Examinando por Autor "Phillips, M.M."
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Ítem 500 days of SN 2013dy: Spectra and photometry from the ultraviolet to the infrared(Oxford University Press, 2015-07) Pan, Y.-C.; Foley, R.J.; Kromer, M.; Fox, O.D.; Zheng, W.; Challis, P.; Clubb, K.; Filippenko, A.V.; Folatelli, G.; Graham, M.L.; Hillebrandt, W.; Kirshner, R.P.; Lee, W.H.; Pakmor, R.; Patat, F.; Phillips, M.M.; Pignata, G.; Röpke, F.; Seitenzahl, I.; Silverman, J.M.; Simon, J.D.; Sternberg, A.; Stritzinger, M.D.; Taubenberger, S.; Vinko, J.; Wheeler, J.C.SN 2013dy is a Type Ia supernova (SN Ia) for which we have compiled an extraordinary data set spanning from 0.1 to ~ 500 d after explosion. We present 10 epochs of ultraviolet (UV) through near-infrared (NIR) spectra with Hubble Space Telescope/Space Telescope Imaging Spectrograph, 47 epochs of optical spectra (15 of them having high resolution), and more than 500 photometric observations in the BVrRiIZYJH bands. SN 2013dy has a broad and slowly declining light curve (Δm15(B)=0.92 mag), shallow Si II λ6355 absorption, and a low velocity gradient. We detect strong C II in our earliest spectra, probing unburned progenitor material in the outermost layers of the SN ejecta, but this feature fades within a few days. The UV continuum of SN 2013dy, which is strongly affected by the metal abundance of the progenitor star, suggests that SN 2013dy had a relatively high-metallicity progenitor. Examining one of the largest single set of high-resolution spectra for an SN Ia, we find no evidence of variable absorption from circumstellar material. Combining our UV spectra, NIR photometry, and high-cadence optical photometry, we construct a bolometric light curve, showing that SN 2013dy had a maximum luminosity of 10.0+4.8 -3.8 × 1042 erg s-1. We compare the synthetic light curves and spectra of several models to SN 2013dy, finding that SN 2013dy is in good agreement with a solar-metallicity W7 model. © 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.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 Extensive HST ultraviolet spectra and multiwavelength observations of SN 2014J in M82 indicate reddening and circumstellar scattering by typical dust(Oxford University Press, 2014) Foley, Ryan J.; Fox, O.D.; McCully, C.; Phillips, M.M.; Sand, D.J.; Zheng, W.; Challis, P.; Filippenko, A.V.; Folatelli, G.; Hillebrandt, W.; Hsiao, E.Y.; Jha, S.W.; Kirshner, R.P.; Kromer, M.; Marion, G.H.; Nelso, M.; Pakmor, R.; Pignata, G.; R̈opke, F.K.; Seitenzahl, I.R.; Silverman, J.M.; Skrutskie, M.; Stritzinger, M.D.SN 2014J in M82 is the closest detected Type Ia supernova (SN Ia) in at least 28 yr and perhaps in 410 yr. Despite its small distance of 3.3 Mpc, SN 2014J is surprisingly faint, peaking at V = 10.6 mag, and assuming a typical SN Ia luminosity, we infer an observed visual extinction of AV = 2.0 ± 0.1 mag. But this picture, with RV = 1.6 ± 0.2, is too simple to account for all observations. We combine 10 epochs (spanning a month) of HST/Space Telescope Imaging Spectrograph (STIS) ultraviolet through near-infrared spectroscopy with HST/Wide Field Camera 3 (WFC3), Katzman Automatic Imaging Telescope, and FanCam photometry from the optical to the infrared and nine epochs of high-resolution TRES (Tillinghast Reflection Echelle Spectrograph) spectroscopy to investigate the sources of extinction and reddening for SN 2014J. We argue that the wide range of observed properties for SN 2014J is caused by a combination of dust reddening, likely originating in the interstellar medium of M82, and scattering off circumstellar material. For this model, roughly half of the extinction is caused by reddening from typical dust (E(B − V) = 0.45 mag and RV = 2.6) and roughly half by scattering off Large Magellanic Cloud-like dust in the circumstellar environment of SN 2014J.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 Observations of the very young Type Ia Supernova 2019np with early-excess emission(Oxford University Press, 2022-08-01) Sai, Hanna; Wang, Xiaofeng; Elias Rosa, Nancy; Yang, Yi; Zhang, Jujia; Lin, Weili; Mo, Jun; Piro, Anthony L; Zeng, Xiangyun; Andrea, Reguitti; Brown, Peter; Burns, Christopher R; Cai, Yongzhi; Fiore, Achille; Hsiao, Eric Y; Isern, Jordi; Itagaki, K.; Li, Wenxiong; Li, Zhitong; Pessi, Priscila J; Phillips, M.M.; Schuldt, Stefan; Shahbandeh, Melissa; Stritzinger, Maximilian D; Tomasella, Lina; Vogl, Christian; Wang, Bo; Wang, Lingzhi; Wu, Chengyuan; Yang, Sheng; Zhang, Jicheng; Zhang, Tianmeng; Zhang, XinghanEarly-time radiative signals from Type Ia supernovae (SNe Ia) can provide important constraints on the explosion mechanism and the progenitor system. We present observations and analysis of SN 2019np, a nearby SN Ia discovered within 1-2 days after the explosion. Follow-up observations were conducted in optical, ultraviolet, and near-infrared bands, covering the phases from ∼-16.7 d to ∼+ 367.8 d relative to its B-band peak luminosity. The photometric and spectral evolutions of SN 2019np resemble the average behaviour of normal SNe Ia. The absolute B-band peak magnitude and the post-peak decline rate are Mmax(B) =-19.52 ± 0.47 mag and Δm15(B) = 1.04 ± 0.04 mag, respectively. No Hydrogen line has been detected in the nebular-phase spectra of SN 2019np. Assuming that the 56Ni powering the light curve is centrally located, we find that the bolometric light curve of SN 2019np shows a flux excess up to 5.0 per cent in the early phase compared to the radiative diffusion model. Such an extra radiation perhaps suggests the presence of an additional energy source beyond the radioactive decay of central nickel. Comparing the observed colour evolution with that predicted by different models, such as interactions of SN ejecta with circumstellar matter (CSM)/companion star, a double-detonation explosion from a sub-Chandrasekhar mass white dwarf (WD) and surface 56Ni mixing, we propose that the nickel mixing is more favoured for SN 2019np. © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.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 2021fxy: mid-ultraviolet flux suppression is a common feature of Type Ia supernovae(Oxford University Press, 2023-07-01) DerKacy, J.M.; Paugh, S.; Baron, E.; Brown, P.J.; Ashall, C.; Burns, C.R.; Hsiao, E.Y.; Kumar, S.; Lu, J.; Morrell, N.; Phillips, M.M.; Shahbandeh, M.; Shappee, B.J.; Stritzinger, M.D.; Tucker, M.A.; Yarbrough, Z.; Boutsia, K.; Hoeflich, P.; Wang, L.; Galbany, L.; Karamehmetoglu, E.; Krisciunas, K.; Mazzali, P.; Piro, A.L.; Suntzeff, N.B.; Fiore, A.; Gutiérrez, C.P.; Lundqvist, P.; Reguitti, A.We present ultraviolet (UV) to near-infrared (NIR) observations and analysis of the nearby Type Ia supernova SN 2021fxy. Our observations include UV photometry from Swift/UVOT, UV spectroscopy from HST/STIS, and high-cadence optical photometry with the Swope 1-m telescope capturing intranight rises during the early light curve. Early B − V colours show SN 2021fxy is the first 'shallow-silicon' (SS) SN Ia to follow a red-to-blue evolution, compared to other SS objects which show blue colours from the earliest observations. Comparisons to other spectroscopically normal SNe Ia with HST UV spectra reveal SN 2021fxy is one of several SNe Ia with flux suppression in the mid-UV. These SNe also show blueshifted mid-UV spectral features and strong high-velocity Ca II features. One possible origin of this mid-UV suppression is the increased effective opacity in the UV due to increased line blanketing from high velocity material, but differences in the explosion mechanism cannot be ruled out. Among SNe Ia with mid-UV suppression, SNe 2021fxy and 2017erp show substantial similarities in their optical properties despite belonging to different Branch subgroups, and UV flux differences of the same order as those found between SNe 2011fe and 2011by. Differential comparisons to multiple sets of synthetic SN Ia UV spectra reveal this UV flux difference likely originates from a luminosity difference between SNe 2021fxy and 2017erp, and not differing progenitor metallicities as suggested for SNe 2011by and 2011fe. These comparisons illustrate the complicated nature of UV spectral formation, and the need for more UV spectra to determine the physical source of SNe Ia UV diversity. © 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Ítem The Early Detection and Follow-up of the Highly Obscured Type II Supernova 2016ija/DLT16am(Institute of Physics Publishing, 2018-01) Tartaglia, L.; Sand, D.J.; Valenti, S.; Wyatt, S.; Anderson, J.P.; Arcavi, I.; Ashall, C.; Botticella, M.T.; Cartier, R.; Chen, T.-W.; Cikota, A.; Coulter, D.; Valle, M.D.; Foley, R.J.; Gal-Yam, A.; Galbany, L.; Gall, C.; Haislip, J.B.; Harmanen, J.; Hosseinzadeh, G.; Howell, D.A.; Hsiao, E.Y.; Inserra, C.; Jha, S.W.; Kankare, E.; Kilpatrick, C.D.; Kouprianov, V.V.; Kuncarayakti, H.; Maccarone, T.J.; Maguire, K.; Mattila, S.; Mazzali, P.A.; McCully, C.; Melandri, A.; Morrell, N.; Phillips, M.M.; Pignata, G.; Piro, A.L.; Prentice, S.; Reichart, D.E.; Rojas-Bravo, C.; Smartt, S.J.; Smith, K.W.; Sollerman, J.; Stritzinger, M.D.; Sullivan, M.; Taddia, F.; Young, D.R.We present our analysis of the Type II supernova DLT16am (SN 2016ija). The object was discovered during theongoing D < 40 Mpc (DLT40) one-day cadence supernova search at r ∼ 20.1 mag in the edge-on nearby(D = 20.0 ± 4.0 Mpc) galaxy NGC 1532. The subsequent prompt and high-cadenced spectroscopic andphotometric follow-up revealed a highly extinguished transient, with E(B - V) = 1.95 ±0.15 mag, consistentwith a standard extinction law with RV=3.1 and a bright (MV = -18.48 ±0.77 mag) absolute peak magnitude. Acomparison of the photometric features with those of large samples of SNe II reveals a fast rise for the derivedluminosity and a relatively short plateau phase, with a slope of S50V = 0.84 ±0.04 mag 50 days, consistent withthe photometric properties typical of those of fast-declining SNe II. Despite the large uncertainties on the distance andthe extinction in the direction of DLT16am, the measured photospheric expansion velocity and the derived absoluteV-band magnitude at ~50 days after the explosion match the existing luminosity-velocity relation for SNe II.Ítem The Emergence of the Infrared Transient VVV-WIT-06(Institute of Physics Publishing, 2017-11) Minniti, D.; Saito, R.K.; Forster, F.; Pignata, G.; Ivanov, V.D.; Lucas, P.W.; Beamin, J.C.; Borissova, J.; Catelan, M.; Gonzalez, O.A.; Hempel, M.; Hsiao, E.; Kurtev, R.; Majaess, D.; Masetti, N.; Morrell, N.I.; Phillips, M.M.; Pullen, J.B.; Rejkuba, M.; Smith, L.; Surot, F.; Valenti, E.; Zoccali, M.We report the discovery of an enigmatic large-amplitude (ΔKs >10.5 mag) transient event in near-IR data obtained by the VISTA Variables in the Via Lactea (VVV) ESO Public Survey. The object (designated VVV-WIT- 06) is located at R.A.=17:07:18.917, decl.=-39:06:26.45 (J2000), corresponding to Galactic coordinates l=347.14539, b=0.88522. It exhibits a clear eruption, peaking at Ks=9 mag during 2013 July and fading to Ks ∼ 16.5 in 2017. Our late near-IR spectra show post-outburst emission lines, including some broad emission lines (upward of FWHM ∼ 3000 km s-1). We estimate a total extinction of AV = 10-15 mag in the surrounding field, and no progenitor was observed in ZYJHKs images obtained during 2010-2012 (down to Ks > 18.5mag). Subsequent deep near-IR imaging and spectroscopy, in concert with the available multiband photometry, indicate that VVV-WIT-06 may be either: (i) the closest Type I SN observed in about 400 years, (ii) an exotic highamplitude nova that would extend the known realm of such objects, or (iii) a stellar merger. In all of these cases, VVV-WIT-06 is a fascinating and curious astrophysical target under any of the scenarios considered.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.Ítem Two transitional type Ia supernovae located in the Fornax cluster member NGC 1404: SN 2007on and SN 2011iv(EDP Sciences, 2018-03) Gall, C.; Stritzinger, M.D.; Ashall, C.; Baron, E.; Burns, C.R.; Hoeflich, P.; Hsiao, E.Y.; Mazzali, P.A.; Phillips, M.M.; Filippenko, A.V.; Anderson, J.P.; Benetti, S.; Brown, P.J.; Campillay, A.; Challis, P.; Contreras, C.; Elias De La Rosa, N.; Folatelli, G.; Foley, R.J.; Fraser, M.; Holmbo, S.; Marion, G.H.; Morrell, N.; Pan, Y.-C.; Pignata, G.; Suntzeff, N.B.; Taddia, F.; Robledo, S.T.; Valenti, S.We present an analysis of ultraviolet (UV) to near-infrared observations of the fast-declining Type Ia supernovae (SNe Ia) 2007on and 2011iv, hosted by the Fornax cluster member NGC 1404. The B-band light curves of SN 2007on and SN 2011iv are characterised by Δm 15 (B) decline-rate values of 1.96 mag and 1.77 mag, respectively. Although they have similar decline rates, their peak B- and H-band magnitudes differ by ~ 0.60 mag and ~0.35 mag, respectively. After correcting for the luminosity vs. decline rate and the luminosity vs. colour relations, the peak B-band and H-band light curves provide distances that differ by ~ 14% and ~ 9%, respectively. These findings serve as a cautionary tale for the use of transitional SNe Ia located in early-type hosts in the quest to measure cosmological parameters. Interestingly, even though SN 2011iv is brighter and bluer at early times, by three weeks past maximum and extending over several months, its B - V colour is 0.12 mag redder than that of SN 2007on. To reconcile this unusual behaviour, we turn to guidance from a suite of spherical one-dimensional Chandrasekhar-mass delayed-detonation explosion models. In this context, 56 Ni production depends on both the so-called transition density and the central density of the progenitor white dwarf. To first order, the transition density drives the luminosity-width relation, while the central density is an important second-order parameter. Within this context, the differences in the B - V colour evolution along the Lira regime suggest that the progenitor of SN 2011iv had a higher central density than SN 2007on. © ESO 2018.