A more complete listing of publications, including minor contributions and collaboration papers, can be found in my ADS library, my Google Scholar profile , and my ORCID profile.
Selected First Author Publications
Link to ADS Library with a full listing.
2026
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Constraints on Late-Time Flaring from Luminous Fast Blue Optical Transients using the Transiting Exoplanet Survey Satellite and the Zwicky Transient Facility
Rahul Jayaraman , Anna Y. Q. Ho , Michael M. Fausnaugh , and 14 more authors
arXiv e-prints, Jun 2026
2025
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Broadband Spectral Modeling of Prompt Emission from Gamma-Ray Bursts Observed by the Transiting Exoplanet Survey Satellite
Rahul Jayaraman , Michael Fausnaugh , George R. Ricker , and 1 more author
The Astrophysical Journal, Sep 2025
2024
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TIC 435850195: The Second Triaxial Tidally Tilted Pulsator
Rahul Jayaraman , Saul A. Rappaport , Brian Powell , and 8 more authors
The Astrophysical Journal, Nov 2024
The Transiting Exoplanet Survey Satellite (TESS) has enabled the discovery of numerous tidally tilted pulsators (TTPs), which are pulsating stars in close binaries where the presence of a tidal bulge has the effect of tilting the primary star’s pulsation axes into the orbital plane. Recently, the modeling framework developed to analyze TTPs has been applied to the emerging class of triaxial pulsators, which exhibit nonradial pulsations about three perpendicular axes. In this work, we report on the identification of the second-ever discovered triaxial pulsator, with 16 robustly detected pulsation multiplets, of which 14 are dipole doublets separated by 2 \nu_orb. We jointly fit the spectral energy distribution and TESS light curve of the star, and find that the primary is slightly evolved off the zero-age main equence, while the less massive secondary still lies on the zero-age main sequence. Of the 14 doublets, we associate eight with Y_10x modes and six with novel Y_10y modes. We exclude the existence of Y_11x modes in this star and show that the observed pulsation modes must be Y_10y . We also present a toy model for the triaxial pulsation framework in the context of this star. The techniques presented here can be utilized to rapidly analyze and confirm future triaxial \ pulsator candidates.
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Gamma-Ray Bursts Observed by the Transiting Exoplanet Survey Satellite: Prompt Optical Counterparts and Afterglows of Swift-XRT-localized Gamma-Ray Bursts
Rahul Jayaraman , Michael Fausnaugh , George R. Ricker , and 2 more authors
The Astrophysical Journal, Sep 2024
Very few detections have been made of optical flashes contemporaneous with prompt high-energy emission from a gamma-ray burst (GRB). In this work, we present and analyze light curves of GRB-associated optical flashes and afterglows from the Transiting Exoplanet Survey Satellite (TESS). Our sample consists of eight GRBs with arcsecond-level localizations from the X-Ray Telescope on board the Neil Gehrels Swift Observatory (Swift). For each burst, we characterize the prompt optical emission and any observed afterglow, and constrain physical parameters for four of these bursts using their TESS light curves. This work also presents a straightforward method to correct for TESS’s cosmic-ray mitigation strategy on 20 s timescales, which allows us to estimate the "true" brightness of optical flashes associated with prompt GRB emission. We also highlight TESS’s continuous wide-field monitoring capability, which provides an efficient means of identifying optical emission from GRBs and characterizing early time afterglow light curves. Based on empirical detection rates from Swift and the Fermi Gamma-ray Space Telescope, up to 10 GRBs per year may fall within the contemporaneous TESS field of view.
2022
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Tidally Tilted Pulsations in HD 265435, a Subdwarf B Star with a Close White Dwarf Companion
Rahul Jayaraman , Gerald Handler , Saul A. Rappaport , and 4 more authors
The Astrophysical Journal Letters, Apr 2022
Tidally tilted pulsators (TTPs) are an intriguing new class of oscillating stars in binary systems; in such stars, the pulsation axis coincides with the line of apsides, or tidal axis, of the binary. All three TTPs discovered so far have been δ Scuti stars. In this Letter, we report the first conclusive discovery of tidally tilted pulsations in a subdwarf B (sdB) star. HD 265435 is an sdB-white dwarf binary with a 1.65 hr period that has been identified and characterized as the nearest potential Type Ia supernova progenitor. Using TESS 20 s cadence data from Sectors 44 and 45, we show that the pulsation axis of the sdB star has been tidally tilted into the orbital plane and aligned with the tidal axis of the binary. We identify 31 independent pulsation frequencies, 27 of which have between 1 and 7 sidebands separated by the orbital frequency (ν orb) or multiples thereof. Using the observed amplitude and phase variability due to tidal tilting, we assign ℓ and m values to most of the observed oscillation modes and use these mode identifications to generate preliminary asteroseismic constraints. Our work significantly expands our understanding of TTPs, as we now know that (i) they can be found in stars other than δ Scuti pulsators, especially highly evolved stars that have lost their H-rich envelopes, and (ii) tidally tilted pulsations can be used to probe the interiors of stars in very tight binaries.
Selected Major Contributions
For a full list, please see
this ADS library.
2026
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Early Multiwavelength Observations of AT 2026fgk: The Luminous Afterglow to Sub-luminous GRB 260310A, Identified Independently of a Gamma-ray Trigger
K.-R. Hinds , A. Y. Q. Ho , Y. Wagh , and 103 more authors
arXiv e-prints, Jun 2026
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Discovery of the first octupole pulsation mode in a delta Scuti star: A stationary \ell = 3 sectoral mode
S. A. Rappaport , R. Jayaraman , G. Handler , and 8 more authors
\aap, Jun 2026
2024
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TIC 184 743 498: the first tri-axial stellar pulsator
Valencia Zhang , Saul Rappaport , Rahul Jayaraman , and 4 more authors
Monthly Notices of the Royal Astronomical Society, Feb 2024
We have discovered a δ Scuti pulsator in a tight binary (P = 1.053 d) with nine pulsation modes whose frequencies are between 38 and 56 d-1. Each of these modes exhibits amplitude modulations and π-rad phase shifts twice per orbital cycle. Five of these modes exhibit amplitude and phase shifts that are readily explained by dipole pulsations along an axis that is aligned with the binary’s tidal axis. The novelty of the system lies in the remaining four pulsation modes, which we show are dipole pulsations along an axis that is perpendicular to both the tidal axis and the binary’s orbital angular momentum axis. There are additionally two pulsation modes whose amplitudes and phases do not change significantly with orbital phase; they are explained as dipole modes along an axis aligned with the orbital/rotation axis. Hence, we propose that TIC 184 743 498 is a tri-axial pulsator, the first of its kind.
2023
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Searching for Gravitational-wave Counterparts Using the Transiting Exoplanet Survey Satellite
Geoffrey Mo , Rahul Jayaraman , Michael Fausnaugh , and 3 more authors
The Astrophysical Journal Letters, May 2023
In 2017, the LIGO and Virgo gravitational-wave (GW) detectors, in conjunction with electromagnetic (EM) astronomers, observed the first GW multimessenger astrophysical event, the binary neutron star (BNS) merger GW170817. This marked the beginning of a new era in multimessenger astrophysics. To discover further GW multimessenger events, we explore the synergies between the Transiting Exoplanet Survey Satellite (TESS) and GW observations triggered by the LIGO-Virgo-KAGRA Collaboration (LVK) detector network. TESS’s extremely wide field of view ( 2300 deg2) means that it could overlap with large swaths of GW localizations, which often span hundreds of square degrees or more. In this work, we use a recently developed transient detection pipeline to search TESS data collected during the LVK’s third observing run, O3, for any EM counterparts. We find no obvious counterparts brighter than about 17th magnitude in the TESS bandpass. Additionally, we present end-to-end simulations of BNS mergers, including their detection in GWs and simulations of light curves, to identify TESS’s kilonova discovery potential for the LVK’s next observing run (O4). In the most optimistic case, TESS will observe up to one GW-found BNS merger counterpart per year. However, TESS may also find up to five kilonovae that did not trigger the LVK network, emphasizing that EM-triggered GW searches may play a key role in future kilonova detections. We also discuss how TESS can help place limits on EM emission from binary black hole mergers and rapidly exclude large sky areas for poorly localized GW events.