Long γ‐Ray Bursts and Type Ic Core‐Collapse Supernovae Have Similar Locations in Hosts

Abstract

When the afterglow fades at the site of a long-duration gamma-ray burst (LGRB), Type Ic supernovae (SNe Ic) are the only type of core-collapse supernova observed. Recent work found that a sample of LGRB in high-redshift galaxies had different environments from a collection of core-collapse environments, which were identified from their colors and light curves. LGRBs were in the brightest regions of their hosts, but the core-collapse sample followed the overall distribution of the galaxy light. Here we examine 504 supernovae with types assigned based on their spectra that are located in nearby (z < 0.06) galaxies for which we have constructed surface photometry from the Sloan Digital Sky Survey (SDSS). The distributions of the thermonuclear supernovae (SNe Ia) and some varieties of core-collapse supernovae (SNe II and SNe Ib) follow the galaxy light, but the SNe Ic (like LGRBs) are much more likely to erupt in the brightest regions of their hosts. The high-redshift hosts of LGRB are overwhelmingly irregulars, without bulges, while many low-redshift SNe Ic hosts are spirals with small bulges. When we remove the bulge light from our low-redshift sample, the SN Ic and LGRB distributions agree extremely well. If both LGRBs and SNe Ic stem from very massive stars, then it seems plausible that the conditions necessary for forming SNe Ic are also required for LGRBs. Additional factors, including metallicity, may determine whether the stellar evolution of a massive star leads to a LGRB with an underlying broad-lined SN Ic, or simply a SN Ic without a gamma-ray burst.