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Title: SLOW-SPEED SUPERNOVAE FROM THE PALOMAR TRANSIENT FACTORY: TWO CHANNELS

Since the discovery of the unusual prototype SN 2002cx, the eponymous class of Type I (hydrogen-poor) supernovae with low ejecta speeds has grown to include approximately two dozen members identified from several heterogeneous surveys, in some cases ambiguously. Here we present the results of a systematic study of 1077 Type I supernovae discovered by the Palomar Transient Factory, leading to nine new members of this peculiar class. Moreover, we find there are two distinct subclasses based on their spectroscopic, photometric, and host galaxy properties: ''SN 2002cx-like'' supernovae tend to be in later-type or more irregular hosts, have more varied and generally dimmer luminosities, have longer rise times, and lack a Ti II trough when compared to ''SN 2002es-like'' supernovae. None of our objects show helium, and we counter a previous claim of two such events. We also find that the occurrence rate of these transients relative to Type Ia supernovae is 5.6{sub −3.8}{sup +22}% (90% confidence), lower compared to earlier estimates. Combining our objects with the literature sample, we propose that these subclasses have two distinct physical origins.
Authors:
 [1] ; ;  [2] ;  [3] ; ; ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ; ;  [9] ; ; ;  [10] ;  [11] ;  [12] ;  [13] ;  [14] more »; « less
  1. Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States)
  2. The Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  3. Computational Cosmology Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
  4. Benoziyo Center for Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel)
  5. Department of Physics, University of California, Santa Barbara, Broida Hall, Mail Code 9530, Santa Barbara, CA 93106-9530 (United States)
  6. School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)
  7. The Oskar Klein Centre, Department of Physics, AlbaNova, Stockholm University, SE-106 91 Stockholm (Sweden)
  8. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
  9. Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
  10. Spitzer Science Center, California Institute of Technology, M/S 314-6, Pasadena, CA 91125 (United States)
  11. Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States)
  12. Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
  13. Savantic AB, Rosenlundsgatan 50, SE-118 63 Stockholm (Sweden)
  14. National Optical Astronomy Observatory, Tucson, AZ 85719-4933 (United States)
Publication Date:
OSTI Identifier:
22364469
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; COMPARATIVE EVALUATIONS; GALAXIES; HELIUM; HYDROGEN; LUMINOSITY; ORIGIN; PHOTOMETRY; TRANSIENTS; TYPE I SUPERNOVAE; VELOCITY