slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
A Subclass of GRBs as Possible LIGO-2 Gravitational-Wave Sources Jay P. Norris NASA/GSFC (1) The prevalent belief struct PowerPoint Presentation
Download Presentation
A Subclass of GRBs as Possible LIGO-2 Gravitational-Wave Sources Jay P. Norris NASA/GSFC (1) The prevalent belief struct

Loading in 2 Seconds...

play fullscreen
1 / 34

A Subclass of GRBs as Possible LIGO-2 Gravitational-Wave Sources Jay P. Norris NASA/GSFC (1) The prevalent belief struct - PowerPoint PPT Presentation


  • 108 Views
  • Uploaded on

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.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'A Subclass of GRBs as Possible LIGO-2 Gravitational-Wave Sources Jay P. Norris NASA/GSFC (1) The prevalent belief struct' - minda


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

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

slide2

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.

slide3

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)?

slide4

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)

slide5

E. Pian

astro-ph/9910236

Revised BeppoSAX

error box for

GRB 980425

slide7

22 days

Iwamoto et al.

(1998):

Modeling yields

core collapse for SN1998bw within +0.7/-2 days of GRB 980425

12

days

40 days

slide9

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

slide13

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 ]

slide15

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.

slide16

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)

slide17

“Typical” long-lag GRB,

detected by BATSE.

> 300 keV : blue

100-300 keV : green

50- 100 keV : yellow

25- 50 keV : red

slide20

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.

slide21

M. J. Hudson (1993)

7200 km/s

100 Mpc

z = 0.024

slide22

980425

971208

Virgo

slide23

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.

slide25

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.

slide26

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 !!!

slide29

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.

slide33

CCF

Lag

Time

GRBs : Lpeak vs. 

slide34

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