Swift J1644+57 as an off-axis Jet

Abstract

One of the intriguing puzzles concerning Swift J1644+57, the first jetted tidal disruption event (TDE) discovered, is the constant increase in its jet energy, as implied by radio observations. During the first two hundred days the jet energy has increased by an order of magnitude. We suggest that the jet was viewed slightly off-axis. In this case, the apparent energy increase arises due to the slowing down of the jet and the corresponding broadening of its beaming cone. Using equipartition analysis, we infer an increasing jet energy as a larger region of the jet is observed. A simple off-axis model accounts nicely for the multi-wavelength radio observations, resolving this long-standing puzzle. The model allows us to self-consistently evolve the synchrotron signature from an off-axis jet as a function of time. It also allows us to estimate, for the first time, the beaming angle of the jet, ${\theta }_0\approx 21^{\circ }$. Considering existing limits on the black hole mass, $\lesssim 10^7{M}_{\odot }$, this angle implies that the prompt phase beaming corrected luminosity of Swift J1644+57, $\sim 10^{47}$ergs/sec, was super Eddington. We also present a closure relation between the spectral and temporal flux for off-axis jets, which can be used to test whether a given radio transient is off-axis or not.

arXiv comment10 pages, 8 figures. Published in MNRAS

References in corpus (51)

• Jets in GRBs
• Illuminating Gravitational Waves: A Concordant Picture of Photons from a Neutron Star Merger
• The Dynamics and Light Curves of Beamed Gamma Ray Burst Afterglows
• The Shape of Spectral Breaks in GRB Afterglows
• A relativistic jetted outburst from a massive black hole fed by a tidally disrupted star
• Discovery of the Onset of Rapid Accretion by a Dormant Massive Black Hole
• On The Synchrotron Self-Compton Emission from Relativistic Shocks and Its Implications for Gamma-Ray Burst Afterglows
• Afterglow lightcurves, viewing angle and the jet structure of gamma-ray bursts
• Analytic Light-Curves of Gamma-Ray Burst Afterglows: Homogeneous versus Wind External Media
• The Birth of a Relativistic Outflow in the Unusual γ-ray Transient Swift J164449.3+573451
• Compact radio emission indicates a structured jet was produced by a binary neutron star merger
• Late time afterglow observations reveal a collimated relativistic jet in the ejecta of the binary neutron star merger GW170817
• Off-Axis Afterglow Emission from Jetted Gamma-Ray Bursts
• An extremely luminous panchromatic outburst from the nucleus of a distant galaxy
• The Binary Neutron Star event LIGO/VIRGO GW170817 a hundred and sixty days after merger: synchrotron emission across the electromagnetic spectrum
• The Evolution of a Structured Relativistic Jet and GRB Afterglow Light-Curves
• Swift J1644+57 gone MAD: the case for dynamically-important magnetic flux threading the black hole in a jetted tidal disruption event
• A year in the life of GW170817: the rise and fall of a structured jet from a binary neutron star merger
• Radio Monitoring of the Tidal Disruption Event Swift J164449.3+573451. I. Jet Energetics and the Pristine Parsec-Scale Environment of a Supermassive Black Hole
• Radio Monitoring of the Tidal Disruption Event Swift J164449.3+573451. II. The Relativistic Jet Shuts Off and a Transition to Forward Shock X-ray/Radio Emission
• A Dynamical Model for Hot Gas in the Galactic Center
• Afterglow Imaging and Polarization of Misaligned Structured GRB Jets and Cocoons: Breaking the Degeneracy in GRB 170817A
• A thousand days after the merger: continued X-ray emission from GW170817
• Afterglow Lightcurves from Misaligned Structured Jets
• The Case for Anisotropic Afterglow Efficiency within Gamma-Ray Burst Jets
• Swift J1644+57: A White Dwarf Tidally Disrupted by a 10^4 M_{odot} Black Hole?
• Radius constraints and minimal equipartition energy of relativistically moving synchrotron sources
• A general scheme for modeling gamma-ray burst prompt emission
• Afterglow Model for the Radio Emission from the Jetted Tidal Disruption Candidate Swift J1644+57
• Radio Monitoring of the Tidal Disruption Event Swift J164449.3+573451. III. Late-time Jet Energetics and a Deviation from Equipartition
• The Synchrotron Spectrum of Fast Cooling Electrons Revisited
• On the lateral expansion of GRB jets
• Constraints on the Synchrotron Emission Mechanism in GRBs
• Synthetic off-axis light curves for low energy gamma-ray bursts
• Relativistic Jet Dynamics and Calorimetry of Gamma-Ray Bursts
• Observational constraints on the structure of gamma-ray burst jets
• The radio afterglow of Swift J1644+57 reveals a powerful jet with fast core and slow sheath
• Light Curves from an Expanding Relativistic Jet
• The influence of circumnuclear environment on the radio emission from TDE jets
• Radio Monitoring of the Tidal Disruption Event Swift J164449.3+573451. IV. Continued Fading and Non-Relativistic Expansion
• Generalized compactness limit from an arbitrary viewing angle
• The Definitive X-ray Light Curve of Swift J164449.3+573451
• Generalized equipartition method from an arbitrary viewing angle
• Numerical Simulations of an Initially Top-Hat Jet and the Afterglow of GW170817/GRB170817A
• Radio constraint on outflows from tidal disruption events
• On the origin of the radio emission of Sw 1644+57
• Diverse Jet Structures Consistent with the Off-axis Afterglow of GRB 170817A
• No apparent superluminal motion in the first-known jetted tidal disruption event Swift J1644+5734
• A model for the multiwavelength radiation from tidal disruption event Swift J1644+57
• Flares in gamma-ray burst X-ray afterglows as prompt emission from slightly misaligned structured jets
• Synchrotron Afterglow Model for AT 2022cmc: Jetted Tidal Disruption Event or Engine-Powered Supernova?

Cited by in corpus (7)

• Two-component off-axis jet model for radio flares of tidal disruption events
• Can GRB 250702B be explained as the tidal disruption of a white dwarf by an intermediate mass black hole? Yes
• Ultra-long MeV transient from a relativistic jet: a tidal disruption event candidate
• Jet Tilt Instability from Stream-Disk Interactions in MAD Disks
• Synchrotron break frequencies of mildly-to-highly relativistic outflows observed off-axis
• AT2019ijn: a fast-rising, slow-decaying blue optical transient with exceptionally bright radio emission
• AT2024lhc and AT2024kmq in the landscape of featureless tidal disruption events