The Broad-band Counterpart of the Short GRB 200522A at $z=0.5536$: A Luminous Kilonova or a Collimated Outflow with a Reverse Shock?

Abstract

We present the discovery of the radio afterglow and near-infrared (NIR) counterpart of the Swift short GRB 200522A, located at a small projected offset of $\approx 1$ kpc from the center of a young, star-forming host galaxy at $z=0.5536$. The radio and X-ray luminosities of the afterglow are consistent with those of on-axis cosmological short GRBs. The NIR counterpart, revealed by our HST observations at a rest-frame time of $\approx 2.3$ days, has a luminosity of $\approx (1.3-1.7)\times 10^{42}$ erg s${}^{-1}$. This is substantially lower than on-axis short GRB afterglow detections, but is a factor of $\approx 8$-$17$ more luminous than the kilonova of GW170817, and significantly more luminous than any kilonova candidate for which comparable observations exist. The combination of the counterpart's color ($i-y=-0.08\pm 0.21$; rest-frame) and luminosity cannot be explained by standard radioactive heating alone. We present two scenarios to interpret the broad-band behavior of GRB 200522A: a synchrotron forward shock with a luminous kilonova (potentially boosted by magnetar energy deposition), or forward and reverse shocks from a $\approx 14^{\circ }$, relativistic (${\Gamma }_0\gtrsim 80$) jet. Models which include a combination of enhanced radioactive heating rates, low-lanthanide mass fractions, or additional sources of heating from late-time central engine activity may provide viable alternate explanations. If a stable magnetar was indeed produced in GRB 200522A, we predict that late-time radio emission will be detectable starting $\approx 0.3$-$6$ years after the burst for a deposited energy of $\approx 10^{53}$ erg. Counterparts of similar luminosity to GRB 200522A associated with gravitational wave events will be detectable with current optical searches to $\approx 250$ Mpc.

33 pages, 13 figures, 5 tables. Submitted to AAS Journals

References in corpus (59)

• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
• Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. II. UV, Optical, and Near-IR Light Curves and Comparison to Kilonova Models
• Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
• An online repository of Swift/XRT light curves of GRBs
• The X-ray counterpart to the gravitational wave event GW 170817
• A kilonova as the electromagnetic counterpart to a gravitational-wave source
• Constraining the Low-Mass Slope of the Star Formation Sequence at 0.5<z<2.5
• Long gamma-ray bursts and core-collapse supernovae have different environments
• Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis
• Illuminating Gravitational Waves: A Concordant Picture of Photons from a Neutron Star Merger
• The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars
• Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger
• The Combined Ultraviolet, Optical, and Near-Infrared Light Curves of the Kilonova Associated with the Binary Neutron Star Merger GW170817: Unified Data Set, Analytic Models, and Physical Implications
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. III. Optical and UV Spectra of a Blue Kilonova From Fast Polar Ejecta
• Neutrino-driven winds from neutron star merger remnants
• Kilonovae
• The discovery of the electromagnetic counterpart of GW170817: kilonova AT 2017gfo/DLT17ck
• No supernovae associated with two long-duration gamma ray bursts
• The 1% Concordance Hubble Constant
• Time Dependent Monte Carlo Radiative Transfer Calculations For 3-Dimensional Supernova Spectra, Lightcurves, and Polarization
• Neutrino signatures and the neutrino-driven wind in Binary Neutron Star Mergers
• Kilonova Light Curves from the Disk Wind Outflows of Compact Object Mergers
• The dynamical mass ejection from binary neutron star mergers: Radiation-hydrodynamics study in general relativity
• New fully empirical calibrations of strong-line metallicity indicators in star forming galaxies
• Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger
• MASTER optical detection of the first LIGO/Virgo neutron stars merging GW170817
• Klein-Nishina Effects on Optically Thin Synchrotron and Synchrotron Self-Compton Spectrum
• Follow up of GW170817 and its electromagnetic counterpart by Australian-led observing programs
• J-GEM observations of an electromagnetic counterpart to the neutron star merger GW170817
• Full Transport Model of GW170817-Like Disk Produces a Blue Kilonova
• A Comparison of the Afterglows of Short- and Long-Duration Gamma-Ray Bursts
• Mass ejection from neutron star mergers: different components and expected radio signals
• Necessary Conditions for Short Gamma-Ray Burst Production in Binary Neutron Star Mergers
• Observations of the first electromagnetic counterpart to a gravitational wave source by the TOROS collaboration
• Setting UBVRI Photometric Zero-Points Using Sloan Digital Sky Survey ugriz Magnitudes
• A magnetar engine for short GRBs and kilonovae
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-ray Bursts
• Correlations of Prompt and Afterglow Emission in Swift Long and Short Gamma Ray Bursts
• Accurate early positions for Swift GRBS: enhancing X-ray positions with UVOT astrometry
• Follow-up of the Neutron Star Bearing Gravitational Wave Candidate Events S190425z and S190426c with MMT and SOAR
• Discovery of the afterglow and host galaxy of the low redshift short GRB 080905A
• Collimated outflows from long-lived binary neutron star merger remnants
• The Afterglow and Early-Type Host Galaxy of the Short GRB 150101B at z=0.1343
• A Reverse Shock in GRB 160509A
• Connecting the progenitors, pre-explosion variability, and giant outbursts of luminous blue variables with Gaia16cfr
• Radio Constraints on Long-Lived Magnetar Remnants in Short Gamma-Ray Bursts
• Constraints on the circumburst environments of short gamma-ray bursts
• A Late-time Radio Survey of Short GRBs at $z<0.5$: New Constraints on the Remnants of Neutron Star Mergers
• Energy Sources and Light Curves of Macronovae
• Precursor flares of short gamma-ray bursts from crust yielding due to tidal resonances in coalescing binaries of rotating, magnetized neutron stars
• Are short gamma-ray bursts collimated? GRB050709, a flare but no break
• Discovery of the optical afterglow and host galaxy of short GRB181123B at $z=1.754$: Implications for Delay Time Distributions
• Constraining the long-lived magnetar remnants in short gamma-ray bursts from late-time radio observations
• The distant, galaxy cluster environment of the short GRB 161104A at $z\sim 0.8$ and a comparison to the short GRB host population
• Deep ATCA and VLA radio observations of short-GRB host galaxies. Constraints on star-formation rates, afterglow flux, and kilonova radio flares

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• Where has all the $r$-process gone? Timescales for GRB-Kilonovae to Enrich their Host Galaxies
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• Characterising EP241107a: Multiwavelength Observations of an Einstein Probe-detected Fast X-ray Transient
• Discovery and Analysis of Afterglows from Poorly Localised GRBs with the Gravitational-wave Optical Transient Observer (GOTO) All-sky Survey
• Exploring Jet Structure and Dynamics in Short Gamma Ray Bursts: A Case Study on GRB 090510
• Kilonova and progenitor properties of merger-driven gamma-ray bursts
• GOTO identification and broadband modelling of the counterpart to the SVOM GRB 250818B