1. Supernova and Cosmology
Xiaofeng Wang
Tsinghua University
FCPPL, 2011 Apr. 8, Shandong University, Jinan

2. Supernova（超新星） 一个星体要到生命尽头的时候，会突然变得特别的亮， 这个时候的星体被称为“超新星”
1987A on Dec (NASA)

3. Before and after explosion of SN 1998dh
AF-03W-138-r (rotated 90 deg).

4. Type Ia Supernova – Explosion of an accreting WD
White Dwarf
An explosion resulting from the thermonuclear detonation
of a White Dwarf Star

5. SNe Ia as Lighthouse in the Universe
Brightness tells us distance away (lookback time)
Redshift measured tells us expansion factor (average distance between galaxies)

6. Gruber prize for Cosmology
2009：Freedman, Kennicutt, and Mould for their Work on Resolving the Value of the Hubble Constant, the Key Determinant for How Fast the Universe Is Expanding
2007: Saul Perlmutter and Brian Schmidt and their teams: the Supernova Cosmology Project and the High-z Supernova Search Team, for independently discovering that the expansion of the universe is accelerating
2000: Allan R. Sandage and Phillip J. E. (Jim) Peebles: Sandage for pursuing the true values of the Hubble constant, the deceleration parameter and the age of the universe; Peebles for advancing our understanding of how energy and matter formed the rich patterns of galaxies observed today

7. Friedmann cosmology Assumption: homogeneous and isotropic universe
Null geodesic in a Friedmann-Robertson-Walker metric:

8. Accelerating Universe from SNe Ia
Riess et al., 1998
Perlmutter et al., 1999

9. SN Ia Hubble diagram SNLS First Year Cosmology（Astier et al. 2006）
Union2 (Amanullah et al. 2010)
SDSS (Kessler et al. 2009)

10. Our Universe
宇宙中95%的内容我们是不知道的！

11. Improvements in dark energy w constraints from SNe Ia over time
Howell (2010)

12. SN Ia observations have evidenced an acceleration of the Universe, which can be explained by the cosmological constant introduced by Einstein with his theory of General Relativity. The existence and value of this cosmological constant are difficult to explain by present quantum field inspired theories which predict in general an evolution of the equation of state describing this mysterious component called “Dark Energy”. SNe Ia remain one of the best probes to date to constrain the equation-of-state parameter and test for its evolution.

13. Standardizing SNe Ia
~9% accuracy in distance measurement

14. Requirement for precise cosmology
Needed mag ~ 0.01 !!!
B. Schmidt, 2005

15. SN Ia Hubble diagram with different spectroscopic subclasses
Improving the measurement of the distance accuracy from 9% to 6%
(Wang et al. 2009,2011)

16. Some projects: SN Factory/SNIFS
The Nearby Supernova Factory (SNfactory) was founded by Lawrence Berkeley National
Lab and a consortium of French laboratories: LPNHE, IPNL and CRAL --- to advance the
study of dark energy through the use of Type Ia supernovae. The project focused on the discovery of nearby supernovae (using the QUEST-II camera at Palomar) and subsequent
follow-up using the SuperNova Integral Field Spectrograph (SNIFS, built by France and Berkeley, and continuously mounted on the University of Hawaii UH/IfA 2.2-m telescope
since spring 2004).

17. Extension of SN Factory/SNIFS : SN Factory II
Lawrence Berkeley National Laboratory
Laboratoire de Physique Nucleaire et de Hautes Energies de Paris (LPNHE)
CNRS/IN2P3 and Universities of Paris VI & VII
Institut de Physique Nucleaire de Lyon (IPNL), CNRS/IN2P3 and University Lyon I
Centre de Recherche Astronomique de Lyon (CRAL), CNRS/INSU and
University Lyon I
Yale University
Tsinghua University
University of Bonn
Max Planck Institute for Astrophysics
Centre de Physique des Particules de Marseille

18. Trigger: XuYu Schmidt Telescope

19. Some projects: Antartic Survey Telescope (AST)

20. Some Projects: AST3

23. Discovery of Young Supernova with AST3
Kasliwal et al (2010)

24. Spectroscopic identifications of AST3 transients
Solutions:
Photometric classifications with existing color and light curve templates
Telescopes in Chile and Australia
1-m dedicated telescope with IFU (collaborating with France)?

25. Tsinghua University Physics Department
Tsinghua University Engineering Department
Tsinghua University Computer Science Department
Collaborations with
IHEP, NAOC, BNU, PMO, YNO
UC Berkeley, LBL, Texas A&M, France(Paris, CPPM)