EM EMISSION FROM
NS-NS AND NS-BH MERGERS
Bruno Giacomazzo
www.brunogiacomazzo.org
TORI MASSES FROM MERGERS
NS-NS
Rezzolla et al 2010
The torus mass increases with the
mass ratio and decreases with the
total mass. Possible to form tori
up to ~0.3 solar masses.
NS-BH
Foucart et al 2012
Even with a 10 Msun BH
it is possible to form
massive disks if the BH is
spinning (a~0.7).
Foucart 2012 derived also a fit from NS-BH GR simulations
M torus /M ⊙
0.9
χ=0
0.22
M torus /M ⊙
0.9
χ = 0.3
0.22
0.8
0.8
0.7
0.5
0.18
0.4
C NS
0.1
C NS
0.2
0.6
0.1
0.2
0.7
0.6
0.5
0.18
0.4
0.2
0.3
0.2
0.16
0.3
0.16
0.2
0.2
0
0
0.1
0.14
2
4
6
1/q
χ = 0.6
8
0.1
0.14 0.3
10
2
4
M torus /M ⊙
0.9
0.22
6
1/q
χ = 0.9
8
10
M torus /M ⊙
0.9
0.22
0.8
0.8
0.7
0.2
0.5
0.18
0.4
C NS
0.6
0.2
C NS
0.2
0.7
0.6
0.5
0
0.18
0.4
0.
1
0.3
0.16
0.
0.2
3
1
0.
0.1
2
4
6
1/q
8
Giacomazzo et al 2013
10
0.2
4
0.
0
0.14
0.3
0.2
0.16
0.3
0.1
0.14
2
4
6
1/q
8
10
BNS MERGER OUTCOME
Depending on mass and EOS several postmerger scenarios:
NS-BH
BH+torus
HMNS
NS-NS
SMNS
BH+torus
NS+torus
BH+torus?
NS+torus
Magnetic fields play fundamental role in post-merger dynamics
(jets from BH/NS+torus, NS collapse to BH, ...)
MAGNETAR FORMATION
Giacomazzo & Perna 2013, ApJ Letters, 771, L26
Investigated merger of
two 1.2 M☉ NSs
Used Ideal Fluid,
Gamma=2.75,
k=30000 (Oechslin et
al 2007)
Produced a stable
“ultraspinning” NS
surrounded by a
magnetized disk of
~0.1 M☉.
MAGNETAR FORMATION
Giacomazzo & Perna 2013, ApJ Letters, 771, L26
MAGNETAR FORMATION
Giacomazzo & Perna 2013, ApJ Letters, 771, L26
Magnetic field amplified of ~2 orders of magnitude. Difference in the
GW signal are small and present only in the post-merger phase.
GWs publicly available for download at www.brunogiacomazzo.org/data.html
JETS FROM BNS MERGERS?
Rezzolla, Giacomazzo, Baiotti, Granot, Kouveliotou, Aloy 2011, ApJL 732, L6
Visualization by Koppitz, Rezzolla, Giacomazzo, Baiotti
Visualization by Koppitz, Rezzolla, Giacomazzo, Baiotti
Visualization by Koppitz, Rezzolla, Giacomazzo, Baiotti
Visualization by Koppitz, Rezzolla, Giacomazzo, Baiotti
BNSs: GW AND EM EMISSIONS
Rezzolla, Giacomazzo et al 2011
EM signal switches on at the
end of GW signal
magnetic field amplified by
several orders of magnitude by
KH and then MRI instabilities
NS-BH: Model B4-0: BH a/M=0.75; MBH/MNS=3; B~1016G
Etienne et al 2012, PRD 86, 084026
Movie produced by Stu Shapiro, his research group and REU team at UIUC:
http://tinyurl.com/shapiromovies
Very weak poloidal component in the disk, not possible to resolve
MRI with current resolutions. But what happens if we seed the
final disk with a poloidal field (~1014 G)?
MRI can now be
resolved.
Magnetic field is
amplified and a jet is
formed.
First time this is
shown for NS-BH
mergers.
Movie produced by Stu Shapiro, his research group and REU team at UIUC:
http://tinyurl.com/shapiromovies
Paschalidis et al 2014, arXiv:1410.7392
Credits: http://research.physics.illinois.edu/cta/movies/BHNS_jets/
JETS FROM NS BINARY MERGERS
NS-NS
Rezzolla et al 2011
NS-BH
Paschalidis et al 2014
Possible to form jets both in NS-NS and NS-BH binaries
Palenzuela et al 2013
NS-NS: EM PRECURSORS
Resistive MHD simulations (full GR)
EM emission during inspiral (~1e43 erg/s)
Emission depends on initial configuration
NS-BH: EM PRECURSORS
Paschalidis et al 2013
Force Free simulations of NS-BH mergers show also 1e43 erg/s
emission (but for larger fields, ~1e13G)
Emission within ~60o from orbital plane (possible lighthouse effect)
POSTMERGER: NEUTRINO EFFECTS
Formed long-living HMNS
Luminosities~1e53 erg/s
Detectable if merger at <~5Mpc
Sekiguchi et al 2011
NS-BH: NEUTRINO EFFECTS
(Deaton et al 2013)
q=1/4, a=0.9, LS 220 EOS
max ~1e54 erg/s in neutrinos
ejected ~0.08 M☉
formed a disk of ~0.3 M☉
Deaton et al 2013