Examinando por Autor "Zampieri, L."
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Ítem Massive stars exploding in a He-rich circumstellar medium - IV. Transitional type Ibn supernovae(Oxford University Press, 2015-05) Pastorello, A.; Benetti, S.; Brown, P.J.; Tsvetkov, D.Y.; Inserra, C.; Taubenberger, S.; Tomasella, L.; Fraser, M.; Rich, D.J.; Botticella, M.T.; Bufano, F.; Cappellaro, E.; Ergon, M.; Gorbovskoy, E.S.; Harutyunyan, A.; Huang, F.; Kotak, R.; Lipunov, V.M.; Magill, L.; Miluzio, M.; Morrell, N.; Ochner, P.; Smartt, S.J.; Sollerman, J.; Spiro, S.; Stritzinger, M.D.; Turatto, M.; Valenti, S.; Wang, X.; Wright, D.E.; Yurkov, V.V.; Zampieri, L.; Zhang, L.We present ultraviolet, optical and near-infrared data of the Type Ibn supernovae (SNe) 2010al and 2011hw. SN 2010al reaches an absolute magnitude at peak of MR = -18.86 ± 0.21. Its early light curve shows similarities with normal SNe Ib, with a rise to maximum slower than most SNe Ibn. The spectra are dominated by a blue continuum at early stages, with narrow P-Cygni He I lines indicating the presence of a slow-moving, He-rich circumstellar medium. At later epochs, the spectra well match those of the prototypical SN Ibn 2006jc, although the broader lines suggest that a significant amount of He was still present in the stellar envelope at the time of the explosion. SN 2011hw is somewhat different. It was discovered after the first maximum, but the light curve shows a double peak. The absolute magnitude at discovery is similar to that of the second peak (MR = -18.59 ± 0.25), and slightly fainter than the average of SNe Ibn. Though the spectra of SN 2011hw are similar to those of SN 2006jc, coronal lines and narrow Balmer lines are clearly detected. This indicates substantial interaction of the SN ejecta with He-rich, but not H-free, circumstellar material. The spectra of SN 2011hw suggest that it is a transitional SN Ibn/IIn event similar to SN 2005la. While for SN 2010al the spectrophotometric evolution favours a H-deprived Wolf-Rayet progenitor (of WN-type), we agree with the conclusion of Smith et al. that the precursor of SN 2011hw was likely in transition from a luminous blue variable to an early Wolf-Rayet (Ofpe/WN9) stage. © 2015 The Authors.Ítem PESSTO: Survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects(EDP Sciences, 2015-07) Smartt, S.J.; Valenti, S.; Fraser, M.; Inserra, C.; Young, D.R.; Sullivan, M.; Pastorello, A.; Benetti, S.; Gal-Yam, A.; Knapic, C.; Molinaro, M.; Smareglia, R.; Smith, K.W.; Taubenberger, S.; Yaron, O.; Anderson, J.P.; Ashall, C.; Balland, C.; Baltay, C.; Barbarino, C.; Bauer, F.E.; Baumont, S.; Bersier, D.; Blagorodnova, N.; Bongard, S.; Botticella, M.T.; Bufano, F.; Bulla, M.; Cappellaro, E.; Campbell, H.; Cellier-Holzem, F.; Chen, T.-W.; Childress, M.J.; Clocchiatti, A.; Contreras, C.; Dall'Ora, M.; Danziger, J.; De Jaeger, T.; De Cia, A.; Della Valle, M.; Dennefeld, M.; Elias-Rosa, N.; Elman, N.; Feindt, U.; Fleury, M.; Gall, E.; Gonzalez-Gaitan, S.; Galbany, L.; Morales Garoffolo, A.; Greggio, L.; Guillou, L.L.; Hachinger, S.; Hadjiyska, E.; Hage, P.E.; Hillebrandt, W.; Hodgkin, S.; Hsiao, E.Y.; James, P.A.; Jerkstrand, A.; Kangas, T.; Kankare, E.; Kotak, R.; Kromer, M.; Kuncarayakti, H.; Leloudas, G.; Lundqvist, P.; Lyman, J.D.; Hook, I.M.; Maguire, K.; Manulis, I.; Margheim, S.J.; Mattila, S.; Maund, J.R.; Mazzali, P.A.; McCrum, M.; McKinnon, R.; Moreno-Raya, M.E.; Nicholl, M.; Nugent, P.; Pain, R.; Pignata, G.; Phillips, M.M.; Polshaw, J.; Pumo, M.; Rabinowitz, D.; Reilly, E.; Romero-Cañizales, C.; Scalzo, R.; Schmidt, B.; Schulze, S.; Sim, S.; Sollerman, J.; Taddia, F.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.; Walker, E.; Walton, N.A.; Wyrzykowski, L.; Yuan, F.; Zampieri, L.Context. The Public European Southern Observatory Spectroscopic Survey of Transient Objects (PESSTO) began as a public spectroscopic survey in April 2012. PESSTO classifies transients from publicly available sources and wide-field surveys, and selects science targets for detailed spectroscopic and photometric follow-up. PESSTO runs for nine months of the year, January - April and August - December inclusive, and typically has allocations of 10 nights per month. Aims. We describe the data reduction strategy and data products that are publicly available through the ESO archive as the Spectroscopic Survey data release 1 (SSDR1). Methods. PESSTO uses the New Technology Telescope with the instruments EFOSC2 and SOFI to provide optical and NIR spectroscopy and imaging. We target supernovae and optical transients brighter than 20.5m for classification. Science targets are selected for follow-up based on the PESSTO science goal of extending knowledge of the extremes of the supernova population. We use standard EFOSC2 set-ups providing spectra with resolutions of 13-18 Å between 3345-9995 Å. A subset of the brighter science targets are selected for SOFI spectroscopy with the blue and red grisms (0.935-2.53 μm and resolutions 23-33 Å) and imaging with broadband JHKs filters. Results. This first data release (SSDR1) contains flux calibrated spectra from the first year (April 2012-2013). A total of 221 confirmed supernovae were classified, and we released calibrated optical spectra and classifications publicly within 24 h of the data being taken (via WISeREP). The data in SSDR1 replace those released spectra. They have more reliable and quantifiable flux calibrations, correction for telluric absorption, and are made available in standard ESO Phase 3 formats. We estimate the absolute accuracy of the flux calibrations for EFOSC2 across the whole survey in SSDR1 to be typically ∼15%, although a number of spectra will have less reliable absolute flux calibration because of weather and slit losses. Acquisition images for each spectrum are available which, in principle, can allow the user to refine the absolute flux calibration. The standard NIR reduction process does not produce high accuracy absolute spectrophotometry but synthetic photometry with accompanying JHKs imaging can improve this. Whenever possible, reduced SOFI images are provided to allow this. Conclusions. Future data releases will focus on improving the automated flux calibration of the data products. The rapid turnaround between discovery and classification and access to reliable pipeline processed data products has allowed early science papers in the first few months of the survey. © ESO, 2015.Ítem SN 2009ib: A Type II-P supernova with an unusually long plateau(Oxford University Press, 2015-05) Takáts, K.; Pignata, G.; Pumo, M.L.; Paillas, E.; Zampieri, L.; Elias-Rosa, N.; Benetti, S.; Bufano, F.; Cappellaro, E.; Ergon, M.; Fraser, M.; Hamuy, M.; Inserra, C.; Kankare, E.; Smartt, S.J.; Stritzinger, M.D.; Van Dyk, S.D.; Haislip, J.B.; LaCluyze, A.P.; Moore, J.P.; Reichart, D.We present optical and near-infrared photometry and spectroscopy of SN 2009ib, a Type II-P supernova in NGC 1559. This object has moderate brightness, similar to those of the intermediate-luminosity SNe 2008in and 2009N. Its plateau phase is unusually long, lasting for about 130 d after explosion. The spectra are similar to those of the subluminous SN 2002gd, with moderate expansion velocities.We estimate the 56Ni mass produced as 0.046±0.015M⊙. We determine the distance to SN 2009ib using both the expanding photosphere method (EPM) and the standard candle method. We also apply EPM to SN 1986L, a Type II-P SN that exploded in the same galaxy. Combining the results of different methods, we conclude the distance to NGC 1559 as D = 19.8 ± 3.0 Mpc. We examine archival, pre-explosion images of the field taken with the Hubble Space Telescope, and find a faint source at the position of the SN, which has a yellow colour [(V - I)0 = 0.85 mag]. Assuming it is a single star, we estimate its initial mass as MZAMS = 20M⊙. We also examine the possibility, that instead of the yellow source the progenitor of SN 2009ib is a red supergiant star too faint to be detected. In this case, we estimate the upper limit for the initial zero-age main sequence (ZAMS) mass of the progenitor to be ~14-17M⊙. In addition, we infer the physical properties of the progenitor at the explosion via hydrodynamical modelling of the observables, and estimate the total energy as ~0.55 × 1051 erg, the pre-explosion radius as ~400 R⊙, and the ejected envelope mass as ~15M⊙, which implies that the mass of the progenitor before explosion was ~16.5-17M⊙. © 2015 The Authors.Ítem SN 2009jf: a slow-evolving stripped-envelope core-collapse supernova(2011) Valenti, S.; Fraser, M.;; Benetti, S.; Pignata, G.; Sollerman, J.; Inserra, C.; Cappellaro, E.; Pastorello, A.; Smartt, S. J.; Ergon, M.; Botticella, M. T.; Brimacombe, J.; Bufano, F.; Crockett, M.; Eder, I.; Fugazza, D.; Haislip, J. B.; Hamuy, M.; Ivarsen, K. M.; Kankare, E.; Kotak, R.; LaCluyze, A. P.; Magill, L.; Mattila, S.; Maza, J.; Mazzali, P. A.; Reichart, D. E.; Taubenberger, S.; Turatto, M.; Zampieri, L.; Harutyunyan, K.M.We present an extensive set of photometric and spectroscopic data for SN 2009jf, a nearby Type Ib supernova, spanning from 20 days before B-band maximum to one year after maximum. We show that SN 2009jf is a slowly evolving and energetic stripped-envelope SN and is likely from a massive progenitor (25-30 solar masses). The large progenitor’s mass allows us to explain the complete hydrogen plus helium strip- ping without invoking the presence of a binary companion. The supernova occurred close to a young cluster, in a crowded environment with ongoing star-formation. The specroscopic similarity with the He-poor Type Ic SN 2007gr suggests a common pro- genitor for some supernovae Ib and Ic. The nebular spectra of SN 2009jf are consistent with an asymmetric explosion, with an off-center dense core. We also find evidence that He-rich Ib supernovae have a rise time longer than other stripped-envelope su- pernovae, however confirmation of this result and further observations are needed.Ítem SN 2012ec: Mass of the progenitor from PESSTO follow-up of the photospheric phase(Oxford University Press, 2015-04) Barbarino, C.; Dall'Ora, M.; Botticella, M.T.; Della Valle, M.; Zampieri, L.; Maund, J.R.; Pumo, M.L.; Jerkstrand, A.; Benetti, S.; Elias-Rosa, N.; Fraser, M.; Gal-Yam, A.; Hamuy, M.; Inserra, C.; Knapic, C.; LaCluyze, A.P.; Molinaro, M.; Ochner, P.; Pastorello, A.; Pignata, G.; Reichart, D.E.; Ries, C.; Riffeser, A.; Schmidt, B.; Schmidt, M.; Smareglia, R.; Smartt, S.J.; Smith, K.; Sollerman, J.; Sullivan, M.; Tomasella, L.; Turatto, M.; Valenti, S.; Yaron, O.; Young, D.We present the results of a photometric and spectroscopic monitoring campaign of SN 2012ec, which exploded in the spiral galaxy NGC 1084, during the photospheric phase. The photometric light curve exhibits a plateau with luminosity L = 0.9 × 1042 erg s-1 and duration ~90 d, which is somewhat shorter than standard Type II-P supernovae (SNe). We estimate the nickel mass M(56Ni) = 0.040 ± 0.015 M⊙ from the luminosity at the beginning of the radioactive tail of the light curve. The explosion parameters of SN 2012ec were estimated from the comparison of the bolometric light curve and the observed temperature and velocity evolution of the ejecta with predictions from hydrodynamical models.We derived an envelope mass of 12.6 M⊙, an initial progenitor radius of 1.6 × 1013 cm and an explosion energy of 1.2 foe. These estimates agree with an independent study of the progenitor star identified in pre-explosion images, for which an initial mass ofM = 14-22 M⊙ was determined.We have applied the same analysis to two other Type II-P SNe (SNe 2012aw and 2012A), and carried out a comparison with the properties of SN 2012ec derived in this paper.We find a reasonable agreement between the masses of the progenitors obtained from pre-explosion images and masses derived from hydrodynamical models. We estimate the distance to SN 2012ec with the standardized candle method (SCM) and compare it with other estimates based on other primary and secondary indicators. SNe 2012A, 2012aw and 2012ec all follow the standard relations for the SCM for the use of Type II-P SNe as distance indicators. © 2015 The Authors.Ítem SNe 2013K and 2013am: Observed and physical properties of two slow, normal Type IIP events(Oxford University Press, 2018-04) Tomasella, L.; Cappellaro, E.; Pumo, M.L.; Jerkstrand, A.; Benetti, S.; Elias-Rosa, N.; Fraser, M.; Inserra, C.; Pastorello, A.; Turatto, M.; Anderson, J.P.; Galbany, L.; Gutiérrez, C.P.; Kankare, E.; Pignata, G.; Terreran, G.; Valenti, S.; Barbarino, C.; Bauer, F.E.; Botticella, M.T.; Chen, T.-W.; Gal-Yam, A.; Harutyunyan, A.; Howell, D.A.; Maguire, K.; Garoffolo, A.M.; Ochner, P.; Smartt, S.J.; Schulze, S.; Young, D.R.; Zampieri, L.We present 1 yr of optical and near-infrared photometry and spectroscopy of the Type IIP SNe 2013K and 2013am. Both objects are affected by significant extinction, due to their location in dusty regions of their respective host galaxies, ESO 009-10 and NGC 3623 (M65). From the photospheric to nebular phases, these objects display spectra congruent with those of underluminous Type IIP SNe (i.e. the archetypal SNe 1997D or 2005cs), showing low photospheric velocities (~2 × 10 3 km s -1 at 50 d) together with features arising from Ba II that are particularly prominent in faint SNe IIP. The peak V-band magnitudes of SN 2013K (-15.6mag) and SN 2013am (-16.2mag) are fainter than standard-luminosity Type IIP SNe. The ejected nickel masses are 0.012 ± 0.010 and 0.015 ± 0.006 M ⊙ for SN 2013K and SN 2013am, respectively. The physical properties of the progenitors at the time of explosion are derived through hydrodynamical modelling. Fitting the bolometric curves, the expansion velocity and the temperature evolution, we infer total ejected masses of 12 and 11.5 M ⊙ , pre- SN radii of~460 and~360 R ⊙ , and explosion energies of 0.34 foe and 0.40 foe for SN 2013K and SN 2013am. Late time spectra are used to estimate the progenitormasses from the strength of nebular emission lines, which turn out to be consistent with red supergiant progenitors of ~15 M ⊙ . For both SNe, a low-energy explosion of a moderate-mass red supergiant star is therefore the favoured scenario. © 2017 The Authors.Ítem THA 15-31: Discovery with VLT/X-shooter and Swift /UVOT of a new symbiotic star of the accreting-only variety(EDP Sciences, 2022-05-01) Munari, U.; Alcalá, J.M.; Frasca, A.; Masetti, N.; Traven, G.; Akras, S.; Zampieri, L.We report the discovery and characterization of a new symbiotic star of the accreting-only variety, which we observed in the optical/near-infrared (NIR) with VLT/X-shooter and in the X-rays/ultraviolet with Swift/UVOT+XRT. The new symbiotic star, THA 15-31, was previously described as a pre-main sequence star belonging to the Lupus 3 association. Our observations, ancillary data, and Gaia EDR3 parallax indicate that THA 15-31 is a symbiotic star composed of an M6III red giant and an accreting companion, is subject to EB 0.38 reddening, and is located at a distance of 12 kpc and at 1.8 kpc above the Galactic plane in the outskirts of the Bulge. The luminosity of the accreting companion is 100, placing THA 15-31 among the symbiotic stars accreting at a high rate (2.5 10-8 yr-1 if the accretion is occurring on a white dwarf of 1M). The observed emission lines originate primarily from H I, He I, and Fe II, with no He II or other high-excitation lines observed; a sharp central absorption superimposed on the Balmer emission lines is observed, while all other lines have a simple Gaussian-like profile. The emission from the companion dominates over the M6III red giant at U and B-band wavelengths, and is consistent with an origin primarily in an optically thick accretion disk. No significant photometric variability is observed at optical or NIR wavelengths, suggesting either a face-on orbital orientation and/or that the red giant is far from Roche-lobe filling conditions. The profile of emission lines supports a low orbital inclination if they form primarily in the accretion disk. An excess emission is present in AllWISE W3 (12 μm) and W4 (22 μm) data, radiating a luminosity, consistent with thermal emission from optically thin circumstellar dust. © 2022 AuthorsÍtem The type IIP supernova 2012aw in m95: Hydrodynamical modeling of the photospheric phase from accurate spectrophotometric monitoring(Institute of Physics Publishing, 2014-06) Dall'Ora, M.; Botticella, M.T.; Pumo, M.L.; Zampieri, L.; Tomasella, L.; Pignata, G.; Bayless, A.J.; Pritchard, T.A.; Taubenberger, S.; Kotak, R.; Inserra, C.; Della Valle, M.; Cappellaro, E.; Benetti, S.; Benitez, S.; Bufano, F.; Elias-Rosa, N.; Fraser, M.; Haislip, J.B.; Harutyunyan, A.; Howell, D.A.; Hsiao, E.Y.; Iijima, T.; Kankare, E.; Kuin, P.; Maund, J.R.; Morales-Garoffolo, A.; Morrell, N.; Munari, U.; Ochner, P.; Pastorello, A.; Patat, F.; Phillips, M.M.; Reichart, D.; Roming, P.W.A.; Siviero, A.; Smartt, S.J.; Sollerman, J.; Taddia, F.; Valenti, S.; Wright, D.We present an extensive optical and near-infrared photometric and spectroscopic campaign of the Type IIP supernova SN 2012aw. The data set densely covers the evolution of SN 2012aw shortly after the explosion through the end of the photospheric phase, with two additional photometric observations collected during the nebular phase, to fit the radioactive tail and estimate the 56Ni mass. Also included in our analysis is the previously published Swift UV data, therefore providing a complete view of the ultraviolet-optical-infrared evolution of the photospheric phase. On the basis of our data set, we estimate all the relevant physical parameters of SN 2012aw with our radiation-hydrodynamics code: envelope mass Menv ∼ 20 M , progenitor radius R ∼ 3 × 1013 cm (∼430 R ), explosion energy E ∼ 1.5 foe, and initial 56Ni mass ∼0.06 M . These mass and radius values are reasonably well supported by independent evolutionary models of the progenitor, and may suggest a progenitor mass higher than the observational limit of 16.5 ± 1.5 M of the Type IIP events.