No supernovae associated with two long-duration γ-ray bursts

It is now accepted that long-duration γ-ray bursts (GRBs) are produced during the collapse of a massive star1,2. The standard ‘collapsar’ model3 predicts that a broad-lined and luminous type Ic core-collapse supernova accompanies every long-duration GRB4. This association has been confirmed in observations of several nearby GRBs5–9. Here we report that GRB 060505 (ref. 10) and GRB 060614 (ref. 11) were not accompanied by supernova emission down to limits hundreds of times fainter than the archetypal supernova SN 1998bw that accompanied GRB 980425, and fainter than any type Ic supernova ever observed12. Multi-band observations of the early afterglows, as well as spectroscopy of the host galaxies, exclude the possibility of significant dust obscuration and show that the bursts originated in actively star-forming regions. The absence of a supernova to such deep limits is qualitatively different from all previous nearby long-duration GRBs and suggests a new phenomenological type of massive stellar death.

[1]  S. Klose,et al.  A Systematic Analysis of Supernova Light in Gamma-Ray Burst Afterglows , 2003, astro-ph/0311610.

[2]  D. Schlegel,et al.  Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds , 1997, astro-ph/9710327.

[3]  S. E. Woosley,et al.  How Massive Single Stars End Their Life , 2003 .

[4]  P. Giommi,et al.  A short γ-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225 , 2005, Nature.

[5]  M. C. Begam,et al.  An unusual supernova in the error box of the γ-ray burst of 25 April 1998 , 1998, Nature.

[6]  E. Rol,et al.  On the Afterglow of the X-Ray Flash of 2003 July 23: Photometric Evidence for an Off-Axis Gamma-Ray Burst with an Associated Supernova?* , 2004 .

[7]  Lifan Wang,et al.  The supernova-gamma-ray burst connection , 1998, astro-ph/9806212.

[8]  R. Lupton,et al.  A Method for Optimal Image Subtraction , 1997, astro-ph/9712287.

[9]  S. B. Cenko,et al.  The Afterglow, Energetics, and Host Galaxy of the Short-Hard Gamma-Ray Burst 051221a , 2006 .

[10]  R. C. Smith,et al.  An HST study of the supernovae accompanying GRB 040924 and GRB 041006 , 2005 .

[11]  D. Fugazza,et al.  An enigmatic long-lasting γ-ray burst not accompanied by a bright supernova , 2006, Nature.

[12]  E. O. Ofek,et al.  A novel explosive process is required for the γ-ray burst GRB 060614 , 2006, Nature.

[13]  D. A. Kann,et al.  An optical supernova associated with X-ray flash 060218 , 2006 .

[14]  L. A. Antonelli,et al.  GRB 060614: an enigmatic long-duration gamma-ray burst not due to a hypernova , 2006 .

[15]  STAR FORMATION IN GALAXIES ALONG THE HUBBLE SEQUENCE , 1998, astro-ph/9807187.

[16]  E. Ramirez-Ruiz,et al.  Closing in on a Short-Hard Burst Progenitor: Constraints from Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b , 2005, astro-ph/0505480.

[17]  K. Pedersen,et al.  A very energetic supernova associated with the γ-ray burst of 29 March 2003 , 2003, Nature.

[18]  D. Branch,et al.  Absolute Magnitude Distributions and Light Curves of Stripped-Envelope Supernovae , 2004, astro-ph/0601136.

[19]  Evert Rol,et al.  A Deep Search with HST for Late Time Supernova Signatures in the Hosts of XRF 011030 and XRF 020427 , 2004 .

[20]  Warren R. Brown,et al.  Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329 , 2003, astro-ph/0304173.

[21]  Jesper Sollerman,et al.  The optical afterglow of the short γ-ray burst GRB 050709 , 2005, Nature.

[22]  J. M. Rodríguez Espinosa,et al.  Evidence for Diverse Optical Emission from Gamma-Ray Burst Sources , 1997, astro-ph/9710322.

[23]  Aimee L. Hungerford,et al.  Explosive Nucleosynthesis from Gamma-Ray Burst and Hypernova Progenitors: Direct Collapse versus Fallback , 2006, astro-ph/0604471.

[24]  N. R. Tanvir,et al.  GRB 050509B: Constraints on Short Gamma-Ray Burst Models , 2005 .

[25]  S. Woosley.  Gamma-ray bursts from stellar mass accretion disks around black holes , 1993 .

[26]  S. B. Cenko,et al.  An HST Search for Supernovae Accompanying X-Ray Flashes , 2005 .

[27]  J. P. U. Fynbo,et al.  On the nature of nearby GRB/SN host galaxies ⋆ , 2005 .

[28]  E. Rol,et al.  The GRB 060218/SN 2006aj event in the context of other gamma-ray burst supernovae , 2006, astro-ph/0605058.

[29]  J. M. Castro Cerón,et al.  Long gamma-ray bursts and core-collapse supernovae have different environments. , 2006, Nature.

[30]  D. Schlegel,et al.  Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds , 1998 .

[31]  A. MacFadyen,et al.  Collapsars: Gamma-Ray Bursts and Explosions in “Failed Supernovae” , 1998, astro-ph/9810274.

[32]  B. L. Jensen,et al.  Supernova 2006aj and the associated X-Ray Flash 060218 , 2006 .

[33]  Ryan Chornock,et al.  Optical Photometry and Spectroscopy of the SN 1998bw–like Type Ic Supernova 2002ap , 2003, astro-ph/0307136.

[34]  D. A. Kann,et al.  An optical supernova associated with the X-ray flash XRF 060218 , 2006, Nature.

[35]  A. J. Levan,et al.  Long γ-ray bursts and core-collapse supernovae have different environments , 2006, Nature.

[36]  L. A. Antonelli,et al.  SN 2003lw and GRB 031203: A Bright Supernova for a Faint Gamma-Ray Burst , 2004, astro-ph/0405449.

[37]  T. Sakamoto,et al.  A new γ-ray burst classification scheme from GRB 060614 , 2006, Nature.