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

By Ryan Chornock, E. Berger, D. Kasen, P. Cowperthwaite, M. Nicholl, V. Villar, K. Alexander, P. Blanchard, T. Eftekhari, W. Fong and 22 more. 2017

389 citations recorded by the source corpus.

We present a near-infrared spectral sequence of the electromagnetic counterpart to the binary neutron star merger GW170817 detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo. Our data set comprises seven epochs of J+H spectra taken with FLAMINGOS-2 on Gemini-South between 1.5 and 10.5 days after the merger. In the initial epoch, the spectrum is dominated by a smooth blue continuum due to a high-velocity, lanthanide-poor blue kilonova component. Starting the following night, all of the subsequent spectra instead show features that are similar to those predicted in model spectra of material with a high concentration of lanthanides, including spectral peaks near 1.07 and 1.55 μm. Our fiducial model with 0.04 M⊙ of ejecta, an ejection velocity of v = 0.1c, and a lanthanide concentration of Xlan = 10−2 provides a good match to the spectra taken in the first five days, although it over-predicts the late-time fluxes. We also explore models with multiple fitting components, in each case finding that a significant abundance of lanthanide elements is necessary to match the broad spectral peaks that we observe starting at 2.5 days after the merger. These data provide direct evidence that binary neutron star mergers are significant production sites of even the heaviest r-process elements.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/272742ce1ddccfa89b26323246dba5061df076b3

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In Astronomy and Astrophysics

1. B. Metzger
2. E. Berger
3. E. Quataert
4. Bing Zhang
5. Michela Mapelli
6. David Radice
7. T. Thompson
8. N. Giacobbo

Citations in the corpus

• A Magnetar Origin for the Kilonova Ejecta in GW170817 (2018, background): “The properties of the optical/NIR emission agreed remarkably well with those predicted for “kilonova” (KN) emission powered by the radioactive decay of r-process nuclei (Li & Paczyński 1998; Metzger et al. 2010; Roberts et al. 2011; Barnes & Kasen 2013; Tanaka & Hotokezaka 2013; Grossman et al. 2014”
• Constraints on the neutron star equation of state from AT2017gfo using radiative transfer simulations (2018, methodology): “These results can be compared to estimates obtained from a reanalysis of GW170817 (De et al. 2018), which incorporates quasi-universal relations for the tidal deformability and obtains 90 per cent lower bounds on the tidal deformability ̃ 117 and 90 per cent upper bounds on the mass ratio q 1.51.”
• Long-term GRMHD simulations of neutron star merger accretion discs: implications for electromagnetic counterparts (2018, methodology): “Evidence for the r-process comes from the photometric and spectroscopic properties of the observed kilonova (e.g., Cowperthwaite et al. 2017; Chornock et al. 2017; Drout et al. 2017; Tanaka et al. 2017; Tanvir et al. 2017).”
• The Binary Neutron Star Event LIGO/Virgo GW170817 160 Days after Merger: Synchrotron Emission across the Electromagnetic Spectrum (2018, background): “…emission powered by the radioactive decay of heavy elements freshly synthesized in the merger ejecta (i.e. the kilonova emission, KN; Metzger 2017; Chornock et al. 2017; Coulter et al. 2017; Cowperthwaite et al. 2017; Drout et al. 2017; Kasliwal et al. 2017; Nicholl et al. 2017; Pian et al.…”
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta (2017, methodology): “For the first time, we can make specific predictions for the KN radio emission using the parameters inferred from modeling of the UV/optical/NIR emission (Chornock et al. 2017; Cowperthwaite et al. 2017; Nicholl et al. 2017).”
• Three-dimensional GRMHD Simulations of Neutrino-cooled Accretion Disks from Neutron Star Mergers (2017, methodology): “We note that v̄∞ of the unbound outflow corresponds to the kinetic energy-averaged value vKN ≈ 0.1c, similar to that required to explain the red KN component observed in the recent GW170817 event (e.g. Chornock et al. 2017; Villar et al. 2017).”
• GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations (2017, background): “05~ of material (Chornock et al. 2017; Cowperthwaite et al. 2017; Drout et al. 2017; Nicholl et al. 2017; Perego et al. 2017; Rosswog et al. 2017; Tanaka et al. 2017; Tanvir et al. 2017; Villar et al. 2017).”
• The progenitors of compact-object binaries: impact of metallicity, common envelope and natal kicks (2018, background): “…gamma-rays (Abbott et al. 2017e; Goldstein et al. 2017; Savchenko et al. 2017; Margutti et al. 2017; Coulter et al. 2017; Soares-Santos et al. 2017; Chornock et al. 2017; Cowperthwaite et al. 2017; Nicholl et al. 2017; Pian et al. 2017; Alexander et al. 2017), marking the beginning of…”
• AT 2017gfo: An Anisotropic and Three-component Kilonova Counterpart of GW170817 (2017, background): “Meanwhile, the near infrared (IR) luminosity raised, reaching a maximum several days after the merger (Chornock et al. 2017).”
• Bayesian inference for compact binary coalescences with bilby: validation and application to the first LIGO–Virgo gravitational-wave transient catalogue (2020, background): “…the structures of gamma-ray bursts (Abbott et al. 2017f; Mooley et al. 2018; Margutti et al. 2018; Fong et al. 2019; Biscoveanu et al. 2020b), and identifying the origins of heavy elements (Abbott et al. 2017g; Chornock et al. 2017; Tanvir et al. 2017; Kasliwal et al. 2019; Watson et al. 2019).”
• Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA (2013, background): “…this involves matching a bank of waveform templates (Sathyaprakash and Dhurandhar 1991; Owen 1996; Owen and Sathyaprakash 1999; Babak et al. 2006; Cokelaer 2007; Prix 2007; Harry et al. 2009; Ajith et al. 2014; Brown et al. 2012; Capano et al. 2016; Dal Canton and Harry 2017) to the data (Abbott…”