Examinando por Autor "Prentice, S.J."

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    A kilonova as the electromagnetic counterpart to a gravitational-wave source
    (Nature Publishing Group, 2017-11) Smartt, S.J.; Chen, T.-W.; Jerkstrand, A.; Coughlin, M.; Kankare, E.; Sim, S.A.; Fraser, M.; Inserra, C.; Maguire, K.; Chambers, K.C.; Huber, M.E.; Krühler, T.; Leloudas, G.; Magee, M.; Shingles, L.J.; Smith, K.W.; Young, D.R.; Tonry, J.; Kotak, R.; Gal-Yam, A.; Lyman, J.D.; Homan, D.S.; Agliozzo, C.; Anderson, J.P.; Angus, C.R.; Ashall, C.; Barbarino, C.; Bauer, F.E.; Berton, M.; Botticella, M.T.; Bulla, M.; Bulger, J.; Cannizzaro, G.; Cano, Z.; Cartier, R.; Cikota, A.; Clark, P.; De Cia, A.; Della Valle, M.; Denneau, L.; Dennefeld, M.; Dessart, L.; Dimitriadis, G.; Elias-Rosa, N.; Firth, R.E.; Flewelling, H.; Flörs, A.; Franckowiak, A.; Frohmaier, C.; Galbany, L.; González-Gaitán, S.; Greiner, J.; Gromadzki, M.; Nicuesa Guelbenzu, A.; Gutiérrez, C.P.; Hamanowicz, A.; Hanlon, L.; Harmanen, J.; Heintz, K.E.; Heinze, A.; Hernandez, M.-S.; Hodgkin, S.T.; Hook, I.M.; Izzo, L.; James, P.A.; Jonker, P.G.; Kerzendorf, W.E.; Klose, S.; Kostrzewa-Rutkowska, Z.; Kowalski, M.; Kromer, M.; Kuncarayakti, H.; Lawrence, A.; Lowe, T.B.; Magnier, E.A.; Manulis, I.; Martin-Carrillo, A.; Mattila, S.; McBrien, O.; Müller, A.; Nordin, J.; O'Neill, D.; Onori, F.; Palmerio, J.T.; Pastorello, A.; Patat, F.; Pignata, G.; Pumo, M.L.; Prentice, S.J.; Rau, A.; Razza, A.; Rest, A.; Reynolds, T.; Roy, R.; Ruiter, A.J.; Rybicki, K.A.; Salmon, L.; Schady, P.; Schultz, A.S.B.; Schweyer, T.; Seitenzahl, I.R.; Smith, M.; Sollerman, J.; Stalder, B.; Stubbs, C.W.; Sullivan, M.; Szegedi, H.; Taddia, F.; Taubenberger, S.; Terreran, G.; Van Soelen, B.; Vos, J.; Wainscoat, R.J.; Waters, C.; Weiland, H.; Willman, M.; Wiseman, P.; Wright, D.E.; Walton, N.A.; Wyrzykowski, L.; Yaron, O.
    Gravitational waves were discovered with the detection of binary black-hole mergers1 and they should also be detectable from lowermass neutron-star mergers. These are predicted to eject material rich in heavy radioactive isotopes that can power an electromagnetic signal. This signal is luminous at optical and infrared wavelengths and is called a kilonova2-5. The gravitational-wave source GW170817 arose from a binary neutron-star merger in the nearby Universe with a relatively well confined sky position and distance estimate6. Here we report observations and physical modelling of a rapidly fading electromagnetic transient in the galaxy NGC 4993, which is spatially coincident with GW170817 and with a weak, short γ-ray burst7,8. The transient has physical parameters that broadly match the theoretical predictions of blue kilonovae from neutron-star mergers. The emitted electromagnetic radiation can be explained with an ejected mass of 0.04 ± 0.01 solar masses, with an opacity of less than 0.5 square centimetres per gram, at a velocity of 0.2 ± 0.1 times light speed. The power source is constrained to have a power-law slope of -1.2 ± 0.3, consistent with radioactive powering from r-process nuclides. (The r-process is a series of neutron capture reactions that synthesise many of the elements heavier than iron.) We identify line features in the spectra that are consistent with light r-process elements (atomic masses of 90-140). As it fades, the transient rapidly becomes red, and a higher-opacity, lanthanide-rich ejecta component may contribute to the emission. This indicates that neutron-star mergers produce gravitational waves and radioactively powered kilonovae, and are a nucleosynthetic source of the r-process elements. © 2017 Macmillan Publishers Limited, part of Springer Nature.
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    SN 2017dio: A Type-Ic Supernova Exploding in a Hydrogen-rich Circumstellar Medium
    (Institute of Physics Publishing, 2018-02) Kuncarayakti, H.; Maeda, K.; Ashall, C.J.; Prentice, S.J.; Mattila, S.; Kankare, E.; Fransson, C.; Lundqvist, P.; Pastorello, A.; Leloudas, G.; Anderson, J.P.; Benetti, S.; Bersten, M.C.; Cappellaro, E.; Cartier, R.; Denneau, L.; Della Valle, M.; Elias-Rosa, N.; Folatelli, G.; Fraser, M.; Galbany, L.; Gall, C.; Gal-Yam, A.; Gutiérrez, C.P.; Hamanowicz, A.; Heinze, A.; Inserra, C.; Kangas, T.; Mazzali, P.; Melandri, A.; Pignata, G.; Rest, A.; Reynolds, T.; Roy, R.; Smartt, S.J.; Smith, K.W.; Sollerman, J.; Somero, A.; Stalder, B.; Stritzinger, M.; Taddia, F.; Tomasella, L.; Tonry, J.; Weiland, H.; Young, D.R.
    SN 2017dio shows both spectral characteristics of a type-Ic supernova (SN) and signs of a hydrogen-rich circumstellar medium (CSM). Prominent, narrow emission lines of H and He are superposed on the continuum. Subsequent evolution revealed that the SN ejecta are interacting with the CSM. The initial SN Ic identification was confirmed by removing the CSM interaction component from the spectrum and comparing with known SNe Ic and, reversely, adding a CSM interaction component to the spectra of known SNe Ic and comparing them to SN 2017dio. Excellent agreement was obtained with both procedures, reinforcing the SN Ic classification. The light curve constrains the pre-interaction SN Ic peak absolute magnitude to be around Mg = -17.6 mag. No evidence of significant extinction is found, ruling out a brighter luminosity required by an SN Ia classification. These pieces of evidence support the view that SN 2017dio is an SN Ic, and therefore the first firm case of an SN Ic with signatures of hydrogen-rich CSM in the early spectrum. The CSM is unlikely to have been shaped by steady-state stellar winds. The mass loss of the progenitor star must have been intense, M ∼ 0.02 ϵ Hα/0.01)-1(vwind/500 km s-1) (vshock 10,000 kms-1)-3Me yr-1, peaking at a few decades before the SN. Such a high mass-loss rate might have been experienced by the progenitor through eruptions or binary stripping.