SNGRB Connection Observations and Questions Massimo Della Valle

SN-GRB Connection: Observations and Questions Massimo Della Valle INAF-Osservatorio Astrofisico di Arcetri, Firenze Bologna, 1 Giugno, 2006 1

Outline • Introduction 2

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 3

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 • Bumps (SN 2002 lt & SN 2005 nc) 4

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 • Bumps (SN 2002 lt & SN 2005 nc) • SNe-Ibc & Hypernova & GRBs rates 5

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 • Bumps (SN 2002 lt & SN 2005 nc) • SNe-Ibc & Hypernova & GRBs rates • Time lag SN-GRBs 6

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 • Bumps (SN 2002 lt & SN 2005 nc) • SNe-Ibc & Hypernova & GRBs rates • Time lag SN-GRBs • GRB hosts 7

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 • Bumps (SN 2002 lt & SN 2005 nc) • • SNe-Ibc & Hypernova & GRBs rates Time lag SN-GRBs GRB hosts Discussion & Conclusions 8

Outline • Introduction • SN 1998 bw/GRB 980425, SN 2003 dh/GRB 030329, SN 2003 lw/GRB 031203 • Bumps (SN 2002 lt & SN 2005 nc) • • • SNe-Ibc & Hypernova & GRBs rates Time lag SN-GRBs GRB hosts Discussion & Conclusions Recent (exciting) Results 9

Gamma-ray bursts: prompt emission “Brief (< 100 sec) and intense (~10 -6 erg/cm 2/s) flashes of soft (~100 ke. V) gamma-ray radiation” Temporal beahviour: wide variety dt << T Highly structured Single pulse 10

Long and short GRBs duration: (0. 01 ÷ 100) s The distribution is bimodal Hardness/duration correlation: Paciesas et al. 2000 short bursts are harder All the results I will present concern the long-duration class of GRBs! 11

Afterglows Long-lived counterparts at X-ray, optical, IR and radio wavelengths Discovery: GRB 970228 by the Beppo. SAX satellite Costa et al. 1997 Optical counterparts soon after van Paradijs et al. 1999 12

Jakobsson et al. 2005 13

Clues about progenitors The distance is ~ a few Gpc 3. 1 1015 cm Observed flux 10 5/-6 erg cm 2 s 1 g-luminosity: 1051 -54 erg 14

Energetic Scale: Jets or Sphere • GRB 990123 has been detected by the robotic telescope ROTSE, 22 s and 47 s after the g-ray trigger at V~11. 7 and 8. 9, respectively. At z=1. 6, the isotropic energy release implies MV ~-35 and a global energetic budget comparable to >M c 2 • All GRBs could be collimated events, with opening angles q ~ 5 -10 degrees (break in the power law decay of the afterglows, polarization) 15

And in fact the jet effect on the light curve was observed in several GRBs. Here is an example. Due to its nature the jet break time measured from the observations (i. e. monitoring) of the burst afterglow allows to estimate the physical aperture of the GRB jet. “Jet break” Jet break time tbreak Jet opening angle 16

“True” energetics: correcting the energyes derived with the assumption that GRBs are isotropic the energy crisis is relaxed. Moreover the typical energetics clusters around a similar value of 10^51 erg which is by far more standard also in comparison to other astro sources. Frail et al. 2001 Isotropic equivalent energy Etrue = Eiso (1 – cos ) 17

X-ray Flashes 18

Probable Sequence of GRB Events • The central engine emits a large amount of energy. • Most of that energy accelerates a small mass (~10 -5 M ) to speeds > 99. 99% of lightspeed (G~100/500) • Collisions between different shells of ejected debris creates the gamma rays. • Collisions between ejected debris and interstellar gas create the afterglow. 19

observer The energy escapes in the form of jets… Dense cloud Kinetic Energy The progenitors collapses or coalesceces, forming a spinning BH Progenitor location: <108 cm …and the colliding shells give rise to the GRB location <1014 cm Shock dissipation Afterglow location <1018 cm 20

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SNe & GRBs Facts • ‘Early Gamma-Rays from Supernovae’ (Colgate 1968 & 1974) • GRB 980425 SN 1998 bw (Galama et al. 1998) 22

• SN 1998 bw was discovered on NTT images of ESO 184 G 82 at z=0. 0085 • The GRB and the SN appeared spatially (P~10 -4/-5) and temporally coincident Dt= +0. 7 d -2. 0 d (Iwamoto et al. 1998) • SN 1998 bw rivals with SN 1991 T: MB =-19. 5 To achieve such a luminosity about 0. 5 -0. 7 M of Ni have to be synthesized in the explosion. This is unprecedented for Core Collapse events (less than 0. 1 M ) • The radio emitting shell was expanding at (mildly) relativistic velocities G~1. 8 (Kulkarni et al. 1998; Weiler et al. 1999) 23

Patat et al. 2001 24

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Patat et al. 2001 Mg I Na I [O I] [Ca II] O I Ca II 26

Patat et al. 2001 27

Pec Type Ic SNe Broad lines Large Kinetic Energy “Hypernovae” (only SN 1998 bw was associated with a GRB) Narrow lines “normal” KE (1051) Normal SN Ic 28

Pec Type Ic SNe = Hypernovae Broad lines Large Kinetic Energy “Hypernovae” (only SN 1998 bw was associated with a GRB) Narrow lines “normal” KE (1051) Normal SN Ic 29

Light Curves of Supernovae & Hypernovae Brightness alone should not be used to define a hypernova, whose main characteristic is the high Ek~1052 ergs (see broad spectral feautures) 30

SN 1998 bw SN 1987 A = E ~ 30× 1051 ergs E ~ 1× 1051 ergs 31

Circumstantial evidence: The Bumps 1999 -2003 (Bloom et al. 1999) Della Valle et al. 2006 Della Valle et al. 2003 (MISTICI Collaboration) 32

Are the bumps representative of signatures of incipient SNe? Or they can be produced by different phenomena as dust echoes or thermal reemission of the afterglow or thermal radiation from a pre-existing SN remnant (e. g. Esin & Blandfors 2000; Waxman & Draine 2000; Dermer 2003) 33

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The spectrum of the afterglow associated with GRB 021211, obtained during the bump, reveals the presence of a broad absorption feature (FWHM~150 A), blueshifted by ~15000 km/s, which has been identified with Ca. II H+KCa SUPERNOVA 2002 lt Della Valle et al. 2003 50

SN 1994 I 51

Evidence for the existence of a SN/GRB connection was circumstantial before March 2003 SN 1998 bw was a peculiar Ic associated with a peculiar GRB (g-energy budget about a few x 1047 ergs) SN bumps were only suggestive for the existence of a SN/GRB connection. The spectroscopic confirmation was obtained only in one case (SN 2002 lt/GRB 021211) and based on one spectrum (z=1). In addition the lightcurve was different from SN 1998 bw 52

2003 dh /GRB 030329 The Smoking Gun (part 1) 53

GRB 030329/SN 2003 dh = Smoking Gun I Stanek et al. 2003; Hjorth et al. 2003 8 Apr Spectrum 1 Apr Spectrum = ? 54

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z=0. 16 Matheson et al. 2003 56

GRB 030329/SN 2003 dh: facts The spectrum is very similar to the one exhibited by the type Ic SN 1998 bw GRB and SN events are spatial coincident and coeval SN 2003 dh was not so bright as 1998 bw (0. 3 -0. 5 M 56 Ni) Modelling (Deng et al. 2005): Mej ~ 7± 3 M ; Prog = 25 -40 M ; MBH ~ 3 M Fe II lines broader than [O I] aspherical explosion (Maeda et al. 2005, 2006) The g-energy associated with GRB 030329 is ‘’standard’’ (6. 9 x 1051 erg) Sakamoto et al. 2004 57

GRB 031203 & SN 2003 lw Malesani et al. 2004 The Smoking Gun (part 2) 58

GRB 031203/2003 lw = Smoking Gun II • Trigger from INTEGRAL Götz et al. 2003 • Afterglow: X-ray (XMM) & radio (VLA) Watson et al. 2004, Soderberg et al. 2004 • Observations: ESO NTT & VLT • Low redshift host galaxy (z = 0. 1) Very faint: E 1049 erg 59

Spectroscopic Observations VLT + FORS Malesani et al. 2004 Bright star-forming host galaxy SFR 10 M /yr Z 0. 1 Z AV 1. 1 Prochaska et al. Chincarini et al. 2004 2014 Broad undulations in the continuum close to the maximum 60

Spectra of SN 2003 lw Host galaxy subtracted EK = 6 x 1052 erg M 56 Ni = 0. 55 M Mej = 13 M Mprg = 40 -50 M Mazzali et al. 2006 Tagliaferri et al. 2004 Malesani et al. 2004 61

The very bright supernova 2003 lw SN 2003 lw vs SN 1998 bw Overall similar With E(B–V) = 1. 1: * 0. 5 mag brighter * Same colors * Slower evolution Malesani et al. 2004 62 See also Bersier et al. 2004; Thomsen et al. 2004, Cobb et al. 2004, Gal-Yam et al. 2004

Conclusions The discovery of the types Ic SNe 2003 dh (Stanek et al. 2003; Hjorth et al. 2003) and SN 2003 lw (Malesani et al. 2004) in the AGs of GRB 030329 and GRB 031203 has conclusively linked long duration GRBs with the death of massive stars Particularly with a subclass of SNe-Ibc, the bright tail of HYPs Is the game over? 63

Not at all. . . …there is an expanding frontier of ignorance… (R. Feynman, Six Easy Pieces) 64

What SN types are connected with GRBs? (only 1998 bw-like? ) There is growing evidence that GRBs can be associated with SNe which are different from SN 1998 bw, both in the peak of luminosity and in spectroscopic type (SN 2002 lt/GRB 021211 SN 1994 I normal Ibc 1994 I) 65

GRB 021211/SN 2002 lt SN in XRF 030723 Lg (Fx/Fg) > 0 XRF >-0. 5 XRR <-0. 5 GRB LC Fits: a normal SN Ic or a low-E Hyp like SN 2002 ap at z~0. 6 Fynbo et al. 2004; Tominaga et al. 2004 66

Levan et al. 2005 67

GRB 011121 IIn? Garnavich et al. 2003 68

Soderberg et al. 2005 69

Soderberg et al. 2005 70

Soderberg et al. 2005 XRF 040701 fainter than 2002 ap/SN 1994 I by 3 -6 mag (i. e. MV ~ -13/-15) 71

1. It is not clear whether or not only Hypernovae are capable to produce GRBs or also “standard” Ib/c events can do it (IIn? ? ) 2. The distributions of the absolute mag at max of GRB/SNe and standard Ibc are statistically indistinguishable effect of scanty statistic? they derive from the same SN population? (very heterogeneous class of objects) • All GRB-SNe which have received a spectroscopic confirmation belong to the bright tail of Ibc distribution observational bias 72?

What is the fraction of SNe-Ib/c which produces GRBs ? • Rate for Ib/c: 0. 22 SNu (Cappellaro et al. 1999) 1. 2 x 108 LB, Mpc-3 (Madau, Della Valle & Panagia 1998) 2. 6 x 104 SNe-Ibc Gpc-3 yr-1 • HYPs/Ibc ? (No absolute rate from controlled time surveys) 5 -10% Podsiadlowski et al. 2004, Della Valle 2005 73

Local rate: Rates of GRBs -1> ~et 200 0. 5 -1 GRB Gpc-3 GRB/Hyp yr-1 (Schmidt Guetta al. 2004) < 1200 ~ 0. 1, 2001, IF <fb -1 (Firmani ~ 1, IF ~ 2000 0. 04 -0. 4 Gpc-3 yr. GRB/Hyp et <fb al. -1> 2004) -1> ~30000 -1 (Matsubayashi /SNe-Ibc ~ 1, <fb 2005) 0. 01 Gpc-3 yr. GRB+XRR+XRF et. IFal. 2. 6 x 104 SNe-Ibc Gpc-3 yr-1 <fb-1> ~500 <fb-1> ~75 (Frail et al. 2001) Podsiadlowski et al. 2004 (Guetta, Piran & Waxman 2004) GRB/Hyp ~1 GRB/Hyp: 25%-4% Soderberg, Nakar & Kulkarni 2005 GRB/SNe-Ibc: 2%-0. 3%Radio survey on 74 Ibc+ 74 Optical Rau et al. 2006

Radio light curves of HNe Only GRB-SNe show strong radio emission. No-GRB-HNe, like 2002 ap, do not. Either no jets or low-density environments. Soderberg et al. 2006 The presence of relativistic jets is the mark between GRB/XRF-HNe and ordinary 75 SNe/HNe

Discussion and Conclusions 76

1. Long duration GRBs are closely connected with the death of massive stars. Spectroscopic observations have been carried out over a large range of redshifts (z=0. 008 1998 bw; z=0. 03 2006 aj z=0. 1 2003 lw; z=0. 16 2003 dh; z=0. 23 XRF 020903; z=0. 6 GRB 050525 a and possibly up to z~1, 2002 lt). 77

2. Only a very small fraction of all massive stars appears capable to produce GRBs. SNe. Ib/c are the natural candidates because of the lack of H envelope. However, this does not seem to be sufficient: only ~ 1% of SNe-Ibc (~10% of Hyps) produce GRBs. Some special circumstances are requested to the GRB star progenitor besides being “only” a massive star (Rotation, e. g. Woosley & Hegel 2006, Binarity, e. g. Podsiadlowski et al. 2004; Mirabel et al. 2003, Asymmetry Maeda et al. 2006). This point is not well understood (yet). 78

3. The unification scheme where every SNe-Ibc is producing a GRB, XRR or XRF according to different viewed angles (e. g. Lamb et al. 2005), is not favored by current estimates of SN/GRB rates and radio observations. Unification works for <fb-1> ~ 30000 (J ~ 0 o. 5 ) HYP & GRB Rates give <fb-1> ~ 200 (J ~ 6 o ) Radio Obs SNe-Ibc give <fb-1> < 1200 (or J > 2 o. 5) 79

Recent Results GRB 050525 A/SN 2005 cn (Della Valle et al. 2006) GRB 060218/SN 2006 aj (Campana et al. 2006) 80

GRB 050525 a: a new SN connection Blustin et al. 2005 Discovered by Swift solid = 15 -25 ke. V dots = 25 -50 ke. V short dashed = 50 -100 ke. V long dashed = 100 -350 ke. V z=0. 606 Della Valle et al. 2006 E(B-V)=0. 1 Blustin et al. 2005 81

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Follow-up at TNG, NTT and VLT+FORS 2 Della Valle et al. 2006 83

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Hyp with short rising time on axis event (Maeda et al. 2006) 89

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Host galaxy of XRF 060218/SN 2006 aj (DSS 2) z = 0. 033 Mv (host) = -16 Host has brightness Similar to SMC Z/Z ~ 0. 3 Associated with SN 2006 aj (Masetti et al. 2006) 94

Examples of Swift-XRT light curves Steep decline common Gets shallower around here Nousek et al. 2005 95

…the internal energy following an adiabatic expansion of the envelope leads to a luminosity peak at 1 day and 1% of the observed luminosity… (Colgate & White 1964) …in any type of SN triggered by core collapse, a shock is generated which propagates through the progenitor star and ejects the envelope. Accompanying the emergence of the shock wave through the surface of the star is a very bright UV/X burst of radiation… (A. Burrows 1992) Campana et al. 2006 96

3 x 104 km/s Campana et al. 2006 97

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We have observed for the first time in a GRB a thermal component which we have interpreted as signature of the shock break-out (Colgate 60 s) We have caught a SN in the act of exploding (about 100 s after the collapse of the core) We have definitely proved that SN and GRB are coeval events 99

Summary of SN-GRB time lag GRB SN +Dt -Dt Ref. 980425 1998 bw +0. 7 -2 Iwamoto et al. 000911 Bump +1. 5 -7 Lazzati et al. 011121 2001 ke 0 -5 Bloom et al. + Garnavich et al 021211 2002 lt +1. 5 -3 Della Valle et al. 030329 2003 dh 2003 lw -8 -2 -2 Kawabata et al Matheson 031203 +2 0 0 041006 Bump 2 0 Stanek et al. 050525 A 2005 nc 2 0 Della Valle et al. 100 Malesani et al.

Observations of SNe and bumps connected with GRBs imply that SNe and gamma bursts are simultaneous events. This favors the collapsar model (Woosley 1993, Paczynski 1998, Mac. Fadyen & Woosley 1999) over competing theories (e. g. Supranova, Vietri & Stella 1998) 101

We have observed for the first time in a GRB a thermal component which we have interpreted as signature of the shock break-out (Colgate 60 s) We have caught a SN in the act of exploding (about 100 s after the collapse of the core) We have definitely proved that SN and GRB are coeval events We have measured the radius of the progenitor star, to be about 4 x 1011 cm which is typical of a W-R star. 102

SNe C-C (II, Ib, Ic) Red Supergiant R~3 x 1013 cm Wolf-Rayet Star Blue Supergiant R~4 x 1012 cm 103 R~4 x 1011 cm

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The properties of the 4 closest SNe associated with GRBs vary by at most 30%. The g-budget covers about 4 order of magnitudes. 105

a) we may be seeing intrinsically similar phenomena under different angles. GRB 030329/SN 2003 dh may be viewed ~ pole-on, GRB 980425/SN 1998 bw considerably off-axis (15 -30°, Maeda et al. 2005). GRB 031203/SN 2003 lw may lie in between (Ramirez-Ruiz et al. 2005) In this scenario the g-properties are a strong function of the angle (Eg ~ J-4 ) whereas the optical properties are not much influenced by this relative small spread in viewing angles. b) GRB 060218/SN 2006 aj there is an intrinsic dispersion in the properties of the relativistic ejecta for SNe with similar optical characteristics. relativistic energies at play in (local) GRB phenomenon (~ 1047 - 1050 erg) are small compared to the KE involved in the “standard” SN-Ibc (1051 erg) or Hyp (1052 erg) explosions. 106

HL-GRBs vs. LL-GRBs 2006 aj • HL-GRBs (g-ray budget of 1051 -52 erg ~ SN/HN KE) • LL-GRBs (intrinsically faint 1047 -49 erg ~ 10 -4/-2 SN KE) • Sampled volume 104 -6 smaller Rate LL-GRBs: 20 -500 x HLGRBs rate (Della Valle 2006, Pian et al. 2006, Soderberg et al. 2006, Liang et al. 2006) • LL-GRBs vs HL-GRBs properties of SN explosions? ? • Different properties in the central engine (=compact stellar remnant NS vs BH)? Nomoto et al. 2003 • Lack of tbreak implies q > 75 o (cfr. 5 o-10 o) • GRBs occur in star forming and low metallicity galaxies. If they are sensitive to metallicity, we can expect systematic differences between nearby and cosmological GRBs (the latter produced in low-metallicity environments). e. g. GRB 050904 at z=6. 3 (Kawai et al. 2005, Tagliaferri et al. 2005) is quite atypical (duration energy content, variability). 107