Off axis counterparts of SGRBs tagged by gravitational waves Kazumi Kashiyama (Penn State) with...
-
Upload
blanche-horton -
Category
Documents
-
view
217 -
download
1
Transcript of Off axis counterparts of SGRBs tagged by gravitational waves Kazumi Kashiyama (Penn State) with...
Off axis counterparts of SGRBs tagged by gravitational waves
Kazumi Kashiyama (Penn State)with K.Ioka, T.Nakamura and P. Meszaros
Why?The era of gravitational wave astronomy will come soon!
The “promising target” : compact binary mergers
Multi-messenger approach
since 2015 〜 20172nd generation network
Distance detectable : 〜 200Mpc, Event rate : 〜 40yr-1 for NS-NS merger
• GW detectors have bad eyesight! Angular resolution of 2nd generation 〜 10deg2
Off-axis X-ray, optical, radio counterpart searches
• SGRBs are the most reliable counterpart, but low-frequent. if θj 〜 0.1, the GW-SGRB simultaneous detection rate 〜 0.1yr-1
Point : “Pre-jet” envelope formation
Mildly relativistic! Optically thick! Neutron-rich!
Hyper-massive neutron star
Pre-jet envelope( Magnetically or Neutrino driven wind )
Tidal mass ejection
Rotational plane of binary
e.g. Lee et al. (2010) , Dessart et al. (2009), Shibata et al. (2011)
Possible off axis emissions from pre-jet envelope
Optical (kilonova) Radio active heating in the envelope (β-decay, fission, 56Ni→56Co→56Fe)
Interaction between the envelope and interstellar medium
Radio (afterglow)
〜 days
〜 years Nakar & Piran (2011)
Li & Paczynski (1998)Metzger et al. (2010)
UV-X-ray Interaction between the envelope and relativistic jets
≤ minutes???
Jet penetration problem in SGRBs
Faile
d Pe
netra
tion
Non-re
lativ
istic p
enet
ratio
n
Rela
tivisti
c pen
etra
tion
No co
coon
( Fail → jet induced supernovae like? )Succeed penetration → jet+cocoon
Two possible off axis emissions from jet-envelope interaction
relativistic jetcocoon
Black hole (magnetar) + accretion disk
1. Hard X-rays from cocoon breakout2. Soft X-ray quasi-thermal emission from cocoon itself
X-rays from cocoon breakout
Too dim to be detected because of the small rcbo
cocoon
jet
Energy budget of breakout photons:
@
Timescale of the emission:
Jet-cocoon dynamics →
UV-Soft X-rays from cocoon itself
cocoon
@
Adiabatic expansion:
Jet-cocoon dynamics →
Marginally detectable by future facilities?
for ~ minute @ soft X-ray or UV (down scattered)
Summary
• Off axis X-ray counterpart of compact binary mergers could be a key for GW astronomy.
• Consider jet and pre-jet envelope interaction– Cocoon breakout emission → too dim– Emission from cocoon itself• could be soft X-ray transient ~minute• might be detected by future facilities? • need to be modeled more precisely.
– Failed penetration cases could be also interesting.