Circumstellar Interaction
in Type IIn supernovae
Poonam Chandra
National Centre for Radio Astrophysics
January 8, 2013
Collaborators:
Roger Chevalier, University of Virginia
Nicolai Chugai, University of Moscow
Alicia Soderberg, Harvard-Smithsonian
Claes Fransson, Stockholm Observatory
Type IIn Supernovae
 Suggested by Schlegel 1990.
 Unusual optical characteristics:
 Very high bolometric and Ha luminosities
 Ha emission, a narrow peak sitting atop of
broad emission
 Slow evolution and blue spectral continuum
 Late infrared excess
 Indicative of dense circumstellar medium.
Circumstellar interaction
Explosion
center
Circumst
ellar
medium
density
~1/r2
Circumstellar
wind (1E-5
Msun/Yr)
Forward Shock
~10,000 km/s
Reverse Shock
~1000 km/s
Ejecta
SN IIn Statistics
 Around ~180 Type IIn supernovae (81 observed)
 Only 10 discovered in Radio (SNe 1986J, 1988Z,
1995N, 1997eg, 1978K, 1998S, 2005kd, 2006jd,
2008iy, 2009ip).
 Only 12 discovered in X-rays (SNe 1986J, 1988Z,
1995N, 1998S, 1978K, 2002hi, 2005kd, 2005ip,
2006jd, 2008iy, 2010jl and 2009ip)
Peak radio and X-ray luminosities
1e+42
2006jd
.
1e+41
Type IIn
2005kd
2008iy
1988Z
1986J
2005ip
1998S
1e+40
2009ip
1980K
2002hh
−1
LX−ray(erg s )
1e+39
1e+38
1991em
1e+37
1995N
1998bw
1993J
1979C
1994I
2002ap
2001ig
1999gi
1e+36
1e+35
1987A
1e+34
1e+22
1e+23
1e+24
1e+27
1e+25
1e+26
−1 −1
L6cm (erg s Hz )
1e+28
1e+29
Type IIn supernovae
 Very diverse stellar evolution and mass loss history.
 SN 1988z, extremely bright even after 20 years
 SN 1994w faded only in 130 days.
 SN 2005gl: LBV progenitor?
 SN 2006gy, extremely bright: PISN progenitor?
 SN 2002ic, SN 2005gj: Hybrid between Ia/IIN.
 SNe 2001em, 1995N, 2008fz: Type Ib/c properties
 SN 2009ip: episodic ejections before turning into true
supernova
Multiwaveband campaign to
understand Type IIn supernovae
Chandra, Soderberg, Chevalier, Fransson, Chugai
Karl G. Jansky Very Large
Array
RADIO
TELESCOPES
Giant Metrewave Radio Telescope
X-ray telescopes
XMM
Swift
VLA observations of Type IIn supernovae
SN
2005kd
2006jd
2008iy
2009ip
2010jl
2007gy
2007nx
2007pk
2007rt
2008B
2008J
2008S
2008X
2008aj
2008am
2008be
2008bk
2008bm
2008cg
2008cu
2008en
2008es
2008gm
Poonam Chandra
2008ip
Days
640-1173
404-1030
300-1300
30-90
30-1000
72-418
22-372
2-342
49-329
21
254-336
8-308
12
6-300
40-337
27-268
4-13
252
39-222
156
132
130
52
5-124
Detection
Y
Y
Y
Y
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Distance
64
79
ATel
1182
1297
24
50
71
96
78
66
5.6
27
108
123
4
152
160
50
65
1271
1359
1366
1382
1410
1409
1408
1470
1452,55,65
1865,69
1594
1776
1891
SN IIn Radio Statistics
 Around ~180 Type IIn supernovae
 So far only 81 observed in radio bands
 43 SN IIn observed by us in radio
 Out of 81, only 10 detected in radio bands
 4 detected by us (SN 2005kd, 2006jd, 2008iy, 2009ip)
 In X-rays detected by us: SN 2006jd, 2010jl, 2009ip
Poonam Chandra
SN 2006jd
 Discovered October 12, 2006 in UGC 4179
 Redshift z=0.0186
 Initial spectrum shows Type IIb and later spectrum
shows IIn
 Radio Observations: VLA(EVLA), GMRT
 X-ray Observations: Swift-XRT, ChandraXO, XMMNewton
SN 2006jd- radio
observations
 With VLA starting from 2007, Nov 21.28 UT
 Epoch: Day 400 until Day 2000.
 Frequency bands: 22.5 (K), 8.5 (X), 4.9 (C) and 1.4 (L)
GHz bands
 With GMRT at three epochs, between 1104 day to 1290
days.
 Frequency bands: 1.4 GHz and 0.61 GHz bands. Not
detected yet in 0.61 GHz bands.
Chandra et al. ApJ 2012, 755, 110
SN 2006jd X-ray observations
 XMM observation on Apr 7, 2009 for 41 ks.
 Total of 1963 counts (6.19E-2 cps).
 Chandra observations on Sep 14, 2009 for 37 ks.
 Total of 888 counts (2.38E-2 cps).
 Swift observations between Nov 2007 and March 2011
at 18 occasions.
 All data fit by high temperatures.
Chandra et al. ApJ 2012, 755, 110
Flux Density (mJy)
Radio light curves
L Band
C Band
X Band
K Band
1000
Flux Density (mJy)
100
1000
100
1000
Days since explosion
1000
Days since explosion
Radio Spectral Evolution
a=-1.04
Chandra et al. ApJ 2012, 755, 110
Chandra et al. ApJ 2012, 755, 110
Flux (mJy)
Flux (mJy)
Flux (mJy)
Radio Spectra
Day 408
Day 579
Day 795
Day 845
Day 903
Day 1045
Day 1305
Day 1742
Day 2000
1000
1000
1000
1
10
Freq (GHz)
1
10
Freq (GHz)
1
10
Freq (GHz)
Frequency
Synchrotron self absorption indicates ejecta speed ~2000-3000 km/s. Too small.
Free-free absorption likely to dominate.
SN 2006jd
VSSA µ
Chevalier &
Fransson
2003
Radio Absorption Models
 External free-free absorption
Fn = K1n a t b exp(-t FFA )
t FFA = K 2n
-2.1 d
t
1- g
-g
where a =
; N(E) µ E
2
b = 3m - (3- a )(ms + 2 - 2m) / 2, and
1
m
d = m(1- 2s), R µ t and r µ s
r
Flux Density (mJy)
Radio light curves
L Band
C Band
X Band
K Band
1000
Flux Density (mJy)
100
1000
100
1000
Days since explosion
1000
Days since explosion
S=1.6, m>1
Flux (mJy)
Flux (mJy)
Flux (mJy)
Radio Spectra
Day 408
Day 579
Day 795
Day 845
Day 903
Day 1045
Day 1305
Day 1742
Day 2000
1000
1000
1000
1
10
Freq (GHz)
1
10
Freq (GHz)
1
10
Freq (GHz)
Radio Absorption Models
 Internal free-free absorption
 Weiler et. Al. 1990 proposed for SN 1986J, that thermal
absorbing material is mixed in with the non-thermal
emission. Later applied for SN1988Z too.
Fn = K1n t
a b
1- exp(-t int FFA )
t intFFA
t int FFA = K 3n t
d' is free parameter.
-2.1 d '
F(n)~n 2.1+a
Flux Density (mJy)
Radio light curves
L Band
C Band
X Band
K Band
1000
Flux Density (mJy)
100
1000
100
1000
Days since explosion
1000
Days since explosion
S=1.6, m=0.9
Flux (mJy)
Flux (mJy)
Flux (mJy)
Radio Spectra
F(n)~n 2.1+a
Day 408
Day 579
Day 795
Day 845
Day 903
Day 1045
Day 1305
Day 1742
Day 2000
1000
1000
1000
1
10
Freq (GHz)
1
10
Freq (GHz)
1
10
Freq (GHz)
Radio Spectral Evolution
a=-1.04
Chandra et al. ApJ 2012, 755, 110
Mass of the cool gas mixed in the
nonthermal emitting region
 Assuming that absorbing gas is in pressure equilibrium with
surrounding hot X-ray emitting gas.
 Temperature of absorbing gas ~104-105K and X-ray emitting
gas 60 keV.
 Then mass of the absorbing cool gas is:
 Ma=2x10-8T45/2 Msun.
 Modest amount of cool gas mixed into radio emitting region
can do the required absorption.
 Source of the cool gas is radiative cooling of the dense gas
in the shocked region.
SN 2006jd-XMM spectra
SN 2006jd-Chandra spectra
SN 2006jd X-rays
 Best fit with T=60-80 keV,
forward shock origin
 NH=1.3x1021 cm-2 (Galactic
4.5x1020 cm-2)
 Detection of 6.9 keV Fe XXVI
line (EW=1.4 keV).
 Possible detection of 8.1 keV
Ni XXVIII line
SN 2006jd X-rays
 Nonthermal model gives very
very flat powerlaw and
predicts F~n-0.2
 5Msun Mekal fits the data well
and reproduces Fe line.
 NEI model also fits data well
but reproduces very low
density ~7E-3 cm-3.
 X-ray also gives s=1.7
(consistent with radio).
 Density 3E6 cm-3
SN 2006jd- X-ray light curves
-0.24=2m(s-1)-1, s=1.7
SN 2006jd: Main Results
 Radio and X-ray both give s~1.6-1.7 (density~1/rs).
 Mass loss rate ~ 5x10-3 Msun/yr (assuming 100 km/s wind
speed).
 Shocked gas density 3x106 cm-3.
 X-ray emission well fit with single temperature model, X-ray
coming from forward shocked shell.
 No indication of reverse shock emission
 RS moved back to centre and weakened.
 RS is a cooking shock and the cool shell absorbing this.
SN 2006jd: Main Results
 Column density is a factor 50 smaller (1.3E21) than needed
to produce the X-ray luminosity (4E22).
 Clumps can give high luminosity but increase shock speed
and predict higher temperature of X-ray emission.
 Global asymmetry with low column density along line of
sight and dense interaction over rest of the solid angle.
 This scenario suggested for SN 1988z too (Chugai &
Danziger 1994).
 Large asymmetries seen in polarization observations of Sne
1998S, 2010jl and 1997eg too.
SN 2006jd: Main Results
 The radio optical depth is consistent with the
observations and observed radio luminosity and
reproduces optical depth of unity around day 1000.
 But Lower column density derives external FFA optical
depth is ~8E-4 at 5 GHz on day 1000.
 Thus this also works against external FFA model.
SN 2006jd: Main Results
 EW of Fe line (1.4keV) much higher than expected (0.1
keV) under collisional equilibrium model.
 NEI gives very low density ~1E3 cm-3.
 Possible region is mixing of cool gas could enhance the
width of the line.
SN 2010jl
 Discovered on 2010 Nov 3.5 UT in UGC 5189A (z=0.011)
 Discovered magnitude 13.5. Brightened to 12.9.
 One of the brightest apparent magnitude. (Absolute visual
magnitude Mv=-20)
 Archival HST image show progenitor star >30Msun.
 Low metallicity host galaxy, Z~0.3Msun, supporting the trend
that luminous SNe occur in low metallicity galaxies..
 Circumstellar expansion speed 40-120 km/s, from optical
spectra.
SN 2010jl
 Radio Observations: EVLA : 10 observations from
November 2010 until Now. No detection.
 X-ray observations: At 3 epochs with Chandra
 December 2010
 October 2011
 June 2012
 Detection at all three epochs in X-ray bands
SN 2010jl Chandra
Observations
Observations
November 2010
October 2011
June 2012
Duration
39.6 ks
41.0ks
39.5ks
Counts
468
1342
1484
Count Rate
1.13E-2 cts
3.29E-2 cts
3.68E-2 cts
Column Density
9.7E23 cm-2
2.67E23 cm-2
6.6E22 cm-2
Temperature
>10 keV
> 10 keV
> 10 keV
Chandra et al. 2012, ApJ Letters 2012, 750, L2
SN 2010jl Chandra X-ray
Spectra Comparison
November 2010
October 2011
June 2012
Chandra et al. 2012, ApJ Letters 2012, 750, L2
SN 2010jl Chandra Spectra
SN 2010jl Chandra Spectra
SN 2010jl Chandra Spectra
SN 2010jl Chandra Spectra
SN 2010jl
 Column density ~1024 cm-2 (1000 times higher than Galactic
absorption). Consistent with decay of 1/t.
 High temperature ~70-80 keV (>10 keV)
 High temp indicates forward shock emission
 High absorbing column density not accompanied by high
extinction of the SN.
 This indicates column near forward shock, due to mass loss,
where dust has been evaporated.
 First time X-ray absorption by external medium, that is not
fully ionized by the energetic medium.
SN 2010jl Main results
 Luminosity (0.2-10 keV) ~7x1041 erg/s, amongst most
luminous X-ray supernovae.
 Since most emission > 10 keV, this is spectral
luminosity
 Ejecta speed (v=sqrt(16 kT/3m) > 2700 km/s.
 Mass loss rate > 4x10-3 Msun/year
SN 2010jl Chandra X-ray
November 2010
SN 2010jl Chandra X-ray
October 2011
SN 2010jl Main results
 Fe 6.4 keV (narrow k-alpha iron line) in the first epoch and not in the second
epoch explains that ejecta has moved past it.
 The equivalent width (EW=0.2 keV) consistent with that expected for this line.
 Low temperature component fit by powerlaw of ~1.7 or ~1-2 keV temperature
and column density is that of Galactic. Luminosity ~4x1039 erg/s.
 Flux change between the two epochs is 20-30%. Consistent with a
background contaminating ULX source.
 Also looked at the possibility that enhanced 1 kev emission is by the CNO
elements. Not possible as this gives too little absorption in 1.5-3 keV range.
 Origin of additional component (NH~8E22, kT~1keV) is not known.
Summary
 A systematic study of this class of objects.
 Understand why so few radio and X-ray emitters
despite dense CSM.
 Late radio emission?
 Understanding early absorption.
 Understand trends in luminosity distribution.
 Two classes of supernovae?
Poonam Chandra
Peak radio and X-ray luminosities
1e+42
2006jd
.
1e+41
Type IIn
2005kd
2008iy
1988Z
1986J
2005ip
1998S
1e+40
2009ip
1980K
2002hh
−1
LX−ray(erg s )
1e+39
1e+38
1991em
1e+37
1995N
1998bw
1993J
1979C
1994I
2002ap
2001ig
1999gi
1e+36
1e+35
1987A
1e+34
1e+22
1e+23
1e+24
1e+27
1e+25
1e+26
−1 −1
L6cm (erg s Hz )
1e+28
1e+29
Peak radio and X-ray luminosities
1e+42
2006jd
.
1e+41
Type IIn
2005kd
2008iy
1988Z
1986J
2005ip
1998S
1e+40
2009ip
1980K
2002hh
−1
LX−ray(erg s )
1e+39
1e+38
1991em
1e+37
1995N
1998bw
1993J
1979C
1994I
2002ap
2001ig
1999gi
1e+36
1e+35
1987A
1e+34
1e+22
1e+23
1e+24
1e+27
1e+25
1e+26
−1 −1
L6cm (erg s Hz )
1e+28
1e+29
Collaborators
 Roger Chevalier, University of Virginia
 Nicolai Chugai, University of Moscow
 Alicia Soderberg, Harvard-Smithsonian
 Claes Fransson, Stockholm Observatory
SN 2006jd X-rays
 Best fit with T=60-80 keV, forward
shock origin
 NH=1.3x1021 cm-2 (Galactic
4.5x1020 cm-2)
 Detection of 6.9 keV Fe XXVI line
(EW=1.4 keV).
 Possible detection of 8.1 keV Ni
XXVIII line
 5Msun Mekal fits the data well and
reproduces Fe line.
 NEI model also fits data well but
reproduces very low density ~7E-3
cm-3.
 X-ray also gives s=1.7 (consistent
with radio).
 Density 3E6 cm-3
Radio Spectral Luminosity (8 GHz) erg/s/Hz
1e+29
.
.
1e+28
1e+27
1e+26
SN 2005kd
SN 2006jd
SN 1986J
SN 1988Z
SN 1995N
1e+25
1e+24
1
Poonam Chandra
10
100
Days since explosion
1000
100
Radio Spectral Evolution
Energy scales in various explosions
Chemical explosives
~10-6 MeV/atom
Nuclear explosives
~ 1MeV/nucleon
Novae explosions
few MeV/nucleon
Thermonuclear explosions
few MeV/nucleon
Core collapse supernovae
100 MeV/nucleon
Supernova Classification
(based on optical spectra and light curve)
Supernovae
Hydrogen
Type II
Narrow H
lines
Type IIn
No Hydrogen
Type I
Silicon
Type Ia
No narrow H
lines
Type IIP/IIL
Plateau
Type IIP
Linear
Type IIL
No Silicon
Type Ib/c
Helium
Type Ib
No Helium
Type Ic
Multiwaveband campaign to
understand Type IIn supernovae
Chandra, Soderberg, Chevalier, Fransson, Chugai
 Observe most the Type IIN supernovae with the JVLA
telescope (PI: Chandra).
 If detected in radio, follow with Swift-XRT (PI: Soderberg).
 Follow radio bright and/or Swift detected Type IIN supernova
with ChandraXO. Get spectroscopy, separate from nearby
contamination (PI: Chandra).
 If bright enough, do spectroscopy with XMM-Newton (PI:
Chandra).
 NIR photometry with PAIRITEL (PI: Soderberg).
 Low frequency radio follow up with the GMRT
Radio Absorption Models
 External free-free absorption
Fn = K1n a t b exp(-t FFA )
t FFA = K 2n -2.1t d
1- g
where a =
;
2
N(E) µ E -g
b = 3m - (3- a )(ms + 2 - 2m) / 2, and
d = m(1- 2s),
Rµt
m
1
and r µ s
r
Radio Absorption Models
 External free-free absorption
Fn = K1n a t b exp(-t FFA )
t FFA = K 2n -2.1t d
1- g
where a =
;
2
N(E) µ E -g
b = 3m - (3- a )(ms + 2 - 2m) / 2, and
1
and r µ s
r
d = m(1- 2s), R µ t
 Internal free-free-absorption
1- exp(-t int FFA )
Fn = K1n a t b
t intFFA
m
t int FFA = K 3n -2.1t d '
d' is free parameter.