was `Origin of Jets: Sub-relativistic to relativistic regime in Microquasars to Quasars'

• Delivered a talk in the National workshop on Radio Studies of Galaxies and Galaxy Systems, held in IUCAA, Pune, India, between 4^th-6^th March, 2014. The title of the talk was, `Simulations of relativistic jets'.

• Delivered a talk in the International conference ``Hard X-ray Astronomy: Astrosat and Beyond'', at the International Centre, Goa, September 24-26, 2014.

• Delivered a talk in the International conference ``Advances in Astroparticle Physics and Cosmology-2015'', at Saha Institute of Nuclear Physics, Kolkata, India during the period October 12 - October 17, 2015.

• Delivered a talk in International conference ``Jet Triggering Mechanisms in Black Hole Sources'' held in January 20-23, 2016 at Tata Institute of Fundamental Research, Mumbai, India.

• Delivered a talk in International conference `Wide Band Spectral and Timing Studies of Cosmic X-ray sources' held in January 10-13, 2017 at Tata Institute of Fundamental Research.

• Delivered a talk in a National conference RETCO-III held in IIST, Trivendrum, 5-7 June 2017.

Popular level articles

On March 20, 2016, ABP published a popular level invited article written by me, on Einstein's gedanken experiments and how it led to the development of general relativity (Bangla article).

Present Address

ARIES, Manora Peak, Nainital-263002, Uttarakhand, India. Telephone: +91-(0)5942-270712; Email: indra[at]aries[dot]res[dot]in