PTF13efv—AN OUTBURST 500 DAYS PRIOR TO THE SNHUNT 275 EXPLOSION AND ITS RADIATIVE EFFICIENCY

Abstract

The progenitors of some supernovae (SNe) exhibit outbursts with super-Eddington luminosities prior to their final explosions. This behavior is common among SNe IIn, but the driving mechanisms of these precursors are not yet well-understood. SNHunt 275 was announced as a possible new SN during 2015 May. Here we report on preexplosion observations of the location of this event by the Palomar Transient Factory (PTF) and report the detection of a precursor about 500 days prior to the 2015 May activity (PTF 13efv). The observed velocities in the 2015 transient and its 2013 precursor absorption spectra are low (1000-2000 km s −1 ), so it is not clear yet if the recent activity indeed marks the final disruption of the progenitor. Regardless of the nature of this event, we use the PTF photometric and spectral observations, as well as Swift-UVOT observations, to constrain the efficiency of the radiated energy relative to the total kinetic energy of the precursor. We find that, using an order-of-magnitude estimate and under the assumption of spherical symmetry, the ratio of the radiated energy to the kinetic energy is in the range of 4 × 10 −2 to 3.4 × 10 3 .

A luminous stellar outburst during a long-lasting eruptive phase first, and then SN IIn 2018cnf

“…During the pre-SN monitoring, a few short-duration outbursts were detected with the most luminous being observed in late 2015, during which the stellar brightness increased by ∼1.2 mag in about one month. This behaviour resembles firstly the strong erratic variability we currently see for the impostor SN 2000ch in NGC 3432 (Wagner et al 2004;Pastorello et al 2010), and secondly one of the major brightenings observed during the pre-SN evolution of SN 2009ip (Pastorello et al 2013) or SN 2015bh (Ofek et al 2016;Elias-Rosa et al 2016;Thöne et al 2017). In both cases, the progenitors are thought to be LBVs (e.g.…”

Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle

“…4, we compare the r-band absolute magnitude light curve of SN 2016bdu to those of SN 2009ip (Smith et al 2010;Fraser et al 2013aFraser et al , 2015Mauerhan et al 2013a;Pastorello et al 2013a;Prieto et al 2013;Graham et al 2014;Margutti et al 2014;Martin et al 2015), SN 2010mc (Ofek et al 2013a), LSQ13zm (Tartaglia et al 2016), and SN 2015bh (Goranskij et al 2016;EliasRosa et al 2016;Ofek et al 2016;Thöne et al 2017). If Sloan-r data are not available, the Johnson-Cousins R-band light curves are shown.…”

“…Fraser et al 2013b;Ofek et al 2014). Pre-SN outbursts were well observed in two Type IIn events: SN 2009ip (Fraser et al 2013a(Fraser et al , 2015Mauerhan et al 2013aMauerhan et al , 2014Ofek et al 2013b;Pastorello et al 2013a;Smith et al 2013;Graham et al 2014Graham et al , 2017Margutti et al 2014;Smith, Andrews & Mauerhan 2016b) and SN 2015bh (Elias-Rosa et al 2016;Goranskij et al 2016;Ofek et al 2016;Thöne et al 2017). Both sources had historical light curves with signatures of erratic variability over time-scales of years (SN impostor phase), followed by two luminous outbursts separated by a few weeks.…”

Optical and IR observations of SN 2013L, a Type IIn Supernova surrounded by asymmetric CSM

“…Luminous blue variables (LBVs), traditionally not considered as a terminal point for massive star evolution, have been cited as progenitors of IIn that show signs of moderately fast winds (∼100-600 km s −1 ) and high mass-loss rates (Mauerhan et al 2013b;Gal-Yam & Leonard 2009;Smith et al 2007aSmith et al , 2008bSmith et al , 2010Smith et al , 2011a, but see Fox et al (2017) for an alternative progenitor scenario of SN 2010jl. These progenitors have masses >30 M , and sometime show signs of presupernova outbursts (Mauerhan et al 2013a;Pastorello et al 2013;Ofek et al 2016), although not always (Bilinski et al 2015). Interestingly, it appears that SNe IIn are not strongly correlated with H α regions (Kangas et al 2017;Habergham et al 2014).…”