1. Tsinghua University Supernova Program
Xiaofeng Wang
Physics Department & THCA
Tsinghua University

2. Supernova Classification and Explosion Mechanism
Thermonuclear Explosion
Core-Collapse Explosion

3. Galactic Supernovae in the past millennium
SN 1006 (brightest)
SN 1054 (Crab Nebula)
Visible during the day
SN 1572 (Tycho’s SN)
SN 1604 (Kepler’s SN)
Nearest ones can be seen with naked eyes: rare! 8 in 2000 years

4. Type Ia supernovae as standard candles
1. “Phillips relation”: A correction to SN Ia light-curves based on light-curve shape drastically improves the quality of the standard candle.
20%
Brightness 
2. SN colour: A correction to the SN luminosity based on the SN colour
Many methods:
Stretch – Perlmutter 97, 99
(M)LCS(2k2) – Riess, 95,96, Jha 07
SALT(2) – Guy 05, 07
ΔC12 – Wang X. 05
CMAGIC – Wang L. 03; Conley 06
Δm15 – Phillips 93; Hamuy 95; Prieto 06
Brightness 
8%!
Time 

5. Type Ia Supernovae— Lighthouse of the Universe
Ia型超新星像标准烛光一样可以用来测宇宙学距离，这就好比同等亮度的蜡烛，放地越远看起来就越暗（出自NASA）。
Image credit from NASA

6. The Accelerating Universe  Nobel Prize for Physics in 2011!
在地球上抛一个苹果上去，其上升的速度不可能越来越大，但在宇宙尺度上，确实是这样的现象。
Riess et al., 1998
Perlmutter et al., 1999

7. Challenges for Precise Cosmology with SNe Ia
B. Schmidt, 2005
Needed mag ~ 0.01 !!!

8. Debate on SNe Ia Progenitor System

9. Systematic uncertainties in SN Ia distances

10. Discovery of a Supernova
(Automatic pipeline)

11. Systematic Errors in SN Ia distances
Dust Absorptions
Phillips Relation
Tausenbeger etal. 2011

12. Circumstellar Dust？ （Wang X F, et al. ApJ, 2008a, 675, 626)

13. CSM Dust? Very blue echo spectrum; Dust with grain size between
m is required
(Wang et al. 2008b)

14. Spectroscopic Diversity of SNe Ia (Benetti et al. 2005; Branch et al
Spectroscopic Diversity of SNe Ia (Benetti et al. 2005; Branch et al. 2006; Wang et al. 2009)
(Wang et al. 2009)

15. Two SN Ia populations?
Wang et al. 2009

16. Other common features in HV SNeIa Evolution of Na I D lines
SN 2006X
Changes in CSM
Ionization due to variable SN
radiation field
CSM around a
Normal SN Ia
50 km/s
Ejected 50 days
before explosion
Patat et al. Science 07

17. Similar variable Na I D in SNe 1999cl and 2007le
Blondin et al. 2009
Simon et al. 2007, 2009

18. Outflow from Na ID
Sternberg et al. 2011, science

19. Outflow from Na ID
Sternberg et al. 2011, science

20. HVG SNe Ia are reported to have systematically positive (redshifted) emission line shift in the nebular phase, while the LVG usually have negative shift (Maeda et al. 2010). This discrepancy was argued to be geometric effect for HVG and LVG SNe Ia.
Maeda et al. 2010

21. Geometric effect?
Maeda et al. 2010,nature

22. PTF11kly/SN 2011fe in M101
Nugent et al. 2011, nature

23. Constraints on progenitor of SN 2011fe
Nugent et al. 2011, nature

24. HST archive image of the site of sn2011fe
Li et al. 2011, nature

25. Tsinghua Univ. Supernova Program
Collaborators:
NAOC: Tianmeng Zhang, Zhou Xu, Jingsong Deng, Chao Wu, Lingzhi Wang
PMO: Haibin Zhao, Xueguang Zhang
CCAA: Lifan Wang, Zhaohui Shang
BNU: Fang Huang, Zhen Liu

26. 1. TNT monitoring of bright SNe (~150 SNe:100 SNe Ia)

27. 2. Spectroscopic Identification and follow up at NAOC 2. 16-m & YNAO 2
2. Spectroscopic Identification and follow up at NAOC 2.16-m & YNAO 2.4-m telescopes
In 2011: 12 nights on NAOC 2.16-m telescope (OMR+BFOSC)
In 2012:7 nights on NAOC 2.16, 10 nights on YNAO 2.4
In 2013, ~30 nights ( ToO) on NAOC 2.16, ~15 nights on YNAO 2.4
At present: ~200 spectra have been obtained for 60 SNe.
Next year: ~200 spectra will be expected.

28. Early Spectra of SN 2011fe
Wang et al. 2012a, in prep.

29. SYNOW Fit to t = -16 d Spectrum of SN 2011fe

30. HV vs. LV (Early Spectra)
Wang et al. 2012a, in prep.

32. Type IIn: SN 2010jl
Zhang, T., Wang, X., Wu, C., et al

33. Type IIn: SN 2010jl
Zhang, T., Wang, X., et al. 2012, AJ

34. Type IIn: SN 2010jl

35. 2.4m
TNT
2.16m
3. Transient Survey
Xuyi
AST3
BATC

37. Discovery of a Nova in
60/90 schmidt telescope

39. Facility: PMO 1.2-m schmidt @Xuyi
Telescope: 1.04/1.20m Schmidt, f/1.8, 3.14o FoV
Location: °E, °N
Sea level: 219m
Observable night: 194
Best seeing: θ = 0.81″
Sky Light: Mag (V), Mag (B)
Temperature: -20o— +40o
Wind Velocity: <20 m/s
Excellent image quality
A very high quality CCD
Good seeing and sky background

40. Antarctic Survey Telescope

41. Antarctic Survey Telescope
1) Adjustable tower height (preliminary designed to be about 1.5m);
2) Foldable dome;
3) Active snow removing;
4) Auto-focusing.

42. Spectral identification of AST3 transients from telescopes in Australia
Collaboration with
Brian Schmidt’s
group
Siding Spring Observatory, ANU 2.3 m
2017/4/24

43. AST3 CCD Camera No shutter
To be operated in Frame Transfer mode，10k x 5k
FOV: ～4.3 sq. degree
16 readout channels

44. Observing Facilities For our Transient Survey
BATC (0.6-m schmidt), Xuyi (1.05m), AST3(0.5m)
 discovering SNe
TNT, Skymapper  photometry
NAOC 2.16m, YNAO 2.4m, ANU 2.3m, SNIFS?  identification, spectroscopic follow up

45. Phase-Space of various transients in the Universe
Cooks Branch

46. Science Goals Key Projects Type Ia SNe Dwarf novae
Transients in nearby galaxies
Core collapse SNe
RR Lyrae
Solar system objects
CVs
AGN
AM CVn
Blazars
Flare stars
Hostless transients

47. Enjoy your stay in Tsinghua Univ.!
Thank you!
Enjoy your stay in Tsinghua Univ.!