1. Observational Signatures of Relativistic and Newtonian Shock Breakouts Ehud Nakar Tel Aviv University  Re’em Sari (Hebrew Univ.)  Gilad Svirsky (Tel Aviv Univ.)  Tomer Goldfriend (Hebrew Univ.) Death of Massive Stars Nikko, Mar 16, 2012

2. Studies of shock breakouts (partial list) Newtonian: Shock breakout Colgate 74; Falk 78; Imshennik and Nadyozhin 88; Matzner & McKee 99; Katz et. al. 10; Nakar & Sari 10; Ofek et al 11, Balberg & Leob 11, Chevalier & Irwin 11 & 12, Svirsky, EN & Sari 12… Planar expansion Piro et. al. 10, EN & Sari 10, Sapir et. al. 11, Katz et. al. 11, … Spherical expansion Chevalier 76, 92; Waxman et. al. 07; Chevalier & Fransson 08; Piro et. al. 10, Rabinak & Waxman 10; EN & Sari 10, … Numerical simulations Klein & Chevalier 78; Ensman & Burrows 92; Blinnikov et. al. 98, 03; Utrobin 07; Tominga et. al. 09, 11; Suzuki & Shigeyama 10; Dessart & Hillier 11; Couch et al 11; Moriya et al 11, Blinnikov & Tolstov 11, … Relativistic: Colgate 1968; Tan et al., 2001, Waxman et al., 2007, Katz et al., 2010, EN & Sari 2011

3. Outline and Conclusions Relativistic breakout (EN & Sari 11)  -ray flare followed by X-ray extended emission Must take place in: long GRBs, low-luminosity GRBs, Ia SNe, Highly compact & energetic core collapse SNe Plausible explanation for the entire emission (including  - rays) of ALL low-luminosity GRBs Breakout through a dense wind (Svirski, EN & Sari 12) Delayed (~10-50 SN rise time), bright (~10 41 -10 43 ) x-ray to soft  -ray emission (See poster P-60) WR and BSG core-collapse SNe (EN & Sari 10) T>>T blackbody (~1-10 keV) throughout the planar phase – minutes (WR) to ~20 min (BSG)

4. Relativistic Shock Breakouts (GRBs, Super-energetic SNe, Type Ia SNe) EN & Sari 2011

5. Relativistic shock breakout Main physical differences from Newtonian breakout: Constant post shock rest frame temperature ~100-200 keV Temperature dependent (pair) opacity Significant post breakout acceleration T BB pairs Katz et. al., 10 Budnik et. al., 10

6. A flash of  -rays from shock breakout A quasi-spherical, windless relativistic breakout  bo – Breakout Lorentz factor R bo – Breakout radius

7. Quasi-spherical, windless relativistic breakouts: Three observables: T bo, t bo, E bo Depend on two physical parameters: R bo and  bo Relativistic breakout relation A test that each quasi-spherical, windless relativistic breakout must pass!

8. Extremely energetic supernovae (e.g., SNe 2002ap, 2007bi; Mazzali et al 2002, Gal-Yam et al 2009 ) Detectable by Swift and Fermi out to 3-30 Mpc Events such as SN 2002ap (@ ~7 Mpc) may be detectable. Events such as 2007bi are too rare to detect.

9. White dwarf explosions Type Ia and.Ia SNe and AIC Detectable within the Milky way

10. Some unique properties (very different than LGRBs): Smooth light curve E  that is a small fraction of the total explosion energy Mildly relativistic ejecta with energy comparable to E  Delayed X-ray emission, with energy comparable to E  Cannot be produced by successful jets (Bromberg, EN, Piran & Sari 11) All properties naturally explained by shock breakout Previously suggested by Colgate 1968, Kulkarni et al., 1998, Tan et al., 2001, Campana et al., 2006, Waxman et al., 2007, Wang et al., 2007, Katz et al., 2010 Low luminosity GRBs

11. GRBE bo (erg) T bo (keV) t bo (s) Relation t bo (s) R bo (cm)  bo 98042510 48 1503010 6  10 12 3 031203 5  10 49 >20030<35 2  10 13 >4 060218 5  10 49 4021001500 5  10 13 1 100316D 5  10 49 4013001500 5  10 13 1 Relativistic breakout relation

12. BUT: the inferred R bo >10 13 cm Much larger than WR radii ! However: R bo is where  ~1 (e.g., m bo ~10 -5 M o ) possible explanations extended very low mass envelope mass ejection just prior to explosion effects of asphericity and/or a wind (needed to be calculated)

13. Newtonian Breakout through a Thick Wind Svirski, EN & Sari 2011 (see also Chevalier & Irwin 12) See more details in poster P-60

14. Soft component (opt-UV) free-free of heated unshocked wind. Main cooling source (via IC) of the hot shocked plasma Hard component (X and  rays) free-free of ~60 keV electrons. Degraded by collisions with the unshocked wind and IC cooling Plasma heated by Collisionless shock (Katz et al. 11) Unshocked wind

15.  Excellent for X-ray searches  May explain PTF 09uj Early breakout (typically 1 d < t bo < 20 d) Late breakout (typically 70 d < t bo )  Brightest emission  X-rays suppressed  May explain SN 2006gy

16. Early Temperature evolution of Regular core- collapse SNe from compact progenitors EN & Sari 10

17. Shock temperature T is set by the ability to produce enough photons (Weaver 76; Katz et. al., 10) Thermal equilibrium: v sh < 15,000 km/s Gas that is not in thermal equilibrium at the shock crossing will not gain it at later phases (EN & Sari 10) T BB Thermal Non-thermal RSG BSG WR

18. Breakout Planar Spherical 10 45 Luminosity [erg/s] Time t -4/3 t -0.17 - t -0.35 Wolf-RayetBlue SupergiantRed Supergiant R/c 10 s2 min20 min R/v bo 1 min20 min10 hr Observed Luminosity (Spherical breakout from stellar surface) EN & Sari 10 Breakout layer Deeper layers

19. Temperature (Spherical breakout from stellar surface) BreakoutPlanar Spherical 1000 T [eV] Time t -0.6 t -1/3 - t -2/3 t -1/3 t -0.6 10 -100 RSG-BSG BSG-WR no thermal equilibrium EN & Sari 10

20. Optical-UV light curves Optical Far UV Breakout Planar Spherical RSG WR RSG WR BSG EN & Sari 10

21. X-ray light curve RSG WR BSG EN & Sari 10

22. Conclusions Relativistic breakout (EN & Sari 11)  -ray flare followed by X-ray extended emission Must take place in: long GRBs, low-luminosity GRBs, Ia SNe, Highly compact & energetic core collapse SNe Plausible explanation for the entire emission (including  - rays) of ALL low-luminosity GRBs Breakout through a dense wind (Svirski, EN & Sari 12) Delayed (~10-50 SN rise time), bright (~10 41 -10 43 ) x-ray to soft  -ray emission (See poster P-60) WR and BSG core-collapse SNe (EN & Sari 10) T>>T blackbody (~1-10 keV) throughout the planar phase – minutes (WR) to ~20 min (BSG)

23. Some topics for future study Newtonian breakout through a wind ( Moriya et al 11, Ofek et al 11, Balberg & Leob 11, Chevalier & Irwin 11) A-spherical breakout ( Suzuki & Shigeyama 10, Couch et al., 11) Effects of metallicity on the color temperature Transition to collisionless shock (Katz et al 11) Relativistic breakouts

24. Wind shock breakout (… Moriya et al 11, Ofek et al 11, Balberg & Leob 11, Chevalier & Irwin 11, Katz et al 11) When?  w >10-30 Main observables: Larger breakout radius Brighter longer and colder Shock transition from radiation to collisionless (Katz et al 11) High energy emission + Fast optical decay

25. Which explosions are expected to have relativistic breakouts? EN & Sari 11

26. Comparison with numerical results L/1.4 Red supergiant R * =800 R sun ; M * =18M sun ; E=1.2×10 51 erg

27. Thermal eq. enforced Blue supergiant R * =45 R sun ; M * =16M sun ; E= 10 51 and 2.3 ×10 51 erg

28. Typical properties of shock breakout Breakout luminosity (all progenitors) ~ 10 45 erg/s Breakout duration ~ R/c

29. Breakout temperature

30. Time = Mass (during the spherical phase) 10 2 10 3 10 4 10 5 10 6 10 -8 10 -6 10 -4 0.011 WR BSG RSG Time [sec] Mass probed [M ] breakout + planarrecombination breakout + planar