SN 2010jl IN UGC 5189: YET ANOTHER LUMINOUS TYPE IIn SUPERNOVA IN A METAL-POOR GALAXY

Abstract

We present All-Sky Automated Survey data starting 25 days before the discovery of the recent type IIn SN 2010jl, and we compare its light curve to other luminous IIn SNe, showing that it is a luminous (M I ≈ −20.5) event. Its host galaxy, UGC 5189, has a low gas-phase oxygen abundance (12 + log(O/H) = 8.2 ± 0.1), which reinforces the emerging trend that over-luminous core-collapse supernovae are found in the low-metallicity tail of the galaxy distribution, similar to the known trend for the hosts of long GRBs. We compile oxygen abundances from the literature and from our own observations of UGC 5189, and we present an unpublished spectrum of the luminous type Ic SN 2010gx that we use to estimate its host metallicity. We discuss these in the context of host metallicity trends for different classes of core-collapse objects. The earliest generations of stars are known to be enhanced in [O/Fe] relative to the Solar mixture; it is therefore likely that the stellar progenitors of these overluminous supernovae are even more iron-poor than they are oxygen-poor. A number of mechanisms and massive star progenitor systems have been proposed to explain the most luminous core-collapse supernovae. Any successful theory that tries to explain these very luminous events will need to include the emerging trend that points towards low-metallicity for the massive progenitor stars. This trend for very luminous supernovae to strongly prefer low-metallicity galaxies should be taken into account when considering various aspects of the evolution of the metal-poor early universe, such as enrichment and reionization.

Numerical simulations of superluminous supernovae of type IIn

“…In this work, we adopt a uniform composition, with a H mass fraction of 0.633, He mass fraction of 0.36564, and an iron mass fraction of 0.00136 to reflect approximately the near-solar composition of a blue or a red supergiant (hereafter BSG/RSG) star (for SN 2010jl, Stoll et al 2011) argue for a sub-solar metallicity, which may be important for understanding how these SNe IIn come about, but is irrelevant for the present radiation-hydrodynamics considerations).…”

“…Two good examples of such SNe IIn are SN 2006gy ) and more recently SN 2010jl (Stoll et al 2011). The latter has extensive photometric and spectroscopic observations (Stoll et al 2011;Zhang et al 2012;Ofek et al 2014;Fransson et al 2014) and also has spectropolarimetric data (Patat et al 2011;Williams et al 2014).…”

“…Two good examples of such SNe IIn are SN 2006gy ) and more recently SN 2010jl (Stoll et al 2011). The latter has extensive photometric and spectroscopic observations (Stoll et al 2011;Zhang et al 2012;Ofek et al 2014;Fransson et al 2014) and also has spectropolarimetric data (Patat et al 2011;Williams et al 2014). How stars produce the outer shell is unclear -it may be material ejected by the pair-production instability (Barkat et al 1967;Woosley et al 2007) or it may be material ejected via a superEddington wind (Owocki et al 2004).…”

Stellar Forensics with the Supernova‐GRB Connection

“…Is is hotly debated what powers their optical brilliance, whether it's due to circumstellar interaction, large amount of synthesized 56 Ni during the explosion of a pair-instability SN or the birth of a magnetar (Kasen & Bildsten 2010). Host galaxy studies show that their host galaxies are of low luminosity, highly starforming and blue (Neill et al 2011), similar to GRB-host galaxies, and similarly of low-metallicity, when measured (Stoll et al 2011), with the exception of the host of SN 2006gy, the SN which was first claimed as a pair-instability SN (Smith et al 2007;Ofek et al 2007). Furthermore, the best candidate for a pair-instability SN, SN 2007bi (Gal-Yam et al 2009) has a host galaxy with a metallicity of 12+log(O/H) M 91 = 8.15 ± 0.15 in the McGaugh scale, and thus, ∼ 0.3 Z (Young et al 2010), so it is a subsolar galaxy, but not of extreme subsolar metallicity, as one might expect from Pop III stars in the high-z universe.…”

Spectropolarimetry of Type IIn SN2010jl: Peering Into the Heart of a Monster

“…SN2010jl was discovered on Nov 3.52 UT, 2010 with a broad visual magnitude of 12.9 (CBET 2532) and was later isolated to have an explosion date prior to Oct 9.60 UT, 2010 (Stoll et al 2011). It was spectroscopically classified as a prompt stronglyinteracting type IIn (CBET 2536), and is ultraviolet-and X-ray-bright, as expected for its class (ATEL 3012).…”