I'm a fourth-year physics PhD student at MIT. I am fortunate to be advised by Erin Kara and work closely with Kevin Burdge and Riccardo Arcodia.
I was an undergrad at Columbia, where I worked with Frits Paerels on X-ray astronomy and David Kipping on extrasolar planets, graduating in 2022. Before that, I grew up in Edison, New Jersey.
This website was last updated in August 2025.
e-mail: joheen (at) mit (dot) edu
Research Interests:
My research is in high-energy astrophysics, which provides a remarkable diversity of mysterious and exciting phenomena to explore. I study electromagnetic radiation produced in the vicinity of compact objects (e.g. black holes, white dwarfs), using a combination of (primarily X-ray) observations and ideas/models from plasma physics, atomic physics, general relativity, and radiative transfer. The overarching goal of this work is to understand how compact objects/binaries form, evolve, influence their surroundings, and power some of the most energetic transient phenomena observed in nature. A mostly accidental theme of my current work is electromagnetic emission from low-frequency (~millihertz) gravitational wave sources. Some topics I work on are:
-Quasi-Periodic Eruptions (QPEs), a newly discovered type of recurring X-ray transient which may be the first-known electromagnetic counterparts to EMRIs. An enticing possibility is using them to map general relativistic precession effects within hundreds of gravitational radii of supermassive black holes. Here are some animations illustrating the timing modulation effects of accretion disk nodal precession and EMRI apsidal precession (the "Q" in QPE). My hope is that QPEs will open up direct measurement of a new region in stellar dynamical phase space in galaxy nuclei---relevant for making a more precise statement about the currently uncertain EMRI rate---and teach us something interesting about relativistic shocks in the process.
-Ultracompact binaries, which are the dominant millihertz gravitational wave sources in the Galaxy. To first order, their period evolution is set by GW emission. To second order, there are further nontrivial effects---like angular momentum transport via mass-transfer and tides---which complicate this picture. The details of these processes are uncertain, but recent observations and discoveries are enabling progress on these questions. Mass-transfering ultracompacts will also uniquely allow multi-messenger ("messengers" = light and gravitational waves) study of accretion disks.
-Tidal Disruption Events, which I'm currently interested in as a laboratory to study the turbulent accretion disks around supermassive black holes.
-X-ray astronomy, high performance computing, large-scale data analysis, Bayesian inference. I am also a member of the NICER science team.
Selected publications:
My first-/second-author papers are listed below. You can find all of my papers on ADS, arXiv, or Google Scholar.
Prospects for EMRI/MBH parameter estimation using Quasi-Periodic Eruption timings: short-timescale analysis
Joheen Chakraborty*, Lisa Drummond*, Matteo Bonetti, Alessia Franchini, Shubham Kejriwal, et al. (*equal contribution)
Accepted to The Astrophysical Journal
[Paper]
[Code]
Rapidly varying ionization features in a Quasi-periodic Eruption: a homologous expansion model for the spectroscopic evolution
Joheen Chakraborty, Peter Kosec, Erin Kara, Giovanni Miniutti, et al.
Astrophysical Journal, May 2025
[Paper]
[Press]
[Summary]
Discovery of extreme Quasi-Periodic Eruptions in a newly accreting massive black hole
Lorena Hernández-García, Joheen Chakraborty, Paula Sánchez-Sáez, Claudi Ricci, et al.
Nature Astronomy, Apr. 2025
[Paper]
[Press]
[Summary]
Discovery of Quasi-periodic Eruptions in the Tidal Disruption Event and Extreme Coronal Line Emitter AT2022upj: implications for the QPE/TDE fraction and a connection to ECLEs
Joheen Chakraborty, Erin Kara, Riccardo Arcodia, Johannes Buchner, et al.
Astrophysical Journal Letters, Apr. 2025
[Paper]
[Summary]
Expanding the ultracompacts: gravitational wave-driven mass transfer in the shortest-period binaries with accretion disks
Joheen Chakraborty, Kevin Burdge, Saul Rappaport, James Munday, et al.
Astrophysical Journal, Dec. 2024
[Paper]
Testing EMRI models for Quasi-periodic Eruptions with 3.5 years of monitoring eRO-QPE1
Joheen Chakraborty, Riccardo Arcodia, Erin Kara, Giovanni Miniutti, Margherita Giustini, et al.
Astrophysical Journal, Apr. 2024
[Paper]
[Summary]
[Talk]
Transit duration and timing variations from binary planets
Joheen Chakraborty, David Kipping
Astrophysical Journal, Feb. 2023
[Paper]
Possible X-ray Quasi-periodic Eruptions in a tidal disruption event candidate
Joheen Chakraborty, Erin Kara, Megan Masterson, Margherita Giustini, Giovanni Miniutti, Richard Saxton
Astrophysical Journal Letters, Nov. 2021
[Paper]
[Press]
[Talk]
Hundreds of new periodic signals detected in the first year of TESS with the weirddetector
Joheen Chakraborty, Adam Wheeler, David Kipping
Astrophysical Journal, Dec. 2020
[Paper]
