Browsing by Author "Hsiao, Eric"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    CHARACTERIZING THE V-BAND LIGHT-CURVES OF HYDROGEN-RICH TYPE II SUPERNOVAE
    (IOP PUBLISHING LTD, 2014) Anderson, Joseph P.; Gonzalez Gaitan, Santiago; Hamuy, Mario; Gutierrez, Claudia P.; Stritzinger, Maximilian D.; Olivares, Felipe E.; Phillips, Mark M.; Schulze, Steve; Antezana, Roberto; Bolt, Luis; Campillay, Abdo; Castellon, Sergio; Contreras, Carlos; de Jaeger, Thomas; Folatelli, Gaston; Foerster, Francisco; Freedman, Wendy L.; Gonzalez, Luis; Hsiao, Eric; Krzeminski, Wojtek; Krisciunas, Kevin; Maza, Jose; McCarthy, Patrick; Morrell, Nidia I.; Persson, Sven E.; Roth, Miguel; Salgado, Francisco; Suntzeff, Nicholas B.; Thomas Osip, Joanna
    We present an analysis of the diversity of V-band light-curves of hydrogen-rich type II supernovae. Analyzing a sample of 116 supernovae, several magnitude measurements are defined, together with decline rates at different epochs, and time durations of different phases. It is found that magnitudes measured at maximum light correlate more strongly with decline rates than those measured at other epochs: brighter supernovae at maximum generally have faster declining light-curves at all epochs. We find a relation between the decline rate during the "plateau" phase and peak magnitudes, which has a dispersion of 0.56 mag, offering the prospect of using type II supernovae as purely photometric distance indicators. Our analysis suggests that the type II population spans a continuum from low-luminosity events which have flat light-curves during the "plateau" stage, through to the brightest events which decline much faster. A large range in optically thick phase durations is observed, implying a range in progenitor envelope masses at the epoch of explosion. During the radioactive tails, we find many supernovae with faster declining light-curves than expected from full trapping of radioactive emission, implying low mass ejecta. It is suggested that the main driver of light-curve diversity is the extent of hydrogen envelopes retained before explosion. Finally, a new classification scheme is introduced where hydrogen-rich events are typed as simply "SN II" with an "s(2)" value giving the decline rate during the "plateau" phase, indicating its morphological type.
  • Thumbnail Image
    Item
    Ground-based and JWST Observations of SN 2022pul. I. Unusual Signatures of Carbon, Oxygen, and Circumstellar Interaction in a Peculiar Type Ia Supernova
    (2024) Siebert, Matthew R.; Kwok, Lindsey A.; Johansson, Joel; Jha, Saurabh W.; Blondin, Stephane; Dessart, Luc; Foley, Ryan J.; Hillier, D. John; Larison, Conor; Pakmor, Ruediger; Temim, Tea; Andrews, Jennifer E.; Auchettl, Katie; Badenes, Carles; Barna, Barnabas; Bostroem, K. Azalee; Brenner Newman, Max J.; Brink, Thomas G.; Bustamante-Rosell, Maria Jose; Camacho-Neves, Yssavo; Clocchiatti, Alejandro; Coulter, David A.; Davis, Kyle W.; Deckers, Maxime; Dimitriadis, Georgios; Dong, Yize; Farah, Joseph; Filippenko, Alexei V.; Floers, Andreas; Fox, Ori D.; Garnavich, Peter; Gonzalez, Estefania Padilla; Graur, Or; Hambsch, Franz-Josef; Hosseinzadeh, Griffin; Howell, D. Andrew; Hughes, John P.; Kerzendorf, Wolfgang E.; Le Saux, Xavier K.; Maeda, Keiichi; Maguire, Kate; McCully, Curtis; Mihalenko, Cassidy; Newsome, Megan; O'Brien, John T.; Pearson, Jeniveve; Pellegrino, Craig; Pierel, Justin D. R.; Polin, Abigail; Rest, Armin; Rojas-Bravo, Cesar; Sand, David J.; Schwab, Michaela; Shahbandeh, Melissa; Shrestha, Manisha; Smith, Nathan; Strolger, Louis-Gregory; Szalai, Tamas; Taggart, Kirsty; Terreran, Giacomo; Terwel, Jacco H.; Tinyanont, Samaporn; Valenti, Stefano; Vinko, Jozsef; Wheeler, J. Craig; Yang, Yi; Zheng, Weikang; Ashall, Chris; DerKacy, James M.; Galbany, Lluis; Hoeflich, Peter; Hsiao, Eric; de Jaeger, Thomas; Lu, Jing; Maund, Justyn; Medler, Kyle; Morrell, Nidia; Shappee, Benjamin J.; Stritzinger, Maximilian; Suntzeff, Nicholas; Tucker, Michael; Wang, Lifan
    Nebular-phase observations of peculiar Type Ia supernovae (SNe Ia) provide important constraints on progenitor scenarios and explosion dynamics for both these rare SNe and the more common, cosmologically useful SNe Ia. We present observations from an extensive ground- and space-based follow-up campaign to characterize SN 2022pul, a super-Chandrasekhar mass SN Ia (alternatively "03fg-like" SN), from before peak brightness to well into the nebular phase across optical to mid-infrared (MIR) wavelengths. The early rise of the light curve is atypical, exhibiting two distinct components, consistent with SN Ia ejecta interacting with dense carbon-oxygen (C/O)-rich circumstellar material (CSM). In the optical, SN 2022pul is most similar to SN 2012dn, having a low estimated peak luminosity (M B = -18.9 mag) and high photospheric velocity relative to other 03fg-like SNe. In the nebular phase, SN 2022pul adds to the increasing diversity of the 03fg-like subclass. From 168 to 336 days after peak B-band brightness, SN 2022pul exhibits asymmetric and narrow emission from [O i] lambda lambda 6300, 6364 (FWHM approximate to 2000 km s-1), strong, broad emission from [Ca ii] lambda lambda 7291, 7323 (FWHM approximate to 7300 km s-1), and a rapid Fe iii to Fe ii ionization change. Finally, we present the first ever optical-to-MIR nebular spectrum of an 03fg-like SN Ia using data from JWST. In the MIR, strong lines of neon and argon, weak emission from stable nickel, and strong thermal dust emission (with T approximate to 500 K), combined with prominent [O i] in the optical, suggest that SN 2022pul was produced by a white dwarf merger within C/O-rich CSM.
  • Thumbnail Image
    Item
    POLARIMETRY OF THE SUPERLUMINOUS SUPERNOVA LSQ14MO: NO EVIDENCE FOR SIGNIFICANT DEVIATIONS FROM SPHERICAL SYMMETRY
    (IOP PUBLISHING LTD, 2015) Leloudas, Giorgos; Patat, Ferdinando; Maund, Justyn R.; Hsiao, Eric; Malesani, Daniele; Schulze, Steve; Contreras, Carlos; D Ugarte Postigo, Antonio; Sollerman, Jesper; Stritzinger, Maximilian D.; Taddia, Francesco; Wheeler, J. Craig; Gorosabel, Javier
    We present the first polarimetric observations of a Type I superluminous supernova (SLSN). LSQ14mo was observed with VLT/FORS2 at five different epochs in the V band, with the observations starting before maximum light and spanning 26 days in the rest frame (z. = 0.256). During this period, we do not detect any statistically significant evolution (<2 sigma) in the Stokes parameters. The average values we obtain, corrected for interstellar polarization in the Galaxy, are Q = -0.01% (+/- 0.15%) and U = -0.50% (+/- 0.14%). This low polarization can be entirely due to interstellar polarization in the SN host galaxy. We conclude that, at least during the period of observations and at the optical depths probed, the photosphere of LSQ14mo does not present significant asymmetries, unlike most lower-luminosity hydrogen-poor SNe Ib/c. Alternatively, it is possible that we may have observed LSQ14mo from a special viewing angle. Supporting spectroscopy and photometry confirm that LSQ14mo is a typical SLSN I. Further studies of the polarization of Type I SLSNe are required to determine whether the low levels of polarization are a characteristic of the entire class and to also study the implications for the proposed explosion models.