GRB-SN connection:
rate and missed opportunities
Jochen Greiner(for the GROND team)
Max-Planck Institut für extraterrestrische Physik
Garching, Germany

 Why do we care?
 GRB-Supernovae detections
Kyoto, 4.-8.11.2013

 Conclusion/Plea

The favored model for
long-duration GRBs:
shocks in relativistic jets
emanating from thecentral collapsed coreplus torus of an evolved
massive star.

GRB-SN connection: massive star origin
GRB 030329

Hjorth et al. 2003, Nat 423, 847
Stanek et al. 2003, ApJ 591, L17
Kosugi et al. 2004, PASJ 56, 61Kawabata et al. 2003, ApJ 593, L19
Matheson et al. 2003, ApJ 599, 394

Long-duration GRBs areconnected to explosion ofmassive stars
This star must have lost its H
and He envelope before it died
Only rare sub-types of SN Ibc
produce GRBs

Innsbruck 22.06.2010

GRBs trace evolution of starformation rate
Jochen GreinerMany open questions
 what kind of progenitor? Different sub-classes, i.e.
BHs vs. magnetars?
 what determines production of a GRB(-jet) in one
out of hundreds of SN?
 are GRB-SNe standard candles?" why are most discovered GRB/SN among the lowluminosity GRBs?
 asphericity of explosions? is there any impact of ajet on the SN?
…

Kyoto, 4.-8.11.2013

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Modelling of GRB/XRF 060218 / SN 2006aj
Pian et al. 2006, Mazzali et al. 2006

 Progenitor mass ~20 M⊙:
M ~ 2 M⊙ , Ekin ~ 2 x 1051 erg
 no BH, but NS forms!
 In contrast:
SNe 1998bw, 2003dh, 2003lw:
52 ergM~8–13ME~
3–7x10⊙,kinKyoto, 4.-8.11.2013

GRB/SN statistics~ 4000 GRBs
~ 850 GRB X-ray afterglows~ 530 GRB optical afterglows~ 330 GRBs with redshifts (some only through host)~
10 spectroscopically confirmed GRB-SN Pretty low success rate!
 Do we miss some GRB/SN, or is
the rate intrinsically so low?
Redshift distribution suggests~15% of GRBs at z<0.5
compared to the above 3%!
Kyoto, 4.-8.11.2013

Savaglio 2011

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Improving searches TACs force us to pre-select few “interesting” GRBs
for ground-based follow-up, but this pre-selection
is often illusive/misleading also selections based in prompt-emission“indicators” (most notably redshift) is very often
wrong

 we need to MUCH more systematically observe all
optical afterglows down to at least 25th mag – thisneeds 3-4m class telescopes (which get out offashion these days)
Kyoto, 4.-8.11.2013

Jochen Greiner - 7

GROND @ 2.2m MPG telescope La Silla
History:First light: Apr 30, 2007
First GRB: May 21, 2007
Photometric calibration: Jul 2007
Routine observations: since Sep 2007
fastest response time: 2 min

Kyoto, 4.-8.11.2013

GRONDJochen Greiner - 8

GROND: General Design
 7 bands: Sloan g’, r’, i’, z’ and J, H, K
One detector for one filter band (no movable filters!)
3 HAWAII 1K*1K Arrays + 4 E2V 2K*2K CCDs Field-of-view: Visual: 5.4´x5.4´ (0.16´´/pixel)
NIR: 10´x10´ (0.59´´/pixel)

 Dichroics tuned to minimize intrinsic polarization effects
 2 shutters, i.e. g’r’ and i’z’ pairs of CCDs have same exposure Combined telescope and intrinsic mirror (K-band) dithering Sensitivity (AB): 4 mingr
21.5 magiz
21.0 mag
J/H/K
19/18/17 mag
Kyoto, 4.-8.11.2013

1 hr
24.5 mag
24.0 mag
22/21/20 mag
Jochen Greiner - 9

GROND=GRB Optical/NIR Detector
Imaging in 7 channels
simultaneouslyrgzi
HK
Kyoto, 4.-8.11.2013

JJochen Greiner -Optial/NIR Afterglow light curves in a nutshell• power law decay• jet breaks (0.5-2.0 d)• Early peaks: reverse shocks• gently rising early emission: deceleration offorward-shock -> Γ-determination• bumps and wiggles on decaying lc:“riding on density waves”• SN bumps at (1+z)*(8-20) days

• Correlated prompt emission

Kyoto, 4.-8.11.2013

GROND examples: Ia clear case from 2009a poor S/N case from 2011

Olivares (talk next week)

Kyoto, 4.-8.11.2013

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GROND examples: II
Olivares et al. 2014 (in press)

Kyoto, 4.-8.11.2013

GRB 101219B: clear case
X-Shooter teaminformed forspectroscopy
 Sparre et al 2011

Jochen Greiner - 13

GRB 120714B / SN 2012eb (z=0.3984)
Klose et al. 2012, GCN 13613 / CBET 3200
Malesani et al. 2004

Figure will be publishedin Klose et al 2014

•at t=18.5 days (obs) = 13.2 d (host frame)

Kyoto, 4.-8.11.2013

GRB 130831A / SN 2013fu (z=0.478)
Klose et al. 2013, CBET 3677

120714B

Figure will be publishedin Klose et al•at2014
t=18.5 days (obs)•= 13.2 d (host frame)•at t=28.5 days (obs)•= 19.3 d (host frame)

130831A (scaled x 4 in flux)

Kyoto, 4.-8.11.2013

 from simple statistics it is clear we miss a good fraction: ~5x
 how many could we realistically re-cover? (brightness, host, …)
 previous examples
were the secure cases;
but there are others
as well, like 100902A
 problem: to be safe,
we only trigger AFTER
maximum, so it isdefinitely not the host: we also miss some just with our GROND
secure cases we double
the present rate

Olivares et al. 2014 (subm)

How many GRB/SN do we miss?

 previous discovery rate of spectr.-confirmed SN: ~0.5/yr  but could be 1-2/yr with more aggressive ground-based follow-up
Kyoto, 4.-8.11.2013

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GRB/SN without spectra better than nothing?
 One would like to get physical parameters, but thoserequire spectroscopy poor man’s version is k vs. s

Kann et al. 2014

Mazzali et al. 2011

Figure will be publishedin Kann et al 2014

Kyoto, 4.-8.11.2013

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Conclusions
 GRB-SN are not as rare as we might deduce from theexisting sample
 suggestions/pleas: to optical astronomers: observe whenever you can;even better if you can organize systematic follow-up
at a 3-4m telescope to TAC members: don’t enforce ‘optimisation’ to Senior Review (USA): Swift/BAT triggers andXRT(/UVOT) follow-up are crucially needed to movefrom few single cases to a sample which allows to draw
some statistics
 We should use the present availability of Swift!
Kyoto, 4.-8.11.2013

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