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.
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 compact objects (e.g. black holes, white dwarfs) using data primarily from X-ray telescopes (e.g. NICER, XMM-Newton) 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 and binaries form, evolve, influence their surroundings, and produce electromagnetic and gravitational radiation to power some of the most energetic phenomena in nature. A mostly accidental theme of my current work is electromagnetic emission from low-frequency (~μHz-mHz) gravitational wave sources, and I am excited by their potential for multi-messenger astrophysics. 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 QPE timings to map general relativistic precession effects within ~hundred gravitational radii of supermassive black holes (see e.g. the effects of frame-dragging and apsidal precession). My hope is that QPEs will enable new direct measurements of orbital dynamics in galaxy nuclei, and teach us something about supermassive black holes in the process.
-Ultracompact binaries, which are the dominant millihertz gravitational wave sources for upcoming space-based gravitational wave detectors. I study their orbital evolution as a probe of angular momentum transport during mass-transfer, and am curious what we may learn from multi-messenger study of their accretion disks.
-Tidal Disruption Events, which provide a unique laboratory to study the formation and evolution of turbulent accretion flows around supermassive black holes.
-X-ray astronomy, high performance computing, large-scale data analysis, Bayesian inference.
Selected publications:
My first-/second-author papers are listed below, along with brief summaries of the main results. You can find all of my papers on ADS, arXiv, or Google Scholar.
An eclipsing 8.56 minute orbital period mass-transferring binary
Emma Chickles, Joheen Chakraborty, Kevin Burdge, Vik Dhillon, et al.
Submitted to Astrophysical Journal
We reported the discovery of a short-period AM CVn-type binary and its period derivative. Using the arguments from our 2024 paper, we inferred the system properties to conclude it will be a high-SNR LISA source.
[Paper]
Prospects for EMRI/MBH parameter estimation using quasi-periodic eruption timings: short-timescale analysis
Joheen Chakraborty*, Lisa Drummond*, Matteo Bonetti, Alessia Franchini, et al. (*equal contribution)
Astrophysical Journal, Oct. 2025
We constructed an open-source Bayesian inference code which models the effects of general relativistic orbital precessions on QPE timings within the EMRI disk collision picture. We used the code to assess how well, in principle, QPE timings may be used for parameter inference (of e.g. SMBH mass, spin, orbital properties...)
[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
We studied the unique time-evolving outflow in a QPE, which provides the first direct constraints on the physical properties of the emission region. In principle, observations and modeling of this kind should be able to distinguish between collisional shock-powered and purely radiation-powered bursts.
[Paper]
[Press]
[Highlight]
Discovery of extreme quasi-periodic eruptions in a newly accreting massive black hole
Lorena Hernández-García, Joheen Chakraborty, Paula Sánchez-Sáez, Claudio Ricci, et al.
Nature Astronomy, Apr. 2025
We reported the discovery of extremely bright, long-lived, long-period QPEs in a system which strains (breaks) previous energetics arguments within the EMRI picture. Follow-up of this source should be interesting.
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[Press]
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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
We reported the discovery of QPEs in an optically-selected TDE (the third such system). With the budding "population", we made a Bayesian argument to conclude that somewhere between 4-18% of optical TDEs show QPEs within five years.
[Paper]
[Highlight]
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
We reported the discovery of three short-period AM CVn-type binaries, and measured the orbital period derivatives in two of them. We outlined some analytical arguments to place system constraints when the angular momentum loss required for mass-transfer is sourced by gravitational waves.
[Paper]
Testing EMRI models for quasi-periodic eruptions with 3.5 years of monitoring eRO-QPE1
Joheen Chakraborty, Riccardo Arcodia, Erin Kara, Giovanni Miniutti, et al.
Astrophysical Journal, Apr. 2024
We reported data from a long-term NICER/XMM monitoring campaign of an erratic QPE source, finding the burst energetics gradually decreased over a few years. We also found the first evidence for super-periodic modulations in the burst timings, potentially indicating orbital precession.
[Paper]
[Highlight]
[Talk]
Transit duration and timing variations from binary planets
Joheen Chakraborty, David Kipping
Astrophysical Journal, Feb. 2023
We computed, via simple geometric arguments, the phase-dependent variation in transit duration for binary planets (e.g. Pluto-Charon). We found they can be up to several hours, which should be observable.
[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
We found, via an algorithmic search of XMM archival data, a new candidate QPE (the fifth known). Its most interesting feature was that it happened shortly after a TDE, a suggestive coincidence given the independent rarity of both. Later work eventually confirmed this connection.
[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
We applied a phase-folding algorithm for periodic signal detection in TESS data designed to be agnostic to the signal shape (only requiring periodicity). We found several previously unreported objects, most of which are probably eclipsing binaries.
[Paper]
