TY - JOUR
T1 - Late-time spectral observations of the strongly interacting type ia supernova PTF11kx
AU - Silverman, Jeffrey M.
AU - Nugent, Peter E.
AU - Gal-Yam, Avishay
AU - Sullivan, Mark
AU - Howell, D. Andrew
AU - Filippenko, Alexei V.
AU - Pan, Yen Chen
AU - Cenko, S. Bradley
AU - Hook, Isobel M.
N1 - W. M. Keck Foundation; NASA; Alfred P. Sloan Foundation; National Science Foundation (NSF); U.S. Department of Energy Office of Science; Richard and Rhoda Goldman Fund; Christopher R. Redlich Fund; TABASGO Foundation; NSF [AST-0908886, AST-1211916]; ISF; BSF; GIF; Minerva, an FP7/ERC grant; Helen and Martin Kimmel Award for Innovative Investigation; Royal SocietyWe thank J. S. Bloom, K. Clubb, A. A. Miller, and A. Morgan for their assistance with some of the observations, B. Dilday, O. Fox, and L. Wang for helpful discussions, and the anonymous referee for providing comments and suggestions that improved the manuscript. We are grateful to the staffs at the WHT and the Keck Observatory for their support. The WHT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration (NASA); the observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community; we are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation (NSF), and the U.S. Department of Energy Office of Science. The SDSS-III Web site is http://www.sdss3.org/. Supernova research by A.V.F.'s group at U.C.
PY - 2013/8/1
Y1 - 2013/8/1
N2 - PTF11kx was a Type Ia supernova (SN Ia) that showed time-variable absorption features, including saturated Ca II H and K lines that weakened and eventually went into emission. The strength of the emission component of Hα gradually increased, implying that the SN was undergoing significant interaction with its circumstellar medium (CSM). These features, and many others, were blueshifted slightly and showed a P-Cygni profile, likely indicating that the CSM was directly related to, and probably previously ejected by, the progenitor system itself. These and other observations led Dilday et al. to conclude that PTF11kx came from a symbiotic nova progenitor like RS Oph. In this work we extend the spectral coverage of PTF11kx to 124-680 rest-frame days past maximum brightness. The late-time spectra of PTF11kx are dominated by Hα emission (with widths of full width at half-maximum intensity ≈2000 km s-1), strong Ca II emission features (∼10,000 km s -1 wide), and a blue "quasi-continuum" due to many overlapping narrow lines of Fe II. Emission from oxygen, He I, and Balmer lines higher than Hα is weak or completely absent at all epochs, leading to large observed Hα/Hβ intensity ratios. The Hα emission appears to increase in strength with time for ∼1 yr, but it subsequently decreases significantly along with the Ca II emission. Our latest spectrum also indicates the possibility of newly formed dust in the system as evidenced by a slight decrease in the red wing of Hα. During the same epochs, multiple narrow emission features from the CSM temporally vary in strength. The weakening of the Hα and Ca II emission at late times is possible evidence that the SN ejecta have overtaken the majority of the CSM and agrees with models of other strongly interacting SNe Ia. The varying narrow emission features, on the other hand, may indicate that the CSM is clumpy or consists of multiple thin shells.
AB - PTF11kx was a Type Ia supernova (SN Ia) that showed time-variable absorption features, including saturated Ca II H and K lines that weakened and eventually went into emission. The strength of the emission component of Hα gradually increased, implying that the SN was undergoing significant interaction with its circumstellar medium (CSM). These features, and many others, were blueshifted slightly and showed a P-Cygni profile, likely indicating that the CSM was directly related to, and probably previously ejected by, the progenitor system itself. These and other observations led Dilday et al. to conclude that PTF11kx came from a symbiotic nova progenitor like RS Oph. In this work we extend the spectral coverage of PTF11kx to 124-680 rest-frame days past maximum brightness. The late-time spectra of PTF11kx are dominated by Hα emission (with widths of full width at half-maximum intensity ≈2000 km s-1), strong Ca II emission features (∼10,000 km s -1 wide), and a blue "quasi-continuum" due to many overlapping narrow lines of Fe II. Emission from oxygen, He I, and Balmer lines higher than Hα is weak or completely absent at all epochs, leading to large observed Hα/Hβ intensity ratios. The Hα emission appears to increase in strength with time for ∼1 yr, but it subsequently decreases significantly along with the Ca II emission. Our latest spectrum also indicates the possibility of newly formed dust in the system as evidenced by a slight decrease in the red wing of Hα. During the same epochs, multiple narrow emission features from the CSM temporally vary in strength. The weakening of the Hα and Ca II emission at late times is possible evidence that the SN ejecta have overtaken the majority of the CSM and agrees with models of other strongly interacting SNe Ia. The varying narrow emission features, on the other hand, may indicate that the CSM is clumpy or consists of multiple thin shells.
UR - http://www.scopus.com/inward/record.url?scp=84880624288&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/772/2/125
DO - 10.1088/0004-637X/772/2/125
M3 - مقالة
SN - 0004-637X
VL - 772
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 125
ER -