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Probing the Supernova Mechanism by Observations 16 July 2012. GRB-Supernova observations: S tate of the art. Elena Pian INAF, Trieste Astronomical Observatory & Scuola Normale Superiore di Pisa, Italy. - PowerPoint PPT Presentation
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GRB-Supernova observations: State of the art
Probing the Supernova Mechanism by Observations 16 July 2012
Elena Pian
INAF, Trieste Astronomical Observatory &Scuola Normale Superiore di Pisa, Italy
GRBs are brief flashes of soft -ray radiation (100 keV), discovered in the 1970’s, the origin of which was not known
until 1997
CGRO-BATSE
The GRB distribution is isotropic
8 hours 3 days
GRB970228: first detection of X-ray and optical afterglow
6 monthslater
Costa et al. 1997
Van Paradijs et al. 1997
Fields of GRBs
(physical scale across each image is about 7 kpc)
Starling et al. 2011
Early Multiwavelength Counterparts
(z = 0.937)
Bloom et al. 2008
(z = 6.29)
(z = 1.6)
Bimodal distribution of GRBdurations
short
long
Different progenitors: SNevs binary NS mergers
Kulkarni 2000Duration (s)
Isotropic irradiated –ray energy vs redshift
Long GRB
Short GRB
Relativistic jet model of a GRB:“Unified scheme” for GRBs and Sne?
GRB980425Supernova 1998bw (Type Ic)
z = 0.0085
Galama et al. 1998
GRB-Supernovae with ESO VLT+FORS
z = 0.168
z = 0.105
GRB031203/SN2003lw
GRB-SNe have kinetic energies exceeding those of normal SNe byan order of magnitude (e52 erg)Hjorth et al. 2003
Malesani et al. 2004
X-ray Flashes
Swift was triggered by XRF060218 on Feb 18.149, 2006 UT
Prompt event
afterglow
Shock breakout or jet cocoon interaction with CSM,Or central engine, or synchrotron + inverse Compton ?
Campana et al. 2006
SN
UVOT
z = 0.033
M(56Ni) = 0.2 MsunM(progenitor) = 20 Msun
Mass of remnant is compatibleWith neutron star rather thanBlack hole
Pian et al. 2006; Mazzali et al. 2006; Ferrero et al. 2006
SN2006aj (z = 0.033)
Starling et al. 2011
X-ray light curves of low-redshift GRBs
Shock breakout in SN2010bh (Cano et al. 2011)
Starling derives an initial radius of 8e11 cm from X-ray spectroscopy
GRB/XRFs associated with supernovae
Zhang et al. 2012, arXiv:1206.0298
z = 0.28
GRB120422A/SN2012bz (z = 0.283)
Perley et al. 2012
26 April 2012
VLT FORS spectra of GRB120422A/SN2012bz
z = 0.283
SN1998bw
SN2006aj
GRB091127/SN2009nz (z = 0.49)
Cobb et al. 2010 Berger et al. 2011
Light Curves of GRB and XRF Supernovae at z < 0.3
Melandri et al. 2012
Photospheric velocities of Type Ic SNe
Pian et al. 2006Bufano et al. 2012
Properties of GRB-SNe
Berger et al. 2011
light curves of the optical afterglow of the “normal” long GRB060614 (z = 0.125)
Della Valle et al. 2006
Gal-Yam et al. 2006
spectra of GRB060614 (z = 0.125): no SN features
GMOS, 15 Jul 06
VLT, 29 Jul 06
Della Valle et al. 2006Gal-Yam et al. 2006
Light curves of Ic SNe: GRB-SNe, broad-lined SNe, normal SNe
-14 GRB060614GRB060505
Della Valle et al. 2006Fynbo et al. 2006Gal-Yam et al. 2006
Summary
Most long GRBs and XRFs are associated with energetic spectroscopically identified Type Ic Sne. SNe associated with GRBs are more luminous than XRF-SNe
Mechanisms:Collapsar: a BH forms after the core collapses, and rapid accretion on it feeds the GRB jet. Magnetar: the NS spin-down powers a relativistic jet
Not all long GRBs are accompanied by energetic Type Ic Sne
Is the early high energy emission due to an engine (jet) or to shock breakout? Late time SN spectroscopy may be a tool to investigate this via reconstruction of supernova explosion geometry (VLT; Subaru)