Gammaray Bursts and Supernovae S R Kulkarni California

Gamma-ray Bursts and Supernovae S. R. Kulkarni California Institute of Technology 10/20/2021 1

TWO BIG QUESTIONS n n Do all cosmological GRBs have an underlying SN? Do all nearby (Ib/c) supernovae have gamma-ray emission? 10/20/2021 2

n Thanks to D. Frail (NRAO) E. Berger, D. Djorgovski, D. Fox, F. Harrison, P. Price, R. Sari, A. Soderberg, S. Yost (Caltech) P. Price & B. Schmidt (ANU) H. S. Park (LLNL) C. Baltay & P. van Dokkum (Yale) R. Chevalier (UVa) 10/20/2021 3

Afterglow Emission: Fireball Model Supernovae: Point Explosion in r-n medium Energy E ~ 1051 erg = 1 FOE Mejecta ~ 1 -10 Msun, Lorentz factor ~ 1. 01 Sedov solution (non-radiative phase) Supernova remnant (radiative phase) GRBs: Point Explosion in r-n medium Energy E ~ 1 -10 FOE Mejecta ~ 10 -4 Msun, Lorentz factor ~ 100 Relativistic Sedov solution (Blandford-Mc. Kee) 10/20/2021 4

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Jet Signatures: Optical/X-ray Piran, Science, 08 Feb 2002 10/20/2021 6

Jet Opening Angles obtained from epoch of breaks in light curves in the homogeneous conical jet framework (Caveat: Structured Jets) n n Narrow Opening Angles! only a few degrees wide Incomplete Statistics for narrow jets 10/20/2021 7

Gamma-ray Energy Release Frail et al. (2001) 10/20/2021 “Infamous” Frail et al. relation 8

Kinetic Energy of Fireballs X-ray Afterglow: L_x(t=8 hr)*8 hr traces E_Kinetic Freedman & Waxman Kumar Application Piro et al. Berger et al. Curiously E_gamma ~ E_Kinetic 10/20/2021 9 Berger et al. 2003

Long Duration GRBs: Massive Stars n GRB host galaxies are star-forming galaxies Bloom Ph. D 2002 n High column density/extincted bursts Galama & Wijers, Djorgovski et al. , Piro et al. n Circumburst medium: Wind-fed (011121) talks by Frail, Chevalier n Most direct evidence comes from associated SNe 10/20/2021 GRB GRB GRB 980326 970828 011121 021211 030329 Bloom et al. 1999 Galama et al. 2000, Reichart et al. 1999 Garnavich et al. 2002, Bloom et al. 2002 Della Valle et al. 2003 Stanek et al. 2003 10

Do all cosmological GRBs (c-GRBs) have underlying SNe? n n n Some c-GRBs have associated bright supernovae Many either do not have an associated SNe or else V > -19 mag A wind circumburst medium may not be present around all GRBs 10/20/2021 11

Do all nearby (Ib/c) supernovae have gamma-ray emission? Once upon a time (25 -April-1998), a non-descript burst of gamma-rays occurred in the Southern hemisphere. Both GRB astronomers and SN astronomers who held each other in contempt were excited and this is how our story begins… 10/20/2021 12

GRB 980425 & SN 1998 bw n GRB 980425, a routine GRB, identified by Beppo. SAX Pian et al. 1999 n Identified with bright optical SN with very wide absorption lines Galama et al. 1998 n Identified with super-bright radio SN Kulkarni et al. 1998 Host Galaxy, distance 44 Mpc E_gamma ~ 1048 erg (isotropic) 10/20/2021 13

Relativistic Ejecta! High Brightness Temperature for first 3 weeks requires Gamma ~2 to 4 10/20/2021 Kulkarni et al. 1998 14

Synchrotron Emission: Fast Primer Basic Parameters: fm, nua, spectral index (p) Example: GRB 030329 (nearest c-GRB) Compute brightness TB and if TB > Teq (1011 K) then pay either in energy or in size. (For 1998 bw, the parametric fit of Weiler et al. violates the above limit) 10/20/2021 15

SN 1998 bw: Underlying Engine! 10/20/2021 Chevalier & Li 16

What is SN 1998 bw? n A c-GRB but viewed at an angle. Unlikely. Nakamura; Iwamoto; Granot et al. ; Ioka; Salmonson n A supernova with large E_K (and thus relativistic ejecta via whip mechanism) Energetically Challenged Model n Matzner, Tan & Mc. Kee An engine-driven supernova i. e. a low-luminosity GRB Kulkarni et al; Bloom et al; Li & Chevalier We term such nearby SN with gamma-ray emission as supernova-GRBs or s-GRBs 10/20/2021 17

s-GRBs and c-GRBs: Cousins? 10/20/2021 Berger et al. 2003 18

f-GRBs: a new sub-class of c-GRBs? Afterglow of GRB 980327 and GRB 980519 were already fading rapidly (t^-2). We term such GRBs as “f-GRBs” (for GRBs with rapidly fading afterglow) 10/20/2021 2003 Bloom, Frail & Kulkarni 19

GRB 030329: an f-GRB? 10/20/2021 Price et al. (2003, submitted to Nature) 20

GRB 991216: Narrow & Wide Jets? n n Differing decay index(X-ray, optical & radio) Optical data shows t_jet~1 day (Halpern et al) A narrow angle jet (X-ray and optical) + A wide angle jet (radio) Frail et al. 1999 10/20/2021 21

Our Working Hypothesis n n Major observational difference between ordinary SN and GRBs is the presence of relativistic ejecta. We suggest that only an underlying ENGINE can drive significant relativistic ejecta. DIRECT TRACERS: synchrotron emission strong afterglow emission INDIRECT (reliable? ) TRACERS: broad optical lines large inferred SN energy release 10/20/2021 22

f-GRBs and wide+narrow jetted GRBs n n n f-GRBs appear to be systematically possess low E_gamma but much larger energy in the afterglow The gamma-ray energy release in GRB 991216 is small compared to that inferred for low-Gamma ejecta (from radio observations) The gamma-ray energy release of GRB 980425 is only 1% of that inferred from radio observations The energy in relativistic ejecta can vary enormously. 10/20/2021 23

In Summary : c-GRBs, s-GRBs and f-GRBs n n n A very small fraction (1%) of the local Ib/Ic SNe can be expected to host c-GRBs. f-GRBs (fast fading afterglows) may constitute a significant fraction of c-GRBs “s-GRBs” (GRB 980425/1998 bw) are arguably a new of Ib/Ic SNe. However, our VLA search for s-GRBs show that these objects are rare, <10% (Berger et al. 2003) The primary parameter differentiating c-GRGBs, f-GRBs and s-GRBs is the amount of ejecta with large Lorentz factor (relativistic ejecta). The sum total of local c-GRBs, s-GRBs and f-GRBs is less than 10% of the local Ib/Ic sample (Berger et al. ) (Norris 2003 estimate appears too optimistic) 10/20/2021 24

The story is just beginning …. . X-ray Flashes 10/20/2021 Short hard bursts SWIFT is expected to be launched in December 2003 25

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Backup Slides 10/20/2021 27

Underlying Supernovae 10/20/2021 Indepth discussion by J. Bloom and T. Matheson 28

Wind or ISM? n n In most afterglows no CLEAR signature for a wind circumstellar medium Clear case for GRB 021121 (Price et al. 2002) 10/20/2021 29

External Shocks – Afterglows GRB 000301 C Sari, Piran, & Narayan 1998 10/20/2021 Berger et al. 2000 30

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Major Clue: Circumstellar Medium n Density ~ r 0 (“Interstellar Medium”) Expected if GRBs result from coalescence n Density ~ r-2 (“Wind Medium”) Expected if GRBs arise result from massive stars Chevalier and Frail talk Note: For GRBs, length ~ 2 * c * t * gamma. In contrast, for SNRs, length ~ v * t ~ 0. 03 * c * t 10/20/2021 32

Diversity in Cosmological High Energy Transients Gamma-ray bursts (GRB) -- peak luminosity in the range 50 to 500 ke. V -- Short duration (T < 1 second) -- Long Duration (T > a few seconds) X-ray Flashes (XRF) -- peak luminosity in the range below 50 ke. V 10/20/2021 33