Simulated Light Curves Research Articles

Gamma-Ray Burst Detection with Poisson-FOCuS and Other Trigger Algorithms

We describe how a novel online change-point detection algorithm, called Poisson-FOCuS, can be used to optimally detect gamma-ray bursts within the computational constraints imposed by miniaturized satellites such as the upcoming HERMES-Pathfinder constellation. Poisson-FOCuS enables testing for gamma-ray burst onset at all intervals in a count time series, across all timescales and offsets, in real time and at a fraction of the computational cost of conventional strategies. We validate an implementation with automatic background assessment through exponential smoothing, using archival data from Fermi-GBM. Through simulations of lightcurves modeled after real short and long gamma-ray bursts, we demonstrate that the same implementation has higher detection power than algorithms designed to emulate the logic of Fermi-GBM and Compton-BATSE, reaching the performance of a brute-force benchmark with oracle information on the true background rate, when not hindered by automatic background assessment. Finally, using simulated data with different lengths and means, we show that Poisson-FOCuS can analyze data twice as fast as a similarly implemented benchmark emulator for the historic Fermi-GBM on-board trigger algorithms.

Computing Transiting Exoplanet Parameters with 1D Convolutional Neural Networks

The transit method allows the detection and characterization of planetary systems by analyzing stellar light curves. Convolutional neural networks appear to offer a viable solution for automating these analyses. In this research, two 1D convolutional neural network models, which work with simulated light curves in which transit-like signals were injected, are presented. One model operates on complete light curves and estimates the orbital period, and the other one operates on phase-folded light curves and estimates the semimajor axis of the orbit and the square of the planet-to-star radius ratio. Both models were tested on real data from TESS light curves with confirmed planets to ensure that they are able to work with real data. The results obtained show that 1D CNNs are able to characterize transiting exoplanets from their host star’s detrended light curve and, furthermore, reducing both the required time and computational costs compared with the current detection and characterization algorithms.

The Distribution of Semidetached Binaries. I. An Efficient Pipeline

Semidetached binaries are in the stage of mass transfer and play a crucial role in studying the physics of mass transfer between interacting binaries. Large-scale time-domain surveys provide many light curves of binary systems, while Gaia offers high-precision astrometric data. In this paper, we develop, validate, and apply a pipeline that combines the Markov Chain Monte Carlo method with a forward model and DBSCAN clustering to search for semidetached binaries and estimate the inclination, relative radius, mass ratio, and temperature ratio of each using light curves. We train our model on the mock light curves from Physics of Eclipsing Binaries (PHOEBE), which provides broad coverage of light-curve simulations for semidetached binaries. Applying our pipeline to Transiting Exoplanet Survey Satellite sectors 1–26, we have identified 77 semidetached binary candidates. Utilizing the distance from Gaia, we determine their masses and radii with median fractional uncertainties of ∼26% and ∼7%, respectively. With the added 77 candidates, the catalog of semidetached binaries with orbital parameters has been expanded by approximately 20%. The comparison and statistical results show that our semidetached binary candidates align well with the compiled samples and the PARSEC model in T eff–L and M–R relations. Combined with the literature samples, comparative analysis with stability criteria for conserved mass transfer indicates that ∼97.4% of samples are undergoing nuclear-timescale mass transfer, and two samples (GO Cyg and TIC 454222105) are located within the limits of stability criteria for dynamical- and thermal-timescale mass transfer, and are currently undergoing thermal-timescale mass transfer. Additionally, one system (IR Lyn) is very close to the upper limit of delayed dynamical-timescale mass transfer.

Kernel-, mean-, and noise-marginalized Gaussian processes for exoplanet transits and H0 inference

ABSTRACT Using a fully Bayesian approach, Gaussian process regression is extended to include marginalization over the kernel choice and hyperparameters. In addition, Bayesian model comparison via the evidence enables direct kernel comparison. The calculation of the joint posterior was implemented with a transdimensional sampler which simultaneously samples over the discrete kernel choice and their hyperparameters by embedding these in a higher dimensional space, from which samples are taken using nested sampling. Kernel recovery and mean function inference were explored on synthetic data from exoplanet transit light-curve simulations. Subsequently, the method was extended to marginalization over mean functions and noise models and applied to the inference of the present-day Hubble parameter, H0, from real measurements of the Hubble parameter as a function of redshift, derived from the cosmologically model-independent cosmic chronometer and lambda-cold dark matter-dependent baryon acoustic oscillation observations. The inferred H0 values from the cosmic chronometers, baryon acoustic oscillations, and combined data sets are $H_0= 66 \pm 6,\, 67 \pm 10,\, \mathrm{ and}\,69 \pm 6\,\mathrm{km}\, \mathrm{s}^{-1}\, \mathrm{Mpc}^{-1}$, respectively. The kernel posterior of the cosmic chronometers data set prefers a non-stationary linear kernel. Finally, the data sets are shown to be not in tension with ln R = 12.17 ± 0.02.

Evolution and Final Fates of a Rotating 25M⊙ Pop III Star

In this manuscript, we present the one-dimensional stellar evolution of two rotating population III (Pop III) star models, each having a mass of 25M⊙ at the zero-age main-sequence (ZAMS). The slowly rotating model has an initial angular rotational velocity of 10% of the critical angular rotational velocity. In contrast, the rapidly rotating model has an initial angular rotational velocity of 70% of the critical angular rotational velocity. As an effect of rotationally enhanced mixing, we find that the rapidly rotating model suffers an enormous mass loss due to the deposition of a significant amount of CNO elements toward the surface after the main-sequence phase. We also display the simulated light curves as these models explode into core-collapse supernovae (CCSNe).

Physical Characterization of Moon Impactor WE0913A

On 2022 March 4, the object known as WE0913A crashed into the Moon after several close flybys of the Earth and the Moon in the previous three months. Leading up to impact, the identity of the lunar impactor was up for debate, with two possibilities: the Falcon 9 from the DSCOVR mission or the Long March 3C from the Chang’e 5-T1 mission. In this paper, we present a trajectory and spectroscopic analysis using ground-based telescope observations to show conclusively that WE0913A is the Long March 3C rocket body (R/B) from the Chang’e 5-T1 mission. Analysis of photometric light curves collected before impact give a spin period of 185.221 ± 6.540 s before the first close Earth flyby on 2022 January 20 and a period of 177.754 ± 0.779 s, both at a 1σ confidence level, before the second close Earth flyby on 2022 February 8. Using Markov Chain Monte Carlo sampling and a predictive light curve simulation based on an anisotropic Phong reflection model, we estimate both physical and dynamical properties of the Chang’e 5-T1 R/B at the start of an observation epoch. The results from the Bayesian analysis imply that there may have been additional mass on the front of the rocket body. Using our predicted impact location, the Lunar Reconnaissance Orbiter was able to image the crater site approximately 7.5 km from the prediction. Comparing the pre- and post-impact images of the location shows two distinct craters that were made, supporting the hypothesis that there was additional mass on the rocket body.

The 2021 mutual phenomena involving the Galilean satellites of Jupiter and the inner satellite Thebe

ABSTRACT Astrometric studies and orbital modelling of planetary moons have contributed significantly to advancing our understanding of their orbital dynamics. These studies require precise positions measured over extended periods. In this paper, we present the results of the 2021 Brazilian Jovian mutual phenomena campaign. The data correspond to eight events between Galilean satellites, in addition to a rare eclipse of Thebe, an inner satellite, totalling nine events. A geometric model along with the DE440/JUP365 ephemerides was used to reproduce the events and simulate the light curves. A Monte Carlo method and chi-squared statistics were used to fit the simulated light curves to the observations. The reflectance model adopted for our simulations was the complete version of the Oren–Nayer model. The average uncertainty of the relative positions of the Galilean satellites was 5 mas (15 km) and for the inner Thebe satellite 32 mas (96 km). The seven mutual events (nine independent observations) here analysed represent an addition of 17 per cent events (10 per cent light curves) with respect to the 2021 international mutual phenomena campaign. Furthermore, our result of Thebe eclipse is only the second measurement published to date. Our results contribute to the ephemeris data base, being fundamental to improving satellite orbits and thus minimizing their uncertainties.

The Upper Atmosphere of Uranus from Stellar Occultations. I. Methods and Validation

Measurements made by the Voyager 2 spacecraft during its flybys of Uranus in 1986 found warm stratospheric and hot thermospheric temperatures that cannot be explained by solar energy alone. It contributes to what has become known as the “giant planet energy crisis”; there is a fundamental lack of understanding of the energy balance of giant planets in the solar system. Uranus, in particular, has both the hottest thermospheric temperatures and the weakest internal heat flux of all four giant planets. Moreover, the Voyager 2 UV temperature measurements are at odds with the many contemporaneous Earth-based stellar occultation observations. In this work, we examine the 1977 Uranus stellar occultation (U0) and compare the observed light curve to reported Voyager 2 temperature profiles by simulating the latter into stellar occultation light curves. In this investigation, we find that the observed light curves are in tension with the simulated light curves to a high degree of statistical confidence. Next, we reprocess the U0 light curves using a modern approach, with some significant adjustments described herein, and report updated profiles. We find that the lower thermosphere of Uranus is much cooler than the Voyager 2 profiles suggest but slightly warmer than those originally published from the U0 occultation. In Paper II, we will present the results of applying these methods to many of the dozens of archival Uranus stellar occultations.

A sub-pc BBH system in SDSS J1609+1756 through optical QPOs in ZTF light curves

ABSTRACT Optical quasi-periodic oscillations (QPOs) are the most preferred signs of sub-pc binary black hole (BBH) systems in active galactic nucleus (AGN). In this manuscript, robust optical QPOs are reported in quasar SDSS J1609+1756 at z = 0.347. In order to detect reliable optical QPOs, four different methods are applied to analyse the 4.45 yr-long Zwicky Transient Facility (ZTF) g/r/i-band light curves of SDSS J1609+1756, direct fitting results by sine function, generalized Lomb–Scargle periodogram, autocross correlation function, and weighted wavelet Z-transform method. The four different methods can lead to well determined reliable optical QPOs with periodicities ∼340 d with confidence levels higher than 5σ, to guarantee the robustness of the optical QPOs in SDSS J1609+1756. Meanwhile, based on simulated light curves through continuous autoregressive process to trace intrinsic AGN activities, confidence level higher than 3σ can be confirmed that the optical QPOs are not misdetected in intrinsic AGN activities, reconfirming the robust optical QPOs and strongly indicating a central sub-pc BBH system in SDSS J1609+1756. Furthermore, based on apparent redshifted shoulders in broad Balmer emission lines in SDSS J1609+1756, space separation of the expected central BBH system can be estimated to be smaller than 107 ± 60 light-days, accepted upper limit of total BH mass ∼(1.03 ± 0.22) × 108 M⊙. Therefore, to detect and report BBH system expected optical QPOs with periodicities around 1 yr is efficiently practicable through ZTF light curves, and combining with peculiar broad-line emission features, further clues should be given on space separations of BBH systems in broad-line AGN in the near future.

Recurrent Symbiotic Nova T Coronae Borealis before Outburst

The results of photometric and spectral observations of T CrB obtained in a wide range of wavelengths in 2011–2023 are presented. We use the near-IR light curves to determine a new ephemeris JDmin=2455828,9+227,55E for the times of light minima when the red giant is located between the observer and the hot component. The flux ratio Ha/Hb varied from -3 to -8 in 2020–2023, which may be due to a change in the flux ratio between the X-ray and optical ranges. It is shown that the value of Ha//Hb anticorrelates with the rate of accretion onto the hot component of the system. Based on high-speed follow-up observations obtained on June 8, 2023, we detected a variability of the He II 4686 line with a characteristic time-scale of -25 min, the amplitude of variability in the B-band was -0.m0,7. Simulations of the near-IR light curves accounting for the ellipsoidal effect allowed us to obtain the parameters of the binary system: the Roche lobe filling factor of the cool component m= 1,0, the mass ratio q=Mcool/Mhot@[0.5,0.77], the orbital inclination i@[55,63]. A comparison of the light curve obtained in 2005–2023 with the 1946 outburst template made it possible to predict the date of the upcoming outburst—January 2024.

SN 2018gj: A Short Plateau Type II Supernova with Persistent Blueshifted Ha Emission

We present an extensive, panchromatic photometric (UV, optical, and near-IR) and low-resolution optical spectroscopic coverage of a Type IIP supernova SN 2018gj that occurred on the outskirts of the host galaxy NGC 6217. From the V-band light curve, we estimate the plateau length to be ∼ 70 ± 2 days, placing it among the very few well-sampled short plateau supernovae (SNe). With V-band peak absolute magnitude M V ≤ −17.0 ± 0.1 mag, it falls in the middle of the luminosity distribution of the Type II SNe. The color evolution is typical to other Type II SNe except for an early elbow-like feature in the evolution of V − R color owing to its early transition from the plateau to the nebular phase. Using the expanding photospheric method, we present an independent estimate of the distance to SN 2018gj. We report the spectral evolution to be typical of a Type II SNe. However, we see a persistent blueshift in emission lines until the late nebular phase, not ordinarily observed in Type II SNe. The amount of radioactive nickel (56Ni) yield in the explosion was estimated to be 0.026 ± 0.007 M ⊙. We infer from semianalytical modeling, nebular spectrum, and 1D hydrodynamical modeling that the probable progenitor was a red supergiant with a zero-age-main-sequence mass ≤13 M ⊙. In the simulated hydrodynamical model light curves, reproducing the early optical bolometric light curve required an additional radiation source, which could be the interaction with the proximal circumstellar matter.

Understanding of the properties of neural network approaches for transient light curve approximations

Context. Modern-day time-domain photometric surveys collect a lot of observations of various astronomical objects and the coming era of large-scale surveys will provide even more information on their properties. Spectroscopic follow-ups are especially crucial for transients such as supernovae and most of these objects have not been subject to such studies. Aims. Flux time series are actively used as an affordable alternative for photometric classification and characterization, for instance, peak identifications and luminosity decline estimations. However, the collected time series are multidimensional and irregularly sampled, while also containing outliers and without any well-defined systematic uncertainties. This paper presents a search for the best-performing methods to approximate the observed light curves over time and wavelength for the purpose of generating time series with regular time steps in each passband. Methods. We examined several light curve approximation methods based on neural networks such as multilayer perceptrons, Bayesian neural networks, and normalizing flows to approximate observations of a single light curve. Test datasets include simulated PLAsTiCC and real Zwicky Transient Facility Bright Transient Survey light curves of transients. Results. The tests demonstrate that even just a few observations are enough to fit the networks and improve the quality of approximation, compared to state-of-the-art models. The methods described in this work have a low computational complexity and are significantly faster than Gaussian processes. Additionally, we analyzed the performance of the approximation techniques from the perspective of further peak identification and transients classification. The study results have been released in an open and user-friendly Fulu Python library available on GitHub for the scientific community.

A candidate of binary black hole system in AGN with broad Balmer emission lines having quite different line widths

ABSTRACT In this paper, a candidate of sub-pc binary black hole (BBH) system is reported in SDSS J1257+2023 through different properties of broad Balmer emission lines. After subtractions of host galaxy contributions, Gaussian functions are applied to measure emission lines in SDSS J1257+2023, leading line width (second moment) 760 km s−1 of broad H β to be 0.69 times of line width 1100 km s−1 of broad H α, quite different from normal line width ratio 1.1 of broad H β to broad H α in quasars. The quite broader component in broad H α in SDSS J1257+2023 can be confirmed with confidence level higher than 5σ through F-test technique, through different model functions applied to measure emission lines. The broad Balmer emission lines having different line widths can be naturally explained by a BBH system with different obscurations on central two independent broad emission line regions. Meanwhile, through Zwicky Transient Facility (ZTF) light curves and corresponding phase folded light curves well described by sinusoidal function, BBH system expected optical quasi-periodic oscillations (QPOs) can be detected with periodicity about 1000 d, confirmed with confidence level higher than 3σ by generalized Lomb–Scargle periodogram. And through Continuous AutoRegressive process simulated light curves, confidence level higher than 2σ can be determined to support the optical QPOs in SDSS J1257+2023 not from intrinsic AGN activities, although the ZTF light curves have short time durations. Moreover, through oversimplified BBH system simulated results, studying different broad Balmer lines as signs of BBH systems in normal quasars with flux ratios around 4 of broad H α to broad H β could be done in near future.

Prospects for the detection rate of very-high-energy γ-ray emissions from short γ-ray bursts with the HADAR experiment* *Supported by the National Natural Science Foundation of China (12263004, 12263005, 12275279).

The observation of short gamma ray bursts (SGRBs) in the TeV energy range plays an important role in understanding the radiation mechanism and probing potential new physics, such as Lorentz invariance violation (LIV). However, no SGRBs have been observed in this energy range owing to the short duration of SGRBs and the weakness of current experiments. New experiments with new technology are required to detect the very high energy (VHE) emission of SGRBs. In this study, we simulate the VHE γ-ray emissions from SGRBs and calculate the annual detection rate with the High Altitude Detection of Astronomical Radiation (HADAR) experiment. First, a set of pseudo-SGRB samples is generated and checked using the observations of the Fermi-GBM, Fermi-LAT, and Swift-BAT measurements. The annual detection rate is calculated from these SGRB samples based on the performance of the HADAR instrument. As a result, the HADAR experiment can detect 0.5 SGRBs per year if the spectral break-off of γ-rays caused by the internal absorption and Klein-Nishina (KN) effect is larger than 100 GeV. For a GRB090510-like GRB in HADAR's view, it should be possible to detect approximately 2000 photons considering the internal absorption and KN effect. With a time delay assumption due to LIV effects, a simulated light curve of GRB090510 has evident energy dependence. We hope that the HADAR experiment can perform SGRB observations and test our calculations in the future.

MOBSTER – VII. Using light curves to infer magnetic and rotational properties of stars with centrifugal magnetospheres

ABSTRACT Early-type B stars with strong magnetic fields and rapid rotation form centrifugal magnetospheres (CMs), as the relatively weak stellar wind becomes magnetically confined and centrifugally supported above the Kepler co-rotation radius. CM plasma is concentrated at and above the Kepler co-rotation radius at the intersection between the rotation and magnetic field axis. Stellar rotation can cause these clouds of material to intersect the viewer’s line of sight, leading to photometric eclipses. However, for stars with strong ($\sim 10\, {\rm kG}$) magnetic fields and rapid rotation, CMs can become optically thick enough for emission to occur via electron scattering. Using high-precision space photometry from a sample of stars with strong H α emission, we apply simulated light curves from the rigidly rotating magnetosphere model to directly infer magnetic and rotational properties of these stars. By comparing the values inferred from photometric modelling to those independently determined by spectropolarimetry, we find that magnetic obliquity angle β, viewer inclination i, and critical rotation fraction W can be approximately recovered for three of the four stars studied here. However, there are large discrepancies between the optical depth at the Kepler radius τK expected from magnetometry, and the values required to match the observations. We show that τK of order unity is needed to reasonably match the light-curve morphology of our sample stars.

A Gaussian process cross-correlation approach to time-delay estimation in active galactic nuclei

Context. We present a probabilistic cross-correlation approach to estimate time delays in the context of reverberation mapping (RM) of active galactic nuclei (AGN). Aims. We reformulate the traditional interpolated cross-correlation method as a statistically principled model that delivers a posterior distribution for the delay. Methods. The method employs Gaussian processes as a model for observed AGN light curves. We describe the mathematical formalism and demonstrate the new approach using both simulated light curves and available RM observations. Results. The proposed method delivers a posterior distribution for the delay that accounts for observational noise and the non-uniform sampling of the light curves. This feature allows us to fully quantify the uncertainty on the delay and propagate it to subsequent calculations of dependant physical quantities, such as black hole masses. The method delivers out-of-sample predictions, which enables us to subject it to model selection, and can calculate the joint posterior delay for more than two light curves. Conclusions. Because of the numerous advantages of our reformulation and the simplicity of its application, we anticipate that our method will find favour not only in the specialised community of RM, but also in all fields where cross-correlation analysis is performed. We provide the algorithms and examples of their application as part of our Julia GPCC package.

Stellar pulsations interfering with the transit light curve: Configurations with false positive misalignment

Aims. Asymmetric features in exoplanet transit light curves are often interpreted as an effect of gravity darkening, especially if there is spectroscopic evidence of a spin-orbit misalignment. Since other processes can also lead to light-curve asymmetries, this may lead to inaccurate gravity darkening parameters. Here, we investigate the case of non-radial pulsations as possible sources of asymmetry and likely source of misinterpreted parameters through simulations. Methods. We obtained a series of simulated transit light curves of a hypothetical exoplanet-star system constructed to study the phenomenon: a host star with no gravity darkening exhibiting small amplitude pulsations and a typical hot Jupiter in a circular, edge-on orbit. Multiple scenarios of single- or multi-periodic, radial-, or non-radial pulsations of various amplitudes have been considered, and a proper account of the obscuring effect of transits on all the surface intensity components was carried out. The magnitude of amplitude and phase modulations of non-radial pulsations during transits was also also investigated. We then fit both a non-gravity-darkened and a gravity-darkened free spin-orbit axis model on the data. The Akaike and Bayesian information criteria were used for an objective selection of the most plausible model. We then explored the dependence of the parameter deviations on the pulsation properties to identify the specific configurations that may lead to falsely misaligned solutions. Results. The modulation of amplitudes of non-radial pulsations during transits have extremely low levels, so that the non-radial nature of pulsations can be safely ignored. Low-amplitude pulsations generally do not affect the determination of the system parameters beyond their noise properties. However, frequencies close to multiples of the orbital frequency (n * forb) are found to cause distortions, leading to solutions that involve a side tilted stellar rotational axis; therefore, it is preferable to clean them beforehand for the sake of a improved accuracy. Additionally, in cases with higher amplitude pulsations, a preprocessing and cleaning of the pulsations before the analysis is recommended.

Constraining AGN Torus Sizes with Optical and Mid-infrared Ensemble Structure Functions

We propose a new method to constrain the size of the dusty torus in broad-line active galactic nuclei (AGNs) using optical and mid-infrared (MIR) ensemble structure functions (SFs). Because of the geometric dilution of the torus, the MIR response to optical continuum variations has suppressed variability with respect to the optical that depends on the geometry (e.g., size, orientation, opening angle) of the torus. More extended tori have steeper MIR SFs with respect to the optical SFs. We demonstrate the feasibility of this SF approach using simulated AGN light curves and a geometric torus model. While it is difficult to use SFs to constrain the orientation and opening angle due to the insensitivity of the SF on these parameters, the size of the torus can be well determined. Applying this method to the ensemble SFs measured for 587 SDSS quasars, we measure a torus R–L relation of in the WISE W1 band and sizes ∼1.4 times larger in the W2 band, which are in good agreement with dust reverberation mapping measurements. Compared with the reverberation mapping technique, the SF method is much less demanding in data quality and can be applied to any optical+MIR light curves for which a lag measurement may not be possible, as long as the variability process and torus structure are stationary. While this SF method does not extract all information contained in the light curves (i.e., the transfer function), it provides an intuitive interpretation for the observed trends of AGN MIR SFs compared with optical SFs.

Probing compact dark matter objects with microlensing in gravitationally lensed quasars

The microlensing signal in the light curves of gravitationally lensed quasars can shed light on the dark matter (DM) composition in their lensing galaxies. Here, we investigate a sample of six lensed quasars from the most recent and best COSMOGRAIL observations: HE 1104−1805, HE 0435−1223, RX J1131−1231, WFI 2033−4723, PG 1115+080, and J1206+4332, yielding a total of eight microlensing light curves, when combining independent image pairs and typically spanning ten years. We explore the microlensing signals to determine whether the standard assumptions on the stellar populations are sufficient to account for the amplitudes of the measured signals or whether additional microlenses are needed. We use the most detailed lens models to date from the H0LiCOW/TDCOSMO collaboration to derive the microlensing parameters, such as the convergence, shear, and stellar/dark matter mass fraction at the position of the quasar images. We use these parameters to generate simulated microlensing light curves. Finally, we propose a methodology based on the Kolmogorov-Smirnov test to verify whether the observed microlensing amplitudes in our data are compatible with the most standard scenario, whereby galaxies are composed of stars as compact bodies and smoothly distributed DM. Given our current sample, we show that the standard scenario cannot be rejected, in contrast with previous results by Hawkins (2020a, A&A, 633, A107), claiming that a population of stellar mass primordial black holes (PBHs) is necessary to explain the observed amplitude of the microlensing signal in lensed quasar light curves. We further estimate the number of microlensing light curves needed to effectively distinguish between the standard scenario with stellar microlensing and a scenario that describes that all the DM contained in galaxies is in the form of compact objects such as PBHs, with a mean mass of 0.2 M⊙. We find that about 900 microlensing curves from the Rubin Observatory will be sufficient to discriminate between the two extreme scenarios at a 95% confidence level.

Searching for Gravitational-wave Counterparts Using the Transiting Exoplanet Survey Satellite

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.