I am an Associate Professor in the Department of Astronomy, Astrophysics and Space Engineering (DAASE) at Indian Institute of Technology, Indore. I have joined IIT Indore as an Assistant Professor in May 2018. I have been promoted to the position of Associate Professor in November 2022. I have received my Ph.D. (Apr, 2013) degree in physics (cosmology) from Indian Institute of Technology, Kharagpur, India, under the supervision of Prof. Somnath Bharadwaj and Prof. Sugata Pratik Khastgir. Before joining at IIT Indore, I was a Research Associate in the Astrophysics Group at Imperial College London, UK (Nov, 2015 - April, 2018). At Imperial, I have worked in the research group of Prof. Jonathan R. Pritchard. Before that, I was a Postdoctoral Fellow in the Department of Astronomy at Stockholm University (Dec, 2012 - Nov, 2015) and worked in the research group of Prof. Garrelt Mellema.
I am presently leading the Cosmology with Statistical Inference (CSI) research group at IIT Indore.
Cosmology is the study of the evolutionary history of our universe. I am specifically interested in studying the period when the first stars and galaxies were formed (Cosmic Dawn - CD) and then they gradually changed the phase of most of the visible matter in our universe from neutral to ionized (Epoch of Reionization - EoR). My research focuses on the possibility of using the existing (e.g. GMRT, LOFAR, MWA, PAPER etc) and the upcoming (Square Kilometre Array - SKA) radio telescopes, along with telescopes at other wavelengths (e.g. Euclid, Athena, WFIRST, JWST, ELT, TMT, SPHEREx, TIME, CONCERTO etc.) to learn about this mysterious mostly unexplored chapter in the history of our universe. These observations will open up a new window onto the early Universe and will give us much better insight about formation of the Large Scale Structures in our Universe.
I am a member of the “Epoch of Reionization and the Dark Ages” international science working group for the SKA. I am also a member of the “Epoch of Reionization” science working group for the LOFAR International Telescope and the “Square Kilometre Array - India” collaboration for the “Cosmic Dwan and the Epoch of Reionization”. I am a long term visitor in the Astrophysics Group at Imperial College London, UK and in the Astroparticle Physics Group at SISSA, Trieste, Italy. I am PI of several ongoing externally funded research projects.
One of the most important missing pictures in our cosmic history is the Cosmic Dawn (CD) and the Epoch of Reionization (EoR), the period during which the very first sources of light were formed. The radiation emitted by these sources gradually heated and “re”-ionized the neutral and cold hydrogen (HI) in their surrounding inter-galactic medium (IGM).
Many fundamental issues regarding this era, such as its timing, duration, and the properties of the sources driving it, are still unresolved. Observations of the redshifted 21-cm signal, emitted by the HI from this era, hold a great promise to resolve many of these puzzles. The observation of this signal effectively allows us to "time travel" and see the state of the IGM during this era as a time lapse movie.
Very recently, the EDGES might have detected the very first glimpse of this signal from Cosmic Dawn. Several other radio telescopes around the world are currently in a race to detect this signal in great detail (for example -- GMRT, LOFAR, MWA, PAPER, 21CMA). The upcoming enormous Square Kilometre Array (SKA), an international radio telescope of which India is also a major member, is expected to be able to image the HI distribution at different cosmic times from the beginning to the end of this era, owing to its great sensitivity. Apart from the 21-cm signal from the IGM, these first luminous sources are expected to be visible via different line emissions at different other wavelengths. The future experiments e.g. Euclid, Athena, Roman Space Telescope (WFIRST), JWST, ELT, TMT, SPHEREx, TIME, CONCERTO etc. are expected to map the sources of CD-EoR via these atomic and molecular line emissions.
It is expected that in a decade or so we will be witnessing a tsunami of observational data of the CD-EoR coming from these next-generation telescopes. Thus it would be crucial to develop effective and fast interpretation pipeline for these observations to answer the unresolved questions regarding this epoch. My research is focused towards building such optimal interpretation pipelines for the future observations of the CD-EoR.
Any interpretation pipeline is made up of several important segments, in the context of CD-EoR observations they are, realistic and fast simulations of the expected signal, modelling the response of the telescope, developing statistics for the signal detection and optimal parameter estimation from the detected signal. In the CSI research group we work on many of these aspects. Below you will find a non-exhaustive list of areas in which we are presently working.
Time evolution of the simulated 21-cm signal (left panel) along with the location of the first sources of lights (right panel). Animation credit: Samanvith A.
The left panel shows time evolution of the EoR 21-cm power spectrum (Mondal et al. 2017). The right panel shows the time evolution of the quadrupole moment of the powerspectrum under different reionization scenarios (Majumdar et al. 2015). Using this higher order multipole moment one can estimate the anisotropy in the signal.
Time evolution of the EoR 21-cm bispectrum for all unique triangle shapes in Fourier space (Majumdar et al. 2020).
Comparison between the simulated and ANN emulated EoR 21-cm bispectrum. Image credit: Himanshu Tiwari.
Schematic diagram to demonstrate the issue of interlopers in an synergistic imaging survey to detect galaxies inside an already detected ionized region from SKA observations. A followup photometric survey becomes less risky when aimed at an SKA detected ionized bubble at higher redshifts (Zackrisson et al. 2020).
We are always looking for highly motivated and enthusiastic PhD and Master's students to join the group. Please check our PhD advertisement here -- https://academic.iiti.ac.in/phdadvt.php. Deadline to apply is 15 May 2023. If you are interested in joining the group please contact me with your CV via email at suman.majumdar at iiti.ac.in.
PhD Students:
Leon Noble (July 2022 - Ongoing)
Research Area: Developing statistical inference pipeline for multi-wavelength observations of the Universe
Chandra Shekhar Murmu (July 2019 - Ongoing)
Research Area: Studying the early Universe through cross-correlations of multi-wavelength observations
Publications:
Mohd Kamran (July 2018 - Nov 2022)
Postdoc at Uppsala University, Sweden.
Research Area: Quantifying the non-Gaussianity in the 21-cm signal from the Cosmic Dawn
Publications:
Master's Project Students:
Priyatam Kumar Mahto (July 2022 - July 2023)
Co-supervisor: Dr. Erik Zackrisson, Uppsala University, Sweden.
M.Sc. Astronomy (2023).
PhD student (since April 2024) at the Department of Astronomy, University of Chile, Santiago, Chile.
Research Area: Searching for extra-terrestrial intelligence through multi-wavelength observations.
Publications:
Vednarayan Iyer (July 2022 - ongoing)
M.Sc. Astronomy (2023).
Will join as a PhD student (starting in October 2023) in the University of Alabama, USA.
Research Area: Building an accurate semi-numerical simulation for the Cosmic Dawn 21-cm signal.
Saswata Dasgupta (July 2021 - ongoing)
MS (Research) in Space Science and Engineering (2023).
PhD student (since October 2023) in the Institute of Astronomy, Cambridge University, UK.
Research Area: Analysis of the 21-cm images from the Cosmic Dawn.
Publications:
Sohini Dutta (July 2021 - July 2022)
M.Sc. Astronomy (2022).
PhD student (since October 2023) at Manchester University., UK.
Former Data Scientist at American Express.
Selected for PhD positions at Swinburne University, University of Heidelberg, Cambridge University and Manchester University.
Research Area: Constraining reionization parameters using 21-cm and CII cross-power spectrum.
Conference Presentations:
Kunal Motghare (July 2021 - July 2022)
M.Sc. Astronomy (2022).
Research Area: Understanding the 21-cm marked power spectrum from the post-reionization era.
Aadarsh Pathak (August 2020 - July 2021)
M.Sc. Astronomy (2021).
PhD student at the University of Melbourne, Australia.
Research Area: Exploring the topology of the hydrogen distribution in the early universe.
Publications:
Anchal Saxena (July 2019 - July 2020)
M.Sc. Astronomy (2020).
Recepient of the Insititute Medal for the Best M.Sc. Project of 2020 (among all M.Sc. students accross all disciplines).
PhD student at the University of Groningen, the Netherlands.
Research Area: Impact of dark matter models on the EoR 21-cm signal.
Publications:
Himanshu Tiwari (July 2019 - July 2020)
M.Sc. Astronomy (2020).
PhD student at Curtin University, Australia.
Research Area: Developing Artificial Neural Network based Bayesian inference tools for the future observations of the Cosmic Dawn and the Epoch of Reionization.
Toolbox developed:
Samanvith A (July 2019 - July 2020)
M.Sc. Astronomy (2020).
Research Area: Visualizations of the Epoch of Reionization.
Following are the externally funded research grants awarded to the group:
Most of my publications can be found in the following arXiv link:
https://arxiv.org/a/majumdar_s_1.html. Our first SETI paper based on the MSc project of Priyatam Kumar has been published in MNRAS.
It has received sigficant media attention as well -- The Print; physics.org; NBC News; Sabine Hossenfelder; Deccan Herald;
New Scientist;
earthsky.org;
Business Today.
We had organized a course on Numerical Radiative Transfer (15-24 January 2024) at IIT Indore. Instructor of the course was Prof. Ilian T. Iliev, University of Sussex, UK.
We are looking for highly motivated and skilled PhD and Master's students to join the group. Please check our PhD advertisement here -- https://academic.iiti.ac.in/phdadvt.php. Deadline to apply is 15 May 2023. If you are interested in joining the group please contact me with your CV via email at suman.majumdar at iiti.ac.in.
We had organized a course on Numerical Astrophysical Gasdynamics (13-18 February 2023) at IIT Indore. Instructor of the course was Prof. Garrelt Mellema, Stockholm University, Sweden.
We had organized a course on Searching for Extraterrestrial Intelligence (9-15 September 2022) at IIT Indore. Instructor of the course was Dr. Erik Zackrisson from Uppsala University, Sweden.
We had organized a four day long (14-17 March 2022) international meeting on the cosmic 21 cm signal from the Dark Ages to the present day over zoom under the framework of SAZERAC. Please check the meeting website for details - SAZERAC 21cm 2022.
We had organized an one day international meeting on the 21 cm signal from Cosmic Dawn and Epoch of Reionization over zoom under the framework of SAZERAC. Please check the meeting website for details - http://sazerac-conference.org/SIPS2021/3.html.
We had organized an international conference and school in DAASE, IIT Indore on "Observing The First Billion Years of the Universe Using Next-Generation Telescopes" during 20-31 January 2020. For further details, please check the conference webpage.
2024 Spring semester:
AA 101: Introduction to Space Engineering
- shared with Dr. Siddharth S. Malu, Prof. Abhirup Datta, Dr. Saurabh Das, Dr. Unmesh Khati and Dr. Bhargav Vaidya.
AA 608: Astrostatistics
- shared with Dr. Siddharth S. Malu.
AA 609: Computational Methods in Astronomy and Space Sciences
- shared with Dr. Bhargav Vaidya and Prof. Ilian T. Iliev (University of Sussex, UK).
2023 Autumn semester:
AA 471/671: Relativity and Cosmology
- shared with Dr. Siddharth S. Malu
AA 411/611: Advanced Optics
- shared with Dr. Manoneeta Chakraborty and Prof. Abhirup Datta
2023 Spring semester:
AA 608: Astrostatistics
- shared with Dr. Abhirup Datta
AA 609: Computational Methods in Astronomy and Space Sciences
- shared with Dr. Bhargav Vaidya
2022 Autumn semester:
AA 471/671: Relativity and Cosmology
- shared with Dr. Manoneeta Chakraborty
AA 651: M.Sc. Astronomy Lab - I
-shared with Dr. Amit Shukla
2022 Spring semester:
AA 608: Astrostatistics
- shared with Dr. Saurabh Das and Dr. Abhirup Datta
AA 609: Computational Methods in Astronomy and Space Sciences
- shared with Dr. Bhargav Vaidya
2021 Autumn semester:
AA 471/671: Relativity and Cosmology
- shared with Dr. Siddharth S. Malu and Dr. Manoneeta Chakraborty
AA 651: M.Sc. Astronomy Lab - I
-shared with Dr. Anjali Rao
2021 Spring semester:
AA 608: Astrostatistics
- shared with Dr. Siddharth S. Malu and Dr. Saurabh Das
2020 Autumn semester:
AA 471/671: Relativity and Cosmology
- shared with Dr. Siddharth S. Malu
AA 301: High Energy Astronomy or Astrophysical Processes.
-shared with Dr. Siddharth S. Malu
2020 Spring semester:
AA 608: Astrostatistics
- shared with Dr. Amit Shukla
AA 698: M.Sc. Astronomy Seminar Course
2019 Autumn semester:
AA 471/671: Relativity and Cosmology
- shared with Dr. Siddharth S. Malu
AA 301: High Energy Astronomy or Astrophysical Processes.
-shared with Dr. Saurabh Das
2019 Spring semester:
AA 608: Astrostatistics
- shared with Dr. Saurabh Das and Dr. Manoneeta Chakraborty
AA 602: Advanced Topics in Astronomy and Astrophysics (Section: Large Scale Structures of the Universe)
- shared with Dr. Bhargav Vaidya.
AA 652: Astronomy Laboratory-II (Section: Optics)
- shared with Dr. Abhirup Datta and Dr. Manoneeta Chakraborty.
2018 Autumn semester:
AA 301: High Energy Astronomy or Astrophysical Processes.
AA 651: Astronomy Laboratory-I (Section: Basics of Numerical Methods in Astrophysics and Cosmology)
- shared with Dr. Abhirup Datta, Dr. Bhargav Vaidya, Dr. Manoneeta Chakraborty and Dr. Saurabh Das.