Radio supernova SN 2001gd
in NGC 5033
Miguel A. Pérez-Torres
(torres@iaa.es)
JENAM 2004
Granada, September 13-17 2004
The Standard Interaction Model (Chevalier, 1982)
ρcsm ~ r-s
(thermal absorber)
ρej ~ r-n
opt. depth ~ (frequency)-2.1
Non-thermal
synchrotron emission
-p
N ~ N0 E
B
nH ~ 3 x 107 (dM/dt)-5 v10-1 r 15-2 cm-3
Ssyn, ν ~ να tβ
Self-similar expansion
R ~ tm
m = (n - 3) / (n-s)
Ssyn, ν ~ να tβ
α = (1 - p)/2
β = (6m - 5 - p)/2
m = (n-3) / (n-2)
(s=2 assumed)
(Weiler et al. 2002, AR&A, 40, 387)
Discovery of a shell-like
structure in an RSN
First movie ever of an
expanding radio supernova
t ~ 239 d
1 mas
1 mas at 3.6 Mpc ~ 0.018 pc
From Marcaide et al. Nature 373, 44-45 (1995)
(Marcaide et al. 1995, Science,270,1475)
1 mas at 3.6 Mpc ~ 0.018 pc
t ~ 239 d
Discovery of a shell-like
structure in an RSN
Average expansion rate:
2.43 ± 0.15 µas/day
~ 15200 ± 900 km/s
1 mas
From Marcaide et al. Nature 373, 44-45 (1995)
First movie ever of an
expanding radio supernova
Average expansion rate
for the first ~ 600 days:
2.39 ± 0.03 µas/day
~ 14900 ± 200 km/s
(Marcaide et al. 1995, Science,270,1475)
SN2001gd
NGC 5033 (D = 13.1 Mpc)
SN2001gd
Prediscovery image
Image taken on 13 Jan 2002
(Discovery date is 4 Dec 2001)
SN2001gd: a SN1993J-like event
SN2001gd spectrum on 4 Dec 2001
(Matheson et al. 2001)
Comparison spectra SN2001gd/SN1993J
(from Matheson et al. 2001)
First radio detection of SN2001gd
1.3 cm
3.6 cm
6 cm
8 Feb 2002
t ~ 150 days
20 cm
(from Stockdale et al. 2002)
L6 cm peak ~ 3 x 1027 erg/s/Hz
First VLBI detection of SN2001gd
VLBI @ 3.6 cm
26 June 2002
(texp ~ 300 days)
Source structure
unresolved
Radio images of SN 2001gd at 3.6 cm
26 June 2002
VLA
3.6 mJy
VLBI
8 April 2003
1.0 mJy
VLBI
MODEL
Angular radius (microarcsec)
2002.48
2003.27
Opt. thin sphere
390 +/- 40
440 +/- 50
Opt. thick disk
350 +/- 30
410 +/- 50
Opt. thin shell
330 +/- 30
370 +/- 40
Expected model is the optically thin shell
R ~ 3.6 x 1016 cm on 8 April 2003
Angular diameter change is barely detectable above 1-sigma
100 micro arcsec @ 13.1 Mpc ~ 0.006 pc ~ 1300 AU
Magnetic Field in SN 2001gd
9
If equipartition betw/ fields and particles
9
Emin ~ (0.2-13) x 1047 erg
9
9
9
B ~ (50-380) mG
Bcsm ~ 2 mG at R=3.6 x 1016 cm
Compression of B_wind is not enough =>
turbulent amplification of B
VLA Radio spectrum of SN 2001gd on 8 April 2003
Pure synchrotron
Synchrotron +
thermal f-f absorption
α
Sν = S1ν exp(−k ν
alpha = -1.0 +/- 0.1
−2.1
)
Free-free optical depth constrains
Te and (dM/dt)/vwind
Sν = S1ν α exp(− k ν −2.1 )
τ ff,ν ≈ 0.17 g ff T ν
-3/2 −2
5
1
τ ff,ν = −kν
2
-5
−2.1
-2 -3
10 16
(dM/dt) v r
Te = (8-20) x 104 K
(dM/dt) = (5-10) x 10-5 Msun/yr
VLA image at 3.6 cm of SN2001gd
on 8 April 2003
Contours of soft (0.5-2.5 keV)
X-rays on 18 Dec 2002
SN 2001gd
NGC 5033
Most X-ray emission comes from a
soft component at T ~ 1.7 keV (reverse shock)
LX-rays ~ 4 x 1038 erg/s
(0.3-5 keV)
SN 2001gd, a sister of SN 1993J
9
9
9
9
9
9
9
9
9
ρcsm ~ r-s ; s = 2
vwind = 10 km/s
dM/dt = (5-10) x 10-5 Msun/yr
Lradio ~ 6 x 1036 erg/s
(1-43 GHz)
L X-rays ~ 4 x 1038 erg/s
(0.3-5 keV)
R ~ 3.7 x 1016 cm
B ~ (50-380) mG » Bcsm ~ 2 mG
Turbulent amplification of B
Emin ~ (0.2-13) x 1047 erg
torres@iaa.es
Summary
SN1979C SN1986J SN2001gd SN1993J
Distance (Mpc)
Time since explosion (yr)
(L6cm / L6cm SN1993J)peak
Resolved by VLBI?
Optically thin phase?
Radio brightness structure
(dM/dt) / (10-5 M_sun/yr)
Deceleration parameter (m)
Asymmetric expansion?
Circumstellar medium
Mswept / Msun
Menv / Msun
Explosion scenario
Magnetic field amplification
tbreak (years)
16.1
20.1
~1.6
Not yet
Yes
shell
~10
0.62
No
--1.6
~0.9
Binary
Turbul.
6±2
9.6
~16
~13
Yes
Yes
13.1?
<2
~2
Not yet
Yes
distorted shell
~20
0.90
Yes
clumpy
2.2
~12
Single
Turbul.
----
---
5-10
1.0?
?
?
?
?
Binary?
Turbul.
----
torres@iaa.es torres@iaa.es
3.63
8.6
1
Yes
Yes
~smooth shell
5
~0.82
No (<5%)
~smooth
~0.4
~0.6
Binary
Turbul.
~0.5