Examinando por Autor "Maund, J.R."
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Ítem Interacting supernovae and supernova impostors. SN 2007sv: The major eruption of a massive star in UGC 5979(Oxford University Press, 2015-02) Tartaglia, L.; Pastorello, A.; Taubenberger, S.; Cappellaro, E.; Maund, J.R.; Benetti, S.; Boles, T.; Bufano, F.; Duszanowicz, G.; Elias-Rosa, N.; Harutyunyan, A.; Hermansson, L.; Höflich, P.; Maguire, K.; Navasardyan, H.; Smartt, S.J.; Taddia, F.; Turatto, M.We report the results of the photometric and spectroscopic monitoring campaign of the transient SN 2007sv. The observables are similar to those of Type IIn supernovae, a well-known class of objects whose ejecta interact with pre-existing circumstellar material (CSM). The spectra show a blue continuum at early phases and prominent Balmer lines in emission; however, the absolute magnitude at the discovery of SN 2007sv (MR=-14.25±0.38) indicate it to be most likely a supernova impostor. This classification is also supported by the lack of evidence in the spectra of very high velocity material as expected in supernova ejecta. In addition, we find no unequivocal evidence of broad lines of α- and/or Fe-peak elements. The comparison with the absolute light curves of other interacting objects (including Type IIn supernovae) highlights the overall similarity with the prototypical impostor SN 1997bs. This supports our claim that SN 2007sv was not a genuine supernova, and was instead a supernova impostor, most likely similar to the major eruption of a luminous blue variable. © 2014 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 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 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.