Examinando por Autor "Bufano, Filomena"
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Ítem High-density circumstellar interaction in the luminous type IIn SN 2010jl: The first 1100 days(Institute of Physics Publishing, 2014) Fransson, Claes; Ergon, Mattias; Challis, Peter J.; Chevalier, Roger A.; France, Kevin; Kirshner, Robert P.; Marion G., H.; Milisavljevic, Dan; Smith, Nathan; Bufano, Filomena; Friedman, Andrew S.; Kangas, Tuomas; Larsson, Josefin; Mattila, Seppo; Benetti, Stefano; Chornock, Ryan; Czekala, Ian; Soderberg, Alicia; Sollerman, JesperHubble Space Telescope and ground-based observations of the Type IIn supernova (SN) 2010jl are analyzed, including photometry and spectroscopy in the ultraviolet, optical, and near-IR bands, 26-1128 days after first detection. At maximum, the bolometric luminosity was ∼ 3 × 1043 erg s-1 and even at 850 days exceeds 1042 erg s-1. A near-IR excess, dominating after 400 days, probably originates in dust in the circumstellar medium (CSM). The total radiated energy is ≳ 6.5 × 1050 erg, excluding the dust component. The spectral lines can be separated into one broad component that is due to electron scattering and one narrow with expansion velocity ∼ 100 km s-1 from the CSM. The broad component is initially symmetric around zero velocity but becomes blueshifted after ∼50 days, while remaining symmetric about a shifted centroid velocity. Dust absorption in the ejecta is unlikely to explain the line shifts, and we attribute the shift instead to acceleration by the SN radiation. From the optical lines and the X-ray and dust properties, there is strong evidence for large-scale asymmetries in the CSM. The ultraviolet lines indicate CNO processing in the progenitor, while the optical shows a number of narrow coronal lines excited by the X-rays. The bolometric light curve is consistent with a radiative shock in an r-2 CSM with a mass-loss rate of M ∼ 0.1 M⊙ yr-1. The total mass lost is ≳3 M⊙. These properties are consistent with the SN expanding into a CSM characteristic of a luminous blue variable progenitor with a bipolar geometry. The apparent absence of nuclear processing is attributed to a CSM that is still opaque to electron scattering. © 2014. The American Astronomical Society. All rights reserved.Ítem Multi-wavelength observations of supernova 2011ei: time-dependent classification of type iib and ib supernovae and implications for their progenitors(2012) Milisavljevic, Dan; Margutti, Raffaella; Soderberg, Alicia M.; Pignata, Giuliano; Chomiuk, Laura; Fesen, Robert A.; Bufano, Filomena; Sanders, Nathan E.; Parrent, Jerod T.; Parker, Stuart; Pickering, Timothy; Buckley, David A. H.; Crawford, Steven M.; Gulbis, Amanda A. S.; Hettlage, Christian; Hooper, Eric; Nordsieck, Kenneth H.; O'Donoghue, Darragh; Husser, Tim-Oliver; Potter, Stephen; Kniazev, Alexei; Kotze, Paul; Romero-Colmenero, Encarni; Vaisanen, Petri; Wolf, Marsha; Bartel, Norbert; Bietenholz, Michael F.; Fransson, Claes; Mazzali, Paolo; Brunthaler, Andreas; Chakraborti, Sayan; Levesque, Emily M.; MacFayden, Andrew; Drescher, Colin; Bock, Greg; Marples, Peter; Anderson, Joseph P.; Benetti, Stefano; Reichart, Daniel; Ivarsen, KevinWe present X-ray, UV/optical, and radio observations of the stripped-envelope, core-collapse supernova (SN) 2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within 1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogen Balmer profiles that subside rapidly and are replaced by Type Ib-like He-rich features on the timescale of one week. High-cadence monitoring of this transition identifies an absorption feature around 6250 °A to be chiefly due to hydrogen, as opposed to C II, Ne I, or Si II. Similarities between this observed feature and several SNe Ib suggest that hydrogen absorption attributable to a high velocity (& 12, 000 km s−1) H-rich shell is not rare in Type Ib events. Radio observations imply a shock velocity of v 0.13c and a progenitor star mass-loss rate of ˙M 1.4 × 10−5 M⊙ yr−1 (assuming wind velocity vw = 103 km s−1). This is consistent with independent constraints estimated from deep X-ray observations with Swift -XRT and Chandra. We find the multi-wavelength properties of SN2011ei to be consistent with the explosion of a lower-mass (3−4 M⊙), compact (R∗ 1×1011 cm), He core star. The star retained a thin hydrogen envelope at the time of outburst, and was embedded in an inhomogeneous circumstellar wind suggestive of modest episodic mass-loss. We conclude that SN2011ei’s rapid spectral metamorphosis calls attention to time-dependent classifications that bias estimates of explosion rates for a subset of Type IIb and Ib objects. Further, that important information about a progenitor star’s evolutionary state and associated mass-loss in the days to years prior to SN outburst can be inferred from timely multi-wavelength observations.Ítem Photometric typing of normal and peculiar type Ia supernovae(Cambridge University Press, 2015) González-Gaitán, Santiago; Bufano, FilomenaWe present a new photometric typing technique for normal type Ia supernovae (SNe Ia) and peculiar SNe Ia such as SN 1991bg-like, type Iax and super-Chandrasekhar SNe Ia. This photometric classifier allows the identification of exclusively normal SNe Ia (with a purity above 99% and an efficiency greater than 80%) in current and future large wide field surveys for cosmological studies. © International Astronomical Union 2015.Ítem Supernova 2010ev: a reddened high velocity gradient type Ia supernova(EDP Sciences, 2016-04) Gutiérrez, Claudia P.; González-Gaitán, Santiago; Folatelli, Gastón; Pignata, Giuliano; Anderson, Joseph P.; Hamuy, Mario; Morrell, Nidia; Stritzinger, Maximilian; Taubenberger, Stefan; Bufano, Filomena; Olivares E., Felipe; Haislip, Joshua B.; Reichart, Daniel E.Ams. We present and study the spectroscopic and photometric evolution of the type Ia supernova (SN Ia) 2010ev. Methods. We obtain and analyze multiband optical light curves and optical/near-infrared spectroscopy at low and medium resolution spanning −7 days to +300 days from the B-band maximum. Results. A photometric analysis shows that SN 2010ev is a SN Ia of normal brightness with a light-curve shape of ∆m15(B) = 1.12 ± 0.02 and a stretch s = 0.94 ± 0.01 suffering significant reddening. From photometric and spectroscopic analysis, we deduce a color excess of E(B − V) = 0.25 ± 0.05 and a reddening law of Rv = 1.54 ± 0.65. Spectroscopically, SN 2010ev belongs to the broad-line SN Ia group, showing stronger than average Si ii λ6355 absorption features. We also find that SN 2010ev is a high velocity gradient SN with ˙vSi = 164 ± 7 km s−1 d −1 . The photometric and spectral comparison with other supernovae shows that SN 2010ev has similar colors and velocities to SN 2002bo and SN 2002dj. The analysis of the nebular spectra indicates that the [Fe ii] λ7155 and [Ni ii] λ7378 lines are redshifted, as expected for a high velocity gradient supernova. All these common intrinsic and extrinsic properties of the high velocity gradient (HVG) group are different from the low velocity gradient (LVG) normal SN Ia population and suggest significant variety in SN Ia explosions.Ítem The Highly Energetic Expansion of SN2010bh Associated with GRB100316D(2012) Bufano, Filomena; Pian, Elena; Sollerman, Jesper; Benetti, Stefano; Pignata, Giuliano; Valenti, Stefano; Covino, Stefano; D’Avanzo, Paolo; Malesani, Daniele; Enrico, Cappellaro; Della Valle, Massimo; Fynbo, Johan; Hjorth, Jens; Mazzali, Paolo A.; Reichart, Daniel E.; Starling, Rhaana L. C.; Turatto, Massimo; Vergani, Susanna D.; Wiersema, Klass; Amati, Lorenzo; Bersier, David; Campana, Sergio; Cano, Zach; Castro-Tirado, Alberto J.; Chincarini, Guido; D’Elia, Valerio; de Ugarte, Antonio; Postigo, Deng, Jinsong; Ferrero, Patrizia; Alexei V., Filippenko; Goldoni, Paolo; Gorosabel, Javier; Greiner, Jochen; Hammer, Francois; Jakobsson, Pall; Kaper, Lex; Kawabata, Koji S.; Klose, Sylvio; Levan, Andrew J.; Maeda, Keiichi; Masetti, Nicola; Milvang-Jensen, Bo; Mirabel, Felix I.; Moller, Palle; Nomoto, Ken’ichi; Palazzi, Eliana; Piranomonte, Silvia; Salvaterra, Ruben; Stratta, Giulia; Tagliaferri, Gianpiero; Tanaka, Masaomi; Tanvir, Nial R.; Wijers, Ralph A.M.J.