Transcript SN 2004dj

Supernova study with
BATC Sky Survey
Wang Xiao-feng
Physics Department and Tsinghua Center for Astrophysics,
Tsinghua University
2005, 8, 12, Weihai
What is supernova
SN in M51! (SN 2005cs)
Stellar explosion with
giant energy release
Energy of the visible
explosion~1051 ergs
Luminosity~109-10 L⊙
Supernovae might be the
brightest objects in the
universe, and can outshine
a whole galaxy (for a few
weeks)
One of the endpoints
of stellar evolution
To measure the universe with supernovae
Extremely bright stellar
explosions
Important for the production of
the heavy elements
Best distance indicators in the
universe
The only reliable way of determining
extragalactic distances is through
supernova investigations.
F. Zwicky
Supernovae
Supernovae
SN classifications
Taxonomy Chart
Spectroscopic classifications
Type II (core-collapse) supernovae
Nonburning H
H
He
C
O
Massive star: Fe is fusion endpoint
electron capturepressure drop
collapse
Si
Fe
density increases
core bounces back
shockwave heating expansion
core collapse supernova mechanism
1.
pre SN star
2.
Fe core
proto neutron star
infalling outer core
inner core
outgoing shock from
rebounce
3.
4.
proto neutron star
infalling outer core
proto neutron star
matter flow gets reversed
- explosion
stalled shock
neutrinos
neutrino heated
layer
revived shock
Type Ia supernovae
white dwarf in binary stellar system
high H accretion rates
growing C/O white dwarf
~Chandrasekhar mass (1.4 Msolar) 
contraction
high central densityC fusion
thermonuclear explosion
SN Ia Differences
SN Ia are not all the same. Variations occur in their light curves
and spectra.
SN Ia correlations
Phillips relation or m15 relation
Luminosity and Light Curve shape
• m15 relation
Phillips (1993), Hamuy et al. (1996), Phillips et al.
(1999)
• MLCS
Riess et al. (1996, 1998), Jha et al. (2003)
• Stretch
Perlmutter et al. (1997, 1999), Goldhaber et al. (2001)
Nearby SN Ia sample
Evidence for good
distances
–distance accuracy around 10%
More precise cosmologyA Novel Color Parameter
Wang et al 2005a
SN Luminosity vs. C12
Precise Hubble diagram of SNe Ia
(Wang et al. 2005c, ApJ, submitted)
The discovery of supernovae
2004年底已发现3031颗
300-400/year since 1998
Multicolor SN study with BATC Sky Survey
•
Multicolor photometry of bright supernovae(Ia, II, Ib, Ic)
SN 1993J:
Circumstellar Interaction around SN 1993J(Wang et al. 2004a)
Late-time photometry of SN 1993J -- heroic observation
compaign (Zhang, Wang, Zhou et al. AJ, 2004, 128, 1857)
SN 2004dj: Progenitor and Light curves
(Wang et al. 2005b; Zhang, Wang, Zhou et al. 2005)
SN 2004et: An atypical type II supernpovae in NGC 6946
(in preparation)
SN 2005cs in M51 (on minitoring)
Ia: SNe 2002er, 2002fk, 2003kf, 2003cg
(Wang et al. 2004b)
•
SN survey plan in Nearby clusters of galaxies
interrupted but contributes to BATC’s image reduction
Progenitor identifications
To confirm stellar evolution models and SN theories
• SN Ia ??
• SN II (SN 1987A, SN 1993J, SN 2003gd)
Smart et al (2004,Science)
Progenitor of SN 2004dj in NGC 2403
SN Position:
R.A. = 7h 37m 17.02s,
Decl. = +65。35’57”.8
offset from the nucleus of NGC
2403: E160”and N10”
Discovery epoch: July 31.76
UT
NGC 2403:
R.A. = 7h 36m54s,
Decl. = +65。35’ 8”
Type: Scd 20’X20’
in the sky
m-M = 27.48 mag
D=3.2Mpc
Spectrum of SN 2004dj
Progenitors for Type II-P Supernovae
Theory predicts:
SNe II P arise from the core collapse of
red supergiant with initial masses > 8Msun
Observations for II P:
SN 1987A -- blue supergiant ~25Msun
SN 2003gd -- red supergiant~8- 9Msun (Smartt et al. 2004)
SN 2004et -- yellow supergiant~15Msun? (Li et al. 2005)
SN 2004dj…?
BATC Images of Pre- and post-explosion
of SN 2004dj
Pre- and post-explosion images of SN 2004dj by 60/90cm Schmidt
telescope of NAOC
Positional Coincidence of the Supernova
Position of SN 2004dj at difference wavelengths


optical: R.A. = 7h 37m 17.01s, Decl. = +65。35’ 58”
X-ray: R.A. = 7h 37m 17.05s, Decl. = +65。35’57”.9
Radio: R.A. = 7h 37m 16.92s, Decl. = +65。35’56”.97
Position of ‘star’96 (Sandage 1984)
R.A. = 7h 37m 16.96s, Decl. = +65。35’58”.2
SN 2004dj coincides with ‘star’ 96 to within 0.”7
The light variation of star96?
Stellar population of Star96
• Stellar model: the spectral flux library (Pickles 1998, PASP)
• Cluster model: a simple stellar population of Galaxy
Isochrone Synthesis spectra Evolution library (Bruzual & Charlot
2003)
To test with Chi-square minimization
Reddening and Metallicity
• Reddening
Na ID interstellar absorption lines can provide clues to the line-of-sight
reddening E(B – V) ~ EW: large uncertainty!
As a fitting parameter along with the T or log t
• Metallicity
Garnett et al. (1997) measured the metallity and its radial distribution in
NGC 2403
log(O/H)+12 ~8.45
Z~0.008
Fitting results for single star
A highly reddened E(B-V)=0.78 B2IV star
2 =24 for 14 BATC points.
Reasons why this fit does not work S96:
1) the corrected intrinsic B – V color is too blue to be
consistent with a B-type star;
2) Such an extremely blue and bright star is most likely to be
a luminous blue variable, but it did not show significant
light variations on a time scale of few years;
3) The high reddening would imply an unrealistic high
luminosity for a SN 2004dj as a type II-P SN.
Fitting results for clusters
Wang et al 2005c, ApJ, 626, L89
Optical Photometry of type II-P SN 2004dj
(Zhang, Wang, & Zhou et al. 2005)
Color Evolution of SN 2004dj
comparison with SN 1999em
Explosion date of SN 2004dj
~ 60 days after explosion
SED of SN 2004dj
Bolometric light curve of SN 2004dj
M(Ni56)~0.02Msun
The Explosion Parameters of SN 2004dj
Litvinova & Nadyozhin (1985) calculated a grid of supernova models
for E, M and R for SN II P.
• Mv(plateau) = -16.5 mag (our light curves)
• Δt = 80 days (comparison with SN 1999em)
• Vp = 3900 km/s (Patat etal. 2004)
• Mej , ,
10Msun
E,
0.7X10^51ergs
R
265Rsun
Zhang, Wang, Zhou et al. 2005, AJ, submitted
Future SN work
• Publishing a series of multicolor light curve data
obtained by BATC observations (~20 SNe Ia)
• Late-time photometry of some bright SNe II,Ib,Ic
• Simultaneous observations of some bright SNe
(TNT UBVRI+BATC intermediate-band filters)
• Progenitor work