Hydrogen-Poor Superluminous Supernovae and Long-Duration Gamma-Ray Bursts Have Similar Host Galaxies

Abstract

We present optical spectroscopy and optical/near-IR photometry of 31 host galaxies of hydrogenpoor superluminous supernovae (SLSNe), including 15 events from the Pan-STARRS1 Medium Deep Survey. Our sample spans the redshift range 0.1 z 1.6 and is the first comprehensive host galaxy study of this specific subclass of cosmic explosions. Combining the multi-band photometry and emission-line measurements, we determine the luminosities, stellar masses, star formation rates and metallicities. We find that as a whole, the hosts of SLSNe are a low-luminosity ( M B ≈ −17.3 mag), low stellar mass ( M * ≈ 2 × 10 8 M ⊙ ) population, with a high median specific star formation rate ( sSFR ≈ 2 Gyr −1 ). The median metallicity of our spectroscopic sample is low, 12 + log(O/H) ≈ 8.35 ≈ 0.45Z ⊙ , although at least one host galaxy has solar metallicity. The host galaxies of H-poor SLSNe are statistically distinct from the hosts of GOODS core-collapse SNe (which cover a similar redshift range), but resemble the host galaxies of long-duration gamma-ray bursts (LGRBs) in terms of stellar mass, SFR, sSFR and metallicity. This result indicates that the environmental causes leading to massive stars forming either SLSNe or LGRBs are similar, and in particular that SLSNe are more effectively formed in low metallicity environments. We speculate that the key ingredient is large core angular momentum, leading to a rapidly-spinning magnetar in SLSNe and an accreting black hole inLGRBs.

Selecting superluminous supernovae in faint galaxies from the first year of the Pan-STARRS1 Medium Deep Survey

“…Young et al (2010) also calculated an absolute magnitude for the host of SN2007bi using SDSS archive images (SDSS J131920.14+085543.7) and found an M B ∼ −16.4. A similar trend has been noted with virtually all subsequent discoveries (Barbary et al 2009;Pastorello et al 2010a;Chomiuk et al 2011;Quimby et al 2011;Leloudas et al 2012;Chen et al 2013;Lunnan et al 2013;Nicholl et al 2014), which led Lunnan et al (2014) to study a large sample of host galaxies and suggest that they are similar hosts to those of gamma-ray bursts (GRBs). An exception to this supposed trend is the event so far reported with one of the highest redshifts.…”

iPTF15dtg: a double-peaked Type Ic supernova from a massive progenitor

“…Based on their flux ratios, we derived a metallicity of 12+log(O/H) = 8.22 ± 0.20 (Z/Z = 0.34) at the SN location using the O3N2 calibration by Pettini & Pagel (2004). The inferred metallicity at the location of iPTF15dtg is lower than that found for most of the other normal SNe Ic (Sanders et al 2012) and more similar to the metallicities for SNe from blue supergiant stars, SLSNe, and SN impostors (Taddia et al 2013(Taddia et al , 2015bLunnan et al 2014). The natal metallicity of iPTF15dtg appears to be comparable with that of long-duration GRBs (Krühler et al 2015 find a range of host metallicities of 12+log(O/H) = 7.9-9.0, with a median of 8.5).…”

Statistical Studies of Supernova Environments

“…While such studies are certainly interesting, most of the published work thus far has concentrated on global host properties (see e.g. Neill et al 2011;Lunnan et al 2014a;Leloudas et al 2014;Chen et al 2014), although a few very recent studies have investigated their immediate environments (Lunnan et al 2014b;Thöne et al 2014). It will be interesting in the future to apply the same methods as used above to study these mysterious explosions.…”