Spectra of High-Redshift Type Ia Supernovae and a Comparison withtheir Low-Redshift Counterparts

Journal Article · Wed Jul 20 00:00:00 EDT 2005 · The Astronomical Journal

DOI:https://doi.org/10.1086/497635· OSTI ID:877680

Hook, I M; Howell, D A; Aldering, G; Amanullah, R; Burns, M S; Conley, A; Deustua, S E; Ellis, R; Fabbro, S; Fadeyev, V; Folatelli, G; Garavini, G; Gibbons, R; Goldhaber, G; Goobar, A; Groom, D E; Kim, A G; Knop, R A; Kowalski, M; Lidman, C ; Nobili, S; Nugent, P E; Pain, R; Pennypacker, C R; Perlmutter, S; Ruiz-Lapuente, P; Sainton, G; Schaefer, B E; Smith, E; Spadafora, A L; Stanishev, V; Thomas, R C; Walton, N A; Wang, L; Wood-Vasey, W M

We present spectra for 14 high-redshift (0.17 < z < 0.83) supernovae, which were discovered by the Supernova Cosmology Project as part of a campaign to measure cosmological parameters. The spectra are used to determine the redshift and classify the supernova type, essential information if the supernovae are to be used for cosmological studies. Redshifts were derived either from the spectrum of the host galaxy or from the spectrum of the supernova itself. We present evidence that these supernovae are of Type Ia by matching to spectra of nearby supernovae. We find that the dates of the spectra relative to maximum light determined from this fitting process are consistent with the dates determined from the photometric light curves, and moreover the spectral time-sequence for SNe Type Ia at low and high redshift is indistinguishable. We also show that the expansion velocities measured from blueshifted Ca H&K are consistent with those measured for low-redshift Type Ia supernovae. From these first-level quantitative comparisons we find no evidence for evolution in SNIa properties between these low- and high-redshift samples. Thus even though our samples may not be complete, we conclude that there is a population of SNe Ia at high redshift whose spectral properties match those at low redshift.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director. Office of Science. Office of High EnergyPhysics; National Aeronautics and Space Administration NAS 5-26555 andHST-GO-7336; Royal Swedish Academy of Sciences
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 877680
• Report Number(s): LBNL--58705; BnR: KA1301020
• Journal Information: The Astronomical Journal, Journal Name: The Astronomical Journal Journal Issue: 6 Vol. 130
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
99 GENERAL AND MISCELLANEOUS
COSMOLOGY
SPECTRA
SUPERNOVAE
Supernovae