Type Ii Supernova Energetics and Comparison of Light Curves to Shock-Cooling Models

Abstract

During the first few days after explosion, Type II supernovae (SNe) are dominated by relatively simple physics. Theoretical predictions regarding early-time SN light curves in the ultraviolet (UV) and optical bands are thus quite robust. We present, for the first time, a sample of 57 R-band SN II light curves that are well-monitored during their rise, with 5 > detections during the first 10 days after discovery, and a well-constrained time of explosion to within 1-3 days. We show that the energy per unit mass (E/M) can be deduced to roughly a factor of five by comparing early-time optical data to the 2011 model of Rabinak & Waxman, while the progenitor radius cannot be determined based on R-band data alone. We find that SN II explosion energies span a range of E/M=(0.2-20)×10 51 erg/ (10 M  ), and have a mean energy per unit mass of E M 0.85 10 51 á ñ =´erg/(10 M  ), corrected for Malmquist bias. Assuming a small spread in progenitor masses, this indicates a large intrinsic diversity in explosion energy. Moreover, E/M is positively correlated with the amount of 56 Ni produced in the explosion, as predicted by some recent models of core-collapse SNe. We further present several empirical correlations. The peak magnitude is correlated with the decline rate ( m 15 D ), the decline rate is weakly correlated with the rise time, and the rise time is not significantly correlated with the peak magnitude. Faster declining SNe are more luminous and have longer rise times. This limits the possible power sources for such events.

Numerical Modeling of the Early Light Curves of Type Iip Supernovae

“…Being more robust and easier to measure than the power-law exponent of the bolometric light curve, the rise time can still give us important information on the progenitor characteristics. Our work is also motivated by a number of recent works considering large sets of early SNIIP light curves and focusing on their rise times (e.g., Gall et al 2015;González-Gaitán et al 2015;Rubin et al 2016). Figure 5 shows g-band light curves for a representative set of models from Figure 2 for a final energy = E 10 erg fin 51…”

“…In addition, based on the results of our numerical models, we derive a relation for the rise time t rise of SN IIP light curves in the g band as a function of the radius R of the progenitor. This relation may be useful in future analyses of observed early rises, especially when comparing large samples of events (e.g., Gall et al 2015;González-Gaitán et al 2015;Rubin et al 2016;Valenti et al 2016). Our results show that the observed rise times are in agreement with the observed red supergiant (RSG) radii from Levesque et al (2005Levesque et al ( , 2006, and there is no need to restrict the progenitor models to small radii   R 500 , as was suggested in some previous studies (see, e.g., Dessart et al 2013;Shussman et al 2016).…”

Light Curves of Hydrogen-poor Superluminous Supernovae from the Palomar Transient Factory

“…In order to avoid mathematical artifacts, a few auxiliary points are added to the observations. The light-curve smoothing algorithm is described in more detail in Rubin et al (2016). In a few cases, to avoid unphysical wiggles in the smoothed light curves for poorly sampled regions, we binned scattered data during small time intervals.…”

Unifying Type II Supernova Light Curves with Dense Circumstellar Material

“…This can manifest itself in narrow optical emission lines (Filippenko 1997;Pastorello et al 2008;Kiewe et al 2012;Taddia et al 2013), X-ray or radio emission (Campana et al 2006;Corsi et al 2014), or a rapid rise at ultraviolet wavelengths (Ofek et al 2010;Gezari et al 2015;Ganot et al 2016;Rubin et al 2016;Tanaka et al 2016). In the most extreme cases, there are the super-luminous SNe and SNe IIn events that can require M 10  or more ejected in the last few years of a massive star's life (Smith et al , 2011Smith & McCray 2007;van Marle et al 2010;Moriya et al 2013;Ofek et al 2013).…”