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
Creators: name: Cowperthwaite, P. S.
name: Berger, E.
name: Villar, V. A.
name: Metzger, B. D.
name: Nicholl, M.
name: Chornock, R.
name: Blanchard, P. K.
name: Fong, W.
name: Margutti, R.
name: Soares-Santos, M.
name: Alexander, K. D.
name: Allam, S.
name: Annis, J.
name: Brout, D.
name: Brown, D. A.
name: Butler, R. E.
name: Chen, H. -Y.
name: Diehl, H. T.
name: Doctor, Z.
name: Drout, M. R.
name: Eftekhari, T.
name: Farr, B.
name: Finley, D. A.
name: Foley, R. J.
name: Frieman, J. A.
name: Fryer, C. L.
name: García-Bellido, J.
name: Gill, M. S. S.
name: Guillochon, J.
name: Herner, K.
name: Holz, D. E.
name: Kasen, D.
name: Kessler, R.
name: Marriner, J.
name: Matheson, T.
name: Neilsen,, E. H.
name: Quataert, E.
name: Palmese, A.
name: Rest, A.
name: Sako, M.
name: Scolnic, D. M.
name: Smith, N.
name: Tucker, D. L.
name: Williams, P. K. G.
name: Balbinot, E.
name: Carlin, J. L.
name: Cook, E. R.
name: Durret, F.
name: Li, T. S.
name: Lopes, P. A. A.
name: Lourenço, A. C. C.
name: Marshall, J. L.
name: Medina, G. E.
name: Muir, J.
name: Muñoz, R. R.
name: Sauseda, M.
name: Schlegel, D. J.
name: Secco, L. F.
name: Vivas, A. K.
name: Wester, W.
name: Zenteno, A.
name: Zhang, Y.
name: Abbott, T. M. C.
name: Banerji, M.
name: Bechtol, K.
name: Benoit-Lévy, A.
name: Bertin, E.
name: Buckley-Geer, E.
name: Burke, D. L.
name: Capozzi, D.
name: Rosell, A. Carnero
name: Kind, M. Carrasco
name: Castander, F. J.
name: Crocce, M.
name: Cunha, C. E.
name: D'Andrea, C. B.
name: da Costa, L. N.
name: Davis, C.
name: DePoy, D. L.
name: Desai, S.
name: Dietrich, J. P.
name: Drlica-Wagner, A.
name: Eifler, T. F.
name: Evrard, A. E.
name: Fernandez, E.
name: Flaugher, B.
name: Fosalba, P.
name: Gaztanaga, E.
name: Gerdes, D. W.
name: Giannantonio, T.
name: Goldstein, D. A.
name: Gruen, D.
name: Gruendl, R. A.
name: Gutierrez, G.
name: Honscheid, K.
name: Jain, B.
name: James, D. J.
name: Jeltema, T.
name: Johnson, M. W. G.
name: Johnson, M. D.
name: Kent, S.
name: Krause, E.
name: Kron, R.
name: Kuehn, K.
name: Kuropatkin, N.
name: Lahav, O.
name: Lima, M.
name: Lin, H.
name: Maia, M. A. G.
name: March, M.
name: Martini, P.
name: McMahon, R. G.
name: Menanteau, F.
name: Miller, C. J.
name: Miquel, R.
name: Mohr, J. J.
name: Neilsen, E.
name: Nichol, R. C.
name: Ogando, R. L. C.
name: Plazas, A. A.
name: Roe, N.
name: Romer, A. K.
name: Roodman, A.
name: Rykoff, E. S.
name: Sanchez, E.
name: Scarpine, V.
name: Schindler, R.
name: Schubnell, M.
name: Sevilla-Noarbe, I.
name: Smith, M.
name: Smith, R. C.
name: Sobreira, F.
name: Suchyta, E.
name: Swanson, M. E. C.
name: Tarle, G.
name: Thomas, D.
name: Thomas, R. C.
name: Troxel, M. A.
name: Vikram, V.
name: Walker, A. R.
name: Wechsler, R. H.
name: Weller, J.
name: Yanny, B.
name: Zuntz, J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present UV, optical, and NIR photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced LIGO/Virgo, the binary neutron star merger GW170817. Our data set extends from the discovery of the optical counterpart at $0.47$ days to $18.5$ days post-merger, and includes observations with the Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), and the {\it Hubble Space Telescope} ({\it HST}). The spectral energy distribution (SED) inferred from this photometry at $0.6$ days is well described by a blackbody model with $T\approx 8300$ K, a radius of $R\approx 4.5\times 10^{14}$ cm (corresponding to an expansion velocity of $v\approx 0.3c$), and a bolometric luminosity of $L_{\rm bol}\approx 5\times10^{41}$ erg s$^{-1}$. At $1.5$ days we find a multi-component SED across the optical and NIR, and subsequently we observe rapid fading in the UV and blue optical bands and significant reddening of the optical/NIR colors. Modeling the entire data set we find that models with heating from radioactive decay of $^{56}$Ni, or those with only a single component of opacity from $r$-process elements, fail to capture the rapid optical decline and red optical/NIR colors. Instead, models with two components consistent with lanthanide-poor and lanthanide-rich ejecta provide a good fit to the data, the resulting "blue" component has $M_\mathrm{ej}^\mathrm{blue}\approx 0.01$ M$_\odot$ and $v_\mathrm{ej}^\mathrm{blue}\approx 0.3$c, and the "red" component has $M_\mathrm{ej}^\mathrm{red}\approx 0.04$ M$_\odot$ and $v_\mathrm{ej}^\mathrm{red}\approx 0.1$c. These ejecta masses are broadly consistent with the estimated $r$-process production rate required to explain the Milky Way $r$-process abundances, providing the first evidence that BNS mergers can be a dominant site of $r$-process enrichment.
description: 13 Pages, 3 Figures, 2 Tables. ApJL, In Press. Keywords: GW170817, LVC