Quark deconfinement in compact stars:. connection with GRBs. Irene Parenti. Univ. of Ferrara Italy. INFN of Ferrara Italy. International summer school: “Hot points in Astrophysics and Cosmology”. Dubna, Russia 2 – 13 August 2004. August 2004. Irene Parenti. Summary.
Quark deconfinement in compact stars:
connection with GRBs
Univ. of Ferrara
INFN of Ferrara
International summer school:
“Hot points in Astrophysics and Cosmology”
2 – 13 August 2004
few ms – 2 s
2 s – few 100 sGamma-Ray Bursts (GRBs)
Distance:cosmological (1-10)∙109 ly
Energy range:100 KeV – a few MeV
Emitted energy:1051 erg (beamed/jets)
J.S. Bloom, D.A. Frail, S.R. Kulkarni, ApJ 594, 2003
time delay Δt between the Supernova
explosion and the Gamma-Ray Burst.GRB and supernovae
Connection between GRB and Supernovae
Evidence for atomic lines in the spectra
of the X-ray afterglow
GRB990705ΔT ≈ 10 yr
Amati et al., Science 290, 2000, 953
GRB011211ΔT ≈ 4 days
Watson et al., ApJ 595, 2003, L29
GRB030227ΔT ≈ 3-80 days
Reeves etal. , Nature 2002Time delay from SN to GRB
OF THE GRB
(ass. with the NS)
(birth of a NS)
Pure HSHybrid Star or Quark Star
when color superconductivity is taken in to account:
A. Drago, A. Lavagno and G. Pagliara
Phys. Rev. D69 (2004) 057505Delayed collapse of a HS to a QS
Z. Berezhiani, I. Bombaci, A. Drago, F. Frontera and
A. Lavagno ApJ. 586 (2003) 1250
engine for GRB
of the surface tension between the HM phase and the QM
pressure of the HS.
converted to a QS or a HyS.
during the deconfinement
It’s necessary to have an overpressure to form a
droplet having a size large enough to overcome the
effect of the surface tension.
potential energy well on a time scale:
ν0-1~10-23 s « τweak
virtual droplet of
real droplet of
real droplet of
hadronic matter in a
This form of deconfined
matter has the same
flavor content of the
β-stable hadronic system
at the same pressure.
We call it: Q*-phase.
The drop grows with no
when p overcomes the
in a time τ
Soon afterwards the weak interactions change the
quark flavor fraction to lower the energy.
Hadronic phase:Relativistic Mean Field Theory
of hadrons interacting via meson exch.
[e.g. Glendenning, Moszkowsky, PRL 67(1991)]
Quark phase:EOS based on the MIT bag model
[Farhi, Jaffe, Phys. Rev. D46(1992)]
Mixed phase:Gibbs construction for a multicom-
ponent system with two conserved “charges”.
[Glendenning, Phys. Rev. D46 (1992)]
I.M. Lifshitz and Y. Kagan, Sov. Phys. JETP 35 (1972) 206
K. Iida and K. Sato, Phys. Rev. C58 (1998) 2538
nQ* baryonic number density
in the Q*-phase at a
fixed pressure P.
at a fixed pressure P.
σ surface tension
Flavor fractions are the
same of the β-stable
hadronic system at the
The pressure needed for
phase transition is much
larger than that without
The nucleation time is the time needed to form
a critical droplet of deconfined quark matter.
It can be calculated for different values of the
stellar central pressure (and then of the stellar
mass, as implied by TOV).
The nucleation time dramatically depends
on the value of the stellar central pressure
and then on the value of the stellar mass.
this nucleation time is called critical mass:
We assume that during the stellar conversion process
the total numbers of baryons in the star (and then the
baryonic mass) is conserved.
[I. Bombaci and B. Datta, ApJ. 530 (2000) L69]
The gravitational mass of the final star
is taken to be the mass in the stable configu-
ration corresponding to that baryonic mass.
MHS < McrHS are metastable with a
long mean-life time.
MHS > McrThis HS are very unlikely
tobe observed.The critical mass of metastable HS
[Cottam et al., Nature 420, 2002]
The total energy released in the stellar conversion
is given by the difference between the gravitational
mass of the initial hadronic star (Min=Mcr) and the
mass of the final hybrid or strange stellar
The energy released is carried out by pairs
of neutrinos – antineutrinos.
The reaction that generate gamma-ray is:
The efficence of this reaction in a strong
gravitational field is:
[J. D. Salmonson and J. R. Wilson, ApJ 545 (1999) 859]
HS ―> QS or to HS ―> HyS
time delay between SN and GRBs.
families of compact stars:
Univ. of Pisa
INFN of Pisa
Ref: I. Bombaci, I. P., I. Vidaña
Astroph. J., accepted
(SS or QS)