I'm a theoretical high energy astrophysicist, currently Flatiron Research/THEA Fellow in the Center for Computational Astrophysics at the Flatiron Institute.
Prior to joining CCA, I was a Rothschild/CIERA fellow at CIERA@Northwestern University.
I completed my Ph.D. with Prof. Ehud Nakar in Tel Aviv University.

I combine state-of-the-art 3D general-relativistic magnetohydrodynamic simulations with analytic calculations to:
(1) Predict new multi-messenger (gravitational-wave, electromagnetic, neutrino and cosmic-ray) signals.
(2) Interpret current multi-messenger observables such as the central engines of long GRBs and short GRBs in binary mergers, superluminous supernovae, and fast blue optical transients.
(3) Formulate theoretical modeling of the fundementral properties of black holes and the underlying physics of associated catactlysmic phenomena.

Download my CV.

Recent research

A Unified Model of Kilonovae and GRBs in Binary Mergers Establishes Neutron Stars as the Central Engines of Short GRBs

What is the remnant of a binary merger? What is the engine of the GRB jets? Can we infer the merger properties from electromagnetic observations? We introduce a theoretical framework that connects binary merger populations with GRB and kilonova observations, enabling us to address these fundemntal questions. Based on our unified model and observations, we find that long binary GRBs, powered by massive accretion disks around black holes, are accompanied by bright, red kilonovae. In contrast, short binary GRBs are accompanied by comparably luminous, but bluer kilonovae, establishing hypermassive neutron stars as their engines. As a result, black hole-neutron star mergers likely contribute exclusively to the long binary GRB population with red kilonovae. Our findings suggest that GW170817 may, in fact, have been an lbGRB to on-axis observers.
Read more in:
Unified Picture of kilonovae and GRBs from Binary Mergers

She’s Got Her Mother’s Hair: End-to-End Collapsar Simulations Unveil the Origin of Black Holes' Magnetic Field

The two key ingredients for a Blandford-Znajek powered jet - rapid rotation and a strong magnetic field - seem mutually exclusive. Strong fields transport angular momentum outwards quickly, slowing down the core prior to collapse. Using MESA stellar evolution models, we show that the low net magnetic flux fed to the black hole (BH) horizon is far too small to power GRB jets. Instead, we propose a novel scenario in which the BH acquires its magnetic ''hair'' from its progenitor proto-neutron star (PNS), which is likely highly magnetized from an internal dynamo. The PNS spin-down energy released before collapse matches the kinetic energy in Ic-BL supernovae, while the nascent BH's spin and magnetic flux produce jets consistent with the characteristics observed in GRBs. We map our MESA models to 3D GRMHD simulations and confirm that accretion disks confine the strong magnetic flux initiated near a rotating BH, enabling the launch of GRB jets, whereas a slower spinning BH or one without a disk fails to do so.
Read more in:
How Collapsar Black Holes Acquire Their Magnetic Fields

Late Jets, Early Sparks: Illuminating the Premaximum Bumps in Superluminous Supernovae

Superluminous supernovae (SLSNe), which radiate 10-100 times more energy than ordinary stellar explsions, are considered to be powered by a millisecond magnetar or accreting black hole. Both black hole and magnetar engines are expected to channel a fraction of their luminosity into a collimated relativistic jet. Using 3D simulations, we explore the interaction of a relativistic jet with a duration of days compatible with those needed to power SLSNe, launched into the envelope of the exploding star. The jet successfully breaks through the expanding ejecta and its radiatively efficient shocked cocoon powers ultraviolet/optical emission lasting several days after the explosion. The luminosity and temperature of the cocoon emission match those of the ''bumps'' in SLSNe light curves observed weeks prior to the optical maximum in many SLSNe.
Read more in:
Jets Illuminating the SLSN Early Bumps

In LIGO’s Sight? Vigorous Coherent Gravitational Waves from Cooled Collapsar Disks

First numerical study of gravitational waves (GWs) from collapsar disks. In strongly-cooled disks, trapped Rossby vortices generate vigorous coherent emission. Assuming an optimistic detection threshold of matched-filter SNR=20 and a rate similar to supernovae Ib/c, LIGO-Virgo-KAGRA (LVK) could detect ~1 event annually, suggesting that GW events may already be hidden in observed data. The GW amplitudes from collapsar disks are >100 higher with a substantially greater event rate than those expected from core-collapse supernovae, making them potentially the most promising burst-type GW class for detection in LVK and Cosmic Explorer. This highlights the importance of further exploration and modeling of GWs from collapsar disks, promising insights into the physics of collapsing stars.
Read more in:
Vigorous Coherent GWs from Collapsar Disks

A Unified Picture of Short and Long Gamma-ray Bursts from Compact Binary Mergers

First theoretical framework that connects the underlying physics of binary systems to GRB observations. It provides a first-pricinples explanation for the origin of the constant power GRB prompt emission and decaying extended emission for the first time. Massive post-merger accretion disks, which arise from unequal-mass NS-NS mergers, inevitably produce long GRBs such as 211211A. At the same time, both meta-stable NSs and newly formed BHs remain viable candidates as central engines for standard short GRBs.
Read more in:
Unified Picture of GRBs from Binary Mergers

BH-NS mergers

First numerical simulations that track the evolution of a black hole-neutron star merger from pre-merger to r>1e11 cm. The disk that forms after a merger of mass ratio q=2 ejects massive disk winds (3e-2−5e−2 Msol). The resulting jets feature excessive duration compared to typical short gamma-ray bursts (sGRBs). This provides a natural explanation for long sGRBs such as GRB 211211A. The jet-wind interaction leads to a power-law angular energy distribution by inflating an energetic cocoon which emits strong wide-angle emission.
Read more in:
Seconds-long GRB emission
Hours-ling cocoon emission

Collapsar black holes are slowly spinning

The connection between the black hole spin and the jet power enables us to contrain the natal spin of black holes from observations of GRBs. The characteristic GRB luminosity indicates that black holes are most likely slowly spinning. Furthermore, collapsar black holes undergo substantial spin-down as the jets extract their angular momentum, converging to dimensionless spins of ~0.2.
Read more in:
Collapsar Black Holes Are Likely Born Slowly Spinning
Collapsar Gamma-ray Bursts Grind their Black Hole Spins to a Halt

New LVK-detectable Gravitational-wave Sources

A new class of noninspiral GW sources-the end states of massive stars-that can produce the brightest simulated stochastic GW burst signal in the LVK bands known to date, and could be detectable in LVK run A+. Some dying massive stars launch bipolar relativistic jets, which inflate a turbulent energetic bubble-cocoon-inside of the star, which emits quasi-isotropic GW emission in the LVK band, ~10-100 Hz, over a characteristic jet activity timescale ~10-100 s.
Read more in:
Jetted and Turbulent Stellar Deaths: New LVK-detectable Gravitational-wave Sources

GRMHD simulations of outflows from black holes to the photosphere

First 3D general-relativity magnetohydrodynamic simulations that span over six orders of magnitude in space and time. The simulations shift the evolution paradigm by revealing inevitable misalignment between the jet and the black hole rotational axis. As a result, the jet wobbles, implying lower intrinsic GRB rates and can naturally explain the long-standing mystery of quiescent times in GRB lightcurves.
Read more in:
Black Hole to Photosphere: 3D GRMHD Simulations of Collapsars Reveal Wobbling and Hybrid Composition Jets

Shocked jets in CCSNe can power FBOTs

Relativistic jets in hydrogen-rich collapsing stars can naturally explain the multi-wavelength fast blue optical transient (FBOT) observables: The jet-star interaction forms a cocoon which powers cooling emission during the first few weeks. The cocoon-CSM interaction generates synchrotron self-absorbed emission in the radio bands, featuring a steady rise on a month timescale. After a few months the relativistic outflow decelerates, enters the observer’s line of sight, peaks in radio and decays thereafter. The cocoon becomes optically thin to X-rays ∼ day after the collapse, allowing X-ray photons to diffuse from the central engine to the observer.
Read more in:
Shocked jets in CCSNe can power the zoo of fast blue optical transients

The propagation of relativistic jets in expanding media

Comprehensive analytic model of relativistic jet propagation in expanding homologous media, covering the entire jet evolution as well as a range of configurations that are relevant to binary mergers. These include low- and high-luminosity jets, unmagnetized and mildly magnetized jets, time-dependent luminosity jets, and Newtonian and relativistic head velocities. The model provides simple analytic formulae (calibrated by 3D simulations) for the jet head propagation and breakout times.
Read more in:
The propagation of relativistic jets in expanding media

Origin of neutrino null detection in GRBs

Mixing between the jet and cocoon, which is present in all types of jets, inhibits the formation of subphotospheric collisionless shocks. However, a mild magnetization may lead to the formation of collisionless subshocks, which allow efficient proton acceleration. Considering shear acceleration and diffusive shock acceleration at collimation shocks, internal shocks, shock breakout, and external shocks, we provided the first estimate for neutrino and cosmic-ray signals from self-consistent simulations of GRBs in binary neutron star (BNS) mergers and collapsars.

Read more about GRBs in BNS mergers in:
The role of jet-cocoon mixing, magnetization and shock breakout in neutrino and cosmic-ray emission from short GRBs

Read more about GRBs in collapsars in:
State-of-the-Art Collapsar Jet Simulations Imply Undetectable Subphotospheric Neutrinos

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