AT2018cow: a luminous millimeter transient

Abstract

We present detailed submillimeter- through centimeter-wave observations of the extraordinary extragalactic transient AT2018cow. The apparent characteristics -- the high radio luminosity, the long-lived emission plateau at millimeter bands, and the sub-relativistic velocity -- have no precedent. A basic interpretation of the data suggests $E_k\gtrsim 10^{48}$ erg coupled to a fast but sub-relativistic ($v\approx 0.13c$) shock in a dense ($n_e\approx 3\times 10^5$cm${}^{-3}$) medium. We find that the X-ray emission is not naturally explained by an extension of the radio-submm synchrotron spectrum, nor by inverse Compton scattering of the dominant blackbody UVOIR photons by energetic electrons within the forward shock. By $\Delta t\approx 20$days, the X-ray emission shows spectral softening and erratic inter-day variability. Taken together, we are led to invoke an additional source of X-ray emission: the central engine of the event. Regardless of the nature of this central engine, this source heralds a new class of energetic transients shocking a dense medium, which at early times are most readily observed at millimeter wavelengths.

Accepted to the Astrophysical Journal on 26 Nov 2018. 41 pages, 9 figures. In this version we replaced the figures with higher-quality versions, and fixed several typos

References in corpus (63)

• Astropy: A Community Python Package for Astronomy
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The Swift X-ray Telescope
• Spectra and Light Curves of Gamma-Ray Burst Afterglows
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• The Swift Ultra-Violet/Optical Telescope
• Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
• ATLAS: A High-Cadence All-Sky Survey System
• The Physics of Gamma-Ray Bursts and Relativistic Jets
• Supernova Light Curves Powered by Young Magnetars
• The Shape of Spectral Breaks in GRB Afterglows
• The Submillimeter Array
• The Birth of a Relativistic Outflow in the Unusual γ-ray Transient Swift J164449.3+573451
• Radio Remnants of Compact Binary Mergers - the Electromagnetic Signal that will follow the Gravitational Waves
• Magnetar Spindown, Hyper-Energetic Supernovae, and Gamma Ray Bursts
• Rapidly-Evolving and Luminous Transients from Pan-STARRS1
• The Australia Telescope Compact Array Broadband Backend (CABB)
• A Common Origin for Cosmic Explosions Inferred from Fireball Calorimetry
• Circumstellar Emission from Type Ib and Ic Supernovae
• A Relativistic Type Ibc Supernova Without a Detected Gamma-ray Burst
• A 450-day light curve of the radio afterglow of GRB 970508: Fireball calorimetry
• The Cow: discovery of a luminous, hot and rapidly evolving transient
• Quasars: the characteristic spectrum and the induced radiative heating
• External forward shock origin of high energy emission for three GRBs detected by Fermi
• The Afterglow of GRB 130427A from 1 to 10^16 GHz
• Discovery of an outflow from radio observations of the tidal disruption event ASASSN-14li
• The sub-energetic GRB 031203 as a cosmic analogue to GRB 980425
• Supernova PTF 09uj: A possible shock breakout from a dense circumstellar wind
• 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
• Rapidly evolving transients in the Dark Energy Survey
• The Radio and X-ray Luminous SN 2003bg and the Circumstellar Density Variations Around Radio Supernovae
• A unified picture for low-luminosity and long gamma-ray bursts based on the extended progenitor of llgrb 060218/SN 2006aj
• 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 Reverse Shock in GRB 130427A
• Magnetar Driven Shock Breakout and Double Peaked Supernova Light Curves
• Magnetar Driven Bubbles and the Origin of Collimated Outflows in Gamma-ray Bursts
• The signature of the central engine in the weakest relativistic explosions: GRB100316D
• A Giant Outburst at Millimeter Wavelengths in the Orion Nebula
• Long Term Radio Monitoring of SN 1993J
• A multi-wavelength investigation of the radio-loud supernova PTF11qcj and its circumstellar environment
• Radio Monitoring of the Tidal Disruption Event Swift J164449.3+573451. III. Late-time Jet Energetics and a Deviation from Equipartition
• The Radio and X-ray Luminous Type Ibc Supernova 2003L
• An Early & Comprehensive Millimeter and Centimeter Wave and X-ray Study of Supernova 2011dh: A Non-Equipartition Blastwave Expanding into A Massive Stellar Wind
• Detailed study of the GRB 030329 radio afterglow deep into the non-relativistic phase
• Timing and Flux Evolution of the Galactic Center Magnetar SGR J1745-2900
• Millimeter Observations of GRB 030329: Continued Evidence for a Two-Component Jet
• X-ray Swift observations of SN 2018cow
• Endurance of SN 2005ip after a decade: X-rays, radio, and H-alpha like SN 1988Z require long-lived pre-supernova mass loss
• How do stars gain their mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star Forming Regions
• EVLA Observations of the Radio Evolution of SN 2011dh
• SN 2007bg: The Complex Circumstellar Environment Around One of the Most Radio-Luminous Broad-Lined Type Ic Supernovae
• Pre-ALMA observations of GRBs in the mm/submm range
• SN2010jp (PTF10aaxi): A Jet-Driven Type II Supernova
• Compton Heating of the Intergalactic Medium by the Hard X-ray Background
• On the radio spectra of supernova remnants
• Towards understanding the physics of collisionless relativistic shocks
• Synchrotron Self-inverse Compton Radiation From Reverse-shock on GRB120326A
• Millimeter Transient Point Sources in the SPTpol 100 Square Degree Survey
• A prompt radio transient associated with a gamma-ray superflare from the young M dwarf binary DG CVn
• Catching jetted tidal disruption events early in millimetre
• The ATCA Seeing Monitor
• GRB 110715A: The peculiar multiwavelength evolution of the first afterglow detected by ALMA
• SPIRITS 16tn in NGC 3556: A heavily obscured and low-luminosity supernova at 8.8 Mpc

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• A Wind-Driven Model: Application to Peculiar Transients AT2018cow and iPTF14hls
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• Dust Echoes from Luminous Fast Blue Optical Transients
• Extragalactic Millimeter Transients in the Era of Next Generation CMB Surveys
• Radio Analysis of SN 2004C Reveals an Unusual CSM Density Profile as a Harbinger of Core Collapse
• Radio Emission from Supernovae in the Very Early Phase: Implications for the Dynamical Mass Loss of Massive Stars
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• The Exotic Type Ic Broad-Lined Supernova SN 2018gep: Blurring the Line Between Supernovae and Fast Optical Transients
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• The Broad-lined Ic Supernova ZTF18aaqjovh (SN 2018bvw): An Optically-discovered Engine-driven Supernova Candidate with Luminous Radio Emission
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• Late-time Hubble Space Telescope Observations of AT 2018cow. II. Evolution of a UV bright Underlying Source 2--4 Yr Post-discovery
• A possible 250-second X-ray quasi-periodicity in the fast blue optical transient AT2018cow
• Explaining the statistical properties of Fast Radio Bursts with suppressed low-frequency emission
• The Atacama Cosmology Telescope: Systematic Transient Search of 3-Day Maps
• Late-Time Evolution and Modeling of the Off-Axis Gamma-ray Burst Candidate FIRST J141918.9+394036
• Modeling kilonova afterglows: Effects of the thermal electron population and interaction with GRB outflows
• A flash of polarized optical light points to an aspherical "cow"
• State-of-the-Art Collapsar Jet Simulations Imply Undetectable Subphotospheric Neutrinos
• Wind-Reprocessed Transients from Stellar-mass Black Hole Tidal Disruption Events
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• AT2018lqh and the nature of the emerging population of day-scale duration optical transients
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• FIRST J153350.8+272729: the radio afterglow of a decades-old tidal disruption event
• ALMA observations of molecular gas in the host galaxy of AT2018cow
• On the nature of Fast Blue Optical Transients
• A Flat-Spectrum Radio Transient at 122 Mpc consistent with an Emerging Pulsar Wind Nebula
• Neutrino Emission from Luminous Fast Blue Optical Transients
• Energy-conserving, Relativistic Corrections to Strong Shock Propagation
• Multi-wavelength observations of the Luminous Fast Blue Optical Transient AT2023fhn
• Radio evolution of a Type IIb supernova SN 2016gkg
• Late-time Hubble Space Telescope Observations of AT 2018cow. I. Further Constraints on the Fading Prompt Emission and Thermal Properties 50--60 Days Post-discovery
• Radiative diffusion in a time-dependent outflow: a model for fast blue optical transients
• On the optical transients from double white-dwarf mergers
• Real-time Discovery of AT2020xnd: A Fast, Luminous Ultraviolet Transient with Minimal Radioactive Ejecta
• VLBI observations of supernova PTF11qcj: Direct constraints on the size of the radio ejecta
• Models of Millimeter and Radio Emission from Interacting Supernovae
• The Atacama Cosmology Telescope: Flux Upper Limits from a Targeted Search for Extragalactic Transients
• Magnetic Field Amplification and Particle Acceleration in Weakly Magnetized Trans-relativistic Electron-ion Shocks
• The soft X-ray transient EP241021a: A cosmic explosion with a complex off-axis jet and cocoon from a massive progenitor
• Cosmic ray acceleration and non-thermal emission from fast luminous optical transient sources
• Searching for Radio Transients with Inverted Spectra in Epoch 1 of VLASS and VCSS, and Identification of a Sample of Candidate Relativistic Nuclear Transients
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• The spectra of a radiative reprocessing outflow model for fast blue optical transients
• Luminous Fast Blue Optical Transients as "Failed" Gravitational-wave Sources: Helium Core$-$Black Hole Mergers Following Delayed Dynamical Instability
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