AAS Meeting #193 - Austin, Texas, January 1999
Session 47. Supernovae
Display, Thursday, January 7, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[47.13] A Universal B-band Lightcurve for Type Ia Supernovae and Direct Evidence for the Expansion of the Universe

Gerson Goldhaber (LBNL and Center for Particle Astrophysics, Univ. of California at Berkeley), Supernova Cosmology Project Collaboration

Intensity measurements for each of 36 high-redshift supernovae, a fully analyzed subset of the 75 discovered by the Supernova Cosmology Project, have been fitted using a standard B-band Leibundgut template with an adjustable time of maximum light, amplitude, and a horizontal (time) axis scale expansion factor s(1+z). Here the redshift z has been determined spectroscopically, and the ``stretch factor'' s, except for a few outliers is within 15% of unity. Appropriate K-corrections from the R-band to the B-band have been made. When this is done and individual lightcurves are normalized to unit maximum brightness, the more than 1400 experimental points are found to lie on a common curve. It is also found that the supernovae, whose light curves act as clocks at cosmological distances, cannot be combined if the Doppler factor 1+z is omitted. This clear evidence for the ``time dilation" of distant supernovae, as expected from cosmological expansion, argues strongly against alternative explanations for the redshift.

If you would like more information about this abstract, please follow the link to http://panisse.lbl.gov:80/public/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: gerson@lbl.gov

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