Browsing by Author "Anderson, Joseph P."

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    A puzzle solved after two decades: SN 2002gh among the brightest of superluminous supernovae
    (2022) Cartier, Regis; Hamuy, Mario; Contreras, Carlos; Anderson, Joseph P.; Phillips, Mark M.; Morrell, Nidia; Stritzinger, Maximilian D.; Hueichapan, Emilio D.; Clocchiatti, Alejandro; Roth, Miguel; Thomas-Osip, Joanna; Gonzalez, Luis E.
    We present optical photometry and spectroscopy of the superluminous SN 2002gh from maximum light to +204 d, obtained as part of the Carnegie Type II Supernova (CATS) project. SN 2002gh is among the most luminous discovered supernovae ever, yet it remained unnoticed for nearly two decades. Using Dark Energy Camera archival images we identify the potential supernova (SN) host galaxy as a faint dwarf galaxy, presumably having low metallicity, and in an apparent merging process with other nearby dwarf galaxies. We show that SN 2002gh is among the brightest hydrogen-poor SLSNe with M-V = -22.40 +/- 0.02, with an estimated peak bolometric luminosity of 2.6 +/- 0.1 x 10(44) erg s(-1). We discount the decay of radioactive nickel as the main SN power mechanism, and assuming that the SN is powered by the spin-down of a magnetar we obtain two alternative solutions. The first case, is characterized by significant magnetar power leakage, and M-ej between 0.6 and 3.2 M-circle dot, P-spin = 3.2 ms, and B = 5 x 10(13) G. The second case does not require power leakage, resulting in a huge ejecta mass of about 30 M-circle dot, a fast spin period of P-spin similar to 1 ms, and B similar to 1.6 x 10(14) G. We estimate a zero-age main-sequence mass between 14 and 25 M-circle dot for the first case and of about 135 M-circle dot for the second case. The latter case would place the SN progenitor among the most massive stars observed to explode as an SN.
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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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    Physical Properties of Type II Supernovae Inferred from ZTF and ATLAS Photometric Data
    (2024) Silva-Farfan, Javier; Forster, Francisco; Moriya, Takashi J.; Hernandez-Garcia, L.; Arancibia, A. M. Munoz; Sanchez-Saez, P.; Anderson, Joseph P.; Tonry, John L.; Clocchiatti, Alejandro
    We report an analysis of a sample of 186 spectroscopically confirmed Type II supernova (SN) light curves (LCs) obtained from a combination of Zwicky Transient Facility (ZTF) and Asteroid Terrestrial-impact Last Alert System observations. We implement a method to infer physical parameters from these LCs using hydrodynamic models that take into account the progenitor mass, the explosion energy, and the presence of circumstellar matter (CSM). The CSM is modeled via the mass-loss rate, wind acceleration at the surface of the progenitor star with a beta velocity law, and the CSM radius. We also infer the time of explosion, attenuation (A (V) ), and the redshift for each SN. Our results favor low-mass progenitor stars (M (ZAMS )< 14 M-circle dot) with a dense CSM ( M > 10(-3) M-circle dot yr(-1), CSM radius similar to 10(15) cm, and beta > 2). Additionally, we find that the redshifts inferred from the SN LCs are significantly more accurate than those inferred using the host galaxy photometric redshift, suggesting that this method could be used to infer more accurate host galaxy redshifts from large samples of Type II SNe in the LSST era. Lastly, we compare our results with similar works from the literature.
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    Supernova 2010ev : a reddened high velocity gradient type Ia supernova
    (2016) Gutiérrez, Caudia P.; González Gaitán, Santiago; Folatelli, Gastón; Pignata, Giuliano; Anderson, Joseph P.; Hamuy, Mario; Morrell, Nidia; Stritzinger, Maximilian; Taubenberger, Stefan; Bufano, Filomena