Supernova Cosmology Project

The Supernova Cosmology Project ( SCP for short ) was an astrophysical research project that was carried out from 1988 by researchers from various international institutes under the direction of Saul Perlmutter . The aim of the SCP and another independent project ( High-Z Supernova Search Team , High-z SS for short; for redshift ) was to measure the rate of expansion of the cosmos . ${\displaystyle z}$

Result

The result of the SCP (as well as the High-z SS) was the discovery of the acceleration of cosmic expansion. The reason for the expansion is not understood today and is generally described by the term “ dark energy ”. In the equations of general relativity , the accelerated expansion is expressed in the fact that the cosmological constant is positive. It has also been using the data of the SCP, the relative matter energy density to and the relative vacuum energy to density (dark energy) determined. ${\displaystyle \Omega _{0}=0{,}3}$ ${\displaystyle \Omega _{\Lambda }=0{,}7}$

methodology

The SCP was looking for distant Type Ia supernovae that were redshifted . For each supernova its redshift , its apparent brightness and its absolute brightness were measured; The latter can be determined in supernovae of this type by observing the light curve . The distance of the respective supernova was determined by comparing the absolute with the apparent brightness . ${\displaystyle z>0{,}1}$ ${\displaystyle z}$ ${\displaystyle d}$

A dependency was obtained that is not a straight line and thus deviates from Hubble's law with a constant Hubble parameter : for a given redshift , the distance is greater than expected or, for a given distance , the redshift is smaller than expected. It follows that the rate of expansion (for which is a measure ) was smaller in the past (that is, for large ones ), which corresponds to an accelerated expansion. ${\displaystyle d(z)}$ ${\displaystyle z}$ ${\displaystyle d}$ ${\displaystyle d}$ ${\displaystyle z}$ ${\displaystyle z}$ ${\displaystyle d}$

Appreciation

The results were published in 1998 by the staff of the SCP and the High-z SS. In the same year, the two collaborations received the “ Breakthrough of the Year ” award, presented annually by the science magazine Science, as well as the Gruber Prize for Cosmology in 2007 and the Nobel Prize for Physics in 2011 . Perlmutter as director also received the Shaw Prize and the Albert Einstein Medal .

Publications

• Supernova Cosmology Project (Perlmutter et al.): Cosmology from Type Ia Supernovae, Bulletin Am. Astron. Soc., Vol. 29, 1997, p. 1351, Arxiv
• Supernova Cosmology Project (Perlmutter et al.): Measurements of the Cosmological Parameters Omega and Lambda from the First 7 Supernovae at z> = 0.35, Astroph. J., Volume 483, 1997, p. 565, Arxiv
• Supernova Cosmology Project (Perlmutter et al.): Measurements of Omega and Lambda from 42 High-Redshift Supernovae, Astrophys. J., Volume 517., 1999, pp. 565-586, Arxiv

See also

• Gerson Goldhaber
• Friedmann equations

Web links

• Page of the SCP
• Christoph Wendel: Seminar paper on the SCP (PDF file; 464 kB)

Individual evidence

1. ↑ James Shine: Cosmic Motion Revealed . In: Science . tape 282 , December 18, 1998, pp. 2156–2157 ( [1] [accessed March 24, 2018]).
2. ↑ Laureate of the Gruber Prize for Cosmology (English)
3. ↑ Press release of the Nobel Prize Committee (English)