# Presentation: 584293

## Largely based on work done in collaboration with: 
Nino Panagia (STScI/ESA) 
Dick Sramek (NRAO)
Chris Stockdale (Marquette Univ.)
Schuyler van Dyk (Caltech/SSC)
Chris Williams (NRL)
and
with help from Poonam Chandra

- Largely based on work done in collaboration with:
- Nino Panagia (STScI/ESA)
- Dick Sramek (NRAO)
- Chris Stockdale (Marquette Univ.)
- Schuyler van Dyk (Caltech/SSC)
- Chris Williams (NRL)
- and
- with help from Poonam Chandra

- Kurt W. Weiler (NRL)

- Radio Emission from Supernovae

## Radio Supernovae (RSNe)

- ~50 RSNe detected in the radio
- ~2 dozen with light curves
- ~1 dozen with extensive light curves
- Many upper limits (~200 )

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Why Study RSNe?

- The study of radio emission provides valuable
- insight into SN shock/CSM interaction
- Structure of the circumstellar medium
- Pre-explosion mass-loss rate and changes therein
- History of pre-SN evolution
- Nature of the progenitor

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## “Turn on”, first at high , progressing to lower  (decreasing absorption)
Power-law decline after maximum at each 
Transition from “optically thick” spectral index  (where S ~ + ) to an “optically thin” asymptotic value
Nonthermal emission with very high TB

- Radio Supernovae

- “Turn on”, first at high , progressing to lower  (decreasing absorption)
- Power-law decline after maximum at each 
- Transition from “optically thick” spectral index  (where *S*** ~ + ) to an “optically thin” asymptotic value
- Nonthermal emission with very high TB

**SN Ib**

**SN II-L**

**SN IIn**

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Standard Model Physical Parameters[Chevalier ApJ, 259, 302, 1982]

- Red Supergiant (RSG) progenitor
- Slow (10 km s-1), dense (10-6 - 10-4 M yr-1) wind
-   r-2 [   Mdot/(wwind r2)] density profile
- Circumstellar Medium (CSM) ionized by SN UV/X-ray flash
- Relativistic electrons & enhanced magnetic field arise from shock/CSM interaction
- Ionized CSM provides free-free absorption (FFA)
- Synchrotron Self-Absorption (SSA) plays a role in some objects at early times

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Circumstellar Interaction

**Circumstellar Interaction**
- parameterized radio light curves
- [Weiler et al.  ARAA 40, 387, 2002]
- K2, K3 = external, homogeneous and clumpy optical depth on day 1;
- K4 = external, distant optical depth;
- K5, K6 = internal SSA and FFA optical depth on day 1

- external = CSMuniform + distant

- internal = internalSSA + internalFFA

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Derived  Properties of RSNe

- Type Ia SNe never detected: very low pre-SN mass loss rates (<3 x 10-8 M yr-1)
- Type II SNe -- slowly evolving radio emitters, with:
- Flatter spectrum:   = > -1.0 (generally)
- Slow decay:   = -0.7 -- -1.4
- Mass loss rates 	10-6 -- 10-4 M yr-1
- Most how late time deviation from a smooth radio light curve
- Type IIP SNe are generally weaker radio emitters and more rapidly evolving that Type IIL and, especially, Type IIn
- Type Ib/c -- rapidly evolving radio emitters, with:
- Steep spectrum:	  = < -1.0 (generally)
- Fast decay:  = -1.2 -- -1.6
- Mass loss rates 	 10-7 -- 10-6 M yr-1
- Associated (rarely) with GRBs
- Deviations from this “standard” picture are, of course, the most interesting

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## All SNIaat once

- The lowest
- 2 upper limit
- is about
- 3  10-8 M yr-1

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Constraints on SNIa Progenitors

- If accretion rates higher than 10-7 M yr-1are needed to make a WD mass exceed the Chandrasekhar mass and
- If an upper limit to the mass-loss rates from the system are < 3 x 10-8 M yr-1:
- Single Degenerate Scenarios:
- Rule out WD accretion via stellar wind from a massive binary companion in a symbiotic system
- WD accretion from a relatively low mass companion via Roche lobe overflow is possible, but requires relatively high efficiency (>60 – 80%)
- Double Degenerate Scenario:
- Not ruled out by the available upper limits
- (Panagia et al. 2006, ApJ 646, 369)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Derived  Properties of RSNe

- Type Ia SNe never detected: very low pre-SN mass loss rates (<3 x 10-8 M yr-1)
- Type II SNe -- slowly evolving radio emitters, with:
- Flatter spectrum:   = > -1.0 (generally)
- Slow decay:   = -0.7 -- -1.4
- Mass loss rates 	10-6 -- 10-4 M yr-1
- Most how late time deviation from a smooth radio light curve
- Type IIP SNe are generally weaker radio emitters and more rapidly evolving that Type IIL and, especially, Type IIn
- Type Ib/c -- rapidly evolving radio emitters, with:
- Steep spectrum:	  = < -1.0 (generally)
- Fast decay:  = -1.2 -- -1.6
- Mass loss rates 	 10-7 -- 10-6 M yr-1
- Associated (rarely) with GRBs
- Deviations from this “standard” picture are, of course, the most interesting

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN1979C: Twenty Years of Observations

- An increase of
- CSM density

- About 10,000 years
- before exploding
- the progenitor
- ejected a discrete shell?
- Pulsational instability?
- Consistent with Immler
- etal. (ApJ 632, 283,
- 2005) constant X-ray
- emission since day
- ~5800.

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN1980K - Radio

- An decrease of
- CSM density (/2)

- Type IIL

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 2001ig Radio “light curve”

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Analogy with SN 1979C

- Schwarz &
- Pringle MNRAS
- 282, 1018, 1996

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Pinwheels in the sky

- WR104
- Tuthill et al.
- 1999

- WR98a
- Monnier et al.
- 1999

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Radio Observations

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Radio Light Curves(SSA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Spectral Index Evolution(SSA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Brightness Temperature(SSA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Radio Light Curves(FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Spectral Index Evolution(FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Brightness Temperature(FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Radio Light Curves(SSA + FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Spectral Index Evolution(SSA + FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Brightness Temperature(SSA + FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Late (>day3100) Evolution(no SSA + no FFA)

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN 1993J – Radio Observations

- Radio data are (arguably) the most detailed set for any SN (except possibly SN 1987A) in any wavelength range
- ~650 measurements from 0.3 -115 GHz (3 mm – 1 m)
- Conclusions
- The best overall fit to the ``early'' (day <3100) includes both non-thermal SSA, and thermal FFA
- Neither pure SSA nor pure FFA absorbing models fit the light curves, the spectral index evolution, and provides a physically realistic brightness temperature evolution.
- After day ~3100 the radio decline rate steepens significantly
- Can be  described as an exponential with an e-folding time of ~1100 days.
- We do not see a break in the spectral index around day 3200
- The spectral index MAY steepen around day 4800 but the data are inconclusive

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SUMMARY - I

*SNe classes are distinct in radio emission properties (thus distinct in CSM environments):*
*SNe Ia are undetectable at VLA’s limiting sensitivity (so far)*
*SNe Ib/c turn on and off quickly*
*SNe II evolve more slowly*
*RSNe are sensitive to M**dot**/w**wind** (~ pre-SN mass loss rate)*
*RSNe sample the CSM **** properties of the pre-SN wind density & structure --  unique stellar evolution probe*
*Because v**wind** ~ 10 km/s and v**shock** ~ 10**4** km/s, radio observations are a “time machine”*

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SUMMARY - II

- SNIa: Very small (<3 x 10-8 Msun yr-1)  matter outflow from pre-SNIa systems
- SNII:
- Red Supergiant Winds (but SN 1987A)
- Essentially all change their evolution on a timescale of ~ x 10^4 yrs
- Clumpy CSM and/or cylindrically symmetric density distributions
- Variable mass loss rates over 104 years time scales
- Evidence for pre-SN binary system wind collisions
- SNIb/c:
- More tenuous CSM than SNII
- Much higher shock speeds
- Evolve much faster

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## FINISH

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Our 

- Our
- most recent
- review
- on RSNe
- ARAA 40,
- 387, 2002

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## The Most Recent Overview of SNe & GRBs

- Springer-Verlag Lecture Notes in Physics LNP-598

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Two Recent Proceedings now Available

- Proceedings of the April 2003 meeting held in Valencia, Spain -- Cosmic Explosions: On the 10th Anniversary of SN 1993J
- Proceedings of the June 2004 meeting held in Padua, Italy – 1604 - 2004: Supernovae as Cosmological Lighthouses

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN1998bw/GRB980425[Weiler, Panagia & Montes ApJ 562, 670, 2001]

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## SN1998bw/GRB980425

- Shock speed = 230,000 km s-1 ( = 1.6)
- 60% increase in emission near Day 25, returns to normal near Day75
- Same increase between Day 149 & Day 249 seen at Day 192
- Implied 30% density enhancement at intervals of ~9,000 yr (Comparable to 1979C & 1980K)
- Highly clumped medium (K2 = 0); filling factor ~ 10%
- Mdot ~ 3.5 x 10-5 M yr-1

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004

## Episodic mass-loss?

- Bumps and dips with *P* ~ 150 days.
- vexp ~ 15,000 km s-1  *R* = 0.006 pc.
*w* = 10 km s-1  *t* ~ 600 yr.
*t *>> stellar pulsation timescales, but perhaps consistent with thermal pulse (C/He flashes) periods in 5–10 M AGB stars.

- Deviations from fit

- Kurt W. Weiler -- Radio Emission from Supernovae

- KITP - February 2004