A Subclass of GRBs as


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• A Subclass of GRBs as
• Possible LIGO-2 Gravitational-Wave Sources
• Jay P. Norris
• NASA/GSFC
• (1) The prevalent belief structure
• Some All GRBs associated with SNe.
• (2) Demographics attributes of possible subclass
  of nearby ultra-low luminosity GRBs and their
  associates nearby type Ib/c SNe.
• (3) Predicted range of GW strains detection rate
  for GRB subclass

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• GRB-SN Belief Sparse Knowledge Structure
• One very close ( 35 Mpc) ultra-low luminosity
  GRB and one not so close ( 680 Mpc) subluminous
  GRB
• Both manifest the presence of Type 1c SNe.
• Constrained but open issue The delay (in some
  cases)
• TSNTGRBsimultaneous
• Detection of GW signal could depend on accurate
  knowledge of TSN or TGRB. Accurate TGRB is easy.
• GW signal requires non-axisymmetric deformation
  () Theoretical core collapses 10-4-10-2
  to unity.
• Is degree of non-axisymmetry related to GRB jet
  opening angle (via BH rotation)

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Figure 2. The detailed classification of SNe
requires not only the identification of specific
features in the early spectra but also the
analysis of the line profiles luminosity and
spectral evolutions. (Cappellero Turrato
astro-ph/0012455)
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E. Pian astro-ph/9910236 Revised BeppoSAX error
box for GRB 980425
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22 days
Iwamoto et al. (1998) Modeling yields core
collapse for SN1998bw within 0.7/-2 days of GRB
980425
12 days
40 days
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Young Baron Branch (1995)
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GRB 011211 z 2.14 Reeves et al.
Nature 2001 416
Blue-shifted X-ray lines ( 0.09) assume jet
20º ne 1015 cm-3 GRB ejecta runs into SN
shell at R 1015 cm TGRB - TSN 4 days
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• Are there T0_SN T0_GRB delays
• SN 1998bw light curve has evidence for upturn
  (end of UV breakout ) which would place T0_SN
  few days before T0_GRB. Modeling T -20.7
  days
• X-ray afterglow spectral analysis (GRB 011211)
  suggests 4-day hiatus SN to GRB.
• Type 1c SNe light curves not well studied and
  are known to vary in width by at least a factor
  of 3
• Cannot gauge T0_SN accurately by comparison with
  SN 1998bw especially given GRB afterglow
  photometry at faint magnitudes.
• Theory T 10s - hrs Woosley et al.
  collapsars
• T van Putten BH-torus

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• Core-collapse SN Explode Asymmetrically
• Images of 1987A (see ST Jan 2002 Wang
  Wheeler)
• Elemental asymmetries in (Wang et al.
  2002)
• SN remnants (1987A Cas A)
• Polarization in SNe (Wang et al.
  2001)
• Type 1a
• Type II 1-2 increasing with time
• Type 1b/c 3-7
• GRB observed by RHESSI Coburn Boggs
  Nature
• Some GRBs beamed into 4/500/2 (Frail et al.
  2002)
• SN Modeling strong polar ejections
• Pulsar space velocities
• Some SNe are rapidly rotating at core-collapse
  high T/W.
• Non-axisymmetric (bar) instabilities
  possible

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• A Sub-Population of Nearby GRBs
• BATSE subsample ( 7) of soft-spectrum GRBs.
  Defining characteristic Very long pulses with
  long spectral lags ( 0.3 s).
• Proportion increases to 50 near BATSE
  threshold.
• Additional Evidence for Nearby Spatial
  Distribution
• GRB980425/SN1998bw is canonical example at 38
  Mpc.
• Log NLog Fp has -3/2 slope cosmology
  unimportant.
• Tendency towards Supergalactic Plane similar to
  SN Ib/c long-lag GRB and nearby galaxy sky
  distributions similar.
• Implications Detected sample d Ultra-low luminosity (RGRB ¼ RSN Ib/c
• Could be LIGO II sources 4 yr-1 within
  50 Mpc
• (see ApJ
  2002 579 386)

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Typical long-lag GRB detected by BATSE.
300 keV blue 100-300 keV green 50-
100 keV yellow 25- 50 keV red
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HETE-2 time profile for GRB 030329 5-120 keV
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A Main Sequence HR Diagram for Gamma-Ray
Bursts L53 1.1 (lag/0.01 s)-1.15
Woosley MacFadyen (1999) Ioka Nakamura
(2001) others predicted subclass of numerous
nearby GRBs low luminosity soft-spectrum
long-lag. Properties attributed to (1) large jet
opening angle (2) low 2-5.
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M. J. Hudson (1993)
7200 km/s 100 Mpc z 0.024
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980425
971208
Virgo
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SNe Ib/Ic 62 detected 1954-2001.75
( 2/3 since 1998.0) With 85 at distances 100 Mpc. Only 10 of nearby SNe are detected.
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RGRB (
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Fryer Holz Hughes (2002) Blondin Mezzacappa
DeMarino (2003) Bar instabilities
likely ( unity). Assuming 100 cycles
f 200-800 Hz source 1.3 10-23 Expect 4 long-lag GRBs yr-1 (50 Mpc) and we know when they occur.
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• Summary
• Very good evidence that high-mass highly
  energetic core-collapse SNe are associated with
  GRBs one nearby a few cosmologically distant
  examples of such associations.
• Evidence indicates that these SNe and GRB events
  are asymmetric ( high T/W). Are SN and GRB
  simultaneous
• Long-lag soft-spectrum apparently nearby ultra
  low-luminosity GRBs are numerous ( 50) near
  BATSE threshold.
• RGRB (RSNIb/c.
• A few yr-1 detectable by LIGO
  II.
• Swift should see a larger fraction of long-lag
  GRBs than BATSE.
• Many chances to find the associated SNe and GW
  signals !!!

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The End
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G.M. Harry et al.
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Lmin
vmax
L const. across jet
vmin
Lmax
jet
jet varies view varies
view varies 220. outside jet
cone. inside profiled jet.
Beaming Fraction Viewing angle
Profiled jet 4 Ld constant Special
Relativity L() reflects () L-1.
Lorentz contraction 30 Doppler boost
(jet fastest on axis) All three models realize
broad observed but narrow actual Luminosity and
Energy distributions.
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GRBs Lpeak vs.
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CCF Lag
Time
GRBs Lpeak vs.
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• Possible Confirmation Approaches
• (1) Untriggered BATSE bursts For Fp cm-2 s-1 long-lag bursts predominate. But
  larger localization errors IDing as bona fide
  GRBs is problematic.
• (2) 400-500 additional triggered BATSE bursts.
• (3) Cross-correlation of nearby matter
  distribution
• (d
• (4) Extrapolation of SNe light curves to T0
  comparison with GRB times and positions (J.
  Bonnell).
• (5) Swift