About

Kevin Burdge is an observational astrophysicist focused on discovering and characterizing compact binary systems—pairs of stellar remnants such as white dwarfs, neutron stars, and black holes. These systems provide exceptional laboratories for exploring compact-object physics, accretion processes, stellar evolution, and explosive cosmic events, including Type Ia supernovae. His research leverages next-generation observatories, including the Vera Rubin Observatory, the Nancy Grace Roman Space Telescope, and the upcoming Laser Interferometer Space Antenna (LISA), to discover and study large, diverse populations of compact binaries. By combining gravitational-wave detections with multi-wavelength electromagnetic observations, Burdge and his group aim to understand how these systems form, evolve, and influence their cosmic environments. His team has significantly expanded the known population of gravitational-wave sources detectable by LISA, identifying rare binary systems and exotic merger remnants that offer unique opportunities to test general relativity and models of binary evolution. This discovery-driven work is supported by innovative GPU-based algorithms developed by his group. Burdge has also used Gaia astrometry to discover the first known black hole in a triple-star system and maintains a strong interest in X-ray binary systems. Additionally, he develops specialized astronomical instrumentation, such as the ultrafast “Lightspeed” camera for the Magellan telescopes, enabling rapid photometric studies of faint, fast astrophysical phenomena. He is pioneering time-domain research with the James Webb Space Telescope, investigating dense stellar environments like globular clusters and the Galactic center to uncover hidden populations of compact binaries. Burdge is a member of the science team for the Advanced X-ray Imaging Satellite (AXIS), where he led the design of a proposed Galactic-plane survey expected to reveal over a million new X-ray sources.

Research topics

• Physics
• Astronomy
• Astrophysics
• Computer Science
• Systems engineering
• Data science

Selected publications

• Disk-to-corona State Transition and Extreme X-Ray Variability in the Tidal Disruption Event AT2019teq

  The Astrophysical Journal · 2026-03-09

  articleOpen accessSenior author

  Abstract We present a 5 yr X-ray spectral and timing analysis of the optically selected tidal disruption event (TDE) AT2019teq, which displays extreme variability, including order-of-magnitude changes in flux on minute-to-day timescales, and a rare late-time emergence of hard X-ray emission leading to the longest-lived corona in a known TDE. In one epoch, we detect submillihertz quasiperiodic oscillations with significance tested via Markov Chain Monte Carlo based red-noise simulations ( p ≤ 0.03). AT2019teq exhibits a clear spectral evolution from a soft (blackbody-dominated) state to a hard (power-law-dominated) state, with a late-time radio brightening that may be associated with the state transition. We identify similarities between AT2019teq’s evolution and X-ray binary soft-to-hard state transitions, albeit at higher luminosity and much faster timescales. We use the presence of both the disk-dominated and corona-dominated states to apply multiple mass estimators from X-ray spectral and variability properties. These techniques are mutually consistent within 2 σ and systematically yield a lower BH mass ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>/</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>5.67</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.09</mml:mn> </mml:math> ) than inferred from host galaxy scaling ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>/</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>6.14</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.19</mml:mn> </mml:math> ).

  PublisherDOI

• JWST observations of three long-period AM CVn binaries: detection of the donors and hints of magnetically truncated disks

  Open MIND · 2026-01-02

  preprintSenior author

  We present JWST/NIRSpec high-cadence infrared spectroscopy of three long-period, eclipsing AM CVn binaries, Gaia14aae, SRGeJ0453, and ZTFJ1637. These systems have orbital periods of 50-62 minutes and cool donors that are undetectable in the optical. The data cover a wavelength range of 1.6-5.2 $μ$m at resolution $R=1000-2000$. We obtained 150-200 spectra of each system over two orbits, split between the G235M and G395M gratings. All three systems show strong, double-peaked He I emission lines dominated by an accretion disk. These lines are nearly stationary but contain radial velocity (RV) variable sub-components that trace stream-disk interactions. In Gaia14aae and SRGeJ0453, we detect two Na I doublets in emission whose RVs track the irradiated face of the donor, marking the first direct detection of the donors of long-period AM CVns. No absorption lines from the donors are detected, implying that the IR excesses observed in many long-period AM CVns primarily trace disks, not donors. The He I emission profiles in all systems lack high-velocity wings and show no emission beyond $\approx 1500,\rm km,s^{-1}$. The morphology of the disk eclipses and Doppler tomograms are best reproduced by models in which the disk is truncated well outside the white dwarf and only material at $r \gtrsim 0.07,R_{\odot}$ contributes to the disk emission. We interpret this as possible evidence of magnetized white dwarf accretors. For plausible mass transfer rates, the truncation radii imply surface magnetic fields of $B = 30-100$ kG, consistent with recent constraints based on X-ray periodicity. The absence of cyclotron humps out to 5 $μ$m rules out stronger MG-level fields. We make the data from the program publicly available to the community.

  DOI

• JWST observations of three long-period AM CVn binaries: detection of the donors and hints of magnetically truncated disks

  ArXiv.org · 2026-01-02

  articleOpen accessSenior author

  We present JWST/NIRSpec high-cadence infrared spectroscopy of three long-period, eclipsing AM CVn binaries, Gaia14aae, SRGeJ0453, and ZTFJ1637. These systems have orbital periods of 50-62 minutes and cool donors that are undetectable in the optical. The data cover a wavelength range of 1.6-5.2 $μ$m at resolution $R=1000-2000$. We obtained 150-200 spectra of each system over two orbits, split between the G235M and G395M gratings. All three systems show strong, double-peaked He I emission lines dominated by an accretion disk. These lines are nearly stationary but contain radial velocity (RV) variable sub-components that trace stream-disk interactions. In Gaia14aae and SRGeJ0453, we detect two Na I doublets in emission whose RVs track the irradiated face of the donor, marking the first direct detection of the donors of long-period AM CVns. No absorption lines from the donors are detected, implying that the IR excesses observed in many long-period AM CVns primarily trace disks, not donors. The He I emission profiles in all systems lack high-velocity wings and show no emission beyond $\approx 1500,\rm km,s^{-1}$. The morphology of the disk eclipses and Doppler tomograms are best reproduced by models in which the disk is truncated well outside the white dwarf and only material at $r \gtrsim 0.07,R_{\odot}$ contributes to the disk emission. We interpret this as possible evidence of magnetized white dwarf accretors. For plausible mass transfer rates, the truncation radii imply surface magnetic fields of $B = 30-100$ kG, consistent with recent constraints based on X-ray periodicity. The absence of cyclotron humps out to 5 $μ$m rules out stronger MG-level fields. We make the data from the program publicly available to the community.

  PublisherOA PDF

• CHIME/Fast Radio Burst/Pulsar Discovery of a Nearby Long-period Radio Transient with a Timing Glitch

  The Astrophysical Journal Letters · 2025-09-04 · 15 citations

  articleOpen accessCorresponding

  Abstract We present the discovery of a 421 s long period transient using the CHIME telescope, CHIME J0630+25. The source is localized to R.A. = 06:30:38.4 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>±</mml:mo> <mml:mn>1</mml:mn> <mml:mo accent="false">′</mml:mo> </mml:math> decl. = 25:26:23 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>±</mml:mo> <mml:mn>1</mml:mn> <mml:mo accent="false">′</mml:mo> </mml:math> using voltage data acquired with the CHIME baseband system. A timing analysis shows that a model including a glitch is preferred over a nonglitch model with dF / F = 1.3 × 10 −6 , consistent with other glitching neutron stars. The timing model suggests a surface magnetic field of ∼1.5 × 10 15 G and a characteristic age of ∼1.28 × 10 6 yr. A separate line of evidence to support a strong local magnetic field is an abnormally high rotation measure of RM = −347.8(6) rad m −2 relative to CHIME J0630+25’s modest dispersion measure of 22(1) pc cm −2 , implying a dense local magneto-ionic structure. As a result, we believe that CHIME J0630+25 is a magnetized, slowly spinning, isolated neutron star. This marks CHIME J0630+25 as the longest period neutron star and the second-longest period neutron star with an inferred magnetar-like field. Based on dispersion measure models and comparison with pulsars with distance measurements, CHIME J0630+25 is located at a nearby distance of 170 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow/> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>100</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>310</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> pc (95.4%), making it an ideal candidate for follow-up studies.

  PublisherDOI

• A half-ring of ionized circumstellar material trapped in the magnetosphere of a white dwarf merger remnant

  ArXiv.org · 2025-07-18

  preprintOpen access

  In the recent years, the wealth of data on potential double white dwarf merger remnants made available by time-domain surveys like the Zwicky Transient Facility (ZTF), ATLAS, Kepler and TESS, together with spectroscopic counterparts such as SDSS V and DESI, has been essential in advancing our knowledge of ompact binary evolution. In particular, the emergence of peculiar systems offers invaluable insight into the limitations of our current best theories. The periodically variable white dwarf ZTF J200832.79+444939.67, hereafter ZTF J2008+4449, is possibly one of the most exotic discovered so far: a likely merger remnant showing signs of accretion from circumstellar material without a stellar or substellar companion. The nature of ZTF J2008+4449 as a merger remnant is supported by its physical properties: hot (35, 500±300 K) and massive (1.12±0.03 M⊙), the white dwarf is rapidly rotating on a period of ≈ 6.6 minutes and likely possesses exceptionally strong magnetic fields (∼ 400 − 600 MG) at its surface. Remarkably, we detect a significant period derivative of (1.8 ± 0.1) × 10^12 s/s, indicating that the white dwarf is spinning down. This, together with the detection of soft X-rays emissions, are tell-tale signs of accretion or, more generally, interaction with circumstellar material; in the absence of a companion, we believe this likely belongs to the fallback of gravitationally bound merger ejecta. We also detect Balmer emission whose unusual variability on the spin period of the white dwarf, showing Doppler shifts as high as ≈ 2, 000 km/s, is consistent with the trapping of a toroidal half-arc of ionised gas in the white dwarf’s magnetosphere.

  PublisherOA PDFDOI

• Eclipsing white dwarf from the Zwicky Transient Facility: II. Seven eclipsing double white dwarfs

  ArXiv.org · 2025-05-21

  preprintOpen access

  In a systematic search for eclipsing white dwarfs using Zwicky transient facility (ZTF) data, we found seven eclipsing double white dwarfs with orbital periods ranging from 45 minutes to 3 hours. We collected high-speed light curves, archival multi-wavelength data, and optical spectra for all systems and determined the binary parameters for each of them. We show that six of the systems are low-mass, double helium-core white dwarf binaries, with the last one a carbon-oxygen -- helium core white dwarf binary. These binaries slowly spiral inwards due to gravitational wave energy losses and are expected to merge within 36Myr--1.2Gyr, and we predict that the shortest orbital period binary will show a measurable eclipse arrival time delay within a decade. The two longest systems show a delay in the arrival time of the secondary eclipse, which we attribute to a small eccentricity of $\approx 2\times10^{-3}$. This is the first time that a non-zero eccentricity is measured in a compact double white dwarf binary. We suggest that these systems emerged from the common envelope with this small eccentricity, and because of the relatively long orbital period, gravitational wave emission has not yet circularised the binaries. Finally, we predict that relativistic apsidal precession will result in a change in the delay of the secondary eclipse that is measurable within a decade.

  PublisherOA PDFDOI

• Prospects for EMRI/MBH Parameter Estimation Using Quasiperiodic Eruption Timings: Short-timescale Analysis

  The Astrophysical Journal · 2025-10-09 · 4 citations

  articleOpen accessSenior author

  Abstract Quasiperiodic eruptions (QPEs) are luminous, recurring X-ray outbursts from galactic nuclei, with timescales of hours to days. While their origin remains uncertain, leading models invoke accretion disk instabilities or the interaction of a massive black hole (MBH) with a lower-mass secondary in an extreme mass ratio inspiral (EMRI). EMRI scenarios offer a robust framework for interpreting QPEs by characterizing observational signatures associated with the secondary’s orbital dynamics. This, in turn, enables extraction of the MBH/EMRI physical properties and provides a means to test the EMRI scenario, distinguishing models and addressing the question: what can QPE timings teach us about MBHs and EMRIs? In this study, we employ analytic expressions for Kerr geodesics to efficiently resolve the trajectory of the secondary object and perform GPU-accelerated Bayesian inference to assess the information content of QPE timings. Using our inference framework, referred to as QPE-FIT (Fast Inference with Timing; https://github.com/joheenc/QPE-FIT/tree/main ), we explore QPE timing constraints on astrophysical parameters, such as EMRI orbital parameters and MBH mass/spin. We find that mild-eccentricity EMRIs ( e ∼ 0.1–0.3) can constrain MBH mass and EMRI semimajor axis/eccentricity to the 10% level within tens of orbital periods, while MBH spin is unconstrained for the explored semimajor axes ≥100 R g and monitoring baselines <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi class="MJX-tex-calligraphic" mathvariant="script">O</mml:mi> </mml:math> (10–100) orbits. Introducing a misaligned precessing disk generally degrades inference of EMRI orbital parameters, but can constrain disk precession properties within 10%–50%. This work both highlights the prospect of QPE observations as dynamical probes of galactic nuclei and outlines the challenge of doing so in the multimodal parameter space of EMRI–disk collisions.

  PublisherDOI

• Double White Dwarf Tides with Multi-messenger Measurements

  ArXiv.org · 2025-04-10

  preprintOpen accessSenior author

  Short-period Galactic double white dwarf (DWD) systems will be observable both in visible light through photometric monitoring and in mHz-range gravitational waves (GWs) with forthcoming space-based laser interferometry such as LISA. When only photometric variability is used to measure DWD intrinsic properties, there is a degeneracy between the chirp mass and binary tidal interaction, as orbital frequency time derivative is set by both GW radiation and tides. Without expensive radial velocity data from spectroscopic monitoring, this degeneracy may be lifted in principle by directly measuring the second time derivative of the orbital frequency through photometric monitoring over an ultra-long time baseline. Alternatively, the degeneracy can be removed by exploiting information in both photometric variability and the coherent GW waveform. Investigating both approaches, we find that direct measurement of the second time derivative is likely infeasible for most DWDs, while the multi-messenger method will disentangle measurements of the chirp mass and the binary moments of inertia, for a large sample of tidally locked systems. The latter information will enable empirical tests of WD structure models with finite temperature effects.

  PublisherOA PDFDOI

• Magnetic Atmospheres and Circumstellar Interaction in J1901+1458: Revisiting the Most Compact White Dwarf Merger Remnant in the light of new UV and X-ray data

  ArXiv.org · 2025-09-03

  preprintOpen access

  Double degenerate white dwarf (WD) mergers can exhibit extreme magnetic fields exceeding $10^{8}$ G and rapid rotation, but their spectral-energy distributions and high-energy emission mechanisms remain poorly characterised. ZTF J1901+1458 stands out as the most compact and strongly magnetised object discovered in this class to date. Recent Chandra observations have revealed that the white dwarf is also a source of soft X-ray emission, inconsistent with a photospheric origin. We analyse new phase resolved UV spectroscopy from the HST combined with optical and near-infrared photometry and spectroscopy, with newly developed magnetic atmosphere models to determine its effective temperature, radius, mass, average surface magnetic field strength, and cooling age. Our results demonstrate that the spectral break at $\approx$3000 Å, observed in several highly magnetised WDs, is well-reproduced by our new models, which take into account the effect of magnetic opacities on the structure of the atmosphere. Our best-fit parameters for the WD yield an effective temperature ($T_{\rm{eff}}=28,015\pm 20$ K) and larger radius ($2630\pm10$ km) than previously reported. Furthermore, the near-infrared data exclude the presence of a stellar or brown dwarf companion hotter than $\approx$700 K. We also jointly analyse the previously published Chandra data and new XMM-Newton X-ray spectra. The faint X-ray emission, $L_X =(1.3\pm0.2)\times10^{27}$ erg/s is very soft and highly pulsed on the rotation period of the WD. We suggest that the X-rays are powered by accretion or via the interaction of the WD magnetosphere with CSM. If the rapidly rotating magnetic field could power a weak wind along open field lines, material could be extracted directly from the surface of the WD. Alternatively, accretion of fallback material from the merger or the tidal disruption of a planetary body are possible sources of CSM.

  PublisherOA PDFDOI

• A Gravitational-wave-detectable Candidate Type Ia Supernova Progenitor

  The Astrophysical Journal · 2025-07-09 · 2 citations

  articleOpen access

  Abstract Type Ia supernovae (SNe Ia), critical for studying cosmic expansion, arise from thermonuclear explosions of white dwarfs, but their precise progenitor pathways remain unclear. Growing evidence supports the “double-degenerate scenario,” where two white dwarfs interact. The absence of nondegenerate companions capable of explaining the observed SN Ia rate, along with observations of hypervelocity white dwarfs, interpreted as surviving companions of such systems, provide compelling evidence for this scenario. Upcoming millihertz gravitational-wave observatories like the Laser Interferometer Space Antenna (LISA) are expected to detect thousands of double-degenerate systems, though the most compact known candidate SN Ia progenitors produce marginally detectable signals. Here, we report observations of ATLAS J1138-5139, a binary white dwarf system with an orbital period of just 28 minutes. Our analysis reveals a 1 M ☉ carbon–oxygen white dwarf accreting from a high-entropy helium-core white dwarf. Given its mass, the accreting carbon–oxygen white dwarf is poised to trigger a typical-luminosity SN Ia within a few million years, to evolve into a stably transferring AM Canum Venaticorum (or AM CVn) system, or undergo a merger into a massive white dwarf. ATLAS J1138-5139 provides a rare opportunity to calibrate binary evolution models by directly comparing observed orbital parameters and mass-transfer rates closer to merger than any known SN Ia progenitor. Its compact orbit ensures detectability by LISA, demonstrating the potential of millihertz gravitational-wave observatories to reveal a population of SN Ia progenitors on a Galactic scale, paving the way for multimessenger studies offering insights into the origins of these cosmologically significant explosions.

  PublisherDOI

Frequent coauthors

• Eric C. Bellm

  91 shared

• Frank J. Masci

  90 shared

• Jan van Roestel

  60 shared

• M. J. Graham

  54 shared

• Russ R. Laher

  52 shared

• S. R. Kulkarni

  49 shared

• Maayane T. Soumagnac

  Bar-Ilan University

  47 shared

• Reed Riddle

  California Institute of Technology

  47 shared

Education

• Doctorate of Philosophy in Physics, Physics

  California Institute of Technology

  2021

• Bachelors of Science in Physics, Physics

  Massachusetts Institute of Technology

  2015

Awards & honors

• Pappalardo Fellowship, MIT (2021)