pdutta.phy's picture
Dr. Prasun Dutta
Assistant Professor
Department of Physics, IIT (BHU), Varanasi
pdutta.phy@iitbhu.ac.in
9405167286
Area of Interest: 
Astronomy and Astrophysics

Research Interests

Astrophysics :
  • Structures and Dynamics of the Interstellar Medium
  • Large-scale gas  fragmentation and star formation in galaxies
  • Gravitational Lensing as an Astrophysical Probe

Observational Techniques:
  •  Radio Interferometric techniques
  • Challenges in observations of  HI 21-cm signal from the  Epoch of Reionization

Others:
  • Steiner Trees and Soap Films
  • Sandpile Problems

Publications  [ Google Scholar Link ]

Academic History
 

Affiliation Institution Duration
Assistant Professor Indian Institute of Technology, (BHU), Varanasi 2015-Present
DST-INSPIRE Faculty Fellow Indian Institute of Science Education and Research, Bhopal 2013-2015
Visiting Fellow [ Post Doc] National Centre for Radio Astrophysics, TIFR, Pune 2010-2013
Doctor of Philosophy Indian Institute of Technology, Kharagpur 2005-2010
Master of Science in Physics Indian Institute of Technology, Kharagpur 2003-2005
Bachelor of Science with Honours in Physics Barasat Govt. College, University of Calcutta 2000-2003

 

“The main objective of teaching is not to give explanations, but to knock at the doors of the mind,”  

R. N. Tagore.

IIT (BHU), Varanasi

  • 2019-20: Spring Semester

          PHY-101: Classical Quantum and Relativistic Physics
          PHY-502: Advanced Classical Mechanics and Electrodynamics
          PYM-401: Advanced Classical Mechanics

  • 2018-19: Autumn Semester

          PHY-504: Advanced Mathematical and Computational Physics
          PHY-311: Introduction to Astronomy and Astrophysics

  • 2018-2019: Autumn Semester
  • 2017-2018: Spring Semester
  • 2016-2017: Autumn Semester
PHY-401: Nuclear and Particle Physics
PHY-502: Advanced Classical Mechanics and Electrodynamics
AP-5105: Fluids and Plasmas
PHY-101: Mechanics Lab
  • 2016-2017: Spring Semester
EP-201:Instrumentation, Measurement and Analysis 
PHY-304: Computational Physics
PHY-311: Introduction to Astronomy and Astrophysics

AP-7102: Mathematical Physics
PHY-101: Mechanics Lab
  • 2015-2016: Autumn Semester
PHY-101: Classical, Quantum and Relativistic Physics
  • 2015-2016: Spring Semester
PHY-302: Relativistic Electrodynamics
AP-7102: Mathematical Physics
PHY-101: Mechanics Lab

 
IISER, BHOPAL
  • 2015-2016: Autumn Semester
ED-401: Electrodynamics and Special Relativity
Physics Lab: 2nd Year
 
  • 2014-2015: Spring Semester
AA-503: Introduction to Astronomy and Astrophysics
Physics Lab: 1st Year
 
  • 2013-2014: Autumn Semester
ED-401: Electrodynamics and Special Relativity
Physics Lab: 2nd Year
 
  • 2012-2013: Spring Semester
Nuclear Physics Lab
 

Collaborators:

  • Prof. Somnath Bharadwaj, IIT Kharagpur
  • Prof. Jayaram N. Chengalur, NCRA-TIFR, Pune
  • Prof. Sugata P. Khastgir, IIT Kharagpur
  • Dr. Ayesha Begum
  • Dr. Nirupam Roy, IISC, Bangalore
  • Dr. Abhirup Datta, IIT Indore
  • Dr. Samir Chowdhuri, NCRA-TIFR

Ph. D. Students

  • Pavan Viswakarma
  • Jais Kumar
  • Meera Nandakumar
  • Urvashi

Undergraduate Students

  • Rajat Raj
  • Pranav Pravin

Past Students

  • Nandini Sahu
  • Vivek Gupta
  • Abhishek Raj
  • Gaurav Tomar
  • Shyam H. Menon
  • Soumyadeep Das
  • Archisha A. Patki

 

Publications  [ Google Scholar Link ]
  • Physical Properties of the Interstellar medium of Galaxies
Graduate Students: Pavan Viswakarma, Meera Nandakumar     
Undergraduate Students: Shyam H Menon, Archisha A Patki

Turbulence at Large Scales

  1. Our investigation of HI column density fluctuation from external spiral galaxies revealed hitherto unknown large-scale coherent structures. Most possible reason for the creation of these structures may be turbulence, at present we are investigating the generating physical processes. We use an estimator of the column density power spectrum that evaluates it directly from  the observed visibilities by the radio interferometers.
  2. In order to understand the energetics of the large-scale structures seen in the external galaxies, we have proposed a visibility based estimator of the HI velocity fluctuation. At present this estimator is being used to capture the interesting dynamics in the ISM of spiral galaxies. 
Turbulence at Small Scales
  1. The dissipation scale of the ISM turbulence is debated and observational evidence is feeble. We have observed the power spectrum of HI opacity fluctuation along a couple of lines of sight in our Galaxy and have inferred on the existence and characteristics of such structures at sub-parsec length scales. At present we are launching a survey of such HI structures by observing them in absorption in the direction of several supernovae remnants in the Galaxy.
  2. We observed scale invarient structures at scales of a few tens of astronomical units along the line of sight of 3C138  in our galaxy. Such scale structures, though are not yet known to be common, but still requires interesting new physics to explain.
Fragmentation and Star formation
  1. Turbulence-induced fragmentation isolates the HI clouds at large scales and helps them to start the gravitational collapse. Given the observed  turbulence, we expect this to play a significant role in cascading the galactic rotational energy to small scales may eventually triggering an evolution from spiral to elliptical. We are using numerical hydrodynamic simulation to investigate the efficacy of turbulent cascade in energy transfer across scales in the galaxies.
  2. Turbulent pressure may play an important role in the thermodynamics of the multiphase ISM. We are involved in a project to investigate the effect of turbulence driven random motion in the thermal balance and hence  stability  of different phases in the ISM.
  • Observational aspects of  radio astronomy
Graduate Students: Jais Kumar, Meera Nandakumar     
Undergraduate Students: Soumyadeep Das
  1. Radio interferometers observe the visibility function, approximately the spatial Fourier transform of the sky brightness distribution. Several statistical estimators are used to infer the properties of the sky from the observed visibilities. We are involved in investigating the efficacy of these estimators and benchmark, prefer or reject them based on results from simulated observations of the model sky. We also are involved in developing statistically viable unbiased and low-risk estimators of one and two-point statistics of the sky brightness distribution from the interferometric observations.
  2. Calibration and high dynamic range observation using radio interferometeris challenging. On top of this, existence of Foregrounds for the Epoch of Reionization observations provides the immense challenge for future experiments in these lines. We are at present in process of accessing the calibration requirements for the planned  intensity mapping experiments with the Square Kilometer Array (SKA) and other instruments. With the normal calibration, polarization leakage from the cross dipoles are expected to affect the intensity mapping experiments, we are investigating the instrumental requirements and improved strategies for polarization calibration.
  • Tools for Gravitational Lensing with Radio Interferometers
Graduate Student: Urvashi
Undergraduate Student: Rajat Raj 
  1. With future telescopes like SKA, it will be possible to observe lensed radio images of high redshift galaxies. Such observations would let us have spatially resolve observations of galaxies at high redshifts and investigate the spatial structure of the ISM therein. We are involved in generating observational tools and providing theoretical prediction for such observations. 

Astronomical Software Developments 

*Repository will be available soon
 

Software Objectives Options 
GalSim Simulates Galaxy Models for Given Density and Velocity structures

[Language: C]

  • Options for different HI density and velocity profile
  • Option for different velocity dispersion model
  • Options for channel resolution, inclination angles etc
VISFITS Simulated observation in radio interferometry

[Language: C]

  • Point Source/Diffuse Emission sky model options
  • Options for different telescopes
  • Options for antenna gain errors, (*leakage)
FitsPack Several operations on image and visibility FITS files

[Language: C, Python]

  • Window function estimator
  • Visibility moment estomators
  • Power spectrum estimators of density and velocity
  • Conversation from image to visibility and vise versa
  • Unbias grinding of visibilities
  • Visualization of data
  • and many more
ITGE Image Based Tapered Gridded Estimator of Power Spectrum

[Language: C]

  • Option for different maskign functions
  • Option for MPI based parallalization
HourGlass Gravitational Lensing Simulator

[Language: C, Python]

  • Option for lens model input as FITS file
  • Option for ray shooting
  • Option for caustics calcultions
  • Options for several different preset potential and source models