Speaker:	Nao Suzuki (Lawrence Berkeley National Lab)
Title:	Towards the Era of High Precision Cosmology
Date (JST):	Mon, Jul 02, 2012, 14:00 - 15:00
Place:	Seminar Room A
Abstract:	In 1997, Schramm and Turner titled their paper as "Big-Bang Nucleosynthesis enters the Precision Era", and it marked the arrival of precision cosmology era. After a decade of discovery of dark energy, the Type Ia Supernova (SNIa) data alone requires the cosmic acceleration at > 99.999% confidence level, and the Nobel Prize in Physics in 2011 was awarded to the discovery of the accelerating universe. http://subarutelescope.org/Topics/2011/12/29/index.html Today, Supernova Cosmology Project (SCP) team reports Omega_Lambda = 0.729 ± 0.014 (68%CL including systematic error for LCDM) and the equation of state parameter w=-1.013+0.068-0.073 (for wCDM) from our Hubble Space Telescope Cluster Supernova Survey. (Suzuki et al. 2012 ApJ, 746, 85) Now, we are facing challenges to reduce the systematic error which becomes larger than the size of the statistical error. I will show the sources of the systematic errors and discuss how we can reduce them for the future surveys. One of the origins is the diversity of SNIa. By using the Principal Component Analysis (PCA) technique, we can quantitatively classify spectral diversity of SNIa. I will also introduce other applications of PCA to the studies of quasar, stellar and galaxy spectra from the ongoing Sloan Digital Sky Survey-III (BOSS). For example, 188,450 quasar spectra are collected from SDSS project, and PCA is the powerful tool to extract cosmological parameters from the quasar spectra. With HyperSuprime-Cam (HSC), and Prime Focus Spectrograph (PFS), Subaru telescope can lead the era of high precision cosmology but I urge you to advance the level of calibrations to compete against other surveys. I will present the forecast of dark energy measurement in the next 5 years and discuss the road map to the high precision cosmology into the next decade.
Seminar Video:	[VIDEO]

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