Examinando por Autor "Wheeler, J. C."

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    EXTENSIVE SPECTROSCOPY AND PHOTOMETRY OF THE TYPE IIP SUPERNOVA 2013ej
    (IOP PUBLISHING, 2016) Dhungana, G.; Kehoe, R.; Vinko, J.; Silverman, J. M.; Wheeler, J. C.; Zheng, W.; Marion, G. H.; Fox, O. D.; Akerlof, C.; Biro, B. I.; Borkovits, T.; Cenko, S. B.; Clubb, K. I.; Filippenko, A. V.; Ferrante, F. V.; Gibson, C. A.; Graham, M. L.; Hegedus, T.; Kelly, P.; Kelemen, J.; Lee, W. H.; Marschalko, G.; Molnár, L.; Nagy, A. P.; Ordasi, A.; Pal, A.; Sarneczky, K.; Shivvers, I.; Szakats, R.; Szalai, T.; Szegedi-Elek, E.; Székely, P.; Szing, A.; Takáts, K.; Vida, K.
    We present extensive optical (UBV RI, g' r' i' z', and open CCD) and near-infrared (ZY JH) photometry for the very nearby Type IIP SN. 2013ej extending from + 1 to + 461 days after shock breakout, estimated to be MJD 56496.9 +/- 0.3. Substantial time series ultraviolet and optical spectroscopy obtained from + 8 to + 135 days are also presented. Considering well-observed SNe IIP from the literature, we derive UBV RIJHK bolometric calibrations from UBV RI and unfiltered measurements that potentially reach 2% precision with a B - V color-dependent correction. We observe moderately strong Si II lambda 6355 as early as + 8 days. The photospheric velocity (vph) is determined by modeling the spectra in the vicinity of Fe II lambda 5169 whenever observed, and interpolating at photometric epochs based on a semianalytic method. This gives vph= 4500. 500 km s(-1) at + 50 days. We also observe spectral homogeneity of ultraviolet spectra at + 10-12 days for SNe IIP, while variations are evident a week after explosion. Using the expanding photosphere method, from combined analysis of SN 2013ej and SN 2002ap, we estimate the distance to the host galaxy to be 9.0(-0.6)(+0.4) Mpc, consistent with distance estimates from other methods. Photometric and spectroscopic analysis during the plateau phase, which we estimated to be 94 +/- 7 days long, yields an explosion energy of 0.9 +/- 0.3 x 10(51) erg, a final pre-explosion progenitor mass of 15.2 +/- 4.2 M-circle dot and a radius of 250 +/- 70 R-circle dot. We observe a broken exponential profile beyond + 120 days, with a break point at + 183 +/- 16 days. Measurements beyond this break time yield a Ni-56 mass of 0.013 +/- 0.001. M-circle dot.
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    Supernova 2013fc in a circumnuclear ring of a luminous infrared galaxy: The big brother of SN 1998S
    (OXFORD UNIV PRESS, 2016-02) Kangas, T.; Mattila, S.; Kankare, E.; Lundqvist, P.; Väisänen, P.; Childress, M.; Pignata, G.; McCully, C.; Valenti, S.; Vinkó, J.; Pastorello, A.; Elias-Rosa, N.; Fraser, M.; Gal-Yam, A.; Kotak, R.; Kotilainen, J. K.; Smartt, S. J.; Galbany, L.; Harmanen, J.; Howell, D. A.; Inserra, C.; Marion, G. H.; Quimby, R. M.; Silverman, J. M.; Szalai, T.; Wheeler, J. C.; Ashall, C.; Benetti, S.; Romero-Cañizales, C.; Smith, K. W.; Sullivan, M.; Takáts, K.; Young, D. R.
    We present photometric and spectroscopic observations of SN 2013fc, a bright type II supernova (SN) in a circumnuclear star-forming ring in the luminous infrared galaxy ESO 154-G010, observed as part of the Public ESO Spectroscopic Survey of Transient Objects. SN 2013fc is both photometrically and spectroscopically similar to the well-studied type IIn SN 1998S and to the bright type II-L SN 1979C. It exhibits an initial linear decline, followed by a short plateau phase and a tail phase with a decline too fast for Co-56 decay with full. gamma-ray trapping. Initially, the spectrum was blue and featureless. Later on, a strong broad (similar to 8000 km s(-1)) H alpha emission profile became prominent. We apply a STARLIGHT stellar population model fit to the SN location (observed when the SN had faded) to estimate a high extinction of A(V) = 2.9 +/- 0.2 mag and an age of 10(+ 3) (- 2) Myr for the underlying cluster. We compare the SN to SNe 1998S and 1979C and discuss its possible progenitor star considering the similarities to these events. With a peak brightness of B = - 20.46 +/- 0.21 mag, SN 2013fc is 0.9 mag brighter than SN 1998S and of comparable brightness to SN 1979C. We suggest that SN 2013fc was consistent with a massive red supergiant (RSG) progenitor. Recent mass loss probably due to a strong RSG wind created the circumstellar matter illuminated through its interaction with the SN ejecta. We also observe a near- infrared excess, possibly due to newly condensed dust.