ACP Seminar (Astronomy - Cosmology - Particle Physics)

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

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
(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

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]