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Title: Timescale stretch parameterization of Type Ia supernova B-band light curves

Abstract

R-band intensity measurements along the light curve of Type Ia supernovae discovered by the Cosmology Project (SCP) are fitted in brightness to templates allowing a free parameter the time-axis width factor w identically equal to s times (1+z). The data points are then individually aligned in the time-axis, normalized and K-corrected back to the rest frame, after which the nearly 1300 normalized intensity measurements are found to lie on a well-determined common rest-frame B-band curve which we call the ''composite curve.'' The same procedure is applied to 18 low-redshift Calan/Tololo SNe with Z < 0.11; these nearly 300 B-band photometry points are found to lie on the composite curve equally well. The SCP search technique produces several measurements before maximum light for each supernova. We demonstrate that the linear stretch factor, s, which parameterizes the light-curve timescale appears independent of z, and applies equally well to the declining and rising parts of the light curve. In fact, the B band template that best fits this composite curve fits the individual supernova photometry data when stretched by a factor s with chi 2/DoF {approx} 1, thus as well as any parameterization can, given the current data sets. The measurement of themore » data of explosion, however, is model dependent and not tightly constrained by the current data. We also demonstrate the 1 + z light-cure time-axis broadening expected from cosmological expansion. This argues strongly against alternative explanations, such as tired light, for the redshift of distant objects.« less

Authors:
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Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Director, Office of Science. Office of High Energy and Nuclear Physics. Division of High Energy Physics; National Aeronautics and Space Administration (US)
OSTI Identifier:
836363
Report Number(s):
LBNL-47884
R&D Project: 419401; TRN: US0500564
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Journal Name:
The Astrophysical Journal
Additional Journal Information:
Journal Volume: 558; Journal Issue: 1; Other Information: Submitted to The Astrophysical Journal: Volume 558, No.1; Journal Publication Date: 09/01/2001; PBD: 1 Apr 2001
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BRIGHTNESS; COSMOLOGY; PHOTOMETRY; SUPERNOVAE; ASTROPHYSICS COSMOLOGY SUPERNOVAE

Citation Formats

Goldhaber, G., Groom, D.E., Kim, A., Aldering, G., Astier, P., Conley, A., Deustua, S.E., Ellis, R., Fabbro, S., Fruchter, A.S., Goobar, A., Hook, I., Irwin, M., Kim, M., Knop, R.A., Lidman, C., McMahon, R., Nugent, P.E., Pain, R., Panagia, N., Pennypacker, C.R., Perlmutter, S., Ruiz-Lapuente, P., Schaefer, B., Walton, N.A., and York, T. Timescale stretch parameterization of Type Ia supernova B-band light curves. United States: N. p., 2001. Web. doi:10.1086/322460.
Goldhaber, G., Groom, D.E., Kim, A., Aldering, G., Astier, P., Conley, A., Deustua, S.E., Ellis, R., Fabbro, S., Fruchter, A.S., Goobar, A., Hook, I., Irwin, M., Kim, M., Knop, R.A., Lidman, C., McMahon, R., Nugent, P.E., Pain, R., Panagia, N., Pennypacker, C.R., Perlmutter, S., Ruiz-Lapuente, P., Schaefer, B., Walton, N.A., & York, T. Timescale stretch parameterization of Type Ia supernova B-band light curves. United States. doi:10.1086/322460.
Goldhaber, G., Groom, D.E., Kim, A., Aldering, G., Astier, P., Conley, A., Deustua, S.E., Ellis, R., Fabbro, S., Fruchter, A.S., Goobar, A., Hook, I., Irwin, M., Kim, M., Knop, R.A., Lidman, C., McMahon, R., Nugent, P.E., Pain, R., Panagia, N., Pennypacker, C.R., Perlmutter, S., Ruiz-Lapuente, P., Schaefer, B., Walton, N.A., and York, T. Sun . "Timescale stretch parameterization of Type Ia supernova B-band light curves". United States. doi:10.1086/322460. https://www.osti.gov/servlets/purl/836363.
@article{osti_836363,
title = {Timescale stretch parameterization of Type Ia supernova B-band light curves},
author = {Goldhaber, G. and Groom, D.E. and Kim, A. and Aldering, G. and Astier, P. and Conley, A. and Deustua, S.E. and Ellis, R. and Fabbro, S. and Fruchter, A.S. and Goobar, A. and Hook, I. and Irwin, M. and Kim, M. and Knop, R.A. and Lidman, C. and McMahon, R. and Nugent, P.E. and Pain, R. and Panagia, N. and Pennypacker, C.R. and Perlmutter, S. and Ruiz-Lapuente, P. and Schaefer, B. and Walton, N.A. and York, T.},
abstractNote = {R-band intensity measurements along the light curve of Type Ia supernovae discovered by the Cosmology Project (SCP) are fitted in brightness to templates allowing a free parameter the time-axis width factor w identically equal to s times (1+z). The data points are then individually aligned in the time-axis, normalized and K-corrected back to the rest frame, after which the nearly 1300 normalized intensity measurements are found to lie on a well-determined common rest-frame B-band curve which we call the ''composite curve.'' The same procedure is applied to 18 low-redshift Calan/Tololo SNe with Z < 0.11; these nearly 300 B-band photometry points are found to lie on the composite curve equally well. The SCP search technique produces several measurements before maximum light for each supernova. We demonstrate that the linear stretch factor, s, which parameterizes the light-curve timescale appears independent of z, and applies equally well to the declining and rising parts of the light curve. In fact, the B band template that best fits this composite curve fits the individual supernova photometry data when stretched by a factor s with chi 2/DoF {approx} 1, thus as well as any parameterization can, given the current data sets. The measurement of the data of explosion, however, is model dependent and not tightly constrained by the current data. We also demonstrate the 1 + z light-cure time-axis broadening expected from cosmological expansion. This argues strongly against alternative explanations, such as tired light, for the redshift of distant objects.},
doi = {10.1086/322460},
journal = {The Astrophysical Journal},
number = 1,
volume = 558,
place = {United States},
year = {2001},
month = {4}
}