The Subluminous Supernova 2007qd: A Missing Link in a Family of Low-luminosity Type Ia Supernovae
2010 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 720, no 1, 704-716 p.Article in journal (Refereed) Published
We present multi-band photometry and multi-epoch spectroscopy of the peculiar Type Ia supernova (SN Ia) 2007qd, discovered by the SDSS-II Supernova Survey. It possesses physical properties intermediate to those of the peculiar SN 2002cx and the extremely low-luminosity SN 2008ha. Optical photometry indicates that it had an extraordinarily fast rise time of lsim10 days and a peak absolute B magnitude of -15.4 ± 0.2 at most, making it one of the most subluminous SN Ia ever observed. Follow-up spectroscopy of SN 2007qd near maximum brightness unambiguously shows the presence of intermediate-mass elements which are likely caused by carbon/oxygen nuclear burning. Near maximum brightness, SN 2007qd had a photospheric velocity of only 2800 km s-1, similar to that of SN 2008ha but about 4000 and 7000 km s-1 less than that of SN 2002cx and normal SN Ia, respectively. We show that the peak luminosities of SN 2002cx like objects are highly correlated with both their light-curve stretch and photospheric velocities. Its strong apparent connection to other SN 2002cx like events suggests that SN 2007qd is also a pure deflagration of a white dwarf, although other mechanisms cannot be ruled out. It may be a critical link between SN 2008ha and the other members of the SN 2002cx like class of objects.
Place, publisher, year, edition, pages
2010. Vol. 720, no 1, 704-716 p.
IdentifiersURN: urn:nbn:se:su:diva-48727DOI: 10.1088/0004-637X/720/1/704ISI: 000281596000061OAI: oai:DiVA.org:su-48727DiVA: diva2:375882