Examinando por Autor "Hamuy, M."
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Ítem Defining photometric peculiar type Ia supernovae(Institute of Physics Publishing, 2014) González-Gaitán, S.; Hsiao, E.Y.; Pignata, G.; Förster, F.; Gutiérrez, C.; Bufano, F.; Galbany, L.; Folatelli, G.; Phillips, M.M.; Hamuy, M.; Anderson, J.P.; De Jaeger, T.Ítem Luminous Type II supernovae for their low expansion velocities(Oxford University Press, 2020-05) Rodríguez, O.; Pignata, G.; Anderson, J.P.; Moriya, T.J.; Clocchiatti, A.; Forster, F.; Prieto, J.L.; Phillips, M.M.; Burns, C.R.; Contreras, C.; Folatelli, G.; Gutierrez, C.P.; Hamuy, M.; Morrell, N.I.; Stritzinger, M.D.; Suntzeff, N.B.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Pastorello, A.; Turatto, M.; Maza, J.; Antezana, R.; Cartier, R.; Gonzalez, L.; Haislip, J.B.; Kouprianov, V.; Lopez, P.; Marchi-Lasch, S.; Reichart, D.We present optical and near-infrared data of three Type II supernovae (SNe II), SN 2008bm, SN 2009aj, and SN 2009au. These SNe display the following common characteristics: signs of early interaction of the ejecta with circumstellar material (CSM), blue B - V colours, weakness of metal lines, low expansion velocities, and V-band absolute magnitudes 2-3 mag brighter than those expected for normal SNe II based on their expansion velocities. Two more SNe reported in the literature (SN 1983K and LSQ13fn) share properties similar to our sample. Analysing this set of five SNe II, which are luminous for their low expansion velocities (LLEV), we find that their properties can be reproduced assuming ejecta-CSM interaction that lasts between 4 and 11 weeks post-explosion. The contribution of this interaction to the radiation field seems to be the dominant component determining the observed weakness of metal lines in the spectra rather than the progenitor metallicity. Based on hydrodynamic simulations, we find that the interaction of the ejecta with a CSM of ∼3.6 M⊙ can reproduce the light curves and expansion velocities of SN 2009aj. Using data collected by the Chilean Automatic Supernova Search, we estimate an upper limit for the LLEV SNe II fraction to be 2-4 per cent of all normal SNe II. With the current data set, it is not clear whether the LLEV events are a separated class of SNe II with a different progenitor system, or whether they are the extreme of a continuum mediated by CSM interaction with the rest of the normal SN II population. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.Ítem Optical photometry and spectroscopy of the 1987A-like supernova 2009mw(OXFORD UNIV PRESS, 2016-08) Takáts, K.; Pignata, G.; Bersten, M.; Rojas Kaufmann, M. L.; Anderson, J. P.; Folatelli, G.; Hamuy, M.; Stritzinger, M.; Haislip, J. B.; LaCluyze, A. P.; Moore, J. P.; Reichart, D.We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our BVRI and g ' r ' i ' z ' photometry covers 167 d of evolution, including the rise to the light-curve maximum, and ends just after the beginning of the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated through hydrodynamical modelling, and yield an explosion energy of 1 foe, a pre-SN mass of 19 M-aS (TM), a progenitor radius of 30 R-aS (TM) and a Ni-56 mass of 0.062 M-aS (TM). These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with a slightly subsolar metallicty.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 2011A: A LOW-LUMINOSITY INTERACTING TRANSIENT WITH A DOUBLE PLATEAU AND STRONG SODIUM ABSORPTION(Institute of Physics Publishing, 2015-07) De Jaeger, T.; Anderson, J.P.; Pignata, G.; Hamuy, M.; Kankare, E.; Stritzinger, M.D.; Benetti, S.; Bufano, F.; Elias-Rosa, N.; Folatelli, G.; Förster, F.; González-Gaitán, S.; Gutiérrez, C.P.; Inserra, C.; Kotak, R.; Lira, P.; Morrell, N.; Taddia, F.; Tomasella, L.We present optical photometry and spectroscopy of the optical transient SN 2011A. Our data span 140 days after discovery including BVRI u′g′r′i′z′ photometry and 11 epochs of optical spectroscopy. Originally classified as a type IIn supernova (SN IIn) due to the presence of narrow Hα emission, this object shows exceptional characteristics. First, the light curve shows a double plateau, a property only observed before in the impostor SN 1997bs. Second, SN 2011A has a very low luminosity (MV=-15.72), placing it between normal luminous SNe IIn and SN impostors. Third, SN 2011A shows low velocity and high equivalent width absorption close to the sodium doublet, which increases with time and is most likely of circumstellar origin. This evolution is also accompanied by a change in line profile; when the absorption becomes stronger, a P Cygni profile appears. We discuss SN 2011A in the context of interacting SNe IIn and SN impostors, which appears to confirm the uniqueness of this transient. While we favor an impostor origin for SN 2011A, we highlight the difficulty in differentiating between terminal and non-terminal interacting transients. © 2015. The American Astronomical Society. All rights reserved.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 High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs(Institute of Physics Publishing, 2018-11) Martínez-Palomera, J.; Förster, F.; Protopapas, P.; Maureira, J.C.; Lira, P.; Cabrera-Vives, G.; Huijse, P.; Galbany, L.; Jaeger, T.D.; González-Gaitán, S.; Medina, G.; Pignata, G.; Martín, J.S.; Hamuy, M.; Muñoz, R.R.The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/). © 2018. The American Astronomical Society. All rights reserved.Ítem The new SOXS instrument for the ESO NTT(SPIE, 2016-06) Schipani, P.; Claudi, R.; Campana, S.; Baruffolo, A.; Basa, S.; Basso, S.; Cappellaro, E.; Cascone, E.; Cosentino, R.; D'Alessio, F.; De Caprio, V.; Della Valle, M.a De Ugarte Postigo A.; D'Orsi, S.; Franzen, R.; Fynbo, J.; Gal-Yam, A.; Gardiol, D.; Giro, E.; Hamuy, M.; Iuzzolino, M.; Loreggia, D.; Mattila, S.; Munari, M.; Pignata, G.; Riva, M.; Savarese, S.; Schmidt, B.; Scuderi, S.; Smartt, S.; Vitali, F.SOXS (Son Of X-Shooter) will be a unique spectroscopic facility for the ESO-NTT 3.5-m telescope in La Silla (Chile), able to cover the optical/NIR band (350-1750 nm). The design foresees a high-efficiency spectrograph with a resolutionslit product of ∼4,500, capable of simultaneously observing the complete spectral range 350 - 1750 nm with a good sensitivity, with light imaging capabilities in the visible band. This paper outlines the status of the project. © 2016 SPIE.Ítem The rise-time of Type II supernovae(Oxford University Press, 2015-05) González-Gaitán, S.; Tominaga, N.; Molina, J.; Galbany, L.; Bufano, F.; Anderson, J.P.; Gutierrez, C.; Förster, F.; Pignata, G.; Bersten, M.; Howell, D.A.; Sullivan, M.; Carlberg, R.; De Jaeger, T.; Hamuy, M.; Baklanov, P.V.; Blinnikov, S.I.We investigate the early-time light curves of a large sample of 223 Type II supernovae (SNe II) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constrain risetimes, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At rest-frame g' band (λeff = 4722 Å), we find a distribution of fast rise-times with median of (7.5 ± 0.3) d. Comparing these durations with analytical shock models of Rabinak &Waxman and Nakar & Sari, and hydrodynamical models of Tominaga et al., which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radii. The inferred radii are on average much smaller than the radii obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either (a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or (b) the delayed and prolonged shock breakout of the collapse of an RSG with an extended atmosphere or embedded within pre-SN circumstellar material. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.