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K-GRB2@hanyang. Introduction to GRB: Classifications and Progenitors. Chang-Hwan Lee @. GRB. Introduction to GRB. Short Hard GRB. NS-NS, NS-BH Mergers. Hee-Suk Cho & Soomin Jeong’s Talk. Long Soft GRB. Supernova Association. Another class ?. Some Recent Issues. GRB. Gamma-ray Bursts.
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K-GRB2@hanyang Introduction to GRB: Classifications and Progenitors Chang-Hwan Lee @
GRB Introduction to GRB Short Hard GRB NS-NS, NS-BH Mergers Hee-Suk Cho & Soomin Jeong’s Talk. Long Soft GRB Supernova Association Another class ? Some Recent Issues
GRB Gamma-ray Bursts
GRB Gamma-Ray Burst Duration: milli sec - min 1970s : Vela Satellite 1990s: CGRO, Beppo-SAX 2000s: HETE-II, Swift
GRB Galactic ?
GRB Two groups of GRBs • Short Hard Gamma-ray Bursts:Duration time < 2 secNS-NS, NS-LMBH mergers • Long-duration Gamma-ray Bursts:from spinning HMBH HMBH (High-mass black hole) 5-10 solar mass
SHB Short-Hard Gamma-ray Bursts Talks by Hee-Suk Cho Soomin Jeong
Short-hard GRBs SHB hard BATSE Sample • No optical counterpart (?) • Origin • Neutron star merger? • Magnetar flare? • Supernova? short long soft 0.01 1000 1
SHB NS (radio pulsar) which coalesce within Hubble time (2003)(2004) (1990) (2004) (1975) (1990)(2000) Not important Globular Cluster : no binary evolution White Dwarf companion
Introduction • All masses are < 1.5 M⊙ • 1534, 2127: masses are within 1% • J0737, J1756: DM = 0.1 - 0.2 M⊙
SHB Short-Hard Gamma-ray Burst : Colliding NS binaries Very Important for Gravitational Waves, too Science 308 (2005) 939
SHB Laser Interferometer Gravitational Wave Observatory LIGO I : in operation (since 2004) LIGO II: in progress (2010 ?)
Introduction Network of Interferometers LIGO Virgo GEO TAMA LIGO Louisiana 4km AIGO
L-GRB Long-duration Gamma-ray Bursts
L-GRB Long-duration GRBs: Afterglow Host Galaxy Association = Distance Estimation
L-GRB GRB/Supernova Association Afterglow GRB980425 SN1998bw
L-GRB • Gamma-Ray Bursts are the brightest events in the Universe. • During their peak, they emit more energy than all the stars and galaxies in the Universe combined !
L-GRB What caused GRB/Supernova ? Most-likely Black Holes Callapsar: Asymmetric Explosion of a Massive Star Most-likely Rapid-Rotation
L-GRB How to form rapidly spinning black holes? Most likely in BH binaries (Soft X-ray Transients) Companion star can keep BH progenitor rotating Formation of rapidly rotating stellar mass BHs
at birth Tidal interaction Fe rapidlyspinning BH
L-GRB Q) How to generate chaotic(?) light curves ?Q) Is there a model that explains all the light curves ?
L-GRB A Generic GRB Fireball UV/opt/IR/radio gamma-ray X-ray UV/optical IR mm radio gamma-ray central photosphere internal external shocks engine shocks (reverse & forward)
Fraction of fainter or equal pixels SN GRBs are concentrated in the more bright regions of galaxy GRBs GRBs from low metallicity galaxies
Fruchter et al. • L-GRBs are far more conentrated in the very brightest regions of their host galaxies than core-collapse SN • Host galaxies of L-GRBs are significantly fainter and more irregular than the hosts of core-collapse SN. • L-GRB are associated with the most extremely massive stars and may be restricted to galaxies of limited chemical evolution (lower metallicity).
GRB 060614 • Duration : 102 sec (Long-GRB ?) • Long-lag : Short-GRB ?(usually, short-lag : Long-GRBs) • Some pulses of GRB 060614 show no lag : consistent with Long-GRBs The existence of new class:still open questions
Key Issues Classifications:Is there third or sub-classes ? Progenitors:S-GRB: NS-NS, NS-BH, …L-GRB: with SN, w/o SN, …. Properties of host galaxies & afterglow!
Korean GRB Theory: -- Progenitors -- Central Engine -- Statistical Approaches Observations & Experiment -- afterglow observations (SHBs & L-GRBs) -- gamma-ray & X-ray telescope