Lankeswar Dey
Visiting Fellow
Email: ldey [at] ncra.tifr.res.in
Phone: 020-2571 9250
Extn: 9250
Office: F218C
National Centre for Radio Astrophysics
Tata Institute of Fundamental Research
Savitribai Phule Pune University Campus,
Pune 411 007
Maharashtra, INDIA
Tata Institute of Fundamental Research
Savitribai Phule Pune University Campus,
Pune 411 007
Maharashtra, INDIA
Main Research Areas: Nanohertz Gravitational Wave Astronomy, Pulsar Timing Array, Supermassive Black Hole Binaries
Biography:
Lankeswar obtained his B.Sc. from Krishnath College, University of Kalyani, in 2015. He then joined TIFR, Mumbai, as an Integrated Ph.D. student in the same year. He completed his Ph.D. in 2022 and moved to NCRA-TIFR in May 2022 as a Visiting Post-doctoral Fellow.Research description:
Pulsar Timing Array (PTA) experiments aim to detect gravitational waves (GWs) in the nanoHz (nHz) frequency regime by observing an ensemble of millisecond pulsars (MSPs). I am a member of the Indian Pulsar Timing Array (InPTA) experiment that uses the upgraded Giant Metrewave Radio Telescope (uGMRT). We regularly observe 6-20 MSPs with uGMRT to obtain high precision pulse times of arrival (TOAs) and dispersion measures (DMs) in order to contribute to the first detection of nHz GWs.Supermassive black hole binaries (SMBHBs) are expected to be the primary sources of nHz GWs and the blazar OJ 287 is the most promising candidate to host an SMBHB at its center. I have been working on modeling the dynamics of the SMBHB in OJ 287 to accurately determine the binary parameters of the system. I am also interested in explaining the variations in the jet's orientation of OJ 287 due to the binary nature of its central engine. Further, I am developing a new accurate and efficient formalism to model PTA signals induced by continuous GWs from individual spinning SMBHBs in relativistic eccentric orbits. All these efforts will help in the first-ever detection of nHz GWs.
Selected publications:
1. Host galaxy magnitude of OJ 287 from its colors at minimum light (M. J. Valtonen, L. Dey, S. Zola et al. 2022, MNRAS, in press, arXiv:2205.15589) 2. Promise of Persistent Multi-Messenger Astronomy with the Blazar OJ 287 (Mauri J. Valtonen, L. Dey, A. Gopakumar et al. 2021, Galaxies, 10, 1) 3. Explaining temporal variations in the jet PA of the blazar OJ 287 using its BBH central engine model (L. Dey, M. J. Valtonen, A. Gopakumar et al. 2021, MNRAS, 503, 4400) 4. Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287 (S. Laine, L. Dey, M. Valtonen et al. 2020, ApJL 894, L1) 5. The Unique Blazar OJ 287 and Its Massive Binary Black Hole Central Engine (L. Dey, A. Gopakumar, M. Valtonen et al. 2019, Universe 5, 108) 6. Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare: Improved Orbital Parameters (L. Dey, M. J. Valtonen, A. Gopakumar et al. 2018, ApJ, 866, 11) 7. Precision pulsar timing with the ORT and the GMRT and its applications in pulsar astrophysics (B. C. Joshi and the InPTA collaboration (including L. Dey), 2018, JAA, 39, 51)
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