“Don't ask yourself what the world needs; ask yourself what makes you come alive. And then go and do that. Because what the world needs is people who have come alive”
--- Howard Thurman, Gil Bailie's Violence Unveiled, p. xv (Thanks to Max Tegmark at MIT from whom I first came to know this quote).
A supreme quality of teaching and top level research are symbiotic in nature. This is apparent at the majority of the premier research universities in the world where students get to learn and draw inspiration from the faculty members who are working on cutting-edge research while the faculty members rejuvenate their drive for research through teaching and spirited discussion with students.
Presidency University is trying to provide such an environment to its students and faculty. I am glad to be a part of this endeavour.
My broad research interest is in astrophysics. More specifically I probe the physics of astronomical objects containing black holes, e.g., active galactic nuclei (AGN) and X-ray binaries, primarily by studying their time variability. Below I give a (relatively) non-technical description of my research. More technical details are in the section named Research / Administrative Experience.
All galaxies are believed to contain a super-massive black hole (having a million to a billion times the mass of the Sun) at their center. About 5% of these black holes are actively accreting mass from its surroundings and as a result producing enormous amount of electromagnetic radiation from gamma-ray to radio frequencies. These galaxies are called active galaxies and the bright central part of the active galaxies are called active galactic nucleus.
There are several reasons for which learning more about the nature of AGNs is important:
1. An active galactic nucleus (AGN) is brighter than the rest of the galaxy and sometimes ten thousand times as bright as an average galaxy. Being the most luminous long-lived class of objects in the sky that are more common at high redshifts, their light comes from a very young universe. They are an important tool for the astronomers to probe the distant and early universe.
2. The extremely high luminosities of AGNs are thought to be produced by the accretion of matter on to a supermassive black hole. Hence, AGN is a natural laboratory to test strong field General Relativity.
3. In many cases AGNs produce two oppositely directed jets of magnetized plasma moving at near-light speed that are equally luminous over a large range of wavelengths from radio to gamma rays. Jets are the brightest non-transient objects in the sky. The apparent brightness of jets is amplified by factors of few-10000 if they are pointed toward our line of sight. Hence we can observe them even if they are far away. In some cases, high-energy emission (X-rays, Gamma-rays) from the jets varies by a factor of a few in minutes. To explain how such large amount of emission is generated at such short-timescales is a challenge for the theories of acceleration of particles.
4. It has been established now that the stellar motion near the center of the galaxies is correlated to the mass of the central super-massive black hole (SMBH). In addition, it has been observed that kinetic energy of the jets affect its environment such as the intra-cluster medium. Hence, the formation and evolution of galaxies are influenced by the SMBH and the jets.
5. Considerable progress has been made in our understanding of the nature of active galactic nuclei (AGNs) over the last two decades. But how and why the jets form is not understood. Knowledge about this will be useful for many astrophysical systems containing a jet such as stellar mass black hole X-ray binaries, and young stellar objects as well as active galactic nuclei.
Due to their large distances, AGNs are not spatially resolved with current and near-future technologies except by radio interferometry. However, one of the defining properties of AGNs is time variability, that is, their brightness significantly varies with time due to changes in emission processes and internal dynamics. Hence, these systems can be probed by analyzing the change of its brightness with time at a given wave band (e.g. X-rays) as well as how the change at different wave bands (e.g. optical vs. gamma-rays) compare.
This analysis and its theoretical interpretation is the central theme of my research.
BSc (Honours) Physics (Presidency College, University of Calcutta, 2001)
MSc Physics (IIT Kanpur, 2003)
PhD Astronomy (Boston University, 2009)
Post-doctoral research experience at Yale University (2009-2012) and University of Wyoming (2012-2013).
Research Grants:
2026: PI of ANRF ARG Research Grant: 3 year, Rs. 36,97,453/-
2023: PI of DST-SERB SURE Research Grant: 3 year, Rs. 26,22,210/-
2022: PI of ISRO (Department of Space) Research Grant: 3 year, Rs. 20,27,696/-.
2020: Co-I of BRNS (Department of Atomic Energy) Research Grant: 3 year, Rs.
31,17,000/- .
2019: PI of ISRO (Department of Space) Research Grant: 3 year, Rs. 18,31,778/- (may
be extended for 1 more year).
2015: PI of UGC BSR Research Start-Up Grant (2 years, Rs. 6,00,000/-).
2012: Co-I of Fermi Cycle 5 Guest Investigator Program titled “Detailed Modeling of
Bright Fermi Blazar Flares” (PI: Paolo Coppi).
2009: PI of Fermi Cycle 2 Guest Investigator Program titled “Investigating the Location
and Mechanism of High Energy Emission in the Jets of Blazars” (1 yr, $69,000).
2008: Co-I of the VLBA program BM256 titled “Probing Blazars through Multi-
Waveband Variability of Flux, Polarization, and Structure”.
Telescope and Supercomputer Time
2026 Jan: Awarded 2,00,000 CPU hours on IUCAA High Performance Computing facility
for project titled “Whether Plasma Composition Can Change the Morphology of
Fanaroff-Riley Radio Jets”.
2025 Jan: Awarded 3,00,000 CPU hours on IUCAA High Performance Computing facility
for the project titled “Modeling the Morphology of FR I Jets: Role of Plasma Composition”.
2024 June: Awarded 90 ks time (PI: Arijit Sar, PhD Fellow) on AstroSat to observe one Seyfert
galaxy.
2023 June: Awarded 210 ks time (PI: Arijit Sar, PhD Fellow) on AstroSat to observe two
Seyfert galaxies.
2023 June: Awarded 100 ks time (PI: Susmita Das, PhD Fellow) on AstroSat to observe two
TeV blazars.
2021 Jul: Awarded 100 ks time on AstroSat to observe a TeV blazar.
2021 Jul: Awarded 60 ks time on AstroSat to observe AGN host galaxies in the UV band.
2020 Sep: Awarded 100 ks time on AstroSat to observe a TeV blazar.
2020 Mar: Awarded 50 ks time on AstroSat to observe a blazar.
2018 June: Awarded 150 ks time on AstroSat to observe four blazars.
2017 September: Awarded two nights on the Devasthal Optical Telescope at Nainital to observe the
radio galaxy 3C 111 simultaneously with AstroSat.
2017 August: Awarded 50 ks time on AstroSat to observe the radio galaxy 3C 111.
2016 Sep: Awarded 100 ks time on AstroSat to observe the blazar Mrk 421.
Please see the CV (in pdf) for most recent updates.
Courses taught since 2013 Odd Semester
PhD Coursework: Professional Research Training (How to Give an Effective Research Talk), Numerical Methods and Computing.
MSc 2nd Yr: Introduction to Astrophysics, Astrophysics Laboratory, Extragalactic Astrophysics Elective.
MSc 1st Yr: Classical Mechanics, General Physics Laboratory, Computational Physics (Fortran/Python based).
BSc 3rd Yr (Major): Electrical and Solid State Laboratory, Computational Physics, Astrophysics & Cosmology Elective.
BSc 2nd Yr (Major): Lagrangian Mechanics, Skill Enhancement Course titled ``Computational and Statistical Methods'', Modern Physics Lab.
BSc 1st Yr (Major): Waves and Optics, Newtonian Mechanics, Newtonian Mechanics Lab, Mathematical Methods Lab (Python-based).
BA/BSc 1st Yr (General Education curriculum): Space, Time and the Universe, Physics of Everyday Life.
2011 Spring: Guest lecturer in the course ``Accretion and Jets: Topics in High Energy Astrophysics (Astro 725)'' at Yale University.
2003-2006: Teaching fellow for the course ``Astronomy 102: Stars and Galaxies'' at Boston University in five semesters. Responsibilities: Teaching the laboratory component and discussion sections with students.
Mentoring Experience: Postdoctoral Fellow
2025 Nov -- Now: Dr. Sangeeta Chatterjee, NPDF Fellow.
Mentoring Experience: PhD Scholars
2025 Apr -- Now: Mr. Ankit Dey, Registration: 28 April 2026, funded by NET JRF.
2023 Oct -- Now: Mr. Arit Bala (jointly with Dr. Saumyadip Samui), Registration: 23 February 2024, funded by NET JRF.
2022 June -- Now: Mr. Arijit Sar, Registration: 21 March 2023, funded by ISRO, ANRF.
2020 Jan -- 2025 Aug: Ms. Susmita Das, Registration: 17 May 2021, Thesis Defense: 1 Aug 2025, funded by ISRO, ANRF.
2021 Oct – Present: Associate Scientist, Major Atmospheric Gamma Imaging Cherenkov (MAGIC)
Telescope.
2021 May – Present: Member, International Astronomical Union.
2020 Oct – Present: Life Member, Indian Physics Association.
2019 – Present: Life Member, Astronomical Society of India.
2014 – Present: IUCAA Associate, Inter University Centre for Astronomy and Astrophysics (IUCAA), Pune, India.
2011 – 2012: Full member, American Astronomical Society.
2006 – 2010: Junior member, American Astronomical Society.
Refereed Publications
36 refereed publications with an average citation of approximately 45 as of 2026 August
[from the SAO/NASA Astrophysics Data System (ADS)]. h-index 17.
Below, I list five recent notable publications. Please see my CV for the full list.
5. “Spectral Energy Distribution Modeling of BL Lacertae during a Large Submillimeter
Outburst and Low X-Ray Polarization State”, Ayon Mondal, Arijit Sar, Maitreya Kundu,
Ritaban Chatterjee, Pratik Majumdar 2025, ApJ, 978, 43.
4. “Location of a Sample of GeV and Optical Outbursts in the Jets of Blazars”, Kundu,
Maitreya; Bala, Arit; Barat, Saugata; Chatterjee, Ritaban 2025, MNRAS, 540, 1379.
3. “Multi-Year Characterisation of the Broad-Band Emission from the Intermittent Extreme
BL Lac 1ES 2344+514” Abe, H. (MAGIC Collaboration), et al. 2024, A&A, 682,
114.
3. “Moderate Correlation between the Accretion Disk and Jet Power in a Large Sample
of Fermi Blazars”, Rajguru, Garima and Chatterjee, Ritaban 2022, Phys. Rev. D 106,
063001.
1. “Rapid Quasi-Periodic Oscillations in the Relativistic Jet of the Blazar BL Lacertae”,
Jorstad, S. G.; Marscher, A. P.; Raiteri, C. M.; ..., Chatterjee, Ritaban 2022, Nature,
609, 265
Popular Level Publications:
8. An Article in Bengali on “Astronomy in Bengal: Past and Present”, Chatterjee, Ritaban 2nd
Year, Issue 2, Nabaparyay Shiksha Darpan (A half-yearly journal and official publication
of the Department of School Education and Higher Education, Government of West Bengal).
7. “An Article in Bengali on the Launch of Aditya-L1 Mission”, Chatterjee, Ritaban Kalantar
Patrika, 03 September, 2023.
6. “An article in Bengali on the Chandrayaan 3 Landing”, Chatterjee, Ritaban Kalantar Patrika,
26 August, 2023.
5. “An article in Bengali on five years of AstroSat”, Chatterjee, Ritaban Anandabazar Patrika,
2021 February 3 (https://www.anandabazar.com/science/india-first-space-lab-astrosat-turned-
6-years-old/cid/1264628)
4. “M. K. Das Gupta, The First Indian Radio Astronomer, and His Connection with the 2020 Physics
Nobel Prize”, Rai Choudhuri, Arnab & Chatterjee, Ritaban 2021, Science and Culture, Vol. 87,
No. 1-2, 6-13. arXiv: 2012.01001
3. “An article in Bengali on the 2020 Nobel prize in Physics”, Chatterjee, Ritaban Bengali Web
Magazine Bigyan, 2020 November 20 (https://bigyan.org.in/2020/11/20/blackhole-theoryand-
observation-nobel-2020/)
2. “An article in Bengali on the 2020 Nobel prize in Physics and its connection to the Indian radio
astronomer Mrinal Kumar Dasgupta”, Rai Choudhuri, Arnab & Chatterjee, Ritaban Anandabazar
Patrika online, 2020November 19 (https://www.anandabazar.com/science/discoveryof-
prof-mrinal-dasgupta-was-pillar-of-discovery-of-supermassive-black-holes-dgtls-1.1225652)
1. “An article in Bengali on the status of Indian higher education in the post-Covid world ”, Chatterjee,
Ritaban Porichoy Patrika, 2020 Sharod Sonkha (https://www.parichayapatrika.com/p/
blog-page.html?fbclid=IwAR1EusdB6ktpcM8crke4Jk2Dr5rCDTklJUTymLJr1gXSPB1hpnFd8L1zdkc)
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