PTF 10bzf (SN2010ah): A broad-line Ic supernova discovered by the Palomar Transient Factory

We present the discovery and follow-up observations of a broad-line Type Ic supernova (SN), PTF 10bzf (SN2010ah), detected by the Palomar Transient Factory (PTF) on 2010 February 23. The SNdistance is ≅218Mpc, greater than GRB980425/SN1998bw and GRB060218/SN2006aj, but smaller than the other SNe firmly associated with gamma-ray bursts (GRBs). We conducted a multi-wavelength follow-up campaign with Palomar 48 inch, Palomar 60 inch, Gemini-N, Keck, Wise, Swift, the Allen Telescope Array, Combined Array for Research in Millimeter-wave Astronomy, Westerbork Synthesis Radio Telescope, and Expanded Very Large Array. Here we compare the properties of PTF10bzf with those of SN1998bw and other broad-line SNe. The optical luminosity and spectral properties of PTF 10bzf suggest that this SNis intermediate, in kinetic energy and amount of ⁵⁶Ni, between non-GRB-associated SNe like 2002ap or 1997ef, and GRB-associated SNe like 1998bw. No X-ray or radio counterpart to PTF10bzf was detected. X-ray upper limits allow us to exclude the presence of an underlying X-ray afterglow as luminous as that of other SN-associated GRBs such as GRB030329 or GRB031203. Early-time radio upper limits do not show evidence for mildly relativistic ejecta. Late-time radio upper limits rule out the presence of an underlying off-axis GRB, with energy and wind density similar to the SN-associated GRB030329 and GRB031203. Finally, by performing a search for a GRB in the time window and at the position of PTF 10bzf, we find that no GRB in the interplanetary network catalog could be associated with this SN.