Bio


In order to cope up with the large photon flux at the focal plane of the next generation large area telescopes (e.g. X-ray mission concepts like Lynx), the focal plane detectors need to be extremely fast (order of magnitude faster compared to the Chandra CCDs) and low noise to avail <1 keV measurements along with small pixel sizes in order to fully utilize the high angular resolution of the next generation X-ray mirrors. One approach towards achieving these goals is to use active pixel sensors. As part of the collaboration between the Penn State University and the Teledyne Imaging Sensors to develop Silicon based X-ray Hybrid CMOS detectors (an active pixel sensor), I was involved in characterizing these X- ray HCDs with Cryogenic SIDECAR ASICs. The other approach is to build upon the success of Chandra by developing faster and low noise X-ray CCDs and readout electronics. As a part of the collaboration between the Stanford University, MIT and MIT Lincoln Laboratory, I have been working on the development of fast low noise readout electronics and characterization of these new generation X-ray CCDs. While the X-ray CCDs are based on traditional source follower voltage readout, a potential solution to this could be by utilizing current readout from these detectors (like in DEPFETs) which can be fast along with extremely low noise yield. I am currently working on one such novel technology called SiSeRO or Single electron sensitive readout manufactured by MITLL. Moreover, SiSeROs are supposed to provide sub-electron read noise by utilizing repetitive non-destructive readout (RNDR) of the charge packets. We are currently working on the readout circuitry to enable this feature and developing a suitable set up to test these aspects. If successful, it might also be possible to develop a matrix of these current readout amplifiers to develop an active pixel sensor.

I am interested in the hard X-ray polarimetric studies of X-ray sources. With the advent of hard X-ray mirrors (e.g. NuSTAR), it is now possible to conceive hard X-ray polarimeters at the focal plane of hard X-ray telescopes. I have been working on the performance study and development of one such instrument which consisted of a central plastic scatterer (viewed by a PMT) surrounded by an array of CsI(Tl) scintillators (read out by Si photo-multipliers). We are also exploring the possibility of replacing the plastic scatterer by a fast Silicon imager (a fast X-ray CCD / SiSeRO matrix / X-ray HCD) to enable simultaneous X-ray spectroscopy, imaging, timing and polarimetry.

I am involved in the X-ray spectro-polarimetric studies with CdZnTe Imager (CZTI) onboard Indian astronomy mission – AstroSat for various bright X-ray sources. We verified polarimetric capabilities of CZTI by measuring polarization of Crab pulsar and nebula. Currently, I am leading the spectro-polarimetry studies of Gamma-ray Bursts and the high mass black hole X-ray binary, Cygnus X-1 using AstroSat-CZTI data.

Academic Appointments


  • Phys Sci Res Assoc, Kavli Institute for Particle Astrophysics and Cosmology

Administrative Appointments


  • Staff Scientist, Stanford University (2021 - Present)
  • Postdoctoral Scholar, Stanford University (2019 - 2021)
  • Postdoctoral Scholar, Pennsylvania State University (2016 - 2019)
  • Postdoctoral Scholar, Physical Research Laboratory (2016 - 2016)

Honors & Awards


  • Justice Oak Award, Astronomical Society of India (2018)

Boards, Advisory Committees, Professional Organizations


  • Full Member, AAS (2022 - Present)

Professional Education


  • PhD, Physical Research Laboratory, Astrophysics (2016)
  • M.Sc., BHU (India), Physics (2010)
  • B.Sc., Burdwan University (India), Physics (2008)

Current Research and Scholarly Interests


1. X-ray astronomical instrumentation - Scintillators, Si-Photomultipliers, CZTs, X-ray CCDs, X-ray Hybrid CMOS detectors, SiSeRO (Single electron Sensitive Read Out) devices
2. Hard X-ray polarimetry and associated instrumentation
3. Polarimetric studies of pulsars, black hole XRBs, Gamma Ray Bursts using AstroSat-CZTI
4. X-ray lobster optic (Schmidt type)

All Publications


  • Extending the energy range of AstroSat-CZTI up to 380 keV with compton spectroscopy MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Kumar, A., Chattopadhyay, T., Vadawale, S. V., Rao, A. R., Mithun, N. S., Bhalerao, V., Bhattacharya, D. 2022; 516 (2): 3102-3112
  • Hard X-Ray Polarization Catalog for a Five-year Sample of Gamma-Ray Bursts Using AstroSat CZT Imager ASTROPHYSICAL JOURNAL Chattopadhyay, T., Gupta, S., Iyyani, S., Saraogi, D., Sharma, V., Tsvetkova, A., Ratheesh, A., Gupta, R., Mithun, N. S., Vaishnava, C. S., Prasad, V., Aarthy, E., Kumar, A., Rao, A. R., Vadawale, S., Bhalerao, V., Bhattacharya, D., Vibhute, A., Frederiks, D. 2022; 936 (1)
  • Experimental verification of off-axis polarimetry with cadmium zinc telluride detectors of AstroSat-CZT Imager JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS Vaishnava, C. S., Mithun, N. S., Vadawale, S. V., Aarthy, E., Patel, A. R., Adalja, H. L., Tiwari, N., Ladiya, T., Navale, N., Chattopadhyay, T., Rao, A. R., Bhalerao, V., Bhattacharya, D. 2022; 8 (3)
  • Probing into emission mechanisms of GRB 190530A using time-resolved spectra and polarization studies: synchrotron origin? MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Gupta, R., Gupta, S., Chattopadhyay, T., Lipunov, Castro-Tirado, A. J., Bhattacharya, D., Pandey, S. B., Oates, S. R., Kumar, A., Hu, Y., Valeev, A. F., Minaev, P., Kumar, H., Vinko, J., Dimple, D., Sharma, Aryan, A., Castellon, A., Gabovich, A., Moskvitin, A., Ordasi, A., Pal, A., Pozanenko, A., Zhang, B., Kumar, B., Svinkin, D., Saraogi, D., Vlasenko, D., Fernandez-Garcia, E., Gorbovskoy, E., Anupama, G. C., Misra, K., Sarneczky, K., Kriskovics, L., Castro-Tirado, M. A., Caballero-Garcia, M. D., Tiurina, N., Balanutsa, P., Lopez, R. R., Sanchez-Ramirez, R., Szakats, R., Belkin, S., Guziy, S., Iyyani, S., Tiwari, S. N., Vadawale, S. V., Sun, T., Bhalerao, Kornilov, Sokolov, V. V. 2022; 511 (2): 1694-1713
  • X-ray speed reading with the MCRC: a low noise CCD readout ASIC enabling readout speeds of 5 Mpixel/s/channel Orel, P., Herrmann, S., Chattopadhyay, T., Morris, G., Allen, S. W., Prigozhin, G. Y., Foster, R., Malonis, A., Bautz, M. W., Cooper, M. J., Donlon, K., Holland, A. D., Beletic, J. SPIE-INT SOC OPTICAL ENGINEERING. 2022

    View details for DOI 10.1117/12.2629049

    View details for Web of Science ID 000860926800057

  • Development and characterization of a fast and low noise readout for the next generation x-ray charge-coupled devices Journal of Astronomical Telescopes, Instruments, and Systems Chattopadhyay, T., et al 2022; 8 (2): 12
  • First results on SiSeRO devices: a new x-ray detector for scientific instrumentation Journal of Astronomical Telescopes, Instruments, and Systems Chattopadhyay, T., et al 2022; 8 (2): 12
  • Sub-MeV spectroscopy with AstroSat-CZT imager for gamma ray bursts JOURNAL OF ASTROPHYSICS AND ASTRONOMY Chattopadhyay, T., Gupta, S., Sharma, V., Iyyani, S., Ratheesh, A., Mithun, N. S., Aarthy, E., Palit, S., Kumar, A., Vadawale, S. V., Rao, A. R., Bhalerao, V., Bhattacharya, D. 2021; 42 (2)
  • The AstroSat mass model: Imaging and flux studies of off-axis sources with CZTI JOURNAL OF ASTROPHYSICS AND ASTRONOMY Mate, S., Chattopadhyay, T., Bhalerao, V., Aarthy, E., Balasubramanian, A., Bhattacharya, D., Gupta, S., Kutty, K., Mithun, N. S., Palit, S., Rao, A. R., Saraogi, D., Vadawale, S., Vibhute, A. 2021; 42 (2)
  • Hard X-ray polarimetry-an overview of the method, science drivers, and recent findings JOURNAL OF ASTROPHYSICS AND ASTRONOMY Chattopadhyay, T. 2021; 42 (2)
  • Exploring sub-MeV sensitivity of AstroSat-CZTI for ON-axis bright sources JOURNAL OF ASTROPHYSICS AND ASTRONOMY Kumar, A., Chattopadhyay, T., Vadawale, S. V., Rao, A. R., Gupta, S., Mithun, N. S., Bhalerao, V., Bhattacharya, D. 2021; 42 (2)
  • Identifying charged particle background events in X-ray imaging detectors with novel machine learning algorithms Wilkins, D. R., Allen, S. W., Miller, E. D., Bautz, M., Chattopadhyay, T., Fort, S., Grant, C. E., Herrmann, S., Kraft, R., Morris, R. G., Nulsen, P., DenHerder, J. W., Nikzad, S., Nakazawa, K. SPIE-INT SOC OPTICAL ENGINEERING. 2021

    View details for DOI 10.1117/12.2562354

    View details for Web of Science ID 000674737700039

  • Progress toward fast, low-noise, low-power digital CCDs for Lynx and other high-energy astrophysics missions Bautz, M., Burke, B., Cooper, M., Craig, D., Donlon, K., Foster, R., Grant, C. E., LaMarr, B., Leitz, C., Malonis, A., Miller, E., Prigozhin, G., Thayer, C., Allen, S., Herrmann, S., Chattopadhyay, T., Morris, R. G., DenHerder, J. W., Nikzad, S., Nakazawa, K. SPIE-INT SOC OPTICAL ENGINEERING. 2021

    View details for DOI 10.1117/12.2561441

    View details for Web of Science ID 000674737700134

  • Spectropolarimetric analysis of prompt emission of GRB 160325A: jet with evolving environment of internal shocks MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Sharma, V., Iyyani, S., Bhattacharya, D., Chattopadhyay, T., Vadawale, S. V., Bhalerao, V. B. 2020; 493 (4): 5218–32
  • Tiny-box: a tool for the versatile development and characterization of low noise fast x-ray imaging detectors X-Ray, Optical, and Infrared Detectors for Astronomy Chattopadhyay, T., Herrmann, S., Allen, S., Hirschman, J., Morris, G., Bautz, M., Malonis, A., Foster, R., Prigozhin, G., Craig, D., Burke, B. 2020

    View details for DOI 10.1117/12.2561826

  • MCRC V1: development of integrated readout electronics for next generation X-ray CCD detectors for future satellite observatories X-Ray, Optical, and Infrared Detectors for Astronomy Herrmann, S., Wong, J., Chattopadhyay, T., Morris, R. G., Burke, B., Prigozhin, G., Cooper, M., Craig, D., Donlon, K., Foster, R., Malonis, A., Bautz, M., Allen, S. 2020

    View details for DOI 10.1117/12.2561741

  • Water Recovery X-Ray Rocket grating spectrometer JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS Miles, D. M., Hull, S., Schultz, T. B., Tutt, J., Wages, M., Donovan, B., Mcentaffer, R. L., Falcone, A. D., Anderson, T., Bray, E., Burrows, D. N., Chattopadhyay, T., Eichfeld, C. M., Empson, N., Grise, F., Hillman, C. R., McCoy, J. A., McQuaide, M., Myers, B. J., Steiner, T., Verschuuren, M. A., Yastishock, D., Zhang, N. 2019; 5 (4)
  • Time-varying Polarized Gamma-Rays from GRB 160821A: Evidence for Ordered Magnetic Fields ASTROPHYSICAL JOURNAL LETTERS Sharma, V., Iyyani, S., Bhattacharya, D., Chattopadhyay, T., Rao, A. R., Aarthy, E., Vadawale, S. V., Mithun, N. S., Bhalerao, V. B., Ryde, F., Pe'er, A. 2019; 882 (1)
  • AstroSat-CZTI Detection of Variable Prompt Emission Polarization in GRB 171010A ASTROPHYSICAL JOURNAL Chand, V., Chattopadhyay, T., Oganesyan, G., Rao, A. R., Vadawale, S. V., Bhattacharya, D., Bhalerao, V. B., Misra, K. 2019; 874 (1)
  • Prompt emission polarimetry of Gamma ray bursts with ASTROSAT CZT-imager The Astrophysical Journal Chattopadhyay, T., et al 2019; 884 (2)

    View details for DOI 10.3847/1538-4357/ab40b7

  • Flight Camera Package Design, Calibration, and Performance for the Water Recovery X-ray Rocket Mission Wages, M., Hull, S. V., Falcone, A. D., Anderson, T. B., McQuaide, M., Bray, E., Chattopadhyay, T., Burrows, D. N., Buntic, L., McEntaffer, R. L., Miles, D. M., Tutt, J. H., Schultz, T. B., Donovan, B. D., Hillman, C. R., Yastishock, D., Siegmund, O. H. SPIE-INT SOC OPTICAL ENGINEERING. 2019

    View details for DOI 10.1117/12.2529361

    View details for Web of Science ID 000511172300008

  • US Contributions to the Athena Wide Field Imager Burrows, D. N., Allen, S., Bautz, M., Bulbul, E., Chattopadhyay, T., Erdley, J., Falcone, A. D., Grant, C. E., Herrmann, S., Hornschemeier, A., Kelly, D., Kennea, J., Kraft, R., LaMarr, B., Mantz, A., Miller, E. D., Morrisb, R., Nulsen, P., Pradhan, P., Vulice, N., Wilkins, D., Zugger, M. E., Siegmund, O. H. SPIE-INT SOC OPTICAL ENGINEERING. 2019

    View details for DOI 10.1117/12.2528532

    View details for Web of Science ID 000511172300026

  • Development of position sensitive detector module using scintillator and Si photomultiplier for hard x-ray imaging and spectroscopy JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS Goyal, S. K., Naik, A. P., Mithun, N. S., Vadawale, S. V., Nagrani, N., Madhvi, S., Tiwari, N. K., Ladiya, T., Patel, A. R., Adalja, H. K., Chattopadhyay, T., Shanmugam, M., Auknoor, A., Sharma, P., Patel, V. R. 2019; 5 (1)
  • Violation of Synchrotron Line of Death by the Highly Polarized GRB 160802A ASTROPHYSICAL JOURNAL Chand, V., Chattopadhyay, T., Iyyani, S., Basak, R., Aarthy, E., Rao, A. R., Vadawale, S. V., Bhattacharya, D., Bhalerao, V. B. 2018; 862 (2)
  • Characterizing subpixel spatial resolution of a hybrid CMOS detector JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS Bray, E., Falcone, A., Wages, M., Chattopadhyay, T., Burrows, D. N. 2018; 4 (3)
  • BlackCAT CubeSat: A Soft X-ray Sky Monitor, Transient Finder, and Burst Detector for High-energy and Multimessenger Astrophysics Chattopadhyay, T., Falcone, A. D., Burrows, D. N., Fox, D. B., Palmer, D., DenHerder, J. W., Nikzad, S., Nakazawa, K. SPIE-INT SOC OPTICAL ENGINEERING. 2018

    View details for DOI 10.1117/12.2314274

    View details for Web of Science ID 000452819200139

  • Phase-resolved X-ray polarimetry of the Crab pulsar with the AstroSat CZT Imager NATURE ASTRONOMY Vadawale, S. V., Chattopadhyay, T., Mithun, N. S., Rao, A. R., Bhattacharya, D., Vibhute, A., Bhalerao, V. B., Dewangan, G. C., Misra, R., Paul, B., Basu, A., Joshi, B. C., Sreekumar, S., Samuel, E., Priya, P., Vinod, P., Seetha, S. 2018; 2 (1): 50–55
  • Surprise in simplicity: an unusual spectral evolution of a single pulse GRB 151006A MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Basak, R., Iyyani, S., Chand, V., Chattopadhyay, T., Bhattacharya, D., Rao, A. R., Vadawale, S. V. 2017; 472 (1): 891–903
  • Recent X-ray hybrid CMOS detector developments and measurements Hull, S. V., Falcone, A. D., Burrows, D. N., Wages, M., Chattopadhyay, T., McQuaide, M., Bray, E., Kern, M., Siegmund, O. H. SPIE-INT SOC OPTICAL ENGINEERING. 2017

    View details for DOI 10.1117/12.2273903

    View details for Web of Science ID 000417112900003

  • Design & development of position sensitive detector for hard X-ray using SiPM and new generation scintillators Goyal, S. K., Naik, A. P., Mithun, N. S., Vadawale, S. V., Tiwari, N. K., Chattopadhyay, T., Nagrani, N., Madhavi, S., Ladiya, T., Patel, A. R., Shanmugam, M., Adalja, H. L., Patel, V. R., Ubale, G. P., Burger, A., James, R. B., Fiederle, M., Franks, L., Payne, S. A. SPIE-INT SOC OPTICAL ENGINEERING. 2017

    View details for DOI 10.1117/12.2275316

    View details for Web of Science ID 000425518900003

  • An introduction to the water recovery x-ray rocket Miles, D. M., McEntaffer, R. L., Schultz, T. B., Donovan, B. D., Tutt, J., Yastishock, D., Steiner, T., Hillman, C. R., McCoy, J. A., Wages, M., Hull, S., Falcone, A., Burrows, D. N., Chattopadhyay, T., Anderson, T., McQuaide, M., Siegmund, O. H. SPIE-INT SOC OPTICAL ENGINEERING. 2017

    View details for DOI 10.1117/12.2274249

    View details for Web of Science ID 000417112900020

  • ASTROSAT CZT IMAGER OBSERVATIONS OF GRB 151006A: TIMING, SPECTROSCOPY, AND POLARIZATION STUDY ASTROPHYSICAL JOURNAL Rao, A. R., Chand, V., Hingar, M. K., Iyyani, S., Khanna, R., Kutty, A. K., Malkar, J. P., Paul, D., Bhalerao, V. B., Bhattacharya, D., Dewangan, G. C., Pawar, P., Vibhute, A. M., Chattopadhyay, T., Mithun, N. S., Vadawale, S. V., Vagshette, N., Basak, R., Pradeep, P., Samuel, E., Sreekumar, S., Vinod, P., Navalgund, K. H., Pandiyan, R., Sarma, K. S., Seetha, S., Subbarao, K. 2016; 833 (1)
  • Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers EXPERIMENTAL ASTRONOMY Chattopadhyay, T., Vadawale, S. V., Goyal, S. K., Mithun, N. S., Patel, A. R., Shukla, R., Ladiya, T., Shanmugam, M., Patel, V. R., Ubale, G. P. 2016; 41 (1-2): 197–214
  • In-orbit performance of AstroSat CZTI Vadawale, S. V., Rao, A. R., Bhattacharya, D., Bhalerao, V. B., Dewangan, G., Vibhute, A. M., Mithun, N. S., Chattopadhyay, T., Sreekumar, S., DenHerder, J. W., Takahashi, T., Bautz, M. SPIE-INT SOC OPTICAL ENGINEERING. 2016

    View details for DOI 10.1117/12.2235373

    View details for Web of Science ID 000387731500038

  • Line profile modelling for multi-pixel CZT detectors Chattopadhyay, T., Vadawale, S. V., Rao, A. R., Bhattacharya, D., Mithun, N. S., Bhalerao, V., DenHerder, J. W., Takahashi, T., Bautz, M. SPIE-INT SOC OPTICAL ENGINEERING. 2016

    View details for DOI 10.1117/12.2234805

    View details for Web of Science ID 000387731500128

  • Hard X-ray polarimetry with Astrosat-CZTI ASTRONOMY & ASTROPHYSICS Vadawale, S. V., Chattopadhyay, T., Rao, A. R., Bhattacharya, D., Bhalerao, V. B., Vagshette, N., Pawar, P., Sreekumar, S. 2015; 578
  • Prospects of hard X-ray polarimetry with Astrosat-CZTI EXPERIMENTAL ASTRONOMY Chattopadhyay, T., Vadawale, S. V., Rao, A. R., Sreekumar, S., Bhattacharya, D. 2014; 37 (3): 555–77
  • MEASUREMENT OF LOW ENERGY DETECTION EFFICIENCY OF A PLASTIC SCINTILLATOR: IMPLICATIONS ON THE LOWER ENERGY LIMIT AND SENSITIVITY OF A HARD X-RAY FOCAL PLANE COMPTON POLARIMETER ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES Chattopadhyay, T., Vadawale, S. V., Shanmugam, M., Goyal, S. K. 2014; 212 (1)
  • Compton polarimeter as a focal plane detector for hard X-ray telescope: sensitivity estimation with Geant4 simulations EXPERIMENTAL ASTRONOMY Chattopadhyay, T., Vadawale, S. V., Pendharkar, J. 2013; 35 (3): 391–412
  • Prospects of Hard X-ray Polarimetry with Astrosat-CZTI Vadawale, S. V., Chattopadhyay, T., Rao, A. R., IEEE IEEE. 2013
  • A conceptual design of hard x-ray focal plane detector for simultaneous x-ray polarimetric, spectroscopic and timing measurements Vadawale, S. V., Chattopadhyay, T., Pendharkar, J., Takahashi, T., Murray, S. S., DenHerder, J. W. SPIE-INT SOC OPTICAL ENGINEERING. 2012

    View details for DOI 10.1117/12.935295

    View details for Web of Science ID 000312391600133