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RADIO EMISSION FROM SNe & GRBs, AND THE NEED FOR SKA. Kurt W. Weiler (NRL) Collaborators: Schuyler D. Van Dyk (IPAC/Caltech) Christina K. Lacey (NRC/NRL) Nino Panagia (STScI/ESA) Richard A. Sramek (NRAO/VLA) Marcos Montes (NRL) http://rsd-www.nrl.navy.mil/7214/weiler/. Supernovae (SNe). - PowerPoint PPT Presentation
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RADIO EMISSION FROM SNe & GRBs, AND THE NEED FOR SKA
Kurt W. Weiler (NRL)
Collaborators:
Schuyler D. Van Dyk (IPAC/Caltech)Christina K. Lacey (NRC/NRL)
Nino Panagia (STScI/ESA)
Richard A. Sramek (NRAO/VLA) Marcos Montes (NRL)
http://rsd-www.nrl.navy.mil/7214/weiler/
Supernovae (SNe)
Play a vital role in galactic evolution:
• Nucleosynthesis, chemical enrichment, energy input into ISM
• production of stellar remnants, production of cosmic rays
A primary goal of SN research: • Understanding progenitor stars and explosion
mechanisms for different SNe types SNe types: Ia, Ib/c, II (also IIn, IIb)
• SNe Ia not radio sources to limit of VLA sensitivity
Radio Supernovae (RSNe) 27 RSNe detected by in the radio; 17 objects extensively
studied Analysis of radio emission provides vital insight into SN
shock/CSM interaction • Nature of pre-SN evolution• Nature of the progenitor
All RSNe have in common: • Nonthermal synchrotron with high TB
• Decrease in - dependent) absorption with time • Power law flux density decline after max • Final approach to optically, thin constant
Radio Supernovae (RSNe) Interesting variations:
• Clumpiness in CSM; variations in Mdot; early time synchrotron self-absorption
“Standard” Light Curves
Type Ib/c Type II
CSM Sampling
‘
More Recent Examples
SN1994I (Ic) SN1993J (II)
SN1993J VLBI
Expansion of SN 1993J from age 5 months to age 31 months
SN1987A -- Radio
SN1987A -- Optical
SN1979C -- Radio
SN1980K -- Radio
Luminosity vs. Time to 6 cm Peak
Evolution of RSNe into SNRs
SUMMARY (1 of 2)
SNe classes are distinct in radio emission properties (thus distinct in CSM environments):• SNe Ia are undetectable at VLA’s limiting sensitivity
• SNe Ib/c turn on and off quickly
• SNe II show a wide range of properties
RSNe are sensitive to Mdot/wwind (~ pre-SN mass loss rate)
RSNe sample the CSM => properties of the pre-SN wind density & structure -- unique stellar evolution probe
SUMMARY (2 of 2) SN 1978K shows evidence for a (possibly
associated) HII region along the line of sight. SN 1979C & SN 1980K show evidence for very
rapid stellar evolution in the presupernova phase SN 1993J shows evidence for a change in mass
loss rate in the last ~10,000 years before explosion RSNe may be distance indicators
Now, what about 1998bw and GRBs?
Gamma-Ray Bursts with Optical Counterparts
Peak Fluxes
GRB -ray1
X-ray2
/X Ratio
Optical3 Radio4
Host Galaxy
Brightness5
z
970228 3.5 2.3 80 20.5 -- 24.6
970508 1.2 3.0 25 19.8 1.2 25.8 0.8356
970828 4.9 1.9 158 -- 0.27 24.5 0.9587
971214 2.3 2.5 56 21.7 -- 25.5 3.4127
980326 1.3 4.7 17 21.0 -- 25.3 --
980329 13.3 7.0 120 23.6 0.25 26.3 < 3.97
980425 1.1 2.6 26 13.7 49 14.3 0.00857
980519 4.7 2.9 100 20.4 0.1 24.7 --
980613 0.63 0.7 57 22.9 -- 24.4 1.0967
980703 2.6 4.0 40 20.1 1.0 23.0 0.9676
990123 16.4 4.0 252 8.95 2.6 24.3 1.6006
990510 8.16 2.02 249 19.2 -- -- 1.6196
990712 ? ? ? 17.85 -- 22.0 0.436
991208 ? -- -- 18.7 2.1 -- 0.7066
991216 67.5 -- -- 18.8 0.94 24.5 1.027
1 photons cm-2 s-1 (50-300 keV); conversion factor, photons to ergs, = 6.15 x 10-7 2 x 10-8 ergs cm-2 s-1 (2-10 keV) 3 R band magnitude 4 milli Jansky, at 8.4 GHz (10 GHz for GRB 970828 and GRB 980425) 5 R band magnitude, corrected for galactic extinction 6 redshift from OT 7 redshift from host galaxy http://cossc.gsfc.gov/cossc/batse/counterparts/GRB_table.html
SN 1998bw Radio Light Curves
1
10
100
1 10 100 1000Time since Explosion (t - t0) in days
GRB 980508 -- Early
GRB 980508 -- Late
GRB 980519
Radio Observations of GRBs
If present, radio observations of the GRB afterglow can yield:• Size and expansion velocity of the fireball
– Through IS scattering– Through changing spectral shape with time
• Density & structure of the CSM– As for RSNe
• VLBI observations– confirming size & shape– Providing lower distance limits
Schematic of Fireball + Relativistic Blast Wave
RSN Luminosity at Peak
Luminosity vs. Time Delay(at 6cm maximum)
23.00
24.00
25.00
26.00
27.00
28.00
29.00
30.00
31.00
32.00
33.00
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
Log(days; explode to 6cm max)
Log
(lu
msi
ty @
6cm
max
; er
g/s/
Hz)
87A
97X 84L
83N 96cb
81K
94I
90B
85L
80K
93J
86E
70G
82aa
79C
78K
86J
88Z
Type IbType Ic
Type II95N
97eg
98bw
Notes to self: (1)Add Ia limits (2) Add T_b = 10^12 K curves
GRB Radio Luminosity at Peak
GRB Radio Luminosity vs. Time Delay(at 6cm maximum)
23.00
24.00
25.00
26.00
27.00
28.00
29.00
30.00
31.00
32.00
33.00
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
Log(days; explode to 6cm max)
Log
(lu
msi
ty @
6cm
max
; er
g/s/
Hz)
980425
GRBs
The Sensitivity Problem
Conclusions Current VLA is severely sensitivity limited for SN
studies
• Can only detect SNe with mvmax ~ 12 -- 14 (out to ~Virgo cluster)
– ~1300 SNe known; ~ 25 radio detections– ~150 new discoveries/year; only 1-2 radio detections– No Type Ia SN ever detected
• No VLA on line mapping precludes RSN searches
SKA could: • Extend RSN detections to mv
max ~ 19 – ~50 radio detections/year
• Discover ``hidden'' SNe • Improve SN statistics not limited by absorption/dust• Improve knowledge of Type Ia progenitors • Provide a new cosmological distance probe
Conclusions Current VLA is severely sensitivity limited for
GRB studies
• Can only detect a few GRBs– Thousands of GRBs known; ~ dozen radio detections– >300 new discoveries/year; only 1-2 radio detections– Not enough radio to distinguish types (fast-hard, slow-soft)
SKA could: • Extend GRB searches
– tens of detections/year• Establish GRB CSM properties• (Possibly) distinguish GRB classes • Increase knowledge of relativistic jet/fireball physics
Recommendations
One would like to see: • Sensitivity of 1 Jy (preferably 0.1 Jy) in 30
minutes• Resolution <1” @ 1.4 GHz (prefer @ 327 MHz) • Simultaneous, multi frequency observations • Real time, on line editing, calibration & snapshot
mapping• Near circular snapshot beam
FINISH