Browsing by Author "Suntzeff, Nicholas B."

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    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.
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    Late-time HST photometry of SN1994I
    (2008) Clocchiatti, Alejandro; Wheeler, J. Craig; Kirshner, Robert P.; Branch, David; Challis, Peter; Chevalier, Roger A.; Filippenko, Alexei V.; Fransson, Claes; Garnavich, Peter; Leibundgut, Bruno; Panagia, Nino; Phillips, Mark M.; Suntzeff, Nicholas B.; Hoeflich, Peter A.; Gallardo, Jose
    We present multicolor Hubble Space Telescope ( HST) WFPC2 broadband observations of the Type Ic SN 1994I obtained similar to 280 d after maximum light. We measure the brightness of the SN and, relying on the detailed spectroscopic database of SN 1994I, we transform the ground-based photometry obtained at early times to the HST photometric system, deriving light curves for the WFPC2 F439W, F555W, F675W, and F814W passbands that extend from 7 days before to 280 days after maximum. We use the multicolor photometry to build a quasi-bolometric light curve of SN 1994I, and compare it with similarly constructed light curves of other supernovae. In doing so, we propose and test a scaling in energy and time that allows for a more meaningful comparison of the exponential tails of different events. Through comparison with models, we find that the late-time light curve of SN 1994I is consistent with that of spherically symmetric ejecta in homologous expansion, for which the ability to trap the gamma-rays produced by the radioactive decay of Co-56 diminishes roughly as the inverse of time squared. We also find that by the time of the HST photometry, the light curve was significantly energized by the annihilation of positrons.
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    Optical and Infrared Photometry of the Type Ia Supernovae 1991T, 1991bg, 1999ek, 2001bt, 2001cn, 2001cz, and 2002bo.
    (2004) Krisciunas, K.; Zapata, Abner; Suntzeff, Nicholas B.; Phillips, Mark M.; Candia, Pablo; Prieto, José Luis; Antezana, Roberto; Chassagne, Robin; Chen, Hsiao-Wen; Dickinson, Mark; Eisenhardt, Peter R.