Spectropolarimetry of the peculiar type Ia supernova 2005hk

Ryan Chornock*, Alexei V. Filippenko, David Branch, Ryan J. Foley, Saurabh Jha, L. I. Weidong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

69 Scopus citations

Abstract

We present Keck spectropolarimetry of the unusual Type la supernova (SN Ia) 2005hk several days before maximum light. An analysis of the high signal-to-noise ratio total-flux spectrum shows the object's extreme similarity to the peculiar SN 2002cx. SN 2005hk has an optical spectrum dominated by Fe III lines and only weak lines of intermediate-mass elements, unlike a normal SN la at this epoch. The photospheric velocity measured from the minima of strong absorption lines is very low for an SN Ia (∼6000 km s -1), solidifying the connection to SN 2002cx. The spectrum-synthesis code SYNOW was used to identify the presence of iron-peak elements, intermediate-mass elements, and possibly unburned carbon at similar velocities in the outer ejecta of SN 2005hk. Many weak spectral features remain unidentified. The spectropolarimetry shows a low level of continuum polarization (∼0.4%) after correction for the interstellar component, and only a weak Fe III line feature is detected. The level of continuum polarization is normal for an SN Ia, implying that the unusual features of SN 2005hk cannot be readily explained by large asymmetries.

Original languageEnglish (US)
Pages (from-to)722-732
Number of pages11
JournalPublications of the Astronomical Society of the Pacific
Volume118
Issue number843
DOIs
StatePublished - May 2006
Externally publishedYes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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