Evidence for Dynamically Driven Formation of the GW170817 Neutron Star Binary in NGC 4993

Abstract

We present a study of NGC 4993, the host galaxy of the GW170817 gravitational wave event, the GRB170817A short gamma-ray burst (sGRB) and the AT2017gfo kilonova. We use Dark Energy Camera imaging, AAT spectra and publicly available data, relating our findings to binary neutron star (BNS) formation scenarios and merger delay timescales. NGC4993 is a nearby (40 Mpc) early-type galaxy, with $i$-band Sérsic index $n=4.0$ and low asymmetry ($A=0.04\pm 0.01$). These properties are unusual for sGRB hosts. However, NGC4993 presents shell-like structures and dust lanes indicative of a recent galaxy merger, with the optical transient located close to a shell. We constrain the star formation history (SFH) of the galaxy assuming that the galaxy merger produced a star formation burst, but find little to no on-going star formation in either spatially-resolved broadband SED or spectral fitting. We use the best-fit SFH to estimate the BNS merger rate in this type of galaxy, as $R_{NSM}^{gal}=5.7_{-3.3}^{+0.57}\times 10^{-6}{\mathrm{yr}}^{-1}$. If star formation is the only considered BNS formation scenario, the expected number of BNS mergers from early-type galaxies detectable with LIGO during its first two observing seasons is $0.038_{-0.022}^{+0.004}$, as opposed to $\sim 0.5$ from all galaxy types. Hypothesizing that the binary system formed due to dynamical interactions during the galaxy merger, the subsequent time elapsed can constrain the delay time of the BNS coalescence. By using velocity dispersion estimates and the position of the shells, we find that the galaxy merger occurred $t_{\mathrm{mer}}\lesssim 200\mathrm{Myr}$ prior to the BNS coalescence.

arXiv comment9 pages, 4 figures, 1 table. Edited to match the ApJL version

References in corpus (29)

• Stellar population synthesis at the resolution of 2003
• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Galactic Stellar and Substellar Initial Mass Function
• Multi-messenger Observations of a Binary Neutron Star Merger
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• The Host Galaxies and Classification of Active Galactic Nuclei
• Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
• Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
• The Dark Energy Camera
• Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
• The Relationship Between Stellar Light Distributions of Galaxies and their Formation Histories
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Dark Energy Camera Discovery of the Optical Counterpart
• The 6dF Galaxy Survey: Samples, Observational Techniques and the First Data Release
• The SAURON project - III. Integral-field absorption-line kinematics of 48 elliptical and lenticular galaxies
• Binary Neutron Star Mergers
• Dynamical Formation of the GW150914 Binary Black Hole
• Formation and coalescence of relativistic binary stars: effect of kick velocity
• Galaxy Groups: A 2MASS Catalog
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale
• The IMACS Cluster Building Survey: IV. The Log-normal Star Formation History of Galaxies
• MegaMorph -- multi-wavelength measurement of galaxy structure: Sérsic profile fits to galaxies near and far
• Stellar mass functions: methods, systematics and results for the local Universe
• Version 1 of the Hubble Source Catalog
• Missing Stellar Mass in SED Fitting: Spatially Unresolved Photometry can Underestimate Galaxy Masses
• Cosmic Neutron Star Merger Rate and Gravitational Waves constrained by the R Process Nucleosynthesis
• A Search for Kilonovae in the Dark Energy Survey
• Structure Through Colour: A Pixel Approach Towards Understanding Galaxies

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• A DESGW Search for the Electromagnetic Counterpart to the LIGO/Virgo Gravitational Wave Binary Neutron Star Merger Candidate S190510g
• Modelling line ratios and continuum SED of NGC4993 and other short GRB host galaxies