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Ultra-Low Luminosity GRBs as Possible LIGO-2 GW Sources

This study explores the prevalence, demographics, and predicted GW strains of a possible subclass of ultra-low luminosity GRBs associated with nearby type Ib/c SNe. The implications of detecting this subclass as potential LIGO-2 gravitational-wave sources are discussed.

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Ultra-Low Luminosity GRBs as Possible LIGO-2 GW Sources

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  1. 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

  2. Obs’d SN zmax=1.77  GRB 030329  SN 2003dh  GRB 980425  SN 1998bw Only 20% of observed GRBs have associated redshifts: Some fraction of the remaining 80% may lie at higher redshifts.

  3. 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) TSN–TGRB<~ few days. Are the events simultaneous? 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)?

  4. 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)

  5. E. Pian astro-ph/9910236 Revised BeppoSAX error box for GRB 980425

  6. 22 days Iwamoto et al. (1998): Modeling yields core collapse for SN1998bw within +0.7/-2 days of GRB 980425 12 days 40 days

  7. Young, Baron & Branch (1995)

  8. 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

  9. Matheson et al., GCN 2120; Stanek et al. (astro-ph/0304173)

  10. 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 =-2,+0.7 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 ]

  11. Core-collapse SN Explode Asymmetrically: • Images of 1987A (see S&T, 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: <~ 0.3% • 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,  <~ unity.

  12. 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 N—Log 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 <~ 100 Mpc. Ultra-low luminosity (<~ 1048 ergs s-1). Rate: RGRB ~ ¼ RSN Ib/c *** Could be LIGO II sources: ~ 4 yr-1 within 50 Mpc *** (see ApJ 2002, 579, 386)

  13. “Typical” long-lag GRB, detected by BATSE. > 300 keV : blue 100-300 keV : green 50- 100 keV : yellow 25- 50 keV : red

  14. HETE-2 time profile for GRB 030329, 5-120 keV

  15. 000131 Prediction: 030329 991216 970228 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.

  16. M. J. Hudson (1993) 7200 km/s 100 Mpc z = 0.024

  17. 980425 971208 Virgo

  18. 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.

  19. RGRB (< 100 Mpc) ~ 30 yr-1 ~ ¼ RSNIb/c

  20. 50 Mpc 680 Mpc Fryer, Holz & Hughes (2002); Blondin, Mezzacappa & DeMarino (2003) : Bar instabilities likely ( ~ unity). Assuming 100 cycles, f ~ 200-800 Hz, source < 50 Mpc  h/Hz ~ 1.3  10-23 Expect ~ 4 long-lag GRBs yr-1 (< 50 Mpc), and we know when they occur.

  21. 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 (<100 Mpc) ~ 30/yr ~ ¼ 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 !!!

  22. The End

  23. G.M. Harry et al.

  24. Lmin L ~ const. across jet v,max v,min Lmax jet jet varies, view varies, view varies, ~ 2–20. outside jet cone. inside profiled jet. Beaming FractionViewing angleProfiled jet 4 Ld ~ constant, Special Relativity: L() reflects ():    L-1. Lorentz contraction 30 < () < 1000 & Doppler boost (jet fastest on axis) All three models realize broad observed, but narrow actual Luminosity and Energy distributions.

  25. GRBs : Lpeak vs. 

  26. CCF Lag Time GRBs : Lpeak vs. 

  27. Possible Confirmation Approaches (1) Untriggered BATSE bursts: For Fp < 0.25 ph cm-2 s-1 long-lag bursts predominate. But, larger localization errors; ID’ing as bona fide GRBs is problematic. (2) ~ 400-500 additional triggered BATSE bursts. (3) Cross-correlation of nearby matter distribution (d < 100 Mpc) and GRB positions (M. Hudson). (4) Extrapolation of SNe light curves to T0, comparison with GRB times and positions (J. Bonnell). (5) Swift

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