testing the blast wave model with swift grbs peter a. curran mullard space science laboratory, ucl...
TRANSCRIPT
Testing the blast wave model with Swift GRBs
Peter A. CurranMullard Space Science Laboratory, UCL
withRLC Starling, AJ van der Horst,
A Kamble, RAMJ Wijers, M de Pasquale & M Page
pre-Swift versus Swift GRBs
pre-Swift versus Swift GRBs
pre-Swift (GRB 990510)
(Kuulkers et al. 2000)
X-ray
Optical
pre-Swift (GRB 990510) Swift era (GRB
070107)
(Evans et al. 2007)
(Kuulkers et al. 2000)
X-ray
Optical
X-ray only
pre-Swift versus Swift GRBs
pre-Swift (GRB 990510) Swift era (GRB
070107)
(Evans et al. 2007)
(Kuulkers et al. 2000)
X-ray
Optical
pre-Swift versus Swift GRBs
Does pre-Swift theory work?
X-ray only
The blast wave model
(CXC/M. Weiss)
The blast wave model
(CXC/M. Weiss)
k – circumburst density profile (ρ ~ r-k)
The blast wave model
(CXC/M. Weiss)
k – circumburst density profile (ρ ~ r-k)
q – continued energy injection
index (E ~ tq)
The blast wave model
(CXC/M. Weiss)
p – electron energy distribution (Fermi; dN/dE ~ E-
p)
k – circumburst density profile (ρ ~ r-k)
q – continued energy injection
index (E ~ tq)
Synchrotron spectra
(Sari et al. 1998)
Synchrotron spectra
Optical / X-ray
(Sari et al. 1998)
Derivation of p
α ➝ p(α,k,q) & accuracy of temporal fit⇒ multiple options
Derivation of p
α ➝ p(α,k,q) & accuracy of temporal fit⇒ multiple options
βopt ➝ p(βopt,EB-V) ⇒ multiple options
Derivation of p
α ➝ p(α,k,q) & accuracy of temporal fit⇒ multiple options
βopt ➝ p(βopt,EB-V) ⇒ multiple options
βX ➝ p(βX,NH) ⇒ multiple options
Derivation of p
α ➝ p(α,k,q) & accuracy of temporal fit⇒ multiple options
βopt ➝ p(βopt,EB-V) ⇒ multiple options
βX ➝ p(βX,NH) ⇒ multiple options⇒ above/below synchrotron cooling
frequency
Derivation of p
Sample of 10 Swift GRB afterglows
Sample of 10 Swift GRB afterglows
(GRB 060729)
X-ray
Optical
Consistent with the
blast wave model?
(GRB 060729)
X-ray
Optical
Sample of 10 Swift GRB afterglows
Blast wave interpretations
Compare possible multi-wavelength interpretations with blast wave†...
(†Nousek et al. 2006; Starling et al. 2008)
Blast wave interpretations
Compare possible multi-wavelength interpretations with blast wave†...
8/10 consistent with blast wave
4/10 unambiguous jet breaks
6/10 calculated k
3/10 require q ; 3/10 don’t
6/10 unambiguous p 4 above cooling break 2 below cooling break
(†Nousek et al. 2006; Starling et al. 2008)
(Curran et al. 2009)
k
Circumburst density profile, k
(Curran et al. 2009)
(Curran et al. 2009)
Circumburst density profile, k
Wind
(Curran et al. 2009)
Wind
ISM
Circumburst density profile, k
(Curran et al. 2009)
Wind
ISM
Circumburst density profile, k
Not consistent with only one of ISM or
Wind
q
Energy injection index, q
(Curran et al. 2009)
E ~ tq
Energy injection index, q
(Curran et al. 2009)
E ~ tq
Energy injection index, q
(Curran et al. 2009)
E ~ tq
Energy injection index, q
(Curran et al. 2009)
E ~ tqRequired but inconclusive..
.so far
p
Distribution of p
(Curran et al. 2009)
(Curran et al. 2009)
Distribution of p
Not consistent with a single, universal
value
Distribution of p
βX
Distribution of p
Distribution of spectral index, β
below cooling break
above cooling break
Distribution of spectral index, β
(Curran et al. in prep; data from Evans et al. 2009)
Distribution of spectral index, β
(Curran et al. in prep; data from Evans et al. 2009)
Distribution of spectral index, β
(Curran et al. in prep; data from Evans et al. 2009)
Most X-rays above cooling break?
Conclusions
8 out of 10 GRBs favour the blast wave model*
(*or at least don't disfavour it)
k is not consistent with only one of ISM or Wind
q is required in some bursts, inconclusive so far
• p is not consistent with a single, universal value
Most X-rays above the cooling break?