Cowperthwaite, PS;
Berger, E;
Villar, VA;
Metzger, BD;
Nicholl, M;
Chornock, R;
Blanchard, PK;
... Zuntz, J; + view all
(2017)
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models.
The Astrophysical Journal Letters
, 848
(2)
10.3847/2041-8213/aa8fc7.
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Abstract
We present UV, optical, and near-infrared (NIR) photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo, the binary neutron star merger GW170817. Our data set extends from the discovery of the optical counterpart at 0.47–18.5 days post-merger, and includes observations with the Dark Energy Camera (DECam), Gemini-South/ FLAMINGOS-2 (GS/F2), and the Hubble Space Telescope (HST). The spectral energy distribution (SED) inferred from this photometry at 0.6 days is well described by a blackbody model with T » 8300 K, a radius of R » ´ 4.5 1014 cm (corresponding to an expansion velocity of v c » 0.3 ), and a bolometric luminosity of Lbol » ´5 1041 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 56Ni, 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 M ej » 0.01 blue and v » 0.3 c ej blue , and the “red” component has M M ej » 0.04 red and v » 0.1 c ej red . 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 binary neutron star (BNS) mergers can be a dominant site of r-process enrichment.
| Type: | Article |
|---|---|
| Title: | The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/aa8fc7 |
| Publisher version: | http://dx.doi.org/10.3847/2041-8213/aa8fc7 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, binaries: close, catalogs, gravitational waves, stars: neutron, surveys, COMPACT OBJECT MERGERS, IA SUPERNOVAE, TELESCOPE, PHOTOMETRY, OUTFLOWS, PROGRAM, PROJECT |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10033852 |
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